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diff --git a/external-libs/pcre/doc/Tech.Notes b/external-libs/pcre/doc/Tech.Notes deleted file mode 100644 index 73c31c7c..00000000 --- a/external-libs/pcre/doc/Tech.Notes +++ /dev/null @@ -1,281 +0,0 @@ -Technical Notes about PCRE --------------------------- - -Many years ago I implemented some regular expression functions to an algorithm -suggested by Martin Richards. These were not Unix-like in form, and were quite -restricted in what they could do by comparison with Perl. The interesting part -about the algorithm was that the amount of space required to hold the compiled -form of an expression was known in advance. The code to apply an expression did -not operate by backtracking, as the original Henry Spencer code and current -Perl code does, but instead checked all possibilities simultaneously by keeping -a list of current states and checking all of them as it advanced through the -subject string. (In the terminology of Jeffrey Friedl's book, it was a "DFA -algorithm".) When the pattern was all used up, all remaining states were -possible matches, and the one matching the longest subset of the subject string -was chosen. This did not necessarily maximize the individual wild portions of -the pattern, as is expected in Unix and Perl-style regular expressions. - -By contrast, the code originally written by Henry Spencer and subsequently -heavily modified for Perl actually compiles the expression twice: once in a -dummy mode in order to find out how much store will be needed, and then for -real. The execution function operates by backtracking and maximizing (or, -optionally, minimizing in Perl) the amount of the subject that matches -individual wild portions of the pattern. This is an "NFA algorithm" in Friedl's -terminology. - -For the set of functions that forms PCRE (which are unrelated to those -mentioned above), I tried at first to invent an algorithm that used an amount -of store bounded by a multiple of the number of characters in the pattern, to -save on compiling time. However, because of the greater complexity in Perl -regular expressions, I couldn't do this. In any case, a first pass through the -pattern is needed, for a number of reasons. PCRE works by running a very -degenerate first pass to calculate a maximum store size, and then a second pass -to do the real compile - which may use a bit less than the predicted amount of -store. The idea is that this is going to turn out faster because the first pass -is degenerate and the second pass can just store stuff straight into the -vector. It does make the compiling functions bigger, of course, but they have -got quite big anyway to handle all the Perl stuff. - -The compiled form of a pattern is a vector of bytes, containing items of -variable length. The first byte in an item is an opcode, and the length of the -item is either implicit in the opcode or contained in the data bytes which -follow it. A list of all the opcodes follows: - -Opcodes with no following data ------------------------------- - -These items are all just one byte long - - OP_END end of pattern - OP_ANY match any character - OP_ANYBYTE match any single byte, even in UTF-8 mode - OP_SOD match start of data: \A - OP_SOM, start of match (subject + offset): \G - OP_CIRC ^ (start of data, or after \n in multiline) - OP_NOT_WORD_BOUNDARY \W - OP_WORD_BOUNDARY \w - OP_NOT_DIGIT \D - OP_DIGIT \d - OP_NOT_WHITESPACE \S - OP_WHITESPACE \s - OP_NOT_WORDCHAR \W - OP_WORDCHAR \w - OP_EODN match end of data or \n at end: \Z - OP_EOD match end of data: \z - OP_DOLL $ (end of data, or before \n in multiline) - - -Repeating single characters ---------------------------- - -The common repeats (*, +, ?) when applied to a single character appear as -two-byte items using the following opcodes: - - OP_STAR - OP_MINSTAR - OP_PLUS - OP_MINPLUS - OP_QUERY - OP_MINQUERY - -Those with "MIN" in their name are the minimizing versions. Each is followed by -the character that is to be repeated. Other repeats make use of - - OP_UPTO - OP_MINUPTO - OP_EXACT - -which are followed by a two-byte count (most significant first) and the -repeated character. OP_UPTO matches from 0 to the given number. A repeat with a -non-zero minimum and a fixed maximum is coded as an OP_EXACT followed by an -OP_UPTO (or OP_MINUPTO). - - -Repeating character types -------------------------- - -Repeats of things like \d are done exactly as for single characters, except -that instead of a character, the opcode for the type is stored in the data -byte. The opcodes are: - - OP_TYPESTAR - OP_TYPEMINSTAR - OP_TYPEPLUS - OP_TYPEMINPLUS - OP_TYPEQUERY - OP_TYPEMINQUERY - OP_TYPEUPTO - OP_TYPEMINUPTO - OP_TYPEEXACT - - -Matching a character string ---------------------------- - -The OP_CHARS opcode is followed by a one-byte count and then that number of -characters. If there are more than 255 characters in sequence, successive -instances of OP_CHARS are used. - - -Character classes ------------------ - -If there is only one character, OP_CHARS is used for a positive class, -and OP_NOT for a negative one (that is, for something like [^a]). However, in -UTF-8 mode, this applies only to characters with values < 128, because OP_NOT -is confined to single bytes. - -Another set of repeating opcodes (OP_NOTSTAR etc.) are used for a repeated, -negated, single-character class. The normal ones (OP_STAR etc.) are used for a -repeated positive single-character class. - -When there's more than one character in a class and all the characters are less -than 256, OP_CLASS is used for a positive class, and OP_NCLASS for a negative -one. In either case, the opcode is followed by a 32-byte bit map containing a 1 -bit for every character that is acceptable. The bits are counted from the least -significant end of each byte. - -The reason for having both OP_CLASS and OP_NCLASS is so that, in UTF-8 mode, -subject characters with values greater than 256 can be handled correctly. For -OP_CLASS they don't match, whereas for OP_NCLASS they do. - -For classes containing characters with values > 255, OP_XCLASS is used. It -optionally uses a bit map (if any characters lie within it), followed by a list -of pairs and single characters. There is a flag character than indicates -whether it's a positive or a negative class. - - -Back references ---------------- - -OP_REF is followed by two bytes containing the reference number. - - -Repeating character classes and back references ------------------------------------------------ - -Single-character classes are handled specially (see above). This applies to -OP_CLASS and OP_REF. In both cases, the repeat information follows the base -item. The matching code looks at the following opcode to see if it is one of - - OP_CRSTAR - OP_CRMINSTAR - OP_CRPLUS - OP_CRMINPLUS - OP_CRQUERY - OP_CRMINQUERY - OP_CRRANGE - OP_CRMINRANGE - -All but the last two are just single-byte items. The others are followed by -four bytes of data, comprising the minimum and maximum repeat counts. - - -Brackets and alternation ------------------------- - -A pair of non-capturing (round) brackets is wrapped round each expression at -compile time, so alternation always happens in the context of brackets. - -Non-capturing brackets use the opcode OP_BRA, while capturing brackets use -OP_BRA+1, OP_BRA+2, etc. [Note for North Americans: "bracket" to some English -speakers, including myself, can be round, square, curly, or pointy. Hence this -usage.] - -Originally PCRE was limited to 99 capturing brackets (so as not to use up all -the opcodes). From release 3.5, there is no limit. What happens is that the -first ones, up to EXTRACT_BASIC_MAX are handled with separate opcodes, as -above. If there are more, the opcode is set to EXTRACT_BASIC_MAX+1, and the -first operation in the bracket is OP_BRANUMBER, followed by a 2-byte bracket -number. This opcode is ignored while matching, but is fished out when handling -the bracket itself. (They could have all been done like this, but I was making -minimal changes.) - -A bracket opcode is followed by two bytes which give the offset to the next -alternative OP_ALT or, if there aren't any branches, to the matching KET -opcode. Each OP_ALT is followed by two bytes giving the offset to the next one, -or to the KET opcode. - -OP_KET is used for subpatterns that do not repeat indefinitely, while -OP_KETRMIN and OP_KETRMAX are used for indefinite repetitions, minimally or -maximally respectively. All three are followed by two bytes giving (as a -positive number) the offset back to the matching BRA opcode. - -If a subpattern is quantified such that it is permitted to match zero times, it -is preceded by one of OP_BRAZERO or OP_BRAMINZERO. These are single-byte -opcodes which tell the matcher that skipping this subpattern entirely is a -valid branch. - -A subpattern with an indefinite maximum repetition is replicated in the -compiled data its minimum number of times (or once with a BRAZERO if the -minimum is zero), with the final copy terminating with a KETRMIN or KETRMAX as -appropriate. - -A subpattern with a bounded maximum repetition is replicated in a nested -fashion up to the maximum number of times, with BRAZERO or BRAMINZERO before -each replication after the minimum, so that, for example, (abc){2,5} is -compiled as (abc)(abc)((abc)((abc)(abc)?)?)?. The 99 and 200 bracket limits do -not apply to these internally generated brackets. - - -Assertions ----------- - -Forward assertions are just like other subpatterns, but starting with one of -the opcodes OP_ASSERT or OP_ASSERT_NOT. Backward assertions use the opcodes -OP_ASSERTBACK and OP_ASSERTBACK_NOT, and the first opcode inside the assertion -is OP_REVERSE, followed by a two byte count of the number of characters to move -back the pointer in the subject string. When operating in UTF-8 mode, the count -is a character count rather than a byte count. A separate count is present in -each alternative of a lookbehind assertion, allowing them to have different -fixed lengths. - - -Once-only subpatterns ---------------------- - -These are also just like other subpatterns, but they start with the opcode -OP_ONCE. - - -Conditional subpatterns ------------------------ - -These are like other subpatterns, but they start with the opcode OP_COND. If -the condition is a back reference, this is stored at the start of the -subpattern using the opcode OP_CREF followed by two bytes containing the -reference number. If the condition is "in recursion" (coded as "(?(R)"), the -same scheme is used, with a "reference number" of 0xffff. Otherwise, a -conditional subpattern always starts with one of the assertions. - - -Recursion ---------- - -Recursion either matches the current regex, or some subexpression. The opcode -OP_RECURSE is followed by an value which is the offset to the starting bracket -from the start of the whole pattern. - - -Callout -------- - -OP_CALLOUT is followed by one byte of data that holds a callout number in the -range 0 to 255. - - -Changing options ----------------- - -If any of the /i, /m, or /s options are changed within a pattern, an OP_OPT -opcode is compiled, followed by one byte containing the new settings of these -flags. If there are several alternatives, there is an occurrence of OP_OPT at -the start of all those following the first options change, to set appropriate -options for the start of the alternative. Immediately after the end of the -group there is another such item to reset the flags to their previous values. A -change of flag right at the very start of the pattern can be handled entirely -at compile time, and so does not cause anything to be put into the compiled -data. - -Philip Hazel -August 2003 diff --git a/external-libs/pcre/doc/html/index.html b/external-libs/pcre/doc/html/index.html deleted file mode 100644 index 3751ff0f..00000000 --- a/external-libs/pcre/doc/html/index.html +++ /dev/null @@ -1,102 +0,0 @@ -<html> -<head> -<title>PCRE specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -<h1>Perl-compatible Regular Expressions (PCRE)</h1> -<p> -The HTML documentation for PCRE comprises the following pages: -</p> - -<table> -<tr><td><a href="pcre.html">pcre</a></td> - <td> Introductory page</td></tr> - -<tr><td><a href="pcreapi.html">pcreapi</a></td> - <td> PCRE's native API</td></tr> - -<tr><td><a href="pcrebuild.html">pcrebuild</a></td> - <td> Options for building PCRE</td></tr> - -<tr><td><a href="pcrecallout.html">pcrecallout</a></td> - <td> The <i>callout</i> facility</td></tr> - -<tr><td><a href="pcrecompat.html">pcrecompat</a></td> - <td> Compability with Perl</td></tr> - -<tr><td><a href="pcregrep.html">pcregrep</a></td> - <td> The <b>pcregrep</b> command</td></tr> - -<tr><td><a href="pcrepattern.html">pcrepattern</a></td> - <td> Regular expressions supported by PCRE</td></tr> - -<tr><td><a href="pcreperform.html">pcreperform</a></td> - <td> Some comments on performance</td></tr> - -<tr><td><a href="pcreposix.html">pcreposix</a></td> - <td> The POSIX API to the PCRE library</td></tr> - -<tr><td><a href="pcresample.html">pcresample</a></td> - <td> Description of the sample program</td></tr> - -<tr><td><a href="pcretest.html">pcretest</a></td> - <td> The <b>pcretest</b> command for testing PCRE</td></tr> -</table> - -<p> -There are also individual pages that summarize the interface for each function -in the library: -</p> - -<table> - -<tr><td><a href="pcre_compile.html">pcre_compile</a></td> - <td> Compile a regular expression</td></tr> - -<tr><td><a href="pcre_config.html">pcre_config</a></td> - <td> Show build-time configuration options</td></tr> - -<tr><td><a href="pcre_copy_named_substring.html">pcre_copy_named_substring</a></td> - <td> Extract named substring into given buffer</td></tr> - -<tr><td><a href="pcre_copy_substring.html">pcre_copy_substring</a></td> - <td> Extract numbered substring into given buffer</td></tr> - -<tr><td><a href="pcre_exec.html">pcre_exec</a></td> - <td> Match a compiled pattern to a subject string</td></tr> - -<tr><td><a href="pcre_free_substring.html">pcre_free_substring</a></td> - <td> Free extracted substring</td></tr> - -<tr><td><a href="pcre_free_substring_list.html">pcre_free_substring_list</a></td> - <td> Free list of extracted substrings</td></tr> - -<tr><td><a href="pcre_fullinfo.html">pcre_fullinfo</a></td> - <td> Extract information about a pattern</td></tr> - -<tr><td><a href="pcre_get_named_substring.html">pcre_get_named_substring</a></td> - <td> Extract named substring into new memory</td></tr> - -<tr><td><a href="pcre_get_stringnumber.html">pcre_get_stringnumber</a></td> - <td> Convert captured string name to number</td></tr> - -<tr><td><a href="pcre_get_substring.html">pcre_get_substring</a></td> - <td> Extract numbered substring into new memory</td></tr> - -<tr><td><a href="pcre_get_substring_list.html">pcre_get_substring_list</a></td> - <td> Extract all substrings into new memory</td></tr> - -<tr><td><a href="pcre_info.html">pcre_info</a></td> - <td> Obsolete information extraction function</td></tr> - -<tr><td><a href="pcre_maketables.html">pcre_maketables</a></td> - <td> Build character tables in current locale</td></tr> - -<tr><td><a href="pcre_study.html">pcre_study</a></td> - <td> Study a compiled pattern</td></tr> - -<tr><td><a href="pcre_version.html">pcre_version</a></td> - <td> Return PCRE version and release date</td></tr> -</table> - -</html> diff --git a/external-libs/pcre/doc/html/pcre.html b/external-libs/pcre/doc/html/pcre.html deleted file mode 100644 index bb0d3548..00000000 --- a/external-libs/pcre/doc/html/pcre.html +++ /dev/null @@ -1,190 +0,0 @@ -<html> -<head> -<title>pcre specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">DESCRIPTION</a> -<li><a name="TOC2" href="#SEC2">USER DOCUMENTATION</a> -<li><a name="TOC3" href="#SEC3">LIMITATIONS</a> -<li><a name="TOC4" href="#SEC4">UTF-8 SUPPORT</a> -<li><a name="TOC5" href="#SEC5">AUTHOR</a> -</ul> -<br><a name="SEC1" href="#TOC1">DESCRIPTION</a><br> -<P> -The PCRE library is a set of functions that implement regular expression -pattern matching using the same syntax and semantics as Perl, with just a few -differences. The current implementation of PCRE (release 4.x) corresponds -approximately with Perl 5.8, including support for UTF-8 encoded strings. -However, this support has to be explicitly enabled; it is not the default. -</P> -<P> -PCRE is written in C and released as a C library. However, a number of people -have written wrappers and interfaces of various kinds. A C++ class is included -in these contributions, which can be found in the <i>Contrib</i> directory at -the primary FTP site, which is: -</P> -<a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre">ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre</a> -<P> -Details of exactly which Perl regular expression features are and are not -supported by PCRE are given in separate documents. See the -<a href="pcrepattern.html"><b>pcrepattern</b></a> -and -<a href="pcrecompat.html"><b>pcrecompat</b></a> -pages. -</P> -<P> -Some features of PCRE can be included, excluded, or changed when the library is -built. The -<a href="pcre_config.html"><b>pcre_config()</b></a> -function makes it possible for a client to discover which features are -available. Documentation about building PCRE for various operating systems can -be found in the <b>README</b> file in the source distribution. -</P> -<br><a name="SEC2" href="#TOC1">USER DOCUMENTATION</a><br> -<P> -The user documentation for PCRE has been split up into a number of different -sections. In the "man" format, each of these is a separate "man page". In the -HTML format, each is a separate page, linked from the index page. In the plain -text format, all the sections are concatenated, for ease of searching. The -sections are as follows: -</P> -<P> -<pre> - pcre this document - pcreapi details of PCRE's native API - pcrebuild options for building PCRE - pcrecallout details of the callout feature - pcrecompat discussion of Perl compatibility - pcregrep description of the <b>pcregrep</b> command - pcrepattern syntax and semantics of supported - regular expressions - pcreperform discussion of performance issues - pcreposix the POSIX-compatible API - pcresample discussion of the sample program - pcretest the <b>pcretest</b> testing command -</PRE> -</P> -<P> -In addition, in the "man" and HTML formats, there is a short page for each -library function, listing its arguments and results. -</P> -<br><a name="SEC3" href="#TOC1">LIMITATIONS</a><br> -<P> -There are some size limitations in PCRE but it is hoped that they will never in -practice be relevant. -</P> -<P> -The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE is -compiled with the default internal linkage size of 2. If you want to process -regular expressions that are truly enormous, you can compile PCRE with an -internal linkage size of 3 or 4 (see the <b>README</b> file in the source -distribution and the -<a href="pcrebuild.html"><b>pcrebuild</b></a> -documentation for details). If these cases the limit is substantially larger. -However, the speed of execution will be slower. -</P> -<P> -All values in repeating quantifiers must be less than 65536. -The maximum number of capturing subpatterns is 65535. -</P> -<P> -There is no limit to the number of non-capturing subpatterns, but the maximum -depth of nesting of all kinds of parenthesized subpattern, including capturing -subpatterns, assertions, and other types of subpattern, is 200. -</P> -<P> -The maximum length of a subject string is the largest positive number that an -integer variable can hold. However, PCRE uses recursion to handle subpatterns -and indefinite repetition. This means that the available stack space may limit -the size of a subject string that can be processed by certain patterns. -</P> -<a name="utf8support"></a><br><a name="SEC4" href="#TOC1">UTF-8 SUPPORT</a><br> -<P> -Starting at release 3.3, PCRE has had some support for character strings -encoded in the UTF-8 format. For release 4.0 this has been greatly extended to -cover most common requirements. -</P> -<P> -In order process UTF-8 strings, you must build PCRE to include UTF-8 support in -the code, and, in addition, you must call -<a href="pcre_compile.html"><b>pcre_compile()</b></a> -with the PCRE_UTF8 option flag. When you do this, both the pattern and any -subject strings that are matched against it are treated as UTF-8 strings -instead of just strings of bytes. -</P> -<P> -If you compile PCRE with UTF-8 support, but do not use it at run time, the -library will be a bit bigger, but the additional run time overhead is limited -to testing the PCRE_UTF8 flag in several places, so should not be very large. -</P> -<P> -The following comments apply when PCRE is running in UTF-8 mode: -</P> -<P> -1. When you set the PCRE_UTF8 flag, the strings passed as patterns and subjects -are checked for validity on entry to the relevant functions. If an invalid -UTF-8 string is passed, an error return is given. In some situations, you may -already know that your strings are valid, and therefore want to skip these -checks in order to improve performance. If you set the PCRE_NO_UTF8_CHECK flag -at compile time or at run time, PCRE assumes that the pattern or subject it -is given (respectively) contains only valid UTF-8 codes. In this case, it does -not diagnose an invalid UTF-8 string. If you pass an invalid UTF-8 string to -PCRE when PCRE_NO_UTF8_CHECK is set, the results are undefined. Your program -may crash. -</P> -<P> -2. In a pattern, the escape sequence \x{...}, where the contents of the braces -is a string of hexadecimal digits, is interpreted as a UTF-8 character whose -code number is the given hexadecimal number, for example: \x{1234}. If a -non-hexadecimal digit appears between the braces, the item is not recognized. -This escape sequence can be used either as a literal, or within a character -class. -</P> -<P> -3. The original hexadecimal escape sequence, \xhh, matches a two-byte UTF-8 -character if the value is greater than 127. -</P> -<P> -4. Repeat quantifiers apply to complete UTF-8 characters, not to individual -bytes, for example: \x{100}{3}. -</P> -<P> -5. The dot metacharacter matches one UTF-8 character instead of a single byte. -</P> -<P> -6. The escape sequence \C can be used to match a single byte in UTF-8 mode, -but its use can lead to some strange effects. -</P> -<P> -7. The character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly -test characters of any code value, but the characters that PCRE recognizes as -digits, spaces, or word characters remain the same set as before, all with -values less than 256. -</P> -<P> -8. Case-insensitive matching applies only to characters whose values are less -than 256. PCRE does not support the notion of "case" for higher-valued -characters. -</P> -<P> -9. PCRE does not support the use of Unicode tables and properties or the Perl -escapes \p, \P, and \X. -</P> -<br><a name="SEC5" href="#TOC1">AUTHOR</a><br> -<P> -Philip Hazel <ph10@cam.ac.uk> -<br> -University Computing Service, -<br> -Cambridge CB2 3QG, England. -<br> -Phone: +44 1223 334714 -</P> -<P> -Last updated: 20 August 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcre_compile.html b/external-libs/pcre/doc/html/pcre_compile.html deleted file mode 100644 index e1a43793..00000000 --- a/external-libs/pcre/doc/html/pcre_compile.html +++ /dev/null @@ -1,71 +0,0 @@ -<html> -<head> -<title>pcre_compile specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>pcre *pcre_compile(const char *<i>pattern</i>, int <i>options</i>,</b> -<b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b> -<b>const unsigned char *<i>tableptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function compiles a regular expression into an internal form. Its -arguments are: -</P> -<P> -<pre> - <i>pattern</i> A zero-terminated string containing the - regular expression to be compiled - <i>options</i> Zero or more option bits - <i>errptr</i> Where to put an error message - <i>erroffset</i> Offset in pattern where error was found - <i>tableptr</i> Pointer to character tables, or NULL to - use the built-in default -</PRE> -</P> -<P> -The option bits are: -</P> -<P> -<pre> - PCRE_ANCHORED Force pattern anchoring - PCRE_CASELESS Do caseless matching - PCRE_DOLLAR_ENDONLY $ not to match newline at end - PCRE_DOTALL . matches anything including NL - PCRE_EXTENDED Ignore whitespace and # comments - PCRE_EXTRA PCRE extra features - (not much use currently) - PCRE_MULTILINE ^ and $ match newlines within data - PCRE_NO_AUTO_CAPTURE Disable numbered capturing paren- - theses (named ones available) - PCRE_UNGREEDY Invert greediness of quantifiers - PCRE_UTF8 Run in UTF-8 mode - PCRE_NO_UTF8_CHECK Do not check the pattern for UTF-8 - validity (only relevant if - PCRE_UTF8 is set) -</PRE> -</P> -<P> -PCRE must be compiled with UTF-8 support in order to use PCRE_UTF8 -(or PCRE_NO_UTF8_CHECK). -</P> -<P> -The yield of the function is a pointer to a private data structure that -contains the compiled pattern, or NULL if an error was detected. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_config.html b/external-libs/pcre/doc/html/pcre_config.html deleted file mode 100644 index 3328b792..00000000 --- a/external-libs/pcre/doc/html/pcre_config.html +++ /dev/null @@ -1,56 +0,0 @@ -<html> -<head> -<title>pcre_config specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function makes it possible for a client program to find out which optional -features are available in the version of the PCRE library it is using. Its -arguments are as follows: -</P> -<P> -<pre> - <i>what</i> A code specifying what information is required - <i>where</i> Points to where to put the data -</PRE> -</P> -<P> -The available codes are: -</P> -<P> -<pre> - PCRE_CONFIG_LINK_SIZE Internal link size: 2, 3, or 4 - PCRE_CONFIG_MATCH_LIMIT Internal resource limit - PCRE_CONFIG_NEWLINE Value of the newline character - PCRE_CONFIG_POSIX_MALLOC_THRESHOLD - Threshold of return slots, above - which <b>malloc()</b> is used by - the POSIX API - PCRE_CONFIG_STACKRECURSE Recursion implementation (1=stack 0=heap) - PCRE_CONFIG_UTF8 Availability of UTF-8 support (1=yes 0=no) -</PRE> -</P> -<P> -The function yields 0 on success or PCRE_ERROR_BADOPTION otherwise. -</P> -<P> -There is a complete description of the PCRE native API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page, and a description of the POSIX API in the -<a href="pcreposix.html"><b>pcreposix</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_copy_named_substring.html b/external-libs/pcre/doc/html/pcre_copy_named_substring.html deleted file mode 100644 index 3b1da364..00000000 --- a/external-libs/pcre/doc/html/pcre_copy_named_substring.html +++ /dev/null @@ -1,46 +0,0 @@ -<html> -<head> -<title>pcre_copy_named_substring specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>char *<i>buffer</i>, int <i>buffersize</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for extracting a captured substring, identified -by name, into a given buffer. The arguments are: -</P> -<P> -<pre> - <i>code</i> Pattern that was successfully matched - <i>subject</i> Subject that has been successfully matched - <i>ovector</i> Offset vector that <b>pcre_exec()</b> used - <i>stringcount</i> Value returned by <b>pcre_exec()</b> - <i>stringname</i> Name of the required substring - <i>buffer</i> Buffer to receive the string - <i>buffersize</i> Size of buffer -</PRE> -</P> -<P> -The yield is the length of the substring, PCRE_ERROR_NOMEMORY if the buffer was -too small, or PCRE_ERROR_NOSUBSTRING if the string name is invalid. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_copy_substring.html b/external-libs/pcre/doc/html/pcre_copy_substring.html deleted file mode 100644 index f5b9b553..00000000 --- a/external-libs/pcre/doc/html/pcre_copy_substring.html +++ /dev/null @@ -1,44 +0,0 @@ -<html> -<head> -<title>pcre_copy_substring specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_copy_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> -<b>int <i>buffersize</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for extracting a captured substring into a given -buffer. The arguments are: -</P> -<P> -<pre> - <i>subject</i> Subject that has been successfully matched - <i>ovector</i> Offset vector that <b>pcre_exec()</b> used - <i>stringcount</i> Value returned by <b>pcre_exec()</b> - <i>stringnumber</i> Number of the required substring - <i>buffer</i> Buffer to receive the string - <i>buffersize</i> Size of buffer -</PRE> -</P> -<P> -The yield is the legnth of the string, PCRE_ERROR_NOMEMORY if the buffer was -too small, or PCRE_ERROR_NOSUBSTRING if the string number is invalid. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_exec.html b/external-libs/pcre/doc/html/pcre_exec.html deleted file mode 100644 index cf86dfda..00000000 --- a/external-libs/pcre/doc/html/pcre_exec.html +++ /dev/null @@ -1,58 +0,0 @@ -<html> -<head> -<title>pcre_exec specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> -<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> -<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function matches a compiled regular expression against a given subject -string, and returns offsets to capturing subexpressions. Its arguments are: -</P> -<P> -<pre> - <i>code</i> Points to the compiled pattern - <i>extra</i> Points to an associated <b>pcre_extra</b> structure, - or is NULL - <i>subject</i> Points to the subject string - <i>length</i> Length of the subject string, in bytes - <i>startoffset</i> Offset in bytes in the subject at which to - start matching - <i>options</i> Option bits - <i>ovector</i> Points to a vector of ints for result offsets - <i>ovecsize</i> Size of the vector (a multiple of 3) -</PRE> -</P> -<P> -The options are: -</P> -<P> -<pre> - PCRE_ANCHORED Match only at the first position - PCRE_NOTBOL Subject is not the beginning of a line - PCRE_NOTEOL Subject is not the end of a line - PCRE_NOTEMPTY An empty string is not a valid match - PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8 - validity (only relevant if PCRE_UTF8 - was set at compile time) -</PRE> -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_free_substring.html b/external-libs/pcre/doc/html/pcre_free_substring.html deleted file mode 100644 index 08b16078..00000000 --- a/external-libs/pcre/doc/html/pcre_free_substring.html +++ /dev/null @@ -1,29 +0,0 @@ -<html> -<head> -<title>pcre_free_substring specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>void pcre_free_substring(const char *<i>stringptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for freeing the store obtained by a previous -call to <b>pcre_get_substring()</b> or <b>pcre_get_named_substring()</b>. Its -only argument is a pointer to the string. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_free_substring_list.html b/external-libs/pcre/doc/html/pcre_free_substring_list.html deleted file mode 100644 index c130f281..00000000 --- a/external-libs/pcre/doc/html/pcre_free_substring_list.html +++ /dev/null @@ -1,29 +0,0 @@ -<html> -<head> -<title>pcre_free_substring_list specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for freeing the store obtained by a previous -call to <b>pcre_get_substring_list()</b>. Its only argument is a pointer to the -list of string pointers. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_fullinfo.html b/external-libs/pcre/doc/html/pcre_fullinfo.html deleted file mode 100644 index f43fa65f..00000000 --- a/external-libs/pcre/doc/html/pcre_fullinfo.html +++ /dev/null @@ -1,68 +0,0 @@ -<html> -<head> -<title>pcre_fullinfo specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_fullinfo(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> -<b>int <i>what</i>, void *<i>where</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function returns information about a compiled pattern. Its arguments are: -</P> -<P> -<pre> - <i>code</i> Compiled regular expression - <i>extra</i> Result of <b>pcre_study()</b> or NULL - <i>what</i> What information is required - <i>where</i> Where to put the information -</PRE> -</P> -<P> -The following information is available: -</P> -<P> -<pre> - PCRE_INFO_BACKREFMAX Number of highest back reference - PCRE_INFO_CAPTURECOUNT Number of capturing subpatterns - PCRE_INFO_FIRSTBYTE Fixed first byte for a match, or - -1 for start of string - or after newline, or - -2 otherwise - PCRE_INFO_FIRSTTABLE Table of first bytes - (after studying) - PCRE_INFO_LASTLITERAL Literal last byte required - PCRE_INFO_NAMECOUNT Number of named subpatterns - PCRE_INFO_NAMEENTRYSIZE Size of name table entry - PCRE_INFO_NAMETABLE Pointer to name table - PCRE_INFO_OPTIONS Options used for compilation - PCRE_INFO_SIZE Size of compiled pattern -</PRE> -</P> -<P> -The yield of the function is zero on success or: -</P> -<P> -<pre> - PCRE_ERROR_NULL the argument <i>code</i> was NULL - the argument <i>where</i> was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - PCRE_ERROR_BADOPTION the value of <i>what</i> was invalid -</PRE> -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_get_named_substring.html b/external-libs/pcre/doc/html/pcre_get_named_substring.html deleted file mode 100644 index 89a2beeb..00000000 --- a/external-libs/pcre/doc/html/pcre_get_named_substring.html +++ /dev/null @@ -1,46 +0,0 @@ -<html> -<head> -<title>pcre_get_named_substring specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for extracting a captured substring by name. The -arguments are: -</P> -<P> -<pre> - <i>code</i> Compiled pattern - <i>subject</i> Subject that has been successfully matched - <i>ovector</i> Offset vector that <b>pcre_exec()</b> used - <i>stringcount</i> Value returned by <b>pcre_exec()</b> - <i>stringname</i> Name of the required substring - <i>stringptr</i> Where to put the string pointer -</PRE> -</P> -<P> -The yield is the length of the extracted substring, PCRE_ERROR_NOMEMORY if -sufficient memory could not be obtained, or PCRE_ERROR_NOSUBSTRING if the -string name is invalid. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_get_stringnumber.html b/external-libs/pcre/doc/html/pcre_get_stringnumber.html deleted file mode 100644 index ee1c0a9c..00000000 --- a/external-libs/pcre/doc/html/pcre_get_stringnumber.html +++ /dev/null @@ -1,39 +0,0 @@ -<html> -<head> -<title>pcre_get_stringnumber specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This convenience function finds the number of a named substring capturing -parenthesis in a compiled pattern. Its arguments are: -</P> -<P> -<pre> - <i>code</i> Compiled regular expression - <i>name</i> Name whose number is required -</PRE> -</P> -<P> -The yield of the function is the number of the parenthesis if the name is -found, or PCRE_ERROR_NOSUBSTRING otherwise. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_get_substring.html b/external-libs/pcre/doc/html/pcre_get_substring.html deleted file mode 100644 index 2a55c10f..00000000 --- a/external-libs/pcre/doc/html/pcre_get_substring.html +++ /dev/null @@ -1,44 +0,0 @@ -<html> -<head> -<title>pcre_get_substring specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_get_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, int <i>stringnumber</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for extracting a captured substring. The -arguments are: -</P> -<P> -<pre> - <i>subject</i> Subject that has been successfully matched - <i>ovector</i> Offset vector that <b>pcre_exec()</b> used - <i>stringcount</i> Value returned by <b>pcre_exec()</b> - <i>stringnumber</i> Number of the required substring - <i>stringptr</i> Where to put the string pointer -</PRE> -</P> -<P> -The yield is the length of the substring, PCRE_ERROR_NOMEMORY if sufficient -memory could not be obtained, or PCRE_ERROR_NOSUBSTRING if the string number is -invalid. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_get_substring_list.html b/external-libs/pcre/doc/html/pcre_get_substring_list.html deleted file mode 100644 index 7e91f56b..00000000 --- a/external-libs/pcre/doc/html/pcre_get_substring_list.html +++ /dev/null @@ -1,41 +0,0 @@ -<html> -<head> -<title>pcre_get_substring_list specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_get_substring_list(const char *<i>subject</i>,</b> -<b>int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This is a convenience function for extracting a list of all the captured -substrings. The arguments are: -</P> -<P> -<pre> - <i>subject</i> Subject that has been successfully matched - <i>ovector</i> Offset vector that <b>pcre_exec</b> used - <i>stringcount</i> Value returned by <b>pcre_exec</b> - <i>listptr</i> Where to put a pointer to the list -</PRE> -</P> -<P> -The yield is zero on success or PCRE_ERROR_NOMEMORY if sufficient memory could -not be obtained. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_info.html b/external-libs/pcre/doc/html/pcre_info.html deleted file mode 100644 index 97fc59b4..00000000 --- a/external-libs/pcre/doc/html/pcre_info.html +++ /dev/null @@ -1,28 +0,0 @@ -<html> -<head> -<title>pcre_info specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>int pcre_info(const pcre *<i>code</i>, int *<i>optptr</i>, int</b> -<b>*<i>firstcharptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function is obsolete. You should be using <b>pcre_fullinfo()</b> instead. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_maketables.html b/external-libs/pcre/doc/html/pcre_maketables.html deleted file mode 100644 index ba3e026b..00000000 --- a/external-libs/pcre/doc/html/pcre_maketables.html +++ /dev/null @@ -1,31 +0,0 @@ -<html> -<head> -<title>pcre_maketables specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>const unsigned char *pcre_maketables(void);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function builds a set of character tables which can be passed to -<b>pcre_compile()</b> to override PCRE's internal, built-in tables (which were -made by <b>pcre_maketables()</b> when PCRE was compiled). You might want to do -this if you are using a non-standard locale. The function yields a pointer to -the tables. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_study.html b/external-libs/pcre/doc/html/pcre_study.html deleted file mode 100644 index f3727d1f..00000000 --- a/external-libs/pcre/doc/html/pcre_study.html +++ /dev/null @@ -1,45 +0,0 @@ -<html> -<head> -<title>pcre_study specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>pcre_extra *pcre_study(const pcre *<i>code</i>, int <i>options</i>,</b> -<b>const char **<i>errptr</i>);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function studies a compiled pattern, to see if additional information can -be extracted that might speed up matching. Its arguments are: -</P> -<P> -<pre> - <i>code</i> A compiled regular expression - <i>options</i> Options for <b>pcre_study()</b> - <i>errptr</i> Where to put an error message -</PRE> -</P> -<P> -If the function returns NULL, either it could not find any additional -information, or there was an error. You can tell the difference by looking at -the error value. It is NULL in first case. -</P> -<P> -There are currently no options defined; the value of the second argument should -always be zero. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcre_version.html b/external-libs/pcre/doc/html/pcre_version.html deleted file mode 100644 index 35c47cd6..00000000 --- a/external-libs/pcre/doc/html/pcre_version.html +++ /dev/null @@ -1,28 +0,0 @@ -<html> -<head> -<title>pcre_version specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<br><b> -SYNOPSIS -</b><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>char *pcre_version(void);</b> -</P> -<br><b> -DESCRIPTION -</b><br> -<P> -This function returns a character string that gives the version number of the -PCRE library, and its date of release. -</P> -<P> -There is a complete description of the PCRE API in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page. diff --git a/external-libs/pcre/doc/html/pcreapi.html b/external-libs/pcre/doc/html/pcreapi.html deleted file mode 100644 index 8ae6fb1e..00000000 --- a/external-libs/pcre/doc/html/pcreapi.html +++ /dev/null @@ -1,1346 +0,0 @@ -<html> -<head> -<title>pcreapi specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">SYNOPSIS OF PCRE API</a> -<li><a name="TOC2" href="#SEC2">PCRE API</a> -<li><a name="TOC3" href="#SEC3">MULTITHREADING</a> -<li><a name="TOC4" href="#SEC4">CHECKING BUILD-TIME OPTIONS</a> -<li><a name="TOC5" href="#SEC5">COMPILING A PATTERN</a> -<li><a name="TOC6" href="#SEC6">STUDYING A PATTERN</a> -<li><a name="TOC7" href="#SEC7">LOCALE SUPPORT</a> -<li><a name="TOC8" href="#SEC8">INFORMATION ABOUT A PATTERN</a> -<li><a name="TOC9" href="#SEC9">OBSOLETE INFO FUNCTION</a> -<li><a name="TOC10" href="#SEC10">MATCHING A PATTERN</a> -<li><a name="TOC11" href="#SEC11">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a> -<li><a name="TOC12" href="#SEC12">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a> -</ul> -<br><a name="SEC1" href="#TOC1">SYNOPSIS OF PCRE API</a><br> -<P> -<b>#include <pcre.h></b> -</P> -<P> -<b>pcre *pcre_compile(const char *<i>pattern</i>, int <i>options</i>,</b> -<b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b> -<b>const unsigned char *<i>tableptr</i>);</b> -</P> -<P> -<b>pcre_extra *pcre_study(const pcre *<i>code</i>, int <i>options</i>,</b> -<b>const char **<i>errptr</i>);</b> -</P> -<P> -<b>int pcre_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> -<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> -<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> -</P> -<P> -<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>char *<i>buffer</i>, int <i>buffersize</i>);</b> -</P> -<P> -<b>int pcre_copy_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> -<b>int <i>buffersize</i>);</b> -</P> -<P> -<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<P> -<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>);</b> -</P> -<P> -<b>int pcre_get_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, int <i>stringnumber</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<P> -<b>int pcre_get_substring_list(const char *<i>subject</i>,</b> -<b>int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> -</P> -<P> -<b>void pcre_free_substring(const char *<i>stringptr</i>);</b> -</P> -<P> -<b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b> -</P> -<P> -<b>const unsigned char *pcre_maketables(void);</b> -</P> -<P> -<b>int pcre_fullinfo(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> -<b>int <i>what</i>, void *<i>where</i>);</b> -</P> -<P> -<b>int pcre_info(const pcre *<i>code</i>, int *<i>optptr</i>, int</b> -<b>*<i>firstcharptr</i>);</b> -</P> -<P> -<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> -</P> -<P> -<b>char *pcre_version(void);</b> -</P> -<P> -<b>void *(*pcre_malloc)(size_t);</b> -</P> -<P> -<b>void (*pcre_free)(void *);</b> -</P> -<P> -<b>void *(*pcre_stack_malloc)(size_t);</b> -</P> -<P> -<b>void (*pcre_stack_free)(void *);</b> -</P> -<P> -<b>int (*pcre_callout)(pcre_callout_block *);</b> -</P> -<br><a name="SEC2" href="#TOC1">PCRE API</a><br> -<P> -PCRE has its own native API, which is described in this document. There is also -a set of wrapper functions that correspond to the POSIX regular expression API. -These are described in the <b>pcreposix</b> documentation. -</P> -<P> -The native API function prototypes are defined in the header file <b>pcre.h</b>, -and on Unix systems the library itself is called <b>libpcre.a</b>, so can be -accessed by adding <b>-lpcre</b> to the command for linking an application which -calls it. The header file defines the macros PCRE_MAJOR and PCRE_MINOR to -contain the major and minor release numbers for the library. Applications can -use these to include support for different releases. -</P> -<P> -The functions <b>pcre_compile()</b>, <b>pcre_study()</b>, and <b>pcre_exec()</b> -are used for compiling and matching regular expressions. A sample program that -demonstrates the simplest way of using them is given in the file -<i>pcredemo.c</i>. The <b>pcresample</b> documentation describes how to run it. -</P> -<P> -There are convenience functions for extracting captured substrings from a -matched subject string. They are: -</P> -<P> -<pre> - <b>pcre_copy_substring()</b> - <b>pcre_copy_named_substring()</b> - <b>pcre_get_substring()</b> - <b>pcre_get_named_substring()</b> - <b>pcre_get_substring_list()</b> -</PRE> -</P> -<P> -<b>pcre_free_substring()</b> and <b>pcre_free_substring_list()</b> are also -provided, to free the memory used for extracted strings. -</P> -<P> -The function <b>pcre_maketables()</b> is used (optionally) to build a set of -character tables in the current locale for passing to <b>pcre_compile()</b>. -</P> -<P> -The function <b>pcre_fullinfo()</b> is used to find out information about a -compiled pattern; <b>pcre_info()</b> is an obsolete version which returns only -some of the available information, but is retained for backwards compatibility. -The function <b>pcre_version()</b> returns a pointer to a string containing the -version of PCRE and its date of release. -</P> -<P> -The global variables <b>pcre_malloc</b> and <b>pcre_free</b> initially contain -the entry points of the standard <b>malloc()</b> and <b>free()</b> functions -respectively. PCRE calls the memory management functions via these variables, -so a calling program can replace them if it wishes to intercept the calls. This -should be done before calling any PCRE functions. -</P> -<P> -The global variables <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> are also -indirections to memory management functions. These special functions are used -only when PCRE is compiled to use the heap for remembering data, instead of -recursive function calls. This is a non-standard way of building PCRE, for use -in environments that have limited stacks. Because of the greater use of memory -management, it runs more slowly. Separate functions are provided so that -special-purpose external code can be used for this case. When used, these -functions are always called in a stack-like manner (last obtained, first -freed), and always for memory blocks of the same size. -</P> -<P> -The global variable <b>pcre_callout</b> initially contains NULL. It can be set -by the caller to a "callout" function, which PCRE will then call at specified -points during a matching operation. Details are given in the <b>pcrecallout</b> -documentation. -</P> -<br><a name="SEC3" href="#TOC1">MULTITHREADING</a><br> -<P> -The PCRE functions can be used in multi-threading applications, with the -proviso that the memory management functions pointed to by <b>pcre_malloc</b>, -<b>pcre_free</b>, <b>pcre_stack_malloc</b>, and <b>pcre_stack_free</b>, and the -callout function pointed to by <b>pcre_callout</b>, are shared by all threads. -</P> -<P> -The compiled form of a regular expression is not altered during matching, so -the same compiled pattern can safely be used by several threads at once. -</P> -<br><a name="SEC4" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br> -<P> -<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> -</P> -<P> -The function <b>pcre_config()</b> makes it possible for a PCRE client to -discover which optional features have been compiled into the PCRE library. The -<a href="pcrebuild.html"><b>pcrebuild</b></a> -documentation has more details about these optional features. -</P> -<P> -The first argument for <b>pcre_config()</b> is an integer, specifying which -information is required; the second argument is a pointer to a variable into -which the information is placed. The following information is available: -</P> -<P> -<pre> - PCRE_CONFIG_UTF8 -</PRE> -</P> -<P> -The output is an integer that is set to one if UTF-8 support is available; -otherwise it is set to zero. -</P> -<P> -<pre> - PCRE_CONFIG_NEWLINE -</PRE> -</P> -<P> -The output is an integer that is set to the value of the code that is used for -the newline character. It is either linefeed (10) or carriage return (13), and -should normally be the standard character for your operating system. -</P> -<P> -<pre> - PCRE_CONFIG_LINK_SIZE -</PRE> -</P> -<P> -The output is an integer that contains the number of bytes used for internal -linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values -allow larger regular expressions to be compiled, at the expense of slower -matching. The default value of 2 is sufficient for all but the most massive -patterns, since it allows the compiled pattern to be up to 64K in size. -</P> -<P> -<pre> - PCRE_CONFIG_POSIX_MALLOC_THRESHOLD -</PRE> -</P> -<P> -The output is an integer that contains the threshold above which the POSIX -interface uses <b>malloc()</b> for output vectors. Further details are given in -the <b>pcreposix</b> documentation. -</P> -<P> -<pre> - PCRE_CONFIG_MATCH_LIMIT -</PRE> -</P> -<P> -The output is an integer that gives the default limit for the number of -internal matching function calls in a <b>pcre_exec()</b> execution. Further -details are given with <b>pcre_exec()</b> below. -</P> -<P> -<pre> - PCRE_CONFIG_STACKRECURSE -</PRE> -</P> -<P> -The output is an integer that is set to one if internal recursion is -implemented by recursive function calls that use the stack to remember their -state. This is the usual way that PCRE is compiled. The output is zero if PCRE -was compiled to use blocks of data on the heap instead of recursive function -calls. In this case, <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> are -called to manage memory blocks on the heap, thus avoiding the use of the stack. -</P> -<br><a name="SEC5" href="#TOC1">COMPILING A PATTERN</a><br> -<P> -<b>pcre *pcre_compile(const char *<i>pattern</i>, int <i>options</i>,</b> -<b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b> -<b>const unsigned char *<i>tableptr</i>);</b> -</P> -<P> -The function <b>pcre_compile()</b> is called to compile a pattern into an -internal form. The pattern is a C string terminated by a binary zero, and -is passed in the argument <i>pattern</i>. A pointer to a single block of memory -that is obtained via <b>pcre_malloc</b> is returned. This contains the compiled -code and related data. The <b>pcre</b> type is defined for the returned block; -this is a typedef for a structure whose contents are not externally defined. It -is up to the caller to free the memory when it is no longer required. -</P> -<P> -Although the compiled code of a PCRE regex is relocatable, that is, it does not -depend on memory location, the complete <b>pcre</b> data block is not -fully relocatable, because it contains a copy of the <i>tableptr</i> argument, -which is an address (see below). -</P> -<P> -The <i>options</i> argument contains independent bits that affect the -compilation. It should be zero if no options are required. Some of the options, -in particular, those that are compatible with Perl, can also be set and unset -from within the pattern (see the detailed description of regular expressions -in the <b>pcrepattern</b> documentation). For these options, the contents of the -<i>options</i> argument specifies their initial settings at the start of -compilation and execution. The PCRE_ANCHORED option can be set at the time of -matching as well as at compile time. -</P> -<P> -If <i>errptr</i> is NULL, <b>pcre_compile()</b> returns NULL immediately. -Otherwise, if compilation of a pattern fails, <b>pcre_compile()</b> returns -NULL, and sets the variable pointed to by <i>errptr</i> to point to a textual -error message. The offset from the start of the pattern to the character where -the error was discovered is placed in the variable pointed to by -<i>erroffset</i>, which must not be NULL. If it is, an immediate error is given. -</P> -<P> -If the final argument, <i>tableptr</i>, is NULL, PCRE uses a default set of -character tables which are built when it is compiled, using the default C -locale. Otherwise, <i>tableptr</i> must be the result of a call to -<b>pcre_maketables()</b>. See the section on locale support below. -</P> -<P> -This code fragment shows a typical straightforward call to <b>pcre_compile()</b>: -</P> -<P> -<pre> - pcre *re; - const char *error; - int erroffset; - re = pcre_compile( - "^A.*Z", /* the pattern */ - 0, /* default options */ - &error, /* for error message */ - &erroffset, /* for error offset */ - NULL); /* use default character tables */ -</PRE> -</P> -<P> -The following option bits are defined: -</P> -<P> -<pre> - PCRE_ANCHORED -</PRE> -</P> -<P> -If this bit is set, the pattern is forced to be "anchored", that is, it is -constrained to match only at the first matching point in the string which is -being searched (the "subject string"). This effect can also be achieved by -appropriate constructs in the pattern itself, which is the only way to do it in -Perl. -</P> -<P> -<pre> - PCRE_CASELESS -</PRE> -</P> -<P> -If this bit is set, letters in the pattern match both upper and lower case -letters. It is equivalent to Perl's /i option, and it can be changed within a -pattern by a (?i) option setting. -</P> -<P> -<pre> - PCRE_DOLLAR_ENDONLY -</PRE> -</P> -<P> -If this bit is set, a dollar metacharacter in the pattern matches only at the -end of the subject string. Without this option, a dollar also matches -immediately before the final character if it is a newline (but not before any -other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is -set. There is no equivalent to this option in Perl, and no way to set it within -a pattern. -</P> -<P> -<pre> - PCRE_DOTALL -</PRE> -</P> -<P> -If this bit is set, a dot metacharater in the pattern matches all characters, -including newlines. Without it, newlines are excluded. This option is -equivalent to Perl's /s option, and it can be changed within a pattern by a -(?s) option setting. A negative class such as [^a] always matches a newline -character, independent of the setting of this option. -</P> -<P> -<pre> - PCRE_EXTENDED -</PRE> -</P> -<P> -If this bit is set, whitespace data characters in the pattern are totally -ignored except when escaped or inside a character class. Whitespace does not -include the VT character (code 11). In addition, characters between an -unescaped # outside a character class and the next newline character, -inclusive, are also ignored. This is equivalent to Perl's /x option, and it can -be changed within a pattern by a (?x) option setting. -</P> -<P> -This option makes it possible to include comments inside complicated patterns. -Note, however, that this applies only to data characters. Whitespace characters -may never appear within special character sequences in a pattern, for example -within the sequence (?( which introduces a conditional subpattern. -</P> -<P> -<pre> - PCRE_EXTRA -</PRE> -</P> -<P> -This option was invented in order to turn on additional functionality of PCRE -that is incompatible with Perl, but it is currently of very little use. When -set, any backslash in a pattern that is followed by a letter that has no -special meaning causes an error, thus reserving these combinations for future -expansion. By default, as in Perl, a backslash followed by a letter with no -special meaning is treated as a literal. There are at present no other features -controlled by this option. It can also be set by a (?X) option setting within a -pattern. -</P> -<P> -<pre> - PCRE_MULTILINE -</PRE> -</P> -<P> -By default, PCRE treats the subject string as consisting of a single "line" of -characters (even if it actually contains several newlines). The "start of line" -metacharacter (^) matches only at the start of the string, while the "end of -line" metacharacter ($) matches only at the end of the string, or before a -terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as -Perl. -</P> -<P> -When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs -match immediately following or immediately before any newline in the subject -string, respectively, as well as at the very start and end. This is equivalent -to Perl's /m option, and it can be changed within a pattern by a (?m) option -setting. If there are no "\n" characters in a subject string, or no -occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect. -</P> -<P> -<pre> - PCRE_NO_AUTO_CAPTURE -</PRE> -</P> -<P> -If this option is set, it disables the use of numbered capturing parentheses in -the pattern. Any opening parenthesis that is not followed by ? behaves as if it -were followed by ?: but named parentheses can still be used for capturing (and -they acquire numbers in the usual way). There is no equivalent of this option -in Perl. -</P> -<P> -<pre> - PCRE_UNGREEDY -</PRE> -</P> -<P> -This option inverts the "greediness" of the quantifiers so that they are not -greedy by default, but become greedy if followed by "?". It is not compatible -with Perl. It can also be set by a (?U) option setting within the pattern. -</P> -<P> -<pre> - PCRE_UTF8 -</PRE> -</P> -<P> -This option causes PCRE to regard both the pattern and the subject as strings -of UTF-8 characters instead of single-byte character strings. However, it is -available only if PCRE has been built to include UTF-8 support. If not, the use -of this option provokes an error. Details of how this option changes the -behaviour of PCRE are given in the -<a href="pcre.html#utf8support">section on UTF-8 support</a> -in the main -<a href="pcre.html"><b>pcre</b></a> -page. -</P> -<P> -<pre> - PCRE_NO_UTF8_CHECK -</PRE> -</P> -<P> -When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is -automatically checked. If an invalid UTF-8 sequence of bytes is found, -<b>pcre_compile()</b> returns an error. If you already know that your pattern is -valid, and you want to skip this check for performance reasons, you can set the -PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid -UTF-8 string as a pattern is undefined. It may cause your program to crash. -Note that there is a similar option for suppressing the checking of subject -strings passed to <b>pcre_exec()</b>. -</P> -<br><a name="SEC6" href="#TOC1">STUDYING A PATTERN</a><br> -<P> -<b>pcre_extra *pcre_study(const pcre *<i>code</i>, int <i>options</i>,</b> -<b>const char **<i>errptr</i>);</b> -</P> -<P> -When a pattern is going to be used several times, it is worth spending more -time analyzing it in order to speed up the time taken for matching. The -function <b>pcre_study()</b> takes a pointer to a compiled pattern as its first -argument. If studing the pattern produces additional information that will help -speed up matching, <b>pcre_study()</b> returns a pointer to a <b>pcre_extra</b> -block, in which the <i>study_data</i> field points to the results of the study. -</P> -<P> -The returned value from a <b>pcre_study()</b> can be passed directly to -<b>pcre_exec()</b>. However, the <b>pcre_extra</b> block also contains other -fields that can be set by the caller before the block is passed; these are -described below. If studying the pattern does not produce any additional -information, <b>pcre_study()</b> returns NULL. In that circumstance, if the -calling program wants to pass some of the other fields to <b>pcre_exec()</b>, it -must set up its own <b>pcre_extra</b> block. -</P> -<P> -The second argument contains option bits. At present, no options are defined -for <b>pcre_study()</b>, and this argument should always be zero. -</P> -<P> -The third argument for <b>pcre_study()</b> is a pointer for an error message. If -studying succeeds (even if no data is returned), the variable it points to is -set to NULL. Otherwise it points to a textual error message. You should -therefore test the error pointer for NULL after calling <b>pcre_study()</b>, to -be sure that it has run successfully. -</P> -<P> -This is a typical call to <b>pcre_study</b>(): -</P> -<P> -<pre> - pcre_extra *pe; - pe = pcre_study( - re, /* result of pcre_compile() */ - 0, /* no options exist */ - &error); /* set to NULL or points to a message */ -</PRE> -</P> -<P> -At present, studying a pattern is useful only for non-anchored patterns that do -not have a single fixed starting character. A bitmap of possible starting -characters is created. -</P> -<a name="localesupport"></a><br><a name="SEC7" href="#TOC1">LOCALE SUPPORT</a><br> -<P> -PCRE handles caseless matching, and determines whether characters are letters, -digits, or whatever, by reference to a set of tables. When running in UTF-8 -mode, this applies only to characters with codes less than 256. The library -contains a default set of tables that is created in the default C locale when -PCRE is compiled. This is used when the final argument of <b>pcre_compile()</b> -is NULL, and is sufficient for many applications. -</P> -<P> -An alternative set of tables can, however, be supplied. Such tables are built -by calling the <b>pcre_maketables()</b> function, which has no arguments, in the -relevant locale. The result can then be passed to <b>pcre_compile()</b> as often -as necessary. For example, to build and use tables that are appropriate for the -French locale (where accented characters with codes greater than 128 are -treated as letters), the following code could be used: -</P> -<P> -<pre> - setlocale(LC_CTYPE, "fr"); - tables = pcre_maketables(); - re = pcre_compile(..., tables); -</PRE> -</P> -<P> -The tables are built in memory that is obtained via <b>pcre_malloc</b>. The -pointer that is passed to <b>pcre_compile</b> is saved with the compiled -pattern, and the same tables are used via this pointer by <b>pcre_study()</b> -and <b>pcre_exec()</b>. Thus, for any single pattern, compilation, studying and -matching all happen in the same locale, but different patterns can be compiled -in different locales. It is the caller's responsibility to ensure that the -memory containing the tables remains available for as long as it is needed. -</P> -<br><a name="SEC8" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br> -<P> -<b>int pcre_fullinfo(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> -<b>int <i>what</i>, void *<i>where</i>);</b> -</P> -<P> -The <b>pcre_fullinfo()</b> function returns information about a compiled -pattern. It replaces the obsolete <b>pcre_info()</b> function, which is -nevertheless retained for backwards compability (and is documented below). -</P> -<P> -The first argument for <b>pcre_fullinfo()</b> is a pointer to the compiled -pattern. The second argument is the result of <b>pcre_study()</b>, or NULL if -the pattern was not studied. The third argument specifies which piece of -information is required, and the fourth argument is a pointer to a variable -to receive the data. The yield of the function is zero for success, or one of -the following negative numbers: -</P> -<P> -<pre> - PCRE_ERROR_NULL the argument <i>code</i> was NULL - the argument <i>where</i> was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - PCRE_ERROR_BADOPTION the value of <i>what</i> was invalid -</PRE> -</P> -<P> -Here is a typical call of <b>pcre_fullinfo()</b>, to obtain the length of the -compiled pattern: -</P> -<P> -<pre> - int rc; - unsigned long int length; - rc = pcre_fullinfo( - re, /* result of pcre_compile() */ - pe, /* result of pcre_study(), or NULL */ - PCRE_INFO_SIZE, /* what is required */ - &length); /* where to put the data */ -</PRE> -</P> -<P> -The possible values for the third argument are defined in <b>pcre.h</b>, and are -as follows: -</P> -<P> -<pre> - PCRE_INFO_BACKREFMAX -</PRE> -</P> -<P> -Return the number of the highest back reference in the pattern. The fourth -argument should point to an <b>int</b> variable. Zero is returned if there are -no back references. -</P> -<P> -<pre> - PCRE_INFO_CAPTURECOUNT -</PRE> -</P> -<P> -Return the number of capturing subpatterns in the pattern. The fourth argument -should point to an \fbint\fR variable. -</P> -<P> -<pre> - PCRE_INFO_FIRSTBYTE -</PRE> -</P> -<P> -Return information about the first byte of any matched string, for a -non-anchored pattern. (This option used to be called PCRE_INFO_FIRSTCHAR; the -old name is still recognized for backwards compatibility.) -</P> -<P> -If there is a fixed first byte, e.g. from a pattern such as (cat|cow|coyote), -it is returned in the integer pointed to by <i>where</i>. Otherwise, if either -</P> -<P> -(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch -starts with "^", or -</P> -<P> -(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set -(if it were set, the pattern would be anchored), -</P> -<P> --1 is returned, indicating that the pattern matches only at the start of a -subject string or after any newline within the string. Otherwise -2 is -returned. For anchored patterns, -2 is returned. -</P> -<P> -<pre> - PCRE_INFO_FIRSTTABLE -</PRE> -</P> -<P> -If the pattern was studied, and this resulted in the construction of a 256-bit -table indicating a fixed set of bytes for the first byte in any matching -string, a pointer to the table is returned. Otherwise NULL is returned. The -fourth argument should point to an <b>unsigned char *</b> variable. -</P> -<P> -<pre> - PCRE_INFO_LASTLITERAL -</PRE> -</P> -<P> -Return the value of the rightmost literal byte that must exist in any matched -string, other than at its start, if such a byte has been recorded. The fourth -argument should point to an <b>int</b> variable. If there is no such byte, -1 is -returned. For anchored patterns, a last literal byte is recorded only if it -follows something of variable length. For example, for the pattern -/^a\d+z\d+/ the returned value is "z", but for /^a\dz\d/ the returned value -is -1. -</P> -<P> -<pre> - PCRE_INFO_NAMECOUNT - PCRE_INFO_NAMEENTRYSIZE - PCRE_INFO_NAMETABLE -</PRE> -</P> -<P> -PCRE supports the use of named as well as numbered capturing parentheses. The -names are just an additional way of identifying the parentheses, which still -acquire a number. A caller that wants to extract data from a named subpattern -must convert the name to a number in order to access the correct pointers in -the output vector (described with <b>pcre_exec()</b> below). In order to do -this, it must first use these three values to obtain the name-to-number mapping -table for the pattern. -</P> -<P> -The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives -the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each -entry; both of these return an <b>int</b> value. The entry size depends on the -length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first -entry of the table (a pointer to <b>char</b>). The first two bytes of each entry -are the number of the capturing parenthesis, most significant byte first. The -rest of the entry is the corresponding name, zero terminated. The names are in -alphabetical order. For example, consider the following pattern (assume -PCRE_EXTENDED is set, so white space - including newlines - is ignored): -</P> -<P> -<pre> - (?P<date> (?P<year>(\d\d)?\d\d) - - (?P<month>\d\d) - (?P<day>\d\d) ) -</PRE> -</P> -<P> -There are four named subpatterns, so the table has four entries, and each entry -in the table is eight bytes long. The table is as follows, with non-printing -bytes shows in hex, and undefined bytes shown as ??: -</P> -<P> -<pre> - 00 01 d a t e 00 ?? - 00 05 d a y 00 ?? ?? - 00 04 m o n t h 00 - 00 02 y e a r 00 ?? -</PRE> -</P> -<P> -When writing code to extract data from named subpatterns, remember that the -length of each entry may be different for each compiled pattern. -</P> -<P> -<pre> - PCRE_INFO_OPTIONS -</PRE> -</P> -<P> -Return a copy of the options with which the pattern was compiled. The fourth -argument should point to an <b>unsigned long int</b> variable. These option bits -are those specified in the call to <b>pcre_compile()</b>, modified by any -top-level option settings within the pattern itself. -</P> -<P> -A pattern is automatically anchored by PCRE if all of its top-level -alternatives begin with one of the following: -</P> -<P> -<pre> - ^ unless PCRE_MULTILINE is set - \A always - \G always - .* if PCRE_DOTALL is set and there are no back - references to the subpattern in which .* appears -</PRE> -</P> -<P> -For such patterns, the PCRE_ANCHORED bit is set in the options returned by -<b>pcre_fullinfo()</b>. -</P> -<P> -<pre> - PCRE_INFO_SIZE -</PRE> -</P> -<P> -Return the size of the compiled pattern, that is, the value that was passed as -the argument to <b>pcre_malloc()</b> when PCRE was getting memory in which to -place the compiled data. The fourth argument should point to a <b>size_t</b> -variable. -</P> -<P> -<pre> - PCRE_INFO_STUDYSIZE -</PRE> -</P> -<P> -Returns the size of the data block pointed to by the <i>study_data</i> field in -a <b>pcre_extra</b> block. That is, it is the value that was passed to -<b>pcre_malloc()</b> when PCRE was getting memory into which to place the data -created by <b>pcre_study()</b>. The fourth argument should point to a -<b>size_t</b> variable. -</P> -<br><a name="SEC9" href="#TOC1">OBSOLETE INFO FUNCTION</a><br> -<P> -<b>int pcre_info(const pcre *<i>code</i>, int *<i>optptr</i>, int</b> -<b>*<i>firstcharptr</i>);</b> -</P> -<P> -The <b>pcre_info()</b> function is now obsolete because its interface is too -restrictive to return all the available data about a compiled pattern. New -programs should use <b>pcre_fullinfo()</b> instead. The yield of -<b>pcre_info()</b> is the number of capturing subpatterns, or one of the -following negative numbers: -</P> -<P> -<pre> - PCRE_ERROR_NULL the argument <i>code</i> was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found -</PRE> -</P> -<P> -If the <i>optptr</i> argument is not NULL, a copy of the options with which the -pattern was compiled is placed in the integer it points to (see -PCRE_INFO_OPTIONS above). -</P> -<P> -If the pattern is not anchored and the <i>firstcharptr</i> argument is not NULL, -it is used to pass back information about the first character of any matched -string (see PCRE_INFO_FIRSTBYTE above). -</P> -<br><a name="SEC10" href="#TOC1">MATCHING A PATTERN</a><br> -<P> -<b>int pcre_exec(const pcre *<i>code</i>, const pcre_extra *<i>extra</i>,</b> -<b>const char *<i>subject</i>, int <i>length</i>, int <i>startoffset</i>,</b> -<b>int <i>options</i>, int *<i>ovector</i>, int <i>ovecsize</i>);</b> -</P> -<P> -The function <b>pcre_exec()</b> is called to match a subject string against a -pre-compiled pattern, which is passed in the <i>code</i> argument. If the -pattern has been studied, the result of the study should be passed in the -<i>extra</i> argument. -</P> -<P> -Here is an example of a simple call to <b>pcre_exec()</b>: -</P> -<P> -<pre> - int rc; - int ovector[30]; - rc = pcre_exec( - re, /* result of pcre_compile() */ - NULL, /* we didn't study the pattern */ - "some string", /* the subject string */ - 11, /* the length of the subject string */ - 0, /* start at offset 0 in the subject */ - 0, /* default options */ - ovector, /* vector for substring information */ - 30); /* number of elements in the vector */ -</PRE> -</P> -<P> -If the <i>extra</i> argument is not NULL, it must point to a <b>pcre_extra</b> -data block. The <b>pcre_study()</b> function returns such a block (when it -doesn't return NULL), but you can also create one for yourself, and pass -additional information in it. The fields in the block are as follows: -</P> -<P> -<pre> - unsigned long int <i>flags</i>; - void *<i>study_data</i>; - unsigned long int <i>match_limit</i>; - void *<i>callout_data</i>; -</PRE> -</P> -<P> -The <i>flags</i> field is a bitmap that specifies which of the other fields -are set. The flag bits are: -</P> -<P> -<pre> - PCRE_EXTRA_STUDY_DATA - PCRE_EXTRA_MATCH_LIMIT - PCRE_EXTRA_CALLOUT_DATA -</PRE> -</P> -<P> -Other flag bits should be set to zero. The <i>study_data</i> field is set in the -<b>pcre_extra</b> block that is returned by <b>pcre_study()</b>, together with -the appropriate flag bit. You should not set this yourself, but you can add to -the block by setting the other fields. -</P> -<P> -The <i>match_limit</i> field provides a means of preventing PCRE from using up a -vast amount of resources when running patterns that are not going to match, -but which have a very large number of possibilities in their search trees. The -classic example is the use of nested unlimited repeats. Internally, PCRE uses a -function called <b>match()</b> which it calls repeatedly (sometimes -recursively). The limit is imposed on the number of times this function is -called during a match, which has the effect of limiting the amount of recursion -and backtracking that can take place. For patterns that are not anchored, the -count starts from zero for each position in the subject string. -</P> -<P> -The default limit for the library can be set when PCRE is built; the default -default is 10 million, which handles all but the most extreme cases. You can -reduce the default by suppling <b>pcre_exec()</b> with a \fRpcre_extra\fR block -in which <i>match_limit</i> is set to a smaller value, and -PCRE_EXTRA_MATCH_LIMIT is set in the <i>flags</i> field. If the limit is -exceeded, <b>pcre_exec()</b> returns PCRE_ERROR_MATCHLIMIT. -</P> -<P> -The <i>pcre_callout</i> field is used in conjunction with the "callout" feature, -which is described in the <b>pcrecallout</b> documentation. -</P> -<P> -The PCRE_ANCHORED option can be passed in the <i>options</i> argument, whose -unused bits must be zero. This limits <b>pcre_exec()</b> to matching at the -first matching position. However, if a pattern was compiled with PCRE_ANCHORED, -or turned out to be anchored by virtue of its contents, it cannot be made -unachored at matching time. -</P> -<P> -When PCRE_UTF8 was set at compile time, the validity of the subject as a UTF-8 -string is automatically checked, and the value of <i>startoffset</i> is also -checked to ensure that it points to the start of a UTF-8 character. If an -invalid UTF-8 sequence of bytes is found, <b>pcre_exec()</b> returns the error -PCRE_ERROR_BADUTF8. If <i>startoffset</i> contains an invalid value, -PCRE_ERROR_BADUTF8_OFFSET is returned. -</P> -<P> -If you already know that your subject is valid, and you want to skip these -checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when -calling <b>pcre_exec()</b>. You might want to do this for the second and -subsequent calls to <b>pcre_exec()</b> if you are making repeated calls to find -all the matches in a single subject string. However, you should be sure that -the value of <i>startoffset</i> points to the start of a UTF-8 character. When -PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a -subject, or a value of <i>startoffset</i> that does not point to the start of a -UTF-8 character, is undefined. Your program may crash. -</P> -<P> -There are also three further options that can be set only at matching time: -</P> -<P> -<pre> - PCRE_NOTBOL -</PRE> -</P> -<P> -The first character of the string is not the beginning of a line, so the -circumflex metacharacter should not match before it. Setting this without -PCRE_MULTILINE (at compile time) causes circumflex never to match. -</P> -<P> -<pre> - PCRE_NOTEOL -</PRE> -</P> -<P> -The end of the string is not the end of a line, so the dollar metacharacter -should not match it nor (except in multiline mode) a newline immediately before -it. Setting this without PCRE_MULTILINE (at compile time) causes dollar never -to match. -</P> -<P> -<pre> - PCRE_NOTEMPTY -</PRE> -</P> -<P> -An empty string is not considered to be a valid match if this option is set. If -there are alternatives in the pattern, they are tried. If all the alternatives -match the empty string, the entire match fails. For example, if the pattern -</P> -<P> -<pre> - a?b? -</PRE> -</P> -<P> -is applied to a string not beginning with "a" or "b", it matches the empty -string at the start of the subject. With PCRE_NOTEMPTY set, this match is not -valid, so PCRE searches further into the string for occurrences of "a" or "b". -</P> -<P> -Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case -of a pattern match of the empty string within its <b>split()</b> function, and -when using the /g modifier. It is possible to emulate Perl's behaviour after -matching a null string by first trying the match again at the same offset with -PCRE_NOTEMPTY set, and then if that fails by advancing the starting offset (see -below) and trying an ordinary match again. -</P> -<P> -The subject string is passed to <b>pcre_exec()</b> as a pointer in -<i>subject</i>, a length in <i>length</i>, and a starting byte offset in -<i>startoffset</i>. Unlike the pattern string, the subject may contain binary -zero bytes. When the starting offset is zero, the search for a match starts at -the beginning of the subject, and this is by far the most common case. -</P> -<P> -If the pattern was compiled with the PCRE_UTF8 option, the subject must be a -sequence of bytes that is a valid UTF-8 string, and the starting offset must -point to the beginning of a UTF-8 character. If an invalid UTF-8 string or -offset is passed, an error (either PCRE_ERROR_BADUTF8 or -PCRE_ERROR_BADUTF8_OFFSET) is returned, unless the option PCRE_NO_UTF8_CHECK is -set, in which case PCRE's behaviour is not defined. -</P> -<P> -A non-zero starting offset is useful when searching for another match in the -same subject by calling <b>pcre_exec()</b> again after a previous success. -Setting <i>startoffset</i> differs from just passing over a shortened string and -setting PCRE_NOTBOL in the case of a pattern that begins with any kind of -lookbehind. For example, consider the pattern -</P> -<P> -<pre> - \Biss\B -</PRE> -</P> -<P> -which finds occurrences of "iss" in the middle of words. (\B matches only if -the current position in the subject is not a word boundary.) When applied to -the string "Mississipi" the first call to <b>pcre_exec()</b> finds the first -occurrence. If <b>pcre_exec()</b> is called again with just the remainder of the -subject, namely "issipi", it does not match, because \B is always false at the -start of the subject, which is deemed to be a word boundary. However, if -<b>pcre_exec()</b> is passed the entire string again, but with <i>startoffset</i> -set to 4, it finds the second occurrence of "iss" because it is able to look -behind the starting point to discover that it is preceded by a letter. -</P> -<P> -If a non-zero starting offset is passed when the pattern is anchored, one -attempt to match at the given offset is tried. This can only succeed if the -pattern does not require the match to be at the start of the subject. -</P> -<P> -In general, a pattern matches a certain portion of the subject, and in -addition, further substrings from the subject may be picked out by parts of the -pattern. Following the usage in Jeffrey Friedl's book, this is called -"capturing" in what follows, and the phrase "capturing subpattern" is used for -a fragment of a pattern that picks out a substring. PCRE supports several other -kinds of parenthesized subpattern that do not cause substrings to be captured. -</P> -<P> -Captured substrings are returned to the caller via a vector of integer offsets -whose address is passed in <i>ovector</i>. The number of elements in the vector -is passed in <i>ovecsize</i>. The first two-thirds of the vector is used to pass -back captured substrings, each substring using a pair of integers. The -remaining third of the vector is used as workspace by <b>pcre_exec()</b> while -matching capturing subpatterns, and is not available for passing back -information. The length passed in <i>ovecsize</i> should always be a multiple of -three. If it is not, it is rounded down. -</P> -<P> -When a match has been successful, information about captured substrings is -returned in pairs of integers, starting at the beginning of <i>ovector</i>, and -continuing up to two-thirds of its length at the most. The first element of a -pair is set to the offset of the first character in a substring, and the second -is set to the offset of the first character after the end of a substring. The -first pair, <i>ovector[0]</i> and <i>ovector[1]</i>, identify the portion of the -subject string matched by the entire pattern. The next pair is used for the -first capturing subpattern, and so on. The value returned by <b>pcre_exec()</b> -is the number of pairs that have been set. If there are no capturing -subpatterns, the return value from a successful match is 1, indicating that -just the first pair of offsets has been set. -</P> -<P> -Some convenience functions are provided for extracting the captured substrings -as separate strings. These are described in the following section. -</P> -<P> -It is possible for an capturing subpattern number <i>n+1</i> to match some -part of the subject when subpattern <i>n</i> has not been used at all. For -example, if the string "abc" is matched against the pattern (a|(z))(bc) -subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset -values corresponding to the unused subpattern are set to -1. -</P> -<P> -If a capturing subpattern is matched repeatedly, it is the last portion of the -string that it matched that gets returned. -</P> -<P> -If the vector is too small to hold all the captured substrings, it is used as -far as possible (up to two-thirds of its length), and the function returns a -value of zero. In particular, if the substring offsets are not of interest, -<b>pcre_exec()</b> may be called with <i>ovector</i> passed as NULL and -<i>ovecsize</i> as zero. However, if the pattern contains back references and -the <i>ovector</i> isn't big enough to remember the related substrings, PCRE has -to get additional memory for use during matching. Thus it is usually advisable -to supply an <i>ovector</i>. -</P> -<P> -Note that <b>pcre_info()</b> can be used to find out how many capturing -subpatterns there are in a compiled pattern. The smallest size for -<i>ovector</i> that will allow for <i>n</i> captured substrings, in addition to -the offsets of the substring matched by the whole pattern, is (<i>n</i>+1)*3. -</P> -<P> -If <b>pcre_exec()</b> fails, it returns a negative number. The following are -defined in the header file: -</P> -<P> -<pre> - PCRE_ERROR_NOMATCH (-1) -</PRE> -</P> -<P> -The subject string did not match the pattern. -</P> -<P> -<pre> - PCRE_ERROR_NULL (-2) -</PRE> -</P> -<P> -Either <i>code</i> or <i>subject</i> was passed as NULL, or <i>ovector</i> was -NULL and <i>ovecsize</i> was not zero. -</P> -<P> -<pre> - PCRE_ERROR_BADOPTION (-3) -</PRE> -</P> -<P> -An unrecognized bit was set in the <i>options</i> argument. -</P> -<P> -<pre> - PCRE_ERROR_BADMAGIC (-4) -</PRE> -</P> -<P> -PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch -the case when it is passed a junk pointer. This is the error it gives when the -magic number isn't present. -</P> -<P> -<pre> - PCRE_ERROR_UNKNOWN_NODE (-5) -</PRE> -</P> -<P> -While running the pattern match, an unknown item was encountered in the -compiled pattern. This error could be caused by a bug in PCRE or by overwriting -of the compiled pattern. -</P> -<P> -<pre> - PCRE_ERROR_NOMEMORY (-6) -</PRE> -</P> -<P> -If a pattern contains back references, but the <i>ovector</i> that is passed to -<b>pcre_exec()</b> is not big enough to remember the referenced substrings, PCRE -gets a block of memory at the start of matching to use for this purpose. If the -call via <b>pcre_malloc()</b> fails, this error is given. The memory is freed at -the end of matching. -</P> -<P> -<pre> - PCRE_ERROR_NOSUBSTRING (-7) -</PRE> -</P> -<P> -This error is used by the <b>pcre_copy_substring()</b>, -<b>pcre_get_substring()</b>, and <b>pcre_get_substring_list()</b> functions (see -below). It is never returned by <b>pcre_exec()</b>. -</P> -<P> -<pre> - PCRE_ERROR_MATCHLIMIT (-8) -</PRE> -</P> -<P> -The recursion and backtracking limit, as specified by the <i>match_limit</i> -field in a <b>pcre_extra</b> structure (or defaulted) was reached. See the -description above. -</P> -<P> -<pre> - PCRE_ERROR_CALLOUT (-9) -</PRE> -</P> -<P> -This error is never generated by <b>pcre_exec()</b> itself. It is provided for -use by callout functions that want to yield a distinctive error code. See the -<b>pcrecallout</b> documentation for details. -</P> -<P> -<pre> - PCRE_ERROR_BADUTF8 (-10) -</PRE> -</P> -<P> -A string that contains an invalid UTF-8 byte sequence was passed as a subject. -</P> -<P> -<pre> - PCRE_ERROR_BADUTF8_OFFSET (-11) -</PRE> -</P> -<P> -The UTF-8 byte sequence that was passed as a subject was valid, but the value -of <i>startoffset</i> did not point to the beginning of a UTF-8 character. -</P> -<br><a name="SEC11" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br> -<P> -<b>int pcre_copy_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> -<b>int <i>buffersize</i>);</b> -</P> -<P> -<b>int pcre_get_substring(const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, int <i>stringnumber</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<P> -<b>int pcre_get_substring_list(const char *<i>subject</i>,</b> -<b>int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> -</P> -<P> -Captured substrings can be accessed directly by using the offsets returned by -<b>pcre_exec()</b> in <i>ovector</i>. For convenience, the functions -<b>pcre_copy_substring()</b>, <b>pcre_get_substring()</b>, and -<b>pcre_get_substring_list()</b> are provided for extracting captured substrings -as new, separate, zero-terminated strings. These functions identify substrings -by number. The next section describes functions for extracting named -substrings. A substring that contains a binary zero is correctly extracted and -has a further zero added on the end, but the result is not, of course, -a C string. -</P> -<P> -The first three arguments are the same for all three of these functions: -<i>subject</i> is the subject string which has just been successfully matched, -<i>ovector</i> is a pointer to the vector of integer offsets that was passed to -<b>pcre_exec()</b>, and <i>stringcount</i> is the number of substrings that were -captured by the match, including the substring that matched the entire regular -expression. This is the value returned by <b>pcre_exec</b> if it is greater than -zero. If <b>pcre_exec()</b> returned zero, indicating that it ran out of space -in <i>ovector</i>, the value passed as <i>stringcount</i> should be the size of -the vector divided by three. -</P> -<P> -The functions <b>pcre_copy_substring()</b> and <b>pcre_get_substring()</b> -extract a single substring, whose number is given as <i>stringnumber</i>. A -value of zero extracts the substring that matched the entire pattern, while -higher values extract the captured substrings. For <b>pcre_copy_substring()</b>, -the string is placed in <i>buffer</i>, whose length is given by -<i>buffersize</i>, while for <b>pcre_get_substring()</b> a new block of memory is -obtained via <b>pcre_malloc</b>, and its address is returned via -<i>stringptr</i>. The yield of the function is the length of the string, not -including the terminating zero, or one of -</P> -<P> -<pre> - PCRE_ERROR_NOMEMORY (-6) -</PRE> -</P> -<P> -The buffer was too small for <b>pcre_copy_substring()</b>, or the attempt to get -memory failed for <b>pcre_get_substring()</b>. -</P> -<P> -<pre> - PCRE_ERROR_NOSUBSTRING (-7) -</PRE> -</P> -<P> -There is no substring whose number is <i>stringnumber</i>. -</P> -<P> -The <b>pcre_get_substring_list()</b> function extracts all available substrings -and builds a list of pointers to them. All this is done in a single block of -memory which is obtained via <b>pcre_malloc</b>. The address of the memory block -is returned via <i>listptr</i>, which is also the start of the list of string -pointers. The end of the list is marked by a NULL pointer. The yield of the -function is zero if all went well, or -</P> -<P> -<pre> - PCRE_ERROR_NOMEMORY (-6) -</PRE> -</P> -<P> -if the attempt to get the memory block failed. -</P> -<P> -When any of these functions encounter a substring that is unset, which can -happen when capturing subpattern number <i>n+1</i> matches some part of the -subject, but subpattern <i>n</i> has not been used at all, they return an empty -string. This can be distinguished from a genuine zero-length substring by -inspecting the appropriate offset in <i>ovector</i>, which is negative for unset -substrings. -</P> -<P> -The two convenience functions <b>pcre_free_substring()</b> and -<b>pcre_free_substring_list()</b> can be used to free the memory returned by -a previous call of <b>pcre_get_substring()</b> or -<b>pcre_get_substring_list()</b>, respectively. They do nothing more than call -the function pointed to by <b>pcre_free</b>, which of course could be called -directly from a C program. However, PCRE is used in some situations where it is -linked via a special interface to another programming language which cannot use -<b>pcre_free</b> directly; it is for these cases that the functions are -provided. -</P> -<br><a name="SEC12" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br> -<P> -<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>char *<i>buffer</i>, int <i>buffersize</i>);</b> -</P> -<P> -<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>);</b> -</P> -<P> -<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<P> -To extract a substring by name, you first have to find associated number. This -can be done by calling <b>pcre_get_stringnumber()</b>. The first argument is the -compiled pattern, and the second is the name. For example, for this pattern -</P> -<P> -<pre> - ab(?<xxx>\d+)... -</PRE> -</P> -<P> -the number of the subpattern called "xxx" is 1. Given the number, you can then -extract the substring directly, or use one of the functions described in the -previous section. For convenience, there are also two functions that do the -whole job. -</P> -<P> -Most of the arguments of <i>pcre_copy_named_substring()</i> and -<i>pcre_get_named_substring()</i> are the same as those for the functions that -extract by number, and so are not re-described here. There are just two -differences. -</P> -<P> -First, instead of a substring number, a substring name is given. Second, there -is an extra argument, given at the start, which is a pointer to the compiled -pattern. This is needed in order to gain access to the name-to-number -translation table. -</P> -<P> -These functions call <b>pcre_get_stringnumber()</b>, and if it succeeds, they -then call <i>pcre_copy_substring()</i> or <i>pcre_get_substring()</i>, as -appropriate. -</P> -<P> -Last updated: 09 December 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcrebuild.html b/external-libs/pcre/doc/html/pcrebuild.html deleted file mode 100644 index c70f8221..00000000 --- a/external-libs/pcre/doc/html/pcrebuild.html +++ /dev/null @@ -1,189 +0,0 @@ -<html> -<head> -<title>pcrebuild specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">PCRE BUILD-TIME OPTIONS</a> -<li><a name="TOC2" href="#SEC2">UTF-8 SUPPORT</a> -<li><a name="TOC3" href="#SEC3">CODE VALUE OF NEWLINE</a> -<li><a name="TOC4" href="#SEC4">BUILDING SHARED AND STATIC LIBRARIES</a> -<li><a name="TOC5" href="#SEC5">POSIX MALLOC USAGE</a> -<li><a name="TOC6" href="#SEC6">LIMITING PCRE RESOURCE USAGE</a> -<li><a name="TOC7" href="#SEC7">HANDLING VERY LARGE PATTERNS</a> -<li><a name="TOC8" href="#SEC8">AVOIDING EXCESSIVE STACK USAGE</a> -<li><a name="TOC9" href="#SEC9">USING EBCDIC CODE</a> -</ul> -<br><a name="SEC1" href="#TOC1">PCRE BUILD-TIME OPTIONS</a><br> -<P> -This document describes the optional features of PCRE that can be selected when -the library is compiled. They are all selected, or deselected, by providing -options to the <b>configure</b> script which is run before the <b>make</b> -command. The complete list of options for <b>configure</b> (which includes the -standard ones such as the selection of the installation directory) can be -obtained by running -</P> -<P> -<pre> - ./configure --help -</PRE> -</P> -<P> -The following sections describe certain options whose names begin with --enable -or --disable. These settings specify changes to the defaults for the -<b>configure</b> command. Because of the way that <b>configure</b> works, ---enable and --disable always come in pairs, so the complementary option always -exists as well, but as it specifies the default, it is not described. -</P> -<br><a name="SEC2" href="#TOC1">UTF-8 SUPPORT</a><br> -<P> -To build PCRE with support for UTF-8 character strings, add -</P> -<P> -<pre> - --enable-utf8 -</PRE> -</P> -<P> -to the <b>configure</b> command. Of itself, this does not make PCRE treat -strings as UTF-8. As well as compiling PCRE with this option, you also have -have to set the PCRE_UTF8 option when you call the <b>pcre_compile()</b> -function. -</P> -<br><a name="SEC3" href="#TOC1">CODE VALUE OF NEWLINE</a><br> -<P> -By default, PCRE treats character 10 (linefeed) as the newline character. This -is the normal newline character on Unix-like systems. You can compile PCRE to -use character 13 (carriage return) instead by adding -</P> -<P> -<pre> - --enable-newline-is-cr -</PRE> -</P> -<P> -to the <b>configure</b> command. For completeness there is also a ---enable-newline-is-lf option, which explicitly specifies linefeed as the -newline character. -</P> -<br><a name="SEC4" href="#TOC1">BUILDING SHARED AND STATIC LIBRARIES</a><br> -<P> -The PCRE building process uses <b>libtool</b> to build both shared and static -Unix libraries by default. You can suppress one of these by adding one of -</P> -<P> -<pre> - --disable-shared - --disable-static -</PRE> -</P> -<P> -to the <b>configure</b> command, as required. -</P> -<br><a name="SEC5" href="#TOC1">POSIX MALLOC USAGE</a><br> -<P> -When PCRE is called through the POSIX interface (see the <b>pcreposix</b> -documentation), additional working storage is required for holding the pointers -to capturing substrings because PCRE requires three integers per substring, -whereas the POSIX interface provides only two. If the number of expected -substrings is small, the wrapper function uses space on the stack, because this -is faster than using <b>malloc()</b> for each call. The default threshold above -which the stack is no longer used is 10; it can be changed by adding a setting -such as -</P> -<P> -<pre> - --with-posix-malloc-threshold=20 -</PRE> -</P> -<P> -to the <b>configure</b> command. -</P> -<br><a name="SEC6" href="#TOC1">LIMITING PCRE RESOURCE USAGE</a><br> -<P> -Internally, PCRE has a function called <b>match()</b> which it calls repeatedly -(possibly recursively) when performing a matching operation. By limiting the -number of times this function may be called, a limit can be placed on the -resources used by a single call to <b>pcre_exec()</b>. The limit can be changed -at run time, as described in the <b>pcreapi</b> documentation. The default is 10 -million, but this can be changed by adding a setting such as -</P> -<P> -<pre> - --with-match-limit=500000 -</PRE> -</P> -<P> -to the <b>configure</b> command. -</P> -<br><a name="SEC7" href="#TOC1">HANDLING VERY LARGE PATTERNS</a><br> -<P> -Within a compiled pattern, offset values are used to point from one part to -another (for example, from an opening parenthesis to an alternation -metacharacter). By default two-byte values are used for these offsets, leading -to a maximum size for a compiled pattern of around 64K. This is sufficient to -handle all but the most gigantic patterns. Nevertheless, some people do want to -process enormous patterns, so it is possible to compile PCRE to use three-byte -or four-byte offsets by adding a setting such as -</P> -<P> -<pre> - --with-link-size=3 -</PRE> -</P> -<P> -to the <b>configure</b> command. The value given must be 2, 3, or 4. Using -longer offsets slows down the operation of PCRE because it has to load -additional bytes when handling them. -</P> -<P> -If you build PCRE with an increased link size, test 2 (and test 5 if you are -using UTF-8) will fail. Part of the output of these tests is a representation -of the compiled pattern, and this changes with the link size. -</P> -<br><a name="SEC8" href="#TOC1">AVOIDING EXCESSIVE STACK USAGE</a><br> -<P> -PCRE implements backtracking while matching by making recursive calls to an -internal function called <b>match()</b>. In environments where the size of the -stack is limited, this can severely limit PCRE's operation. (The Unix -environment does not usually suffer from this problem.) An alternative approach -that uses memory from the heap to remember data, instead of using recursive -function calls, has been implemented to work round this problem. If you want to -build a version of PCRE that works this way, add -</P> -<P> -<pre> - --disable-stack-for-recursion -</PRE> -</P> -<P> -to the <b>configure</b> command. With this configuration, PCRE will use the -<b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> variables to call memory -management functions. Separate functions are provided because the usage is very -predictable: the block sizes requested are always the same, and the blocks are -always freed in reverse order. A calling program might be able to implement -optimized functions that perform better than the standard <b>malloc()</b> and -<b>free()</b> functions. PCRE runs noticeably more slowly when built in this -way. -</P> -<br><a name="SEC9" href="#TOC1">USING EBCDIC CODE</a><br> -<P> -PCRE assumes by default that it will run in an environment where the character -code is ASCII (or UTF-8, which is a superset of ASCII). PCRE can, however, be -compiled to run in an EBCDIC environment by adding -</P> -<P> -<pre> - --enable-ebcdic -</PRE> -</P> -<P> -to the <b>configure</b> command. -</P> -<P> -Last updated: 09 December 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcrecallout.html b/external-libs/pcre/doc/html/pcrecallout.html deleted file mode 100644 index f4b7104e..00000000 --- a/external-libs/pcre/doc/html/pcrecallout.html +++ /dev/null @@ -1,117 +0,0 @@ -<html> -<head> -<title>pcrecallout specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">PCRE CALLOUTS</a> -<li><a name="TOC2" href="#SEC2">RETURN VALUES</a> -</ul> -<br><a name="SEC1" href="#TOC1">PCRE CALLOUTS</a><br> -<P> -<b>int (*pcre_callout)(pcre_callout_block *);</b> -</P> -<P> -PCRE provides a feature called "callout", which is a means of temporarily -passing control to the caller of PCRE in the middle of pattern matching. The -caller of PCRE provides an external function by putting its entry point in the -global variable <i>pcre_callout</i>. By default, this variable contains NULL, -which disables all calling out. -</P> -<P> -Within a regular expression, (?C) indicates the points at which the external -function is to be called. Different callout points can be identified by putting -a number less than 256 after the letter C. The default value is zero. -For example, this pattern has two callout points: -</P> -<P> -<pre> - (?C1)\dabc(?C2)def -</PRE> -</P> -<P> -During matching, when PCRE reaches a callout point (and <i>pcre_callout</i> is -set), the external function is called. Its only argument is a pointer to a -<b>pcre_callout</b> block. This contains the following variables: -</P> -<P> -<pre> - int <i>version</i>; - int <i>callout_number</i>; - int *<i>offset_vector</i>; - const char *<i>subject</i>; - int <i>subject_length</i>; - int <i>start_match</i>; - int <i>current_position</i>; - int <i>capture_top</i>; - int <i>capture_last</i>; - void *<i>callout_data</i>; -</PRE> -</P> -<P> -The <i>version</i> field is an integer containing the version number of the -block format. The current version is zero. The version number may change in -future if additional fields are added, but the intention is never to remove any -of the existing fields. -</P> -<P> -The <i>callout_number</i> field contains the number of the callout, as compiled -into the pattern (that is, the number after ?C). -</P> -<P> -The <i>offset_vector</i> field is a pointer to the vector of offsets that was -passed by the caller to <b>pcre_exec()</b>. The contents can be inspected in -order to extract substrings that have been matched so far, in the same way as -for extracting substrings after a match has completed. -</P> -<P> -The <i>subject</i> and <i>subject_length</i> fields contain copies the values -that were passed to <b>pcre_exec()</b>. -</P> -<P> -The <i>start_match</i> field contains the offset within the subject at which the -current match attempt started. If the pattern is not anchored, the callout -function may be called several times for different starting points. -</P> -<P> -The <i>current_position</i> field contains the offset within the subject of the -current match pointer. -</P> -<P> -The <i>capture_top</i> field contains one more than the number of the highest -numbered captured substring so far. If no substrings have been captured, -the value of <i>capture_top</i> is one. -</P> -<P> -The <i>capture_last</i> field contains the number of the most recently captured -substring. -</P> -<P> -The <i>callout_data</i> field contains a value that is passed to -<b>pcre_exec()</b> by the caller specifically so that it can be passed back in -callouts. It is passed in the <i>pcre_callout</i> field of the <b>pcre_extra</b> -data structure. If no such data was passed, the value of <i>callout_data</i> in -a <b>pcre_callout</b> block is NULL. There is a description of the -<b>pcre_extra</b> structure in the <b>pcreapi</b> documentation. -</P> -<br><a name="SEC2" href="#TOC1">RETURN VALUES</a><br> -<P> -The callout function returns an integer. If the value is zero, matching -proceeds as normal. If the value is greater than zero, matching fails at the -current point, but backtracking to test other possibilities goes ahead, just as -if a lookahead assertion had failed. If the value is less than zero, the match -is abandoned, and <b>pcre_exec()</b> returns the value. -</P> -<P> -Negative values should normally be chosen from the set of PCRE_ERROR_xxx -values. In particular, PCRE_ERROR_NOMATCH forces a standard "no match" failure. -The error number PCRE_ERROR_CALLOUT is reserved for use by callout functions; -it will never be used by PCRE itself. -</P> -<P> -Last updated: 21 January 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcrecompat.html b/external-libs/pcre/doc/html/pcrecompat.html deleted file mode 100644 index 1ec22038..00000000 --- a/external-libs/pcre/doc/html/pcrecompat.html +++ /dev/null @@ -1,136 +0,0 @@ -<html> -<head> -<title>pcrecompat specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">DIFFERENCES FROM PERL</a> -</ul> -<br><a name="SEC1" href="#TOC1">DIFFERENCES FROM PERL</a><br> -<P> -This document describes the differences in the ways that PCRE and Perl handle -regular expressions. The differences described here are with respect to Perl -5.8. -</P> -<P> -1. PCRE does not have full UTF-8 support. Details of what it does have are -given in the -<a href="pcre.html#utf8support">section on UTF-8 support</a> -in the main -<a href="pcre.html"><b>pcre</b></a> -page. -</P> -<P> -2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl permits -them, but they do not mean what you might think. For example, (?!a){3} does -not assert that the next three characters are not "a". It just asserts that the -next character is not "a" three times. -</P> -<P> -3. Capturing subpatterns that occur inside negative lookahead assertions are -counted, but their entries in the offsets vector are never set. Perl sets its -numerical variables from any such patterns that are matched before the -assertion fails to match something (thereby succeeding), but only if the -negative lookahead assertion contains just one branch. -</P> -<P> -4. Though binary zero characters are supported in the subject string, they are -not allowed in a pattern string because it is passed as a normal C string, -terminated by zero. The escape sequence "\0" can be used in the pattern to -represent a binary zero. -</P> -<P> -5. The following Perl escape sequences are not supported: \l, \u, \L, -\U, \P, \p, \N, and \X. In fact these are implemented by Perl's general -string-handling and are not part of its pattern matching engine. If any of -these are encountered by PCRE, an error is generated. -</P> -<P> -6. PCRE does support the \Q...\E escape for quoting substrings. Characters in -between are treated as literals. This is slightly different from Perl in that $ -and @ are also handled as literals inside the quotes. In Perl, they cause -variable interpolation (but of course PCRE does not have variables). Note the -following examples: -</P> -<P> -<pre> - Pattern PCRE matches Perl matches -</PRE> -</P> -<P> -<pre> - \Qabc$xyz\E abc$xyz abc followed by the - contents of $xyz - \Qabc\$xyz\E abc\$xyz abc\$xyz - \Qabc\E\$\Qxyz\E abc$xyz abc$xyz -</PRE> -</P> -<P> -The \Q...\E sequence is recognized both inside and outside character classes. -</P> -<P> -7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code}) -constructions. However, there is some experimental support for recursive -patterns using the non-Perl items (?R), (?number) and (?P>name). Also, the PCRE -"callout" feature allows an external function to be called during pattern -matching. -</P> -<P> -8. There are some differences that are concerned with the settings of captured -strings when part of a pattern is repeated. For example, matching "aba" against -the pattern /^(a(b)?)+$/ in Perl leaves $2 unset, but in PCRE it is set to "b". -</P> -<P> -9. PCRE provides some extensions to the Perl regular expression facilities: -</P> -<P> -(a) Although lookbehind assertions must match fixed length strings, each -alternative branch of a lookbehind assertion can match a different length of -string. Perl requires them all to have the same length. -</P> -<P> -(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ -meta-character matches only at the very end of the string. -</P> -<P> -© If PCRE_EXTRA is set, a backslash followed by a letter with no special -meaning is faulted. -</P> -<P> -(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is -inverted, that is, by default they are not greedy, but if followed by a -question mark they are. -</P> -<P> -(e) PCRE_ANCHORED can be used to force a pattern to be tried only at the first -matching position in the subject string. -</P> -<P> -(f) The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAPTURE -options for <b>pcre_exec()</b> have no Perl equivalents. -</P> -<P> -(g) The (?R), (?number), and (?P>name) constructs allows for recursive pattern -matching (Perl can do this using the (?p{code}) construct, which PCRE cannot -support.) -</P> -<P> -(h) PCRE supports named capturing substrings, using the Python syntax. -</P> -<P> -(i) PCRE supports the possessive quantifier "++" syntax, taken from Sun's Java -package. -</P> -<P> -(j) The (R) condition, for testing recursion, is a PCRE extension. -</P> -<P> -(k) The callout facility is PCRE-specific. -</P> -<P> -Last updated: 09 December 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcregrep.html b/external-libs/pcre/doc/html/pcregrep.html deleted file mode 100644 index a76cac21..00000000 --- a/external-libs/pcre/doc/html/pcregrep.html +++ /dev/null @@ -1,153 +0,0 @@ -<html> -<head> -<title>pcregrep specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> -<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> -<li><a name="TOC3" href="#SEC3">OPTIONS</a> -<li><a name="TOC4" href="#SEC4">LONG OPTIONS</a> -<li><a name="TOC5" href="#SEC5">DIAGNOSTICS</a> -<li><a name="TOC6" href="#SEC6">AUTHOR</a> -</ul> -<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> -<P> -<b>pcregrep [-Vcfhilnrsuvx] [long options] [pattern] [file1 file2 ...]</b> -</P> -<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> -<P> -<b>pcregrep</b> searches files for character patterns, in the same way as other -grep commands do, but it uses the PCRE regular expression library to support -patterns that are compatible with the regular expressions of Perl 5. See -<a href="pcrepattern.html"><b>pcrepattern</b></a> -for a full description of syntax and semantics of the regular expressions that -PCRE supports. -</P> -<P> -A pattern must be specified on the command line unless the <b>-f</b> option is -used (see below). -</P> -<P> -If no files are specified, <b>pcregrep</b> reads the standard input. By default, -each line that matches the pattern is copied to the standard output, and if -there is more than one file, the file name is printed before each line of -output. However, there are options that can change how <b>pcregrep</b> behaves. -</P> -<P> -Lines are limited to BUFSIZ characters. BUFSIZ is defined in <b><stdio.h></b>. -The newline character is removed from the end of each line before it is matched -against the pattern. -</P> -<br><a name="SEC3" href="#TOC1">OPTIONS</a><br> -<P> -<b>-V</b> -Write the version number of the PCRE library being used to the standard error -stream. -</P> -<P> -<b>-c</b> -Do not print individual lines; instead just print a count of the number of -lines that would otherwise have been printed. If several files are given, a -count is printed for each of them. -</P> -<P> -<b>-f</b><i>filename</i> -Read a number of patterns from the file, one per line, and match all of them -against each line of input. A line is output if any of the patterns match it. -When <b>-f</b> is used, no pattern is taken from the command line; all arguments -are treated as file names. There is a maximum of 100 patterns. Trailing white -space is removed, and blank lines are ignored. An empty file contains no -patterns and therefore matches nothing. -</P> -<P> -<b>-h</b> -Suppress printing of filenames when searching multiple files. -</P> -<P> -<b>-i</b> -Ignore upper/lower case distinctions during comparisons. -</P> -<P> -<b>-l</b> -Instead of printing lines from the files, just print the names of the files -containing lines that would have been printed. Each file name is printed -once, on a separate line. -</P> -<P> -<b>-n</b> -Precede each line by its line number in the file. -</P> -<P> -<b>-r</b> -If any file is a directory, recursively scan the files it contains. Without -<b>-r</b> a directory is scanned as a normal file. -</P> -<P> -<b>-s</b> -Work silently, that is, display nothing except error messages. -The exit status indicates whether any matches were found. -</P> -<P> -<b>-u</b> -Operate in UTF-8 mode. This option is available only if PCRE has been compiled -with UTF-8 support. Both the pattern and each subject line are assumed to be -valid strings of UTF-8 characters. -</P> -<P> -<b>-v</b> -Invert the sense of the match, so that lines which do <i>not</i> match the -pattern are now the ones that are found. -</P> -<P> -<b>-x</b> -Force the pattern to be anchored (it must start matching at the beginning of -the line) and in addition, require it to match the entire line. This is -equivalent to having ^ and $ characters at the start and end of each -alternative branch in the regular expression. -</P> -<br><a name="SEC4" href="#TOC1">LONG OPTIONS</a><br> -<P> -Long forms of all the options are available, as in GNU grep. They are shown in -the following table: -</P> -<P> -<pre> - -c --count - -h --no-filename - -i --ignore-case - -l --files-with-matches - -n --line-number - -r --recursive - -s --no-messages - -u --utf-8 - -V --version - -v --invert-match - -x --line-regex - -x --line-regexp -</PRE> -</P> -<P> -In addition, --file=<i>filename</i> is equivalent to -f<i>filename</i>, and ---help shows the list of options and then exits. -</P> -<br><a name="SEC5" href="#TOC1">DIAGNOSTICS</a><br> -<P> -Exit status is 0 if any matches were found, 1 if no matches were found, and 2 -for syntax errors or inacessible files (even if matches were found). -</P> -<br><a name="SEC6" href="#TOC1">AUTHOR</a><br> -<P> -Philip Hazel <ph10@cam.ac.uk> -<br> -University Computing Service -<br> -Cambridge CB2 3QG, England. -</P> -<P> -Last updated: 03 February 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcrepattern.html b/external-libs/pcre/doc/html/pcrepattern.html deleted file mode 100644 index 65abcc21..00000000 --- a/external-libs/pcre/doc/html/pcrepattern.html +++ /dev/null @@ -1,1607 +0,0 @@ -<html> -<head> -<title>pcrepattern specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION DETAILS</a> -<li><a name="TOC2" href="#SEC2">BACKSLASH</a> -<li><a name="TOC3" href="#SEC3">CIRCUMFLEX AND DOLLAR</a> -<li><a name="TOC4" href="#SEC4">FULL STOP (PERIOD, DOT)</a> -<li><a name="TOC5" href="#SEC5">MATCHING A SINGLE BYTE</a> -<li><a name="TOC6" href="#SEC6">SQUARE BRACKETS</a> -<li><a name="TOC7" href="#SEC7">POSIX CHARACTER CLASSES</a> -<li><a name="TOC8" href="#SEC8">VERTICAL BAR</a> -<li><a name="TOC9" href="#SEC9">INTERNAL OPTION SETTING</a> -<li><a name="TOC10" href="#SEC10">SUBPATTERNS</a> -<li><a name="TOC11" href="#SEC11">NAMED SUBPATTERNS</a> -<li><a name="TOC12" href="#SEC12">REPETITION</a> -<li><a name="TOC13" href="#SEC13">ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS</a> -<li><a name="TOC14" href="#SEC14">BACK REFERENCES</a> -<li><a name="TOC15" href="#SEC15">ASSERTIONS</a> -<li><a name="TOC16" href="#SEC16">CONDITIONAL SUBPATTERNS</a> -<li><a name="TOC17" href="#SEC17">COMMENTS</a> -<li><a name="TOC18" href="#SEC18">RECURSIVE PATTERNS</a> -<li><a name="TOC19" href="#SEC19">SUBPATTERNS AS SUBROUTINES</a> -<li><a name="TOC20" href="#SEC20">CALLOUTS</a> -</ul> -<br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION DETAILS</a><br> -<P> -The syntax and semantics of the regular expressions supported by PCRE are -described below. Regular expressions are also described in the Perl -documentation and in a number of other books, some of which have copious -examples. Jeffrey Friedl's "Mastering Regular Expressions", published by -O'Reilly, covers them in great detail. The description here is intended as -reference documentation. -</P> -<P> -The basic operation of PCRE is on strings of bytes. However, there is also -support for UTF-8 character strings. To use this support you must build PCRE to -include UTF-8 support, and then call <b>pcre_compile()</b> with the PCRE_UTF8 -option. How this affects the pattern matching is mentioned in several places -below. There is also a summary of UTF-8 features in the -<a href="pcre.html#utf8support">section on UTF-8 support</a> -in the main -<a href="pcre.html"><b>pcre</b></a> -page. -</P> -<P> -A regular expression is a pattern that is matched against a subject string from -left to right. Most characters stand for themselves in a pattern, and match the -corresponding characters in the subject. As a trivial example, the pattern -</P> -<P> -<pre> - The quick brown fox -</PRE> -</P> -<P> -matches a portion of a subject string that is identical to itself. The power of -regular expressions comes from the ability to include alternatives and -repetitions in the pattern. These are encoded in the pattern by the use of -<i>meta-characters</i>, which do not stand for themselves but instead are -interpreted in some special way. -</P> -<P> -There are two different sets of meta-characters: those that are recognized -anywhere in the pattern except within square brackets, and those that are -recognized in square brackets. Outside square brackets, the meta-characters are -as follows: -</P> -<P> -<pre> - \ general escape character with several uses - ^ assert start of string (or line, in multiline mode) - $ assert end of string (or line, in multiline mode) - . match any character except newline (by default) - [ start character class definition - | start of alternative branch - ( start subpattern - ) end subpattern - ? extends the meaning of ( - also 0 or 1 quantifier - also quantifier minimizer - * 0 or more quantifier - + 1 or more quantifier - also "possessive quantifier" - { start min/max quantifier -</PRE> -</P> -<P> -Part of a pattern that is in square brackets is called a "character class". In -a character class the only meta-characters are: -</P> -<P> -<pre> - \ general escape character - ^ negate the class, but only if the first character - - indicates character range - [ POSIX character class (only if followed by POSIX - syntax) - ] terminates the character class -</PRE> -</P> -<P> -The following sections describe the use of each of the meta-characters. -</P> -<br><a name="SEC2" href="#TOC1">BACKSLASH</a><br> -<P> -The backslash character has several uses. Firstly, if it is followed by a -non-alphameric character, it takes away any special meaning that character may -have. This use of backslash as an escape character applies both inside and -outside character classes. -</P> -<P> -For example, if you want to match a * character, you write \* in the pattern. -This escaping action applies whether or not the following character would -otherwise be interpreted as a meta-character, so it is always safe to precede a -non-alphameric with backslash to specify that it stands for itself. In -particular, if you want to match a backslash, you write \\. -</P> -<P> -If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the -pattern (other than in a character class) and characters between a # outside -a character class and the next newline character are ignored. An escaping -backslash can be used to include a whitespace or # character as part of the -pattern. -</P> -<P> -If you want to remove the special meaning from a sequence of characters, you -can do so by putting them between \Q and \E. This is different from Perl in -that $ and @ are handled as literals in \Q...\E sequences in PCRE, whereas in -Perl, $ and @ cause variable interpolation. Note the following examples: -</P> -<P> -<pre> - Pattern PCRE matches Perl matches -</PRE> -</P> -<P> -<pre> - \Qabc$xyz\E abc$xyz abc followed by the - contents of $xyz - \Qabc\$xyz\E abc\$xyz abc\$xyz - \Qabc\E\$\Qxyz\E abc$xyz abc$xyz -</PRE> -</P> -<P> -The \Q...\E sequence is recognized both inside and outside character classes. -</P> -<P> -A second use of backslash provides a way of encoding non-printing characters -in patterns in a visible manner. There is no restriction on the appearance of -non-printing characters, apart from the binary zero that terminates a pattern, -but when a pattern is being prepared by text editing, it is usually easier to -use one of the following escape sequences than the binary character it -represents: -</P> -<P> -<pre> - \a alarm, that is, the BEL character (hex 07) - \cx "control-x", where x is any character - \e escape (hex 1B) - \f formfeed (hex 0C) - \n newline (hex 0A) - \r carriage return (hex 0D) - \t tab (hex 09) - \ddd character with octal code ddd, or backreference - \xhh character with hex code hh - \x{hhh..} character with hex code hhh... (UTF-8 mode only) -</PRE> -</P> -<P> -The precise effect of \cx is as follows: if x is a lower case letter, it -is converted to upper case. Then bit 6 of the character (hex 40) is inverted. -Thus \cz becomes hex 1A, but \c{ becomes hex 3B, while \c; becomes hex -7B. -</P> -<P> -After \x, from zero to two hexadecimal digits are read (letters can be in -upper or lower case). In UTF-8 mode, any number of hexadecimal digits may -appear between \x{ and }, but the value of the character code must be less -than 2**31 (that is, the maximum hexadecimal value is 7FFFFFFF). If characters -other than hexadecimal digits appear between \x{ and }, or if there is no -terminating }, this form of escape is not recognized. Instead, the initial -\x will be interpreted as a basic hexadecimal escape, with no following -digits, giving a byte whose value is zero. -</P> -<P> -Characters whose value is less than 256 can be defined by either of the two -syntaxes for \x when PCRE is in UTF-8 mode. There is no difference in the -way they are handled. For example, \xdc is exactly the same as \x{dc}. -</P> -<P> -After \0 up to two further octal digits are read. In both cases, if there -are fewer than two digits, just those that are present are used. Thus the -sequence \0\x\07 specifies two binary zeros followed by a BEL character -(code value 7). Make sure you supply two digits after the initial zero if the -character that follows is itself an octal digit. -</P> -<P> -The handling of a backslash followed by a digit other than 0 is complicated. -Outside a character class, PCRE reads it and any following digits as a decimal -number. If the number is less than 10, or if there have been at least that many -previous capturing left parentheses in the expression, the entire sequence is -taken as a <i>back reference</i>. A description of how this works is given -later, following the discussion of parenthesized subpatterns. -</P> -<P> -Inside a character class, or if the decimal number is greater than 9 and there -have not been that many capturing subpatterns, PCRE re-reads up to three octal -digits following the backslash, and generates a single byte from the least -significant 8 bits of the value. Any subsequent digits stand for themselves. -For example: -</P> -<P> -<pre> - \040 is another way of writing a space - \40 is the same, provided there are fewer than 40 - previous capturing subpatterns - \7 is always a back reference - \11 might be a back reference, or another way of - writing a tab - \011 is always a tab - \0113 is a tab followed by the character "3" - \113 might be a back reference, otherwise the - character with octal code 113 - \377 might be a back reference, otherwise - the byte consisting entirely of 1 bits - \81 is either a back reference, or a binary zero - followed by the two characters "8" and "1" -</PRE> -</P> -<P> -Note that octal values of 100 or greater must not be introduced by a leading -zero, because no more than three octal digits are ever read. -</P> -<P> -All the sequences that define a single byte value or a single UTF-8 character -(in UTF-8 mode) can be used both inside and outside character classes. In -addition, inside a character class, the sequence \b is interpreted as the -backspace character (hex 08). Outside a character class it has a different -meaning (see below). -</P> -<P> -The third use of backslash is for specifying generic character types: -</P> -<P> -<pre> - \d any decimal digit - \D any character that is not a decimal digit - \s any whitespace character - \S any character that is not a whitespace character - \w any "word" character - \W any "non-word" character -</PRE> -</P> -<P> -Each pair of escape sequences partitions the complete set of characters into -two disjoint sets. Any given character matches one, and only one, of each pair. -</P> -<P> -In UTF-8 mode, characters with values greater than 255 never match \d, \s, or -\w, and always match \D, \S, and \W. -</P> -<P> -For compatibility with Perl, \s does not match the VT character (code 11). -This makes it different from the the POSIX "space" class. The \s characters -are HT (9), LF (10), FF (12), CR (13), and space (32). -</P> -<P> -A "word" character is any letter or digit or the underscore character, that is, -any character which can be part of a Perl "word". The definition of letters and -digits is controlled by PCRE's character tables, and may vary if locale- -specific matching is taking place (see -<a href="pcreapi.html#localesupport">"Locale support"</a> -in the -<a href="pcreapi.html"><b>pcreapi</b></a> -page). For example, in the "fr" (French) locale, some character codes greater -than 128 are used for accented letters, and these are matched by \w. -</P> -<P> -These character type sequences can appear both inside and outside character -classes. They each match one character of the appropriate type. If the current -matching point is at the end of the subject string, all of them fail, since -there is no character to match. -</P> -<P> -The fourth use of backslash is for certain simple assertions. An assertion -specifies a condition that has to be met at a particular point in a match, -without consuming any characters from the subject string. The use of -subpatterns for more complicated assertions is described below. The backslashed -assertions are -</P> -<P> -<pre> - \b matches at a word boundary - \B matches when not at a word boundary - \A matches at start of subject - \Z matches at end of subject or before newline at end - \z matches at end of subject - \G matches at first matching position in subject -</PRE> -</P> -<P> -These assertions may not appear in character classes (but note that \b has a -different meaning, namely the backspace character, inside a character class). -</P> -<P> -A word boundary is a position in the subject string where the current character -and the previous character do not both match \w or \W (i.e. one matches -\w and the other matches \W), or the start or end of the string if the -first or last character matches \w, respectively. -</P> -<P> -The \A, \Z, and \z assertions differ from the traditional circumflex and -dollar (described below) in that they only ever match at the very start and end -of the subject string, whatever options are set. Thus, they are independent of -multiline mode. -</P> -<P> -They are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options. If the -<i>startoffset</i> argument of <b>pcre_exec()</b> is non-zero, indicating that -matching is to start at a point other than the beginning of the subject, \A -can never match. The difference between \Z and \z is that \Z matches before -a newline that is the last character of the string as well as at the end of the -string, whereas \z matches only at the end. -</P> -<P> -The \G assertion is true only when the current matching position is at the -start point of the match, as specified by the <i>startoffset</i> argument of -<b>pcre_exec()</b>. It differs from \A when the value of <i>startoffset</i> is -non-zero. By calling <b>pcre_exec()</b> multiple times with appropriate -arguments, you can mimic Perl's /g option, and it is in this kind of -implementation where \G can be useful. -</P> -<P> -Note, however, that PCRE's interpretation of \G, as the start of the current -match, is subtly different from Perl's, which defines it as the end of the -previous match. In Perl, these can be different when the previously matched -string was empty. Because PCRE does just one match at a time, it cannot -reproduce this behaviour. -</P> -<P> -If all the alternatives of a pattern begin with \G, the expression is anchored -to the starting match position, and the "anchored" flag is set in the compiled -regular expression. -</P> -<br><a name="SEC3" href="#TOC1">CIRCUMFLEX AND DOLLAR</a><br> -<P> -Outside a character class, in the default matching mode, the circumflex -character is an assertion which is true only if the current matching point is -at the start of the subject string. If the <i>startoffset</i> argument of -<b>pcre_exec()</b> is non-zero, circumflex can never match if the PCRE_MULTILINE -option is unset. Inside a character class, circumflex has an entirely different -meaning (see below). -</P> -<P> -Circumflex need not be the first character of the pattern if a number of -alternatives are involved, but it should be the first thing in each alternative -in which it appears if the pattern is ever to match that branch. If all -possible alternatives start with a circumflex, that is, if the pattern is -constrained to match only at the start of the subject, it is said to be an -"anchored" pattern. (There are also other constructs that can cause a pattern -to be anchored.) -</P> -<P> -A dollar character is an assertion which is true only if the current matching -point is at the end of the subject string, or immediately before a newline -character that is the last character in the string (by default). Dollar need -not be the last character of the pattern if a number of alternatives are -involved, but it should be the last item in any branch in which it appears. -Dollar has no special meaning in a character class. -</P> -<P> -The meaning of dollar can be changed so that it matches only at the very end of -the string, by setting the PCRE_DOLLAR_ENDONLY option at compile time. This -does not affect the \Z assertion. -</P> -<P> -The meanings of the circumflex and dollar characters are changed if the -PCRE_MULTILINE option is set. When this is the case, they match immediately -after and immediately before an internal newline character, respectively, in -addition to matching at the start and end of the subject string. For example, -the pattern /^abc$/ matches the subject string "def\nabc" in multiline mode, -but not otherwise. Consequently, patterns that are anchored in single line mode -because all branches start with ^ are not anchored in multiline mode, and a -match for circumflex is possible when the <i>startoffset</i> argument of -<b>pcre_exec()</b> is non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if -PCRE_MULTILINE is set. -</P> -<P> -Note that the sequences \A, \Z, and \z can be used to match the start and -end of the subject in both modes, and if all branches of a pattern start with -\A it is always anchored, whether PCRE_MULTILINE is set or not. -</P> -<br><a name="SEC4" href="#TOC1">FULL STOP (PERIOD, DOT)</a><br> -<P> -Outside a character class, a dot in the pattern matches any one character in -the subject, including a non-printing character, but not (by default) newline. -In UTF-8 mode, a dot matches any UTF-8 character, which might be more than one -byte long, except (by default) for newline. If the PCRE_DOTALL option is set, -dots match newlines as well. The handling of dot is entirely independent of the -handling of circumflex and dollar, the only relationship being that they both -involve newline characters. Dot has no special meaning in a character class. -</P> -<br><a name="SEC5" href="#TOC1">MATCHING A SINGLE BYTE</a><br> -<P> -Outside a character class, the escape sequence \C matches any one byte, both -in and out of UTF-8 mode. Unlike a dot, it always matches a newline. The -feature is provided in Perl in order to match individual bytes in UTF-8 mode. -Because it breaks up UTF-8 characters into individual bytes, what remains in -the string may be a malformed UTF-8 string. For this reason it is best avoided. -</P> -<P> -PCRE does not allow \C to appear in lookbehind assertions (see below), because -in UTF-8 mode it makes it impossible to calculate the length of the lookbehind. -</P> -<br><a name="SEC6" href="#TOC1">SQUARE BRACKETS</a><br> -<P> -An opening square bracket introduces a character class, terminated by a closing -square bracket. A closing square bracket on its own is not special. If a -closing square bracket is required as a member of the class, it should be the -first data character in the class (after an initial circumflex, if present) or -escaped with a backslash. -</P> -<P> -A character class matches a single character in the subject. In UTF-8 mode, the -character may occupy more than one byte. A matched character must be in the set -of characters defined by the class, unless the first character in the class -definition is a circumflex, in which case the subject character must not be in -the set defined by the class. If a circumflex is actually required as a member -of the class, ensure it is not the first character, or escape it with a -backslash. -</P> -<P> -For example, the character class [aeiou] matches any lower case vowel, while -[^aeiou] matches any character that is not a lower case vowel. Note that a -circumflex is just a convenient notation for specifying the characters which -are in the class by enumerating those that are not. It is not an assertion: it -still consumes a character from the subject string, and fails if the current -pointer is at the end of the string. -</P> -<P> -In UTF-8 mode, characters with values greater than 255 can be included in a -class as a literal string of bytes, or by using the \x{ escaping mechanism. -</P> -<P> -When caseless matching is set, any letters in a class represent both their -upper case and lower case versions, so for example, a caseless [aeiou] matches -"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a -caseful version would. PCRE does not support the concept of case for characters -with values greater than 255. -</P> -<P> -The newline character is never treated in any special way in character classes, -whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE options is. A class -such as [^a] will always match a newline. -</P> -<P> -The minus (hyphen) character can be used to specify a range of characters in a -character class. For example, [d-m] matches any letter between d and m, -inclusive. If a minus character is required in a class, it must be escaped with -a backslash or appear in a position where it cannot be interpreted as -indicating a range, typically as the first or last character in the class. -</P> -<P> -It is not possible to have the literal character "]" as the end character of a -range. A pattern such as [W-]46] is interpreted as a class of two characters -("W" and "-") followed by a literal string "46]", so it would match "W46]" or -"-46]". However, if the "]" is escaped with a backslash it is interpreted as -the end of range, so [W-\]46] is interpreted as a single class containing a -range followed by two separate characters. The octal or hexadecimal -representation of "]" can also be used to end a range. -</P> -<P> -Ranges operate in the collating sequence of character values. They can also be -used for characters specified numerically, for example [\000-\037]. In UTF-8 -mode, ranges can include characters whose values are greater than 255, for -example [\x{100}-\x{2ff}]. -</P> -<P> -If a range that includes letters is used when caseless matching is set, it -matches the letters in either case. For example, [W-c] is equivalent to -[][\^_`wxyzabc], matched caselessly, and if character tables for the "fr" -locale are in use, [\xc8-\xcb] matches accented E characters in both cases. -</P> -<P> -The character types \d, \D, \s, \S, \w, and \W may also appear in a -character class, and add the characters that they match to the class. For -example, [\dABCDEF] matches any hexadecimal digit. A circumflex can -conveniently be used with the upper case character types to specify a more -restricted set of characters than the matching lower case type. For example, -the class [^\W_] matches any letter or digit, but not underscore. -</P> -<P> -All non-alphameric characters other than \, -, ^ (at the start) and the -terminating ] are non-special in character classes, but it does no harm if they -are escaped. -</P> -<br><a name="SEC7" href="#TOC1">POSIX CHARACTER CLASSES</a><br> -<P> -Perl supports the POSIX notation for character classes, which uses names -enclosed by [: and :] within the enclosing square brackets. PCRE also supports -this notation. For example, -</P> -<P> -<pre> - [01[:alpha:]%] -</PRE> -</P> -<P> -matches "0", "1", any alphabetic character, or "%". The supported class names -are -</P> -<P> -<pre> - alnum letters and digits - alpha letters - ascii character codes 0 - 127 - blank space or tab only - cntrl control characters - digit decimal digits (same as \d) - graph printing characters, excluding space - lower lower case letters - print printing characters, including space - punct printing characters, excluding letters and digits - space white space (not quite the same as \s) - upper upper case letters - word "word" characters (same as \w) - xdigit hexadecimal digits -</PRE> -</P> -<P> -The "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13), and -space (32). Notice that this list includes the VT character (code 11). This -makes "space" different to \s, which does not include VT (for Perl -compatibility). -</P> -<P> -The name "word" is a Perl extension, and "blank" is a GNU extension from Perl -5.8. Another Perl extension is negation, which is indicated by a ^ character -after the colon. For example, -</P> -<P> -<pre> - [12[:^digit:]] -</PRE> -</P> -<P> -matches "1", "2", or any non-digit. PCRE (and Perl) also recognize the POSIX -syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not -supported, and an error is given if they are encountered. -</P> -<P> -In UTF-8 mode, characters with values greater than 255 do not match any of -the POSIX character classes. -</P> -<br><a name="SEC8" href="#TOC1">VERTICAL BAR</a><br> -<P> -Vertical bar characters are used to separate alternative patterns. For example, -the pattern -</P> -<P> -<pre> - gilbert|sullivan -</PRE> -</P> -<P> -matches either "gilbert" or "sullivan". Any number of alternatives may appear, -and an empty alternative is permitted (matching the empty string). -The matching process tries each alternative in turn, from left to right, -and the first one that succeeds is used. If the alternatives are within a -subpattern (defined below), "succeeds" means matching the rest of the main -pattern as well as the alternative in the subpattern. -</P> -<br><a name="SEC9" href="#TOC1">INTERNAL OPTION SETTING</a><br> -<P> -The settings of the PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and -PCRE_EXTENDED options can be changed from within the pattern by a sequence of -Perl option letters enclosed between "(?" and ")". The option letters are -</P> -<P> -<pre> - i for PCRE_CASELESS - m for PCRE_MULTILINE - s for PCRE_DOTALL - x for PCRE_EXTENDED -</PRE> -</P> -<P> -For example, (?im) sets caseless, multiline matching. It is also possible to -unset these options by preceding the letter with a hyphen, and a combined -setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and -PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also -permitted. If a letter appears both before and after the hyphen, the option is -unset. -</P> -<P> -When an option change occurs at top level (that is, not inside subpattern -parentheses), the change applies to the remainder of the pattern that follows. -If the change is placed right at the start of a pattern, PCRE extracts it into -the global options (and it will therefore show up in data extracted by the -<b>pcre_fullinfo()</b> function). -</P> -<P> -An option change within a subpattern affects only that part of the current -pattern that follows it, so -</P> -<P> -<pre> - (a(?i)b)c -</PRE> -</P> -<P> -matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used). -By this means, options can be made to have different settings in different -parts of the pattern. Any changes made in one alternative do carry on -into subsequent branches within the same subpattern. For example, -</P> -<P> -<pre> - (a(?i)b|c) -</PRE> -</P> -<P> -matches "ab", "aB", "c", and "C", even though when matching "C" the first -branch is abandoned before the option setting. This is because the effects of -option settings happen at compile time. There would be some very weird -behaviour otherwise. -</P> -<P> -The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed in the -same way as the Perl-compatible options by using the characters U and X -respectively. The (?X) flag setting is special in that it must always occur -earlier in the pattern than any of the additional features it turns on, even -when it is at top level. It is best put at the start. -</P> -<br><a name="SEC10" href="#TOC1">SUBPATTERNS</a><br> -<P> -Subpatterns are delimited by parentheses (round brackets), which can be nested. -Marking part of a pattern as a subpattern does two things: -</P> -<P> -1. It localizes a set of alternatives. For example, the pattern -</P> -<P> -<pre> - cat(aract|erpillar|) -</PRE> -</P> -<P> -matches one of the words "cat", "cataract", or "caterpillar". Without the -parentheses, it would match "cataract", "erpillar" or the empty string. -</P> -<P> -2. It sets up the subpattern as a capturing subpattern (as defined above). -When the whole pattern matches, that portion of the subject string that matched -the subpattern is passed back to the caller via the <i>ovector</i> argument of -<b>pcre_exec()</b>. Opening parentheses are counted from left to right (starting -from 1) to obtain the numbers of the capturing subpatterns. -</P> -<P> -For example, if the string "the red king" is matched against the pattern -</P> -<P> -<pre> - the ((red|white) (king|queen)) -</PRE> -</P> -<P> -the captured substrings are "red king", "red", and "king", and are numbered 1, -2, and 3, respectively. -</P> -<P> -The fact that plain parentheses fulfil two functions is not always helpful. -There are often times when a grouping subpattern is required without a -capturing requirement. If an opening parenthesis is followed by a question mark -and a colon, the subpattern does not do any capturing, and is not counted when -computing the number of any subsequent capturing subpatterns. For example, if -the string "the white queen" is matched against the pattern -</P> -<P> -<pre> - the ((?:red|white) (king|queen)) -</PRE> -</P> -<P> -the captured substrings are "white queen" and "queen", and are numbered 1 and -2. The maximum number of capturing subpatterns is 65535, and the maximum depth -of nesting of all subpatterns, both capturing and non-capturing, is 200. -</P> -<P> -As a convenient shorthand, if any option settings are required at the start of -a non-capturing subpattern, the option letters may appear between the "?" and -the ":". Thus the two patterns -</P> -<P> -<pre> - (?i:saturday|sunday) - (?:(?i)saturday|sunday) -</PRE> -</P> -<P> -match exactly the same set of strings. Because alternative branches are tried -from left to right, and options are not reset until the end of the subpattern -is reached, an option setting in one branch does affect subsequent branches, so -the above patterns match "SUNDAY" as well as "Saturday". -</P> -<br><a name="SEC11" href="#TOC1">NAMED SUBPATTERNS</a><br> -<P> -Identifying capturing parentheses by number is simple, but it can be very hard -to keep track of the numbers in complicated regular expressions. Furthermore, -if an expression is modified, the numbers may change. To help with the -difficulty, PCRE supports the naming of subpatterns, something that Perl does -not provide. The Python syntax (?P<name>...) is used. Names consist of -alphanumeric characters and underscores, and must be unique within a pattern. -</P> -<P> -Named capturing parentheses are still allocated numbers as well as names. The -PCRE API provides function calls for extracting the name-to-number translation -table from a compiled pattern. For further details see the -<a href="pcreapi.html"><b>pcreapi</b></a> -documentation. -</P> -<br><a name="SEC12" href="#TOC1">REPETITION</a><br> -<P> -Repetition is specified by quantifiers, which can follow any of the following -items: -</P> -<P> -<pre> - a literal data character - the . metacharacter - the \C escape sequence - escapes such as \d that match single characters - a character class - a back reference (see next section) - a parenthesized subpattern (unless it is an assertion) -</PRE> -</P> -<P> -The general repetition quantifier specifies a minimum and maximum number of -permitted matches, by giving the two numbers in curly brackets (braces), -separated by a comma. The numbers must be less than 65536, and the first must -be less than or equal to the second. For example: -</P> -<P> -<pre> - z{2,4} -</PRE> -</P> -<P> -matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special -character. If the second number is omitted, but the comma is present, there is -no upper limit; if the second number and the comma are both omitted, the -quantifier specifies an exact number of required matches. Thus -</P> -<P> -<pre> - [aeiou]{3,} -</PRE> -</P> -<P> -matches at least 3 successive vowels, but may match many more, while -</P> -<P> -<pre> - \d{8} -</PRE> -</P> -<P> -matches exactly 8 digits. An opening curly bracket that appears in a position -where a quantifier is not allowed, or one that does not match the syntax of a -quantifier, is taken as a literal character. For example, {,6} is not a -quantifier, but a literal string of four characters. -</P> -<P> -In UTF-8 mode, quantifiers apply to UTF-8 characters rather than to individual -bytes. Thus, for example, \x{100}{2} matches two UTF-8 characters, each of -which is represented by a two-byte sequence. -</P> -<P> -The quantifier {0} is permitted, causing the expression to behave as if the -previous item and the quantifier were not present. -</P> -<P> -For convenience (and historical compatibility) the three most common -quantifiers have single-character abbreviations: -</P> -<P> -<pre> - * is equivalent to {0,} - + is equivalent to {1,} - ? is equivalent to {0,1} -</PRE> -</P> -<P> -It is possible to construct infinite loops by following a subpattern that can -match no characters with a quantifier that has no upper limit, for example: -</P> -<P> -<pre> - (a?)* -</PRE> -</P> -<P> -Earlier versions of Perl and PCRE used to give an error at compile time for -such patterns. However, because there are cases where this can be useful, such -patterns are now accepted, but if any repetition of the subpattern does in fact -match no characters, the loop is forcibly broken. -</P> -<P> -By default, the quantifiers are "greedy", that is, they match as much as -possible (up to the maximum number of permitted times), without causing the -rest of the pattern to fail. The classic example of where this gives problems -is in trying to match comments in C programs. These appear between the -sequences /* and */ and within the sequence, individual * and / characters may -appear. An attempt to match C comments by applying the pattern -</P> -<P> -<pre> - /\*.*\*/ -</PRE> -</P> -<P> -to the string -</P> -<P> -<pre> - /* first command */ not comment /* second comment */ -</PRE> -</P> -<P> -fails, because it matches the entire string owing to the greediness of the .* -item. -</P> -<P> -However, if a quantifier is followed by a question mark, it ceases to be -greedy, and instead matches the minimum number of times possible, so the -pattern -</P> -<P> -<pre> - /\*.*?\*/ -</PRE> -</P> -<P> -does the right thing with the C comments. The meaning of the various -quantifiers is not otherwise changed, just the preferred number of matches. -Do not confuse this use of question mark with its use as a quantifier in its -own right. Because it has two uses, it can sometimes appear doubled, as in -</P> -<P> -<pre> - \d??\d -</PRE> -</P> -<P> -which matches one digit by preference, but can match two if that is the only -way the rest of the pattern matches. -</P> -<P> -If the PCRE_UNGREEDY option is set (an option which is not available in Perl), -the quantifiers are not greedy by default, but individual ones can be made -greedy by following them with a question mark. In other words, it inverts the -default behaviour. -</P> -<P> -When a parenthesized subpattern is quantified with a minimum repeat count that -is greater than 1 or with a limited maximum, more store is required for the -compiled pattern, in proportion to the size of the minimum or maximum. -</P> -<P> -If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent -to Perl's /s) is set, thus allowing the . to match newlines, the pattern is -implicitly anchored, because whatever follows will be tried against every -character position in the subject string, so there is no point in retrying the -overall match at any position after the first. PCRE normally treats such a -pattern as though it were preceded by \A. -</P> -<P> -In cases where it is known that the subject string contains no newlines, it is -worth setting PCRE_DOTALL in order to obtain this optimization, or -alternatively using ^ to indicate anchoring explicitly. -</P> -<P> -However, there is one situation where the optimization cannot be used. When .* -is inside capturing parentheses that are the subject of a backreference -elsewhere in the pattern, a match at the start may fail, and a later one -succeed. Consider, for example: -</P> -<P> -<pre> - (.*)abc\1 -</PRE> -</P> -<P> -If the subject is "xyz123abc123" the match point is the fourth character. For -this reason, such a pattern is not implicitly anchored. -</P> -<P> -When a capturing subpattern is repeated, the value captured is the substring -that matched the final iteration. For example, after -</P> -<P> -<pre> - (tweedle[dume]{3}\s*)+ -</PRE> -</P> -<P> -has matched "tweedledum tweedledee" the value of the captured substring is -"tweedledee". However, if there are nested capturing subpatterns, the -corresponding captured values may have been set in previous iterations. For -example, after -</P> -<P> -<pre> - /(a|(b))+/ -</PRE> -</P> -<P> -matches "aba" the value of the second captured substring is "b". -</P> -<br><a name="SEC13" href="#TOC1">ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS</a><br> -<P> -With both maximizing and minimizing repetition, failure of what follows -normally causes the repeated item to be re-evaluated to see if a different -number of repeats allows the rest of the pattern to match. Sometimes it is -useful to prevent this, either to change the nature of the match, or to cause -it fail earlier than it otherwise might, when the author of the pattern knows -there is no point in carrying on. -</P> -<P> -Consider, for example, the pattern \d+foo when applied to the subject line -</P> -<P> -<pre> - 123456bar -</PRE> -</P> -<P> -After matching all 6 digits and then failing to match "foo", the normal -action of the matcher is to try again with only 5 digits matching the \d+ -item, and then with 4, and so on, before ultimately failing. "Atomic grouping" -(a term taken from Jeffrey Friedl's book) provides the means for specifying -that once a subpattern has matched, it is not to be re-evaluated in this way. -</P> -<P> -If we use atomic grouping for the previous example, the matcher would give up -immediately on failing to match "foo" the first time. The notation is a kind of -special parenthesis, starting with (?> as in this example: -</P> -<P> -<pre> - (?>\d+)foo -</PRE> -</P> -<P> -This kind of parenthesis "locks up" the part of the pattern it contains once -it has matched, and a failure further into the pattern is prevented from -backtracking into it. Backtracking past it to previous items, however, works as -normal. -</P> -<P> -An alternative description is that a subpattern of this type matches the string -of characters that an identical standalone pattern would match, if anchored at -the current point in the subject string. -</P> -<P> -Atomic grouping subpatterns are not capturing subpatterns. Simple cases such as -the above example can be thought of as a maximizing repeat that must swallow -everything it can. So, while both \d+ and \d+? are prepared to adjust the -number of digits they match in order to make the rest of the pattern match, -(?>\d+) can only match an entire sequence of digits. -</P> -<P> -Atomic groups in general can of course contain arbitrarily complicated -subpatterns, and can be nested. However, when the subpattern for an atomic -group is just a single repeated item, as in the example above, a simpler -notation, called a "possessive quantifier" can be used. This consists of an -additional + character following a quantifier. Using this notation, the -previous example can be rewritten as -</P> -<P> -<pre> - \d++bar -</PRE> -</P> -<P> -Possessive quantifiers are always greedy; the setting of the PCRE_UNGREEDY -option is ignored. They are a convenient notation for the simpler forms of -atomic group. However, there is no difference in the meaning or processing of a -possessive quantifier and the equivalent atomic group. -</P> -<P> -The possessive quantifier syntax is an extension to the Perl syntax. It -originates in Sun's Java package. -</P> -<P> -When a pattern contains an unlimited repeat inside a subpattern that can itself -be repeated an unlimited number of times, the use of an atomic group is the -only way to avoid some failing matches taking a very long time indeed. The -pattern -</P> -<P> -<pre> - (\D+|<\d+>)*[!?] -</PRE> -</P> -<P> -matches an unlimited number of substrings that either consist of non-digits, or -digits enclosed in <>, followed by either ! or ?. When it matches, it runs -quickly. However, if it is applied to -</P> -<P> -<pre> - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa -</PRE> -</P> -<P> -it takes a long time before reporting failure. This is because the string can -be divided between the two repeats in a large number of ways, and all have to -be tried. (The example used [!?] rather than a single character at the end, -because both PCRE and Perl have an optimization that allows for fast failure -when a single character is used. They remember the last single character that -is required for a match, and fail early if it is not present in the string.) -If the pattern is changed to -</P> -<P> -<pre> - ((?>\D+)|<\d+>)*[!?] -</PRE> -</P> -<P> -sequences of non-digits cannot be broken, and failure happens quickly. -</P> -<br><a name="SEC14" href="#TOC1">BACK REFERENCES</a><br> -<P> -Outside a character class, a backslash followed by a digit greater than 0 (and -possibly further digits) is a back reference to a capturing subpattern earlier -(that is, to its left) in the pattern, provided there have been that many -previous capturing left parentheses. -</P> -<P> -However, if the decimal number following the backslash is less than 10, it is -always taken as a back reference, and causes an error only if there are not -that many capturing left parentheses in the entire pattern. In other words, the -parentheses that are referenced need not be to the left of the reference for -numbers less than 10. See the section entitled "Backslash" above for further -details of the handling of digits following a backslash. -</P> -<P> -A back reference matches whatever actually matched the capturing subpattern in -the current subject string, rather than anything matching the subpattern -itself (see -<a href="#subpatternsassubroutines">"Subpatterns as subroutines"</a> -below for a way of doing that). So the pattern -</P> -<P> -<pre> - (sens|respons)e and \1ibility -</PRE> -</P> -<P> -matches "sense and sensibility" and "response and responsibility", but not -"sense and responsibility". If caseful matching is in force at the time of the -back reference, the case of letters is relevant. For example, -</P> -<P> -<pre> - ((?i)rah)\s+\1 -</PRE> -</P> -<P> -matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original -capturing subpattern is matched caselessly. -</P> -<P> -Back references to named subpatterns use the Python syntax (?P=name). We could -rewrite the above example as follows: -</P> -<P> -<pre> - (?<p1>(?i)rah)\s+(?P=p1) -</PRE> -</P> -<P> -There may be more than one back reference to the same subpattern. If a -subpattern has not actually been used in a particular match, any back -references to it always fail. For example, the pattern -</P> -<P> -<pre> - (a|(bc))\2 -</PRE> -</P> -<P> -always fails if it starts to match "a" rather than "bc". Because there may be -many capturing parentheses in a pattern, all digits following the backslash are -taken as part of a potential back reference number. If the pattern continues -with a digit character, some delimiter must be used to terminate the back -reference. If the PCRE_EXTENDED option is set, this can be whitespace. -Otherwise an empty comment can be used. -</P> -<P> -A back reference that occurs inside the parentheses to which it refers fails -when the subpattern is first used, so, for example, (a\1) never matches. -However, such references can be useful inside repeated subpatterns. For -example, the pattern -</P> -<P> -<pre> - (a|b\1)+ -</PRE> -</P> -<P> -matches any number of "a"s and also "aba", "ababbaa" etc. At each iteration of -the subpattern, the back reference matches the character string corresponding -to the previous iteration. In order for this to work, the pattern must be such -that the first iteration does not need to match the back reference. This can be -done using alternation, as in the example above, or by a quantifier with a -minimum of zero. -</P> -<br><a name="SEC15" href="#TOC1">ASSERTIONS</a><br> -<P> -An assertion is a test on the characters following or preceding the current -matching point that does not actually consume any characters. The simple -assertions coded as \b, \B, \A, \G, \Z, \z, ^ and $ are described above. -More complicated assertions are coded as subpatterns. There are two kinds: -those that look ahead of the current position in the subject string, and those -that look behind it. -</P> -<P> -An assertion subpattern is matched in the normal way, except that it does not -cause the current matching position to be changed. Lookahead assertions start -with (?= for positive assertions and (?! for negative assertions. For example, -</P> -<P> -<pre> - \w+(?=;) -</PRE> -</P> -<P> -matches a word followed by a semicolon, but does not include the semicolon in -the match, and -</P> -<P> -<pre> - foo(?!bar) -</PRE> -</P> -<P> -matches any occurrence of "foo" that is not followed by "bar". Note that the -apparently similar pattern -</P> -<P> -<pre> - (?!foo)bar -</PRE> -</P> -<P> -does not find an occurrence of "bar" that is preceded by something other than -"foo"; it finds any occurrence of "bar" whatsoever, because the assertion -(?!foo) is always true when the next three characters are "bar". A -lookbehind assertion is needed to achieve this effect. -</P> -<P> -If you want to force a matching failure at some point in a pattern, the most -convenient way to do it is with (?!) because an empty string always matches, so -an assertion that requires there not to be an empty string must always fail. -</P> -<P> -Lookbehind assertions start with (?<= for positive assertions and (?<! for -negative assertions. For example, -</P> -<P> -<pre> - (?<!foo)bar -</PRE> -</P> -<P> -does find an occurrence of "bar" that is not preceded by "foo". The contents of -a lookbehind assertion are restricted such that all the strings it matches must -have a fixed length. However, if there are several alternatives, they do not -all have to have the same fixed length. Thus -</P> -<P> -<pre> - (?<=bullock|donkey) -</PRE> -</P> -<P> -is permitted, but -</P> -<P> -<pre> - (?<!dogs?|cats?) -</PRE> -</P> -<P> -causes an error at compile time. Branches that match different length strings -are permitted only at the top level of a lookbehind assertion. This is an -extension compared with Perl (at least for 5.8), which requires all branches to -match the same length of string. An assertion such as -</P> -<P> -<pre> - (?<=ab(c|de)) -</PRE> -</P> -<P> -is not permitted, because its single top-level branch can match two different -lengths, but it is acceptable if rewritten to use two top-level branches: -</P> -<P> -<pre> - (?<=abc|abde) -</PRE> -</P> -<P> -The implementation of lookbehind assertions is, for each alternative, to -temporarily move the current position back by the fixed width and then try to -match. If there are insufficient characters before the current position, the -match is deemed to fail. -</P> -<P> -PCRE does not allow the \C escape (which matches a single byte in UTF-8 mode) -to appear in lookbehind assertions, because it makes it impossible to calculate -the length of the lookbehind. -</P> -<P> -Atomic groups can be used in conjunction with lookbehind assertions to specify -efficient matching at the end of the subject string. Consider a simple pattern -such as -</P> -<P> -<pre> - abcd$ -</PRE> -</P> -<P> -when applied to a long string that does not match. Because matching proceeds -from left to right, PCRE will look for each "a" in the subject and then see if -what follows matches the rest of the pattern. If the pattern is specified as -</P> -<P> -<pre> - ^.*abcd$ -</PRE> -</P> -<P> -the initial .* matches the entire string at first, but when this fails (because -there is no following "a"), it backtracks to match all but the last character, -then all but the last two characters, and so on. Once again the search for "a" -covers the entire string, from right to left, so we are no better off. However, -if the pattern is written as -</P> -<P> -<pre> - ^(?>.*)(?<=abcd) -</PRE> -</P> -<P> -or, equivalently, -</P> -<P> -<pre> - ^.*+(?<=abcd) -</PRE> -</P> -<P> -there can be no backtracking for the .* item; it can match only the entire -string. The subsequent lookbehind assertion does a single test on the last four -characters. If it fails, the match fails immediately. For long strings, this -approach makes a significant difference to the processing time. -</P> -<P> -Several assertions (of any sort) may occur in succession. For example, -</P> -<P> -<pre> - (?<=\d{3})(?<!999)foo -</PRE> -</P> -<P> -matches "foo" preceded by three digits that are not "999". Notice that each of -the assertions is applied independently at the same point in the subject -string. First there is a check that the previous three characters are all -digits, and then there is a check that the same three characters are not "999". -This pattern does <i>not</i> match "foo" preceded by six characters, the first -of which are digits and the last three of which are not "999". For example, it -doesn't match "123abcfoo". A pattern to do that is -</P> -<P> -<pre> - (?<=\d{3}...)(?<!999)foo -</PRE> -</P> -<P> -This time the first assertion looks at the preceding six characters, checking -that the first three are digits, and then the second assertion checks that the -preceding three characters are not "999". -</P> -<P> -Assertions can be nested in any combination. For example, -</P> -<P> -<pre> - (?<=(?<!foo)bar)baz -</PRE> -</P> -<P> -matches an occurrence of "baz" that is preceded by "bar" which in turn is not -preceded by "foo", while -</P> -<P> -<pre> - (?<=\d{3}(?!999)...)foo -</PRE> -</P> -<P> -is another pattern which matches "foo" preceded by three digits and any three -characters that are not "999". -</P> -<P> -Assertion subpatterns are not capturing subpatterns, and may not be repeated, -because it makes no sense to assert the same thing several times. If any kind -of assertion contains capturing subpatterns within it, these are counted for -the purposes of numbering the capturing subpatterns in the whole pattern. -However, substring capturing is carried out only for positive assertions, -because it does not make sense for negative assertions. -</P> -<br><a name="SEC16" href="#TOC1">CONDITIONAL SUBPATTERNS</a><br> -<P> -It is possible to cause the matching process to obey a subpattern -conditionally or to choose between two alternative subpatterns, depending on -the result of an assertion, or whether a previous capturing subpattern matched -or not. The two possible forms of conditional subpattern are -</P> -<P> -<pre> - (?(condition)yes-pattern) - (?(condition)yes-pattern|no-pattern) -</PRE> -</P> -<P> -If the condition is satisfied, the yes-pattern is used; otherwise the -no-pattern (if present) is used. If there are more than two alternatives in the -subpattern, a compile-time error occurs. -</P> -<P> -There are three kinds of condition. If the text between the parentheses -consists of a sequence of digits, the condition is satisfied if the capturing -subpattern of that number has previously matched. The number must be greater -than zero. Consider the following pattern, which contains non-significant white -space to make it more readable (assume the PCRE_EXTENDED option) and to divide -it into three parts for ease of discussion: -</P> -<P> -<pre> - ( \( )? [^()]+ (?(1) \) ) -</PRE> -</P> -<P> -The first part matches an optional opening parenthesis, and if that -character is present, sets it as the first captured substring. The second part -matches one or more characters that are not parentheses. The third part is a -conditional subpattern that tests whether the first set of parentheses matched -or not. If they did, that is, if subject started with an opening parenthesis, -the condition is true, and so the yes-pattern is executed and a closing -parenthesis is required. Otherwise, since no-pattern is not present, the -subpattern matches nothing. In other words, this pattern matches a sequence of -non-parentheses, optionally enclosed in parentheses. -</P> -<P> -If the condition is the string (R), it is satisfied if a recursive call to the -pattern or subpattern has been made. At "top level", the condition is false. -This is a PCRE extension. Recursive patterns are described in the next section. -</P> -<P> -If the condition is not a sequence of digits or (R), it must be an assertion. -This may be a positive or negative lookahead or lookbehind assertion. Consider -this pattern, again containing non-significant white space, and with the two -alternatives on the second line: -</P> -<P> -<pre> - (?(?=[^a-z]*[a-z]) - \d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} ) -</PRE> -</P> -<P> -The condition is a positive lookahead assertion that matches an optional -sequence of non-letters followed by a letter. In other words, it tests for the -presence of at least one letter in the subject. If a letter is found, the -subject is matched against the first alternative; otherwise it is matched -against the second. This pattern matches strings in one of the two forms -dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits. -</P> -<br><a name="SEC17" href="#TOC1">COMMENTS</a><br> -<P> -The sequence (?# marks the start of a comment which continues up to the next -closing parenthesis. Nested parentheses are not permitted. The characters -that make up a comment play no part in the pattern matching at all. -</P> -<P> -If the PCRE_EXTENDED option is set, an unescaped # character outside a -character class introduces a comment that continues up to the next newline -character in the pattern. -</P> -<br><a name="SEC18" href="#TOC1">RECURSIVE PATTERNS</a><br> -<P> -Consider the problem of matching a string in parentheses, allowing for -unlimited nested parentheses. Without the use of recursion, the best that can -be done is to use a pattern that matches up to some fixed depth of nesting. It -is not possible to handle an arbitrary nesting depth. Perl has provided an -experimental facility that allows regular expressions to recurse (amongst other -things). It does this by interpolating Perl code in the expression at run time, -and the code can refer to the expression itself. A Perl pattern to solve the -parentheses problem can be created like this: -</P> -<P> -<pre> - $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x; -</PRE> -</P> -<P> -The (?p{...}) item interpolates Perl code at run time, and in this case refers -recursively to the pattern in which it appears. Obviously, PCRE cannot support -the interpolation of Perl code. Instead, it supports some special syntax for -recursion of the entire pattern, and also for individual subpattern recursion. -</P> -<P> -The special item that consists of (? followed by a number greater than zero and -a closing parenthesis is a recursive call of the subpattern of the given -number, provided that it occurs inside that subpattern. (If not, it is a -"subroutine" call, which is described in the next section.) The special item -(?R) is a recursive call of the entire regular expression. -</P> -<P> -For example, this PCRE pattern solves the nested parentheses problem (assume -the PCRE_EXTENDED option is set so that white space is ignored): -</P> -<P> -<pre> - \( ( (?>[^()]+) | (?R) )* \) -</PRE> -</P> -<P> -First it matches an opening parenthesis. Then it matches any number of -substrings which can either be a sequence of non-parentheses, or a recursive -match of the pattern itself (that is a correctly parenthesized substring). -Finally there is a closing parenthesis. -</P> -<P> -If this were part of a larger pattern, you would not want to recurse the entire -pattern, so instead you could use this: -</P> -<P> -<pre> - ( \( ( (?>[^()]+) | (?1) )* \) ) -</PRE> -</P> -<P> -We have put the pattern into parentheses, and caused the recursion to refer to -them instead of the whole pattern. In a larger pattern, keeping track of -parenthesis numbers can be tricky. It may be more convenient to use named -parentheses instead. For this, PCRE uses (?P>name), which is an extension to -the Python syntax that PCRE uses for named parentheses (Perl does not provide -named parentheses). We could rewrite the above example as follows: -</P> -<P> -<pre> - (?P<pn> \( ( (?>[^()]+) | (?P>pn) )* \) ) -</PRE> -</P> -<P> -This particular example pattern contains nested unlimited repeats, and so the -use of atomic grouping for matching strings of non-parentheses is important -when applying the pattern to strings that do not match. For example, when this -pattern is applied to -</P> -<P> -<pre> - (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() -</PRE> -</P> -<P> -it yields "no match" quickly. However, if atomic grouping is not used, -the match runs for a very long time indeed because there are so many different -ways the + and * repeats can carve up the subject, and all have to be tested -before failure can be reported. -</P> -<P> -At the end of a match, the values set for any capturing subpatterns are those -from the outermost level of the recursion at which the subpattern value is set. -If you want to obtain intermediate values, a callout function can be used (see -below and the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation). If the pattern above is matched against -</P> -<P> -<pre> - (ab(cd)ef) -</PRE> -</P> -<P> -the value for the capturing parentheses is "ef", which is the last value taken -on at the top level. If additional parentheses are added, giving -</P> -<P> -<pre> - \( ( ( (?>[^()]+) | (?R) )* ) \) - ^ ^ - ^ ^ -</PRE> -</P> -<P> -the string they capture is "ab(cd)ef", the contents of the top level -parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE -has to obtain extra memory to store data during a recursion, which it does by -using <b>pcre_malloc</b>, freeing it via <b>pcre_free</b> afterwards. If no -memory can be obtained, the match fails with the PCRE_ERROR_NOMEMORY error. -</P> -<P> -Do not confuse the (?R) item with the condition (R), which tests for recursion. -Consider this pattern, which matches text in angle brackets, allowing for -arbitrary nesting. Only digits are allowed in nested brackets (that is, when -recursing), whereas any characters are permitted at the outer level. -</P> -<P> -<pre> - < (?: (?(R) \d++ | [^<>]*+) | (?R)) * > -</PRE> -</P> -<P> -In this pattern, (?(R) is the start of a conditional subpattern, with two -different alternatives for the recursive and non-recursive cases. The (?R) item -is the actual recursive call. -</P> -<a name="subpatternsassubroutines"></a><br><a name="SEC19" href="#TOC1">SUBPATTERNS AS SUBROUTINES</a><br> -<P> -If the syntax for a recursive subpattern reference (either by number or by -name) is used outside the parentheses to which it refers, it operates like a -subroutine in a programming language. An earlier example pointed out that the -pattern -</P> -<P> -<pre> - (sens|respons)e and \1ibility -</PRE> -</P> -<P> -matches "sense and sensibility" and "response and responsibility", but not -"sense and responsibility". If instead the pattern -</P> -<P> -<pre> - (sens|respons)e and (?1)ibility -</PRE> -</P> -<P> -is used, it does match "sense and responsibility" as well as the other two -strings. Such references must, however, follow the subpattern to which they -refer. -</P> -<br><a name="SEC20" href="#TOC1">CALLOUTS</a><br> -<P> -Perl has a feature whereby using the sequence (?{...}) causes arbitrary Perl -code to be obeyed in the middle of matching a regular expression. This makes it -possible, amongst other things, to extract different substrings that match the -same pair of parentheses when there is a repetition. -</P> -<P> -PCRE provides a similar feature, but of course it cannot obey arbitrary Perl -code. The feature is called "callout". The caller of PCRE provides an external -function by putting its entry point in the global variable <i>pcre_callout</i>. -By default, this variable contains NULL, which disables all calling out. -</P> -<P> -Within a regular expression, (?C) indicates the points at which the external -function is to be called. If you want to identify different callout points, you -can put a number less than 256 after the letter C. The default value is zero. -For example, this pattern has two callout points: -</P> -<P> -<pre> - (?C1)\dabc(?C2)def -</PRE> -</P> -<P> -During matching, when PCRE reaches a callout point (and <i>pcre_callout</i> is -set), the external function is called. It is provided with the number of the -callout, and, optionally, one item of data originally supplied by the caller of -<b>pcre_exec()</b>. The callout function may cause matching to backtrack, or to -fail altogether. A complete description of the interface to the callout -function is given in the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation. -</P> -<P> -Last updated: 03 February 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcreperform.html b/external-libs/pcre/doc/html/pcreperform.html deleted file mode 100644 index 418ac6d4..00000000 --- a/external-libs/pcre/doc/html/pcreperform.html +++ /dev/null @@ -1,93 +0,0 @@ -<html> -<head> -<title>pcreperform specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">PCRE PERFORMANCE</a> -</ul> -<br><a name="SEC1" href="#TOC1">PCRE PERFORMANCE</a><br> -<P> -Certain items that may appear in regular expression patterns are more efficient -than others. It is more efficient to use a character class like [aeiou] than a -set of alternatives such as (a|e|i|o|u). In general, the simplest construction -that provides the required behaviour is usually the most efficient. Jeffrey -Friedl's book contains a lot of discussion about optimizing regular expressions -for efficient performance. -</P> -<P> -When a pattern begins with .* not in parentheses, or in parentheses that are -not the subject of a backreference, and the PCRE_DOTALL option is set, the -pattern is implicitly anchored by PCRE, since it can match only at the start of -a subject string. However, if PCRE_DOTALL is not set, PCRE cannot make this -optimization, because the . metacharacter does not then match a newline, and if -the subject string contains newlines, the pattern may match from the character -immediately following one of them instead of from the very start. For example, -the pattern -</P> -<P> -<pre> - .*second -</PRE> -</P> -<P> -matches the subject "first\nand second" (where \n stands for a newline -character), with the match starting at the seventh character. In order to do -this, PCRE has to retry the match starting after every newline in the subject. -</P> -<P> -If you are using such a pattern with subject strings that do not contain -newlines, the best performance is obtained by setting PCRE_DOTALL, or starting -the pattern with ^.* to indicate explicit anchoring. That saves PCRE from -having to scan along the subject looking for a newline to restart at. -</P> -<P> -Beware of patterns that contain nested indefinite repeats. These can take a -long time to run when applied to a string that does not match. Consider the -pattern fragment -</P> -<P> -<pre> - (a+)* -</PRE> -</P> -<P> -This can match "aaaa" in 33 different ways, and this number increases very -rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4 -times, and for each of those cases other than 0, the + repeats can match -different numbers of times.) When the remainder of the pattern is such that the -entire match is going to fail, PCRE has in principle to try every possible -variation, and this can take an extremely long time. -</P> -<P> -An optimization catches some of the more simple cases such as -</P> -<P> -<pre> - (a+)*b -</PRE> -</P> -<P> -where a literal character follows. Before embarking on the standard matching -procedure, PCRE checks that there is a "b" later in the subject string, and if -there is not, it fails the match immediately. However, when there is no -following literal this optimization cannot be used. You can see the difference -by comparing the behaviour of -</P> -<P> -<pre> - (a+)*\d -</PRE> -</P> -<P> -with the pattern above. The former gives a failure almost instantly when -applied to a whole line of "a" characters, whereas the latter takes an -appreciable time with strings longer than about 20 characters. -</P> -<P> -Last updated: 03 February 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcreposix.html b/external-libs/pcre/doc/html/pcreposix.html deleted file mode 100644 index d0a5e127..00000000 --- a/external-libs/pcre/doc/html/pcreposix.html +++ /dev/null @@ -1,237 +0,0 @@ -<html> -<head> -<title>pcreposix specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">SYNOPSIS OF POSIX API</a> -<li><a name="TOC2" href="#SEC2">DESCRIPTION</a> -<li><a name="TOC3" href="#SEC3">COMPILING A PATTERN</a> -<li><a name="TOC4" href="#SEC4">MATCHING NEWLINE CHARACTERS</a> -<li><a name="TOC5" href="#SEC5">MATCHING A PATTERN</a> -<li><a name="TOC6" href="#SEC6">ERROR MESSAGES</a> -<li><a name="TOC7" href="#SEC7">STORAGE</a> -<li><a name="TOC8" href="#SEC8">AUTHOR</a> -</ul> -<br><a name="SEC1" href="#TOC1">SYNOPSIS OF POSIX API</a><br> -<P> -<b>#include <pcreposix.h></b> -</P> -<P> -<b>int regcomp(regex_t *<i>preg</i>, const char *<i>pattern</i>,</b> -<b>int <i>cflags</i>);</b> -</P> -<P> -<b>int regexec(regex_t *<i>preg</i>, const char *<i>string</i>,</b> -<b>size_t <i>nmatch</i>, regmatch_t <i>pmatch</i>[], int <i>eflags</i>);</b> -</P> -<P> -<b>size_t regerror(int <i>errcode</i>, const regex_t *<i>preg</i>,</b> -<b>char *<i>errbuf</i>, size_t <i>errbuf_size</i>);</b> -</P> -<P> -<b>void regfree(regex_t *<i>preg</i>);</b> -</P> -<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br> -<P> -This set of functions provides a POSIX-style API to the PCRE regular expression -package. See the -<a href="pcreapi.html"><b>pcreapi</b></a> -documentation for a description of the native API, which contains additional -functionality. -</P> -<P> -The functions described here are just wrapper functions that ultimately call -the PCRE native API. Their prototypes are defined in the <b>pcreposix.h</b> -header file, and on Unix systems the library itself is called -<b>pcreposix.a</b>, so can be accessed by adding <b>-lpcreposix</b> to the -command for linking an application which uses them. Because the POSIX functions -call the native ones, it is also necessary to add \fR-lpcre\fR. -</P> -<P> -I have implemented only those option bits that can be reasonably mapped to PCRE -native options. In addition, the options REG_EXTENDED and REG_NOSUB are defined -with the value zero. They have no effect, but since programs that are written -to the POSIX interface often use them, this makes it easier to slot in PCRE as -a replacement library. Other POSIX options are not even defined. -</P> -<P> -When PCRE is called via these functions, it is only the API that is POSIX-like -in style. The syntax and semantics of the regular expressions themselves are -still those of Perl, subject to the setting of various PCRE options, as -described below. "POSIX-like in style" means that the API approximates to the -POSIX definition; it is not fully POSIX-compatible, and in multi-byte encoding -domains it is probably even less compatible. -</P> -<P> -The header for these functions is supplied as <b>pcreposix.h</b> to avoid any -potential clash with other POSIX libraries. It can, of course, be renamed or -aliased as <b>regex.h</b>, which is the "correct" name. It provides two -structure types, <i>regex_t</i> for compiled internal forms, and -<i>regmatch_t</i> for returning captured substrings. It also defines some -constants whose names start with "REG_"; these are used for setting options and -identifying error codes. -</P> -<br><a name="SEC3" href="#TOC1">COMPILING A PATTERN</a><br> -<P> -The function <b>regcomp()</b> is called to compile a pattern into an -internal form. The pattern is a C string terminated by a binary zero, and -is passed in the argument <i>pattern</i>. The <i>preg</i> argument is a pointer -to a regex_t structure which is used as a base for storing information about -the compiled expression. -</P> -<P> -The argument <i>cflags</i> is either zero, or contains one or more of the bits -defined by the following macros: -</P> -<P> -<pre> - REG_ICASE -</PRE> -</P> -<P> -The PCRE_CASELESS option is set when the expression is passed for compilation -to the native function. -</P> -<P> -<pre> - REG_NEWLINE -</PRE> -</P> -<P> -The PCRE_MULTILINE option is set when the expression is passed for compilation -to the native function. Note that this does <i>not</i> mimic the defined POSIX -behaviour for REG_NEWLINE (see the following section). -</P> -<P> -In the absence of these flags, no options are passed to the native function. -This means the the regex is compiled with PCRE default semantics. In -particular, the way it handles newline characters in the subject string is the -Perl way, not the POSIX way. Note that setting PCRE_MULTILINE has only -<i>some</i> of the effects specified for REG_NEWLINE. It does not affect the way -newlines are matched by . (they aren't) or by a negative class such as [^a] -(they are). -</P> -<P> -The yield of <b>regcomp()</b> is zero on success, and non-zero otherwise. The -<i>preg</i> structure is filled in on success, and one member of the structure -is public: <i>re_nsub</i> contains the number of capturing subpatterns in -the regular expression. Various error codes are defined in the header file. -</P> -<br><a name="SEC4" href="#TOC1">MATCHING NEWLINE CHARACTERS</a><br> -<P> -This area is not simple, because POSIX and Perl take different views of things. -It is not possible to get PCRE to obey POSIX semantics, but then PCRE was never -intended to be a POSIX engine. The following table lists the different -possibilities for matching newline characters in PCRE: -</P> -<P> -<pre> - Default Change with -</PRE> -</P> -<P> -<pre> - . matches newline no PCRE_DOTALL - newline matches [^a] yes not changeable - $ matches \n at end yes PCRE_DOLLARENDONLY - $ matches \n in middle no PCRE_MULTILINE - ^ matches \n in middle no PCRE_MULTILINE -</PRE> -</P> -<P> -This is the equivalent table for POSIX: -</P> -<P> -<pre> - Default Change with -</PRE> -</P> -<P> -<pre> - . matches newline yes REG_NEWLINE - newline matches [^a] yes REG_NEWLINE - $ matches \n at end no REG_NEWLINE - $ matches \n in middle no REG_NEWLINE - ^ matches \n in middle no REG_NEWLINE -</PRE> -</P> -<P> -PCRE's behaviour is the same as Perl's, except that there is no equivalent for -PCRE_DOLLARENDONLY in Perl. In both PCRE and Perl, there is no way to stop -newline from matching [^a]. -</P> -<P> -The default POSIX newline handling can be obtained by setting PCRE_DOTALL and -PCRE_DOLLARENDONLY, but there is no way to make PCRE behave exactly as for the -REG_NEWLINE action. -</P> -<br><a name="SEC5" href="#TOC1">MATCHING A PATTERN</a><br> -<P> -The function <b>regexec()</b> is called to match a pre-compiled pattern -<i>preg</i> against a given <i>string</i>, which is terminated by a zero byte, -subject to the options in <i>eflags</i>. These can be: -</P> -<P> -<pre> - REG_NOTBOL -</PRE> -</P> -<P> -The PCRE_NOTBOL option is set when calling the underlying PCRE matching -function. -</P> -<P> -<pre> - REG_NOTEOL -</PRE> -</P> -<P> -The PCRE_NOTEOL option is set when calling the underlying PCRE matching -function. -</P> -<P> -The portion of the string that was matched, and also any captured substrings, -are returned via the <i>pmatch</i> argument, which points to an array of -<i>nmatch</i> structures of type <i>regmatch_t</i>, containing the members -<i>rm_so</i> and <i>rm_eo</i>. These contain the offset to the first character of -each substring and the offset to the first character after the end of each -substring, respectively. The 0th element of the vector relates to the entire -portion of <i>string</i> that was matched; subsequent elements relate to the -capturing subpatterns of the regular expression. Unused entries in the array -have both structure members set to -1. -</P> -<P> -A successful match yields a zero return; various error codes are defined in the -header file, of which REG_NOMATCH is the "expected" failure code. -</P> -<br><a name="SEC6" href="#TOC1">ERROR MESSAGES</a><br> -<P> -The <b>regerror()</b> function maps a non-zero errorcode from either -<b>regcomp()</b> or <b>regexec()</b> to a printable message. If <i>preg</i> is not -NULL, the error should have arisen from the use of that structure. A message -terminated by a binary zero is placed in <i>errbuf</i>. The length of the -message, including the zero, is limited to <i>errbuf_size</i>. The yield of the -function is the size of buffer needed to hold the whole message. -</P> -<br><a name="SEC7" href="#TOC1">STORAGE</a><br> -<P> -Compiling a regular expression causes memory to be allocated and associated -with the <i>preg</i> structure. The function <b>regfree()</b> frees all such -memory, after which <i>preg</i> may no longer be used as a compiled expression. -</P> -<br><a name="SEC8" href="#TOC1">AUTHOR</a><br> -<P> -Philip Hazel <ph10@cam.ac.uk> -<br> -University Computing Service, -<br> -Cambridge CB2 3QG, England. -</P> -<P> -Last updated: 03 February 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcresample.html b/external-libs/pcre/doc/html/pcresample.html deleted file mode 100644 index fed41f62..00000000 --- a/external-libs/pcre/doc/html/pcresample.html +++ /dev/null @@ -1,79 +0,0 @@ -<html> -<head> -<title>pcresample specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">PCRE SAMPLE PROGRAM</a> -</ul> -<br><a name="SEC1" href="#TOC1">PCRE SAMPLE PROGRAM</a><br> -<P> -A simple, complete demonstration program, to get you started with using PCRE, -is supplied in the file <i>pcredemo.c</i> in the PCRE distribution. -</P> -<P> -The program compiles the regular expression that is its first argument, and -matches it against the subject string in its second argument. No PCRE options -are set, and default character tables are used. If matching succeeds, the -program outputs the portion of the subject that matched, together with the -contents of any captured substrings. -</P> -<P> -If the -g option is given on the command line, the program then goes on to -check for further matches of the same regular expression in the same subject -string. The logic is a little bit tricky because of the possibility of matching -an empty string. Comments in the code explain what is going on. -</P> -<P> -On a Unix system that has PCRE installed in <i>/usr/local</i>, you can compile -the demonstration program using a command like this: -</P> -<P> -<pre> - gcc -o pcredemo pcredemo.c -I/usr/local/include \ - -L/usr/local/lib -lpcre -</PRE> -</P> -<P> -Then you can run simple tests like this: -</P> -<P> -<pre> - ./pcredemo 'cat|dog' 'the cat sat on the mat' - ./pcredemo -g 'cat|dog' 'the dog sat on the cat' -</PRE> -</P> -<P> -Note that there is a much more comprehensive test program, called -<b>pcretest</b>, which supports many more facilities for testing regular -expressions and the PCRE library. The <b>pcredemo</b> program is provided as a -simple coding example. -</P> -<P> -On some operating systems (e.g. Solaris) you may get an error like this when -you try to run <b>pcredemo</b>: -</P> -<P> -<pre> - ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory -</PRE> -</P> -<P> -This is caused by the way shared library support works on those systems. You -need to add -</P> -<P> -<pre> - -R/usr/local/lib -</PRE> -</P> -<P> -to the compile command to get round this problem. -</P> -<P> -Last updated: 28 January 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/html/pcretest.html b/external-libs/pcre/doc/html/pcretest.html deleted file mode 100644 index 2ba9893d..00000000 --- a/external-libs/pcre/doc/html/pcretest.html +++ /dev/null @@ -1,443 +0,0 @@ -<html> -<head> -<title>pcretest specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -This HTML document has been generated automatically from the original man page. -If there is any nonsense in it, please consult the man page, in case the -conversion went wrong.<br> -<ul> -<li><a name="TOC1" href="#SEC1">SYNOPSIS</a> -<li><a name="TOC2" href="#SEC2">OPTIONS</a> -<li><a name="TOC3" href="#SEC3">DESCRIPTION</a> -<li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a> -<li><a name="TOC5" href="#SEC5">CALLOUTS</a> -<li><a name="TOC6" href="#SEC6">DATA LINES</a> -<li><a name="TOC7" href="#SEC7">OUTPUT FROM PCRETEST</a> -<li><a name="TOC8" href="#SEC8">AUTHOR</a> -</ul> -<br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br> -<P> -<b>pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]</b> -</P> -<P> -<b>pcretest</b> was written as a test program for the PCRE regular expression -library itself, but it can also be used for experimenting with regular -expressions. This document describes the features of the test program; for -details of the regular expressions themselves, see the -<a href="pcrepattern.html"><b>pcrepattern</b></a> -documentation. For details of PCRE and its options, see the -<a href="pcreapi.html"><b>pcreapi</b></a> -documentation. -</P> -<br><a name="SEC2" href="#TOC1">OPTIONS</a><br> -<P> -<b>-C</b> -Output the version number of the PCRE library, and all available information -about the optional features that are included, and then exit. -</P> -<P> -<b>-d</b> -Behave as if each regex had the <b>/D</b> modifier (see below); the internal -form is output after compilation. -</P> -<P> -<b>-i</b> -Behave as if each regex had the <b>/I</b> modifier; information about the -compiled pattern is given after compilation. -</P> -<P> -<b>-m</b> -Output the size of each compiled pattern after it has been compiled. This is -equivalent to adding /M to each regular expression. For compatibility with -earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>. -</P> -<P> -<b>-o</b> <i>osize</i> -Set the number of elements in the output vector that is used when calling PCRE -to be <i>osize</i>. The default value is 45, which is enough for 14 capturing -subexpressions. The vector size can be changed for individual matching calls by -including \O in the data line (see below). -</P> -<P> -<b>-p</b> -Behave as if each regex has <b>/P</b> modifier; the POSIX wrapper API is used -to call PCRE. None of the other options has any effect when <b>-p</b> is set. -</P> -<P> -<b>-t</b> -Run each compile, study, and match many times with a timer, and output -resulting time per compile or match (in milliseconds). Do not set <b>-t</b> with -<b>-m</b>, because you will then get the size output 20000 times and the timing -will be distorted. -</P> -<br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br> -<P> -If <b>pcretest</b> is given two filename arguments, it reads from the first and -writes to the second. If it is given only one filename argument, it reads from -that file and writes to stdout. Otherwise, it reads from stdin and writes to -stdout, and prompts for each line of input, using "re>" to prompt for regular -expressions, and "data>" to prompt for data lines. -</P> -<P> -The program handles any number of sets of input on a single input file. Each -set starts with a regular expression, and continues with any number of data -lines to be matched against the pattern. -</P> -<P> -Each line is matched separately and independently. If you want to do -multiple-line matches, you have to use the \n escape sequence in a single line -of input to encode the newline characters. The maximum length of data line is -30,000 characters. -</P> -<P> -An empty line signals the end of the data lines, at which point a new regular -expression is read. The regular expressions are given enclosed in any -non-alphameric delimiters other than backslash, for example -</P> -<P> -<pre> - /(a|bc)x+yz/ -</PRE> -</P> -<P> -White space before the initial delimiter is ignored. A regular expression may -be continued over several input lines, in which case the newline characters are -included within it. It is possible to include the delimiter within the pattern -by escaping it, for example -</P> -<P> -<pre> - /abc\/def/ -</PRE> -</P> -<P> -If you do so, the escape and the delimiter form part of the pattern, but since -delimiters are always non-alphameric, this does not affect its interpretation. -If the terminating delimiter is immediately followed by a backslash, for -example, -</P> -<P> -<pre> - /abc/\ -</PRE> -</P> -<P> -then a backslash is added to the end of the pattern. This is done to provide a -way of testing the error condition that arises if a pattern finishes with a -backslash, because -</P> -<P> -<pre> - /abc\/ -</PRE> -</P> -<P> -is interpreted as the first line of a pattern that starts with "abc/", causing -pcretest to read the next line as a continuation of the regular expression. -</P> -<br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br> -<P> -The pattern may be followed by <b>i</b>, <b>m</b>, <b>s</b>, or <b>x</b> to set the -PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, -respectively. For example: -</P> -<P> -<pre> - /caseless/i -</PRE> -</P> -<P> -These modifier letters have the same effect as they do in Perl. There are -others that set PCRE options that do not correspond to anything in Perl: -<b>/A</b>, <b>/E</b>, <b>/N</b>, <b>/U</b>, and <b>/X</b> set PCRE_ANCHORED, -PCRE_DOLLAR_ENDONLY, PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA -respectively. -</P> -<P> -Searching for all possible matches within each subject string can be requested -by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called -again to search the remainder of the subject string. The difference between -<b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to -<b>pcre_exec()</b> to start searching at a new point within the entire string -(which is in effect what Perl does), whereas the latter passes over a shortened -substring. This makes a difference to the matching process if the pattern -begins with a lookbehind assertion (including \b or \B). -</P> -<P> -If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an -empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED -flags set in order to search for another, non-empty, match at the same point. -If this second match fails, the start offset is advanced by one, and the normal -match is retried. This imitates the way Perl handles such cases when using the -<b>/g</b> modifier or the <b>split()</b> function. -</P> -<P> -There are a number of other modifiers for controlling the way <b>pcretest</b> -operates. -</P> -<P> -The <b>/+</b> modifier requests that as well as outputting the substring that -matched the entire pattern, pcretest should in addition output the remainder of -the subject string. This is useful for tests where the subject contains -multiple copies of the same substring. -</P> -<P> -The <b>/L</b> modifier must be followed directly by the name of a locale, for -example, -</P> -<P> -<pre> - /pattern/Lfr -</PRE> -</P> -<P> -For this reason, it must be the last modifier letter. The given locale is set, -<b>pcre_maketables()</b> is called to build a set of character tables for the -locale, and this is then passed to <b>pcre_compile()</b> when compiling the -regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables -pointer; that is, <b>/L</b> applies only to the expression on which it appears. -</P> -<P> -The <b>/I</b> modifier requests that <b>pcretest</b> output information about the -compiled expression (whether it is anchored, has a fixed first character, and -so on). It does this by calling <b>pcre_fullinfo()</b> after compiling an -expression, and outputting the information it gets back. If the pattern is -studied, the results of that are also output. -</P> -<P> -The <b>/D</b> modifier is a PCRE debugging feature, which also assumes <b>/I</b>. -It causes the internal form of compiled regular expressions to be output after -compilation. If the pattern was studied, the information returned is also -output. -</P> -<P> -The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the -expression has been compiled, and the results used when the expression is -matched. -</P> -<P> -The <b>/M</b> modifier causes the size of memory block used to hold the compiled -pattern to be output. -</P> -<P> -The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper -API rather than its native API. When this is done, all other modifiers except -<b>/i</b>, <b>/m</b>, and <b>/+</b> are ignored. REG_ICASE is set if <b>/i</b> is -present, and REG_NEWLINE is set if <b>/m</b> is present. The wrapper functions -force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. -</P> -<P> -The <b>/8</b> modifier causes <b>pcretest</b> to call PCRE with the PCRE_UTF8 -option set. This turns on support for UTF-8 character handling in PCRE, -provided that it was compiled with this support enabled. This modifier also -causes any non-printing characters in output strings to be printed using the -\x{hh...} notation if they are valid UTF-8 sequences. -</P> -<P> -If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to -call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the -checking of the string for UTF-8 validity. -</P> -<br><a name="SEC5" href="#TOC1">CALLOUTS</a><br> -<P> -If the pattern contains any callout requests, <b>pcretest</b>'s callout function -will be called. By default, it displays the callout number, and the start and -current positions in the text at the callout time. For example, the output -</P> -<P> -<pre> - --->pqrabcdef - 0 ^ ^ -</PRE> -</P> -<P> -indicates that callout number 0 occurred for a match attempt starting at the -fourth character of the subject string, when the pointer was at the seventh -character. The callout function returns zero (carry on matching) by default. -</P> -<P> -Inserting callouts may be helpful when using <b>pcretest</b> to check -complicated regular expressions. For further information about callouts, see -the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation. -</P> -<P> -For testing the PCRE library, additional control of callout behaviour is -available via escape sequences in the data, as described in the following -section. In particular, it is possible to pass in a number as callout data (the -default is zero). If the callout function receives a non-zero number, it -returns that value instead of zero. -</P> -<br><a name="SEC6" href="#TOC1">DATA LINES</a><br> -<P> -Before each data line is passed to <b>pcre_exec()</b>, leading and trailing -whitespace is removed, and it is then scanned for \ escapes. Some of these are -pretty esoteric features, intended for checking out some of the more -complicated features of PCRE. If you are just testing "ordinary" regular -expressions, you probably don't need any of these. The following escapes are -recognized: -</P> -<P> -<pre> - \a alarm (= BEL) - \b backspace - \e escape - \f formfeed - \n newline - \r carriage return - \t tab - \v vertical tab - \nnn octal character (up to 3 octal digits) - \xhh hexadecimal character (up to 2 hex digits) - \x{hh...} hexadecimal character, any number of digits - in UTF-8 mode - \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> - \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> - \Cdd call pcre_copy_substring() for substring dd - after a successful match (any decimal number - less than 32) - \Cname call pcre_copy_named_substring() for substring - "name" after a successful match (name termin- - ated by next non alphanumeric character) - \C+ show the current captured substrings at callout - time - \C- do not supply a callout function - \C!n return 1 instead of 0 when callout number n is - reached - \C!n!m return 1 instead of 0 when callout number n is - reached for the nth time - \C*n pass the number n (may be negative) as callout - data - \Gdd call pcre_get_substring() for substring dd - after a successful match (any decimal number - less than 32) - \Gname call pcre_get_named_substring() for substring - "name" after a successful match (name termin- - ated by next non-alphanumeric character) - \L call pcre_get_substringlist() after a - successful match - \M discover the minimum MATCH_LIMIT setting - \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> - \Odd set the size of the output vector passed to - <b>pcre_exec()</b> to dd (any number of decimal - digits) - \S output details of memory get/free calls during matching - \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> - \? pass the PCRE_NO_UTF8_CHECK option to - <b>pcre_exec()</b> -</PRE> -</P> -<P> -If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with -different values in the <i>match_limit</i> field of the <b>pcre_extra</b> data -structure, until it finds the minimum number that is needed for -<b>pcre_exec()</b> to complete. This number is a measure of the amount of -recursion and backtracking that takes place, and checking it out can be -instructive. For most simple matches, the number is quite small, but for -patterns with very large numbers of matching possibilities, it can become large -very quickly with increasing length of subject string. -</P> -<P> -When \O is used, it may be higher or lower than the size set by the <b>-O</b> -option (or defaulted to 45); \O applies only to the call of <b>pcre_exec()</b> -for the line in which it appears. -</P> -<P> -A backslash followed by anything else just escapes the anything else. If the -very last character is a backslash, it is ignored. This gives a way of passing -an empty line as data, since a real empty line terminates the data input. -</P> -<P> -If <b>/P</b> was present on the regex, causing the POSIX wrapper API to be used, -only <b>\B</b>, and <b>\Z</b> have any effect, causing REG_NOTBOL and REG_NOTEOL -to be passed to <b>regexec()</b> respectively. -</P> -<P> -The use of \x{hh...} to represent UTF-8 characters is not dependent on the use -of the <b>/8</b> modifier on the pattern. It is recognized always. There may be -any number of hexadecimal digits inside the braces. The result is from one to -six bytes, encoded according to the UTF-8 rules. -</P> -<br><a name="SEC7" href="#TOC1">OUTPUT FROM PCRETEST</a><br> -<P> -When a match succeeds, pcretest outputs the list of captured substrings that -<b>pcre_exec()</b> returns, starting with number 0 for the string that matched -the whole pattern. Here is an example of an interactive pcretest run. -</P> -<P> -<pre> - $ pcretest - PCRE version 4.00 08-Jan-2003 -</PRE> -</P> -<P> -<pre> - re> /^abc(\d+)/ - data> abc123 - 0: abc123 - 1: 123 - data> xyz - No match -</PRE> -</P> -<P> -If the strings contain any non-printing characters, they are output as \0x -escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the -pattern. If the pattern has the <b>/+</b> modifier, then the output for -substring 0 is followed by the the rest of the subject string, identified by -"0+" like this: -</P> -<P> -<pre> - re> /cat/+ - data> cataract - 0: cat - 0+ aract -</PRE> -</P> -<P> -If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive -matching attempts are output in sequence, like this: -</P> -<P> -<pre> - re> /\Bi(\w\w)/g - data> Mississippi - 0: iss - 1: ss - 0: iss - 1: ss - 0: ipp - 1: pp -</PRE> -</P> -<P> -"No match" is output only if the first match attempt fails. -</P> -<P> -If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a -data line that is successfully matched, the substrings extracted by the -convenience functions are output with C, G, or L after the string number -instead of a colon. This is in addition to the normal full list. The string -length (that is, the return from the extraction function) is given in -parentheses after each string for <b>\C</b> and <b>\G</b>. -</P> -<P> -Note that while patterns can be continued over several lines (a plain ">" -prompt is used for continuations), data lines may not. However newlines can be -included in data by means of the \n escape. -</P> -<br><a name="SEC8" href="#TOC1">AUTHOR</a><br> -<P> -Philip Hazel <ph10@cam.ac.uk> -<br> -University Computing Service, -<br> -Cambridge CB2 3QG, England. -</P> -<P> -Last updated: 09 December 2003 -<br> -Copyright © 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcre.3 b/external-libs/pcre/doc/pcre.3 deleted file mode 100644 index c0c71419..00000000 --- a/external-libs/pcre/doc/pcre.3 +++ /dev/null @@ -1,174 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH DESCRIPTION -.rs -.sp -The PCRE library is a set of functions that implement regular expression -pattern matching using the same syntax and semantics as Perl, with just a few -differences. The current implementation of PCRE (release 4.x) corresponds -approximately with Perl 5.8, including support for UTF-8 encoded strings. -However, this support has to be explicitly enabled; it is not the default. - -PCRE is written in C and released as a C library. However, a number of people -have written wrappers and interfaces of various kinds. A C++ class is included -in these contributions, which can be found in the \fIContrib\fR directory at -the primary FTP site, which is: - -.\" HTML <a href="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre"> -.\" </a> -ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre - -Details of exactly which Perl regular expression features are and are not -supported by PCRE are given in separate documents. See the -.\" HREF -\fBpcrepattern\fR -.\" -and -.\" HREF -\fBpcrecompat\fR -.\" -pages. - -Some features of PCRE can be included, excluded, or changed when the library is -built. The -.\" HREF -\fBpcre_config()\fR -.\" -function makes it possible for a client to discover which features are -available. Documentation about building PCRE for various operating systems can -be found in the \fBREADME\fR file in the source distribution. - -.SH USER DOCUMENTATION -.rs -.sp -The user documentation for PCRE has been split up into a number of different -sections. In the "man" format, each of these is a separate "man page". In the -HTML format, each is a separate page, linked from the index page. In the plain -text format, all the sections are concatenated, for ease of searching. The -sections are as follows: - - pcre this document - pcreapi details of PCRE's native API - pcrebuild options for building PCRE - pcrecallout details of the callout feature - pcrecompat discussion of Perl compatibility - pcregrep description of the \fBpcregrep\fR command - pcrepattern syntax and semantics of supported - regular expressions - pcreperform discussion of performance issues - pcreposix the POSIX-compatible API - pcresample discussion of the sample program - pcretest the \fBpcretest\fR testing command - -In addition, in the "man" and HTML formats, there is a short page for each -library function, listing its arguments and results. - -.SH LIMITATIONS -.rs -.sp -There are some size limitations in PCRE but it is hoped that they will never in -practice be relevant. - -The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE is -compiled with the default internal linkage size of 2. If you want to process -regular expressions that are truly enormous, you can compile PCRE with an -internal linkage size of 3 or 4 (see the \fBREADME\fR file in the source -distribution and the -.\" HREF -\fBpcrebuild\fR -.\" -documentation for details). If these cases the limit is substantially larger. -However, the speed of execution will be slower. - -All values in repeating quantifiers must be less than 65536. -The maximum number of capturing subpatterns is 65535. - -There is no limit to the number of non-capturing subpatterns, but the maximum -depth of nesting of all kinds of parenthesized subpattern, including capturing -subpatterns, assertions, and other types of subpattern, is 200. - -The maximum length of a subject string is the largest positive number that an -integer variable can hold. However, PCRE uses recursion to handle subpatterns -and indefinite repetition. This means that the available stack space may limit -the size of a subject string that can be processed by certain patterns. - -.\" HTML <a name="utf8support"></a> -.SH UTF-8 SUPPORT -.rs -.sp -Starting at release 3.3, PCRE has had some support for character strings -encoded in the UTF-8 format. For release 4.0 this has been greatly extended to -cover most common requirements. - -In order process UTF-8 strings, you must build PCRE to include UTF-8 support in -the code, and, in addition, you must call -.\" HREF -\fBpcre_compile()\fR -.\" -with the PCRE_UTF8 option flag. When you do this, both the pattern and any -subject strings that are matched against it are treated as UTF-8 strings -instead of just strings of bytes. - -If you compile PCRE with UTF-8 support, but do not use it at run time, the -library will be a bit bigger, but the additional run time overhead is limited -to testing the PCRE_UTF8 flag in several places, so should not be very large. - -The following comments apply when PCRE is running in UTF-8 mode: - -1. When you set the PCRE_UTF8 flag, the strings passed as patterns and subjects -are checked for validity on entry to the relevant functions. If an invalid -UTF-8 string is passed, an error return is given. In some situations, you may -already know that your strings are valid, and therefore want to skip these -checks in order to improve performance. If you set the PCRE_NO_UTF8_CHECK flag -at compile time or at run time, PCRE assumes that the pattern or subject it -is given (respectively) contains only valid UTF-8 codes. In this case, it does -not diagnose an invalid UTF-8 string. If you pass an invalid UTF-8 string to -PCRE when PCRE_NO_UTF8_CHECK is set, the results are undefined. Your program -may crash. - -2. In a pattern, the escape sequence \\x{...}, where the contents of the braces -is a string of hexadecimal digits, is interpreted as a UTF-8 character whose -code number is the given hexadecimal number, for example: \\x{1234}. If a -non-hexadecimal digit appears between the braces, the item is not recognized. -This escape sequence can be used either as a literal, or within a character -class. - -3. The original hexadecimal escape sequence, \\xhh, matches a two-byte UTF-8 -character if the value is greater than 127. - -4. Repeat quantifiers apply to complete UTF-8 characters, not to individual -bytes, for example: \\x{100}{3}. - -5. The dot metacharacter matches one UTF-8 character instead of a single byte. - -6. The escape sequence \\C can be used to match a single byte in UTF-8 mode, -but its use can lead to some strange effects. - -7. The character escapes \\b, \\B, \\d, \\D, \\s, \\S, \\w, and \\W correctly -test characters of any code value, but the characters that PCRE recognizes as -digits, spaces, or word characters remain the same set as before, all with -values less than 256. - -8. Case-insensitive matching applies only to characters whose values are less -than 256. PCRE does not support the notion of "case" for higher-valued -characters. - -9. PCRE does not support the use of Unicode tables and properties or the Perl -escapes \\p, \\P, and \\X. - -.SH AUTHOR -.rs -.sp -Philip Hazel <ph10@cam.ac.uk> -.br -University Computing Service, -.br -Cambridge CB2 3QG, England. -.br -Phone: +44 1223 334714 - -.in 0 -Last updated: 20 August 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcre.txt b/external-libs/pcre/doc/pcre.txt deleted file mode 100644 index 698baa52..00000000 --- a/external-libs/pcre/doc/pcre.txt +++ /dev/null @@ -1,3169 +0,0 @@ -This file contains a concatenation of the PCRE man pages, converted to plain -text format for ease of searching with a text editor, or for use on systems -that do not have a man page processor. The small individual files that give -synopses of each function in the library have not been included. There are -separate text files for the pcregrep and pcretest commands. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -DESCRIPTION - - The PCRE library is a set of functions that implement regular expres- - sion pattern matching using the same syntax and semantics as Perl, with - just a few differences. The current implementation of PCRE (release - 4.x) corresponds approximately with Perl 5.8, including support for - UTF-8 encoded strings. However, this support has to be explicitly - enabled; it is not the default. - - PCRE is written in C and released as a C library. However, a number of - people have written wrappers and interfaces of various kinds. A C++ - class is included in these contributions, which can be found in the - Contrib directory at the primary FTP site, which is: - - ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre - - Details of exactly which Perl regular expression features are and are - not supported by PCRE are given in separate documents. See the pcrepat- - tern and pcrecompat pages. - - Some features of PCRE can be included, excluded, or changed when the - library is built. The pcre_config() function makes it possible for a - client to discover which features are available. Documentation about - building PCRE for various operating systems can be found in the README - file in the source distribution. - - -USER DOCUMENTATION - - The user documentation for PCRE has been split up into a number of dif- - ferent sections. In the "man" format, each of these is a separate "man - page". In the HTML format, each is a separate page, linked from the - index page. In the plain text format, all the sections are concate- - nated, for ease of searching. The sections are as follows: - - pcre this document - pcreapi details of PCRE's native API - pcrebuild options for building PCRE - pcrecallout details of the callout feature - pcrecompat discussion of Perl compatibility - pcregrep description of the pcregrep command - pcrepattern syntax and semantics of supported - regular expressions - pcreperform discussion of performance issues - pcreposix the POSIX-compatible API - pcresample discussion of the sample program - pcretest the pcretest testing command - - In addition, in the "man" and HTML formats, there is a short page for - each library function, listing its arguments and results. - - -LIMITATIONS - - There are some size limitations in PCRE but it is hoped that they will - never in practice be relevant. - - The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE - is compiled with the default internal linkage size of 2. If you want to - process regular expressions that are truly enormous, you can compile - PCRE with an internal linkage size of 3 or 4 (see the README file in - the source distribution and the pcrebuild documentation for details). - If these cases the limit is substantially larger. However, the speed - of execution will be slower. - - All values in repeating quantifiers must be less than 65536. The maxi- - mum number of capturing subpatterns is 65535. - - There is no limit to the number of non-capturing subpatterns, but the - maximum depth of nesting of all kinds of parenthesized subpattern, - including capturing subpatterns, assertions, and other types of subpat- - tern, is 200. - - The maximum length of a subject string is the largest positive number - that an integer variable can hold. However, PCRE uses recursion to han- - dle subpatterns and indefinite repetition. This means that the avail- - able stack space may limit the size of a subject string that can be - processed by certain patterns. - - -UTF-8 SUPPORT - - Starting at release 3.3, PCRE has had some support for character - strings encoded in the UTF-8 format. For release 4.0 this has been - greatly extended to cover most common requirements. - - In order process UTF-8 strings, you must build PCRE to include UTF-8 - support in the code, and, in addition, you must call pcre_compile() - with the PCRE_UTF8 option flag. When you do this, both the pattern and - any subject strings that are matched against it are treated as UTF-8 - strings instead of just strings of bytes. - - If you compile PCRE with UTF-8 support, but do not use it at run time, - the library will be a bit bigger, but the additional run time overhead - is limited to testing the PCRE_UTF8 flag in several places, so should - not be very large. - - The following comments apply when PCRE is running in UTF-8 mode: - - 1. When you set the PCRE_UTF8 flag, the strings passed as patterns and - subjects are checked for validity on entry to the relevant functions. - If an invalid UTF-8 string is passed, an error return is given. In some - situations, you may already know that your strings are valid, and - therefore want to skip these checks in order to improve performance. If - you set the PCRE_NO_UTF8_CHECK flag at compile time or at run time, - PCRE assumes that the pattern or subject it is given (respectively) - contains only valid UTF-8 codes. In this case, it does not diagnose an - invalid UTF-8 string. If you pass an invalid UTF-8 string to PCRE when - PCRE_NO_UTF8_CHECK is set, the results are undefined. Your program may - crash. - - 2. In a pattern, the escape sequence \x{...}, where the contents of the - braces is a string of hexadecimal digits, is interpreted as a UTF-8 - character whose code number is the given hexadecimal number, for exam- - ple: \x{1234}. If a non-hexadecimal digit appears between the braces, - the item is not recognized. This escape sequence can be used either as - a literal, or within a character class. - - 3. The original hexadecimal escape sequence, \xhh, matches a two-byte - UTF-8 character if the value is greater than 127. - - 4. Repeat quantifiers apply to complete UTF-8 characters, not to indi- - vidual bytes, for example: \x{100}{3}. - - 5. The dot metacharacter matches one UTF-8 character instead of a - single byte. - - 6. The escape sequence \C can be used to match a single byte in UTF-8 - mode, but its use can lead to some strange effects. - - 7. The character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly - test characters of any code value, but the characters that PCRE recog- - nizes as digits, spaces, or word characters remain the same set as - before, all with values less than 256. - - 8. Case-insensitive matching applies only to characters whose values - are less than 256. PCRE does not support the notion of "case" for - higher-valued characters. - - 9. PCRE does not support the use of Unicode tables and properties or - the Perl escapes \p, \P, and \X. - - -AUTHOR - - Philip Hazel <ph10@cam.ac.uk> - University Computing Service, - Cambridge CB2 3QG, England. - Phone: +44 1223 334714 - -Last updated: 20 August 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -PCRE BUILD-TIME OPTIONS - - This document describes the optional features of PCRE that can be - selected when the library is compiled. They are all selected, or dese- - lected, by providing options to the configure script which is run - before the make command. The complete list of options for configure - (which includes the standard ones such as the selection of the instal- - lation directory) can be obtained by running - - ./configure --help - - The following sections describe certain options whose names begin with - --enable or --disable. These settings specify changes to the defaults - for the configure command. Because of the way that configure works, - --enable and --disable always come in pairs, so the complementary - option always exists as well, but as it specifies the default, it is - not described. - - -UTF-8 SUPPORT - - To build PCRE with support for UTF-8 character strings, add - - --enable-utf8 - - to the configure command. Of itself, this does not make PCRE treat - strings as UTF-8. As well as compiling PCRE with this option, you also - have have to set the PCRE_UTF8 option when you call the pcre_compile() - function. - - -CODE VALUE OF NEWLINE - - By default, PCRE treats character 10 (linefeed) as the newline charac- - ter. This is the normal newline character on Unix-like systems. You can - compile PCRE to use character 13 (carriage return) instead by adding - - --enable-newline-is-cr - - to the configure command. For completeness there is also a --enable- - newline-is-lf option, which explicitly specifies linefeed as the new- - line character. - - -BUILDING SHARED AND STATIC LIBRARIES - - The PCRE building process uses libtool to build both shared and static - Unix libraries by default. You can suppress one of these by adding one - of - - --disable-shared - --disable-static - - to the configure command, as required. - - -POSIX MALLOC USAGE - - When PCRE is called through the POSIX interface (see the pcreposix - documentation), additional working storage is required for holding the - pointers to capturing substrings because PCRE requires three integers - per substring, whereas the POSIX interface provides only two. If the - number of expected substrings is small, the wrapper function uses space - on the stack, because this is faster than using malloc() for each call. - The default threshold above which the stack is no longer used is 10; it - can be changed by adding a setting such as - - --with-posix-malloc-threshold=20 - - to the configure command. - - -LIMITING PCRE RESOURCE USAGE - - Internally, PCRE has a function called match() which it calls repeat- - edly (possibly recursively) when performing a matching operation. By - limiting the number of times this function may be called, a limit can - be placed on the resources used by a single call to pcre_exec(). The - limit can be changed at run time, as described in the pcreapi documen- - tation. The default is 10 million, but this can be changed by adding a - setting such as - - --with-match-limit=500000 - - to the configure command. - - -HANDLING VERY LARGE PATTERNS - - Within a compiled pattern, offset values are used to point from one - part to another (for example, from an opening parenthesis to an alter- - nation metacharacter). By default two-byte values are used for these - offsets, leading to a maximum size for a compiled pattern of around - 64K. This is sufficient to handle all but the most gigantic patterns. - Nevertheless, some people do want to process enormous patterns, so it - is possible to compile PCRE to use three-byte or four-byte offsets by - adding a setting such as - - --with-link-size=3 - - to the configure command. The value given must be 2, 3, or 4. Using - longer offsets slows down the operation of PCRE because it has to load - additional bytes when handling them. - - If you build PCRE with an increased link size, test 2 (and test 5 if - you are using UTF-8) will fail. Part of the output of these tests is a - representation of the compiled pattern, and this changes with the link - size. - - -AVOIDING EXCESSIVE STACK USAGE - - PCRE implements backtracking while matching by making recursive calls - to an internal function called match(). In environments where the size - of the stack is limited, this can severely limit PCRE's operation. (The - Unix environment does not usually suffer from this problem.) An alter- - native approach that uses memory from the heap to remember data, - instead of using recursive function calls, has been implemented to work - round this problem. If you want to build a version of PCRE that works - this way, add - - --disable-stack-for-recursion - - to the configure command. With this configuration, PCRE will use the - pcre_stack_malloc and pcre_stack_free variables to call memory - management functions. Separate functions are provided because the usage - is very predictable: the block sizes requested are always the same, and - the blocks are always freed in reverse order. A calling program might - be able to implement optimized functions that perform better than the - standard malloc() and free() functions. PCRE runs noticeably more - slowly when built in this way. - - -USING EBCDIC CODE - - PCRE assumes by default that it will run in an environment where the - character code is ASCII (or UTF-8, which is a superset of ASCII). PCRE - can, however, be compiled to run in an EBCDIC environment by adding - - --enable-ebcdic - - to the configure command. - -Last updated: 09 December 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -SYNOPSIS OF PCRE API - - #include <pcre.h> - - pcre *pcre_compile(const char *pattern, int options, - const char **errptr, int *erroffset, - const unsigned char *tableptr); - - pcre_extra *pcre_study(const pcre *code, int options, - const char **errptr); - - int pcre_exec(const pcre *code, const pcre_extra *extra, - const char *subject, int length, int startoffset, - int options, int *ovector, int ovecsize); - - int pcre_copy_named_substring(const pcre *code, - const char *subject, int *ovector, - int stringcount, const char *stringname, - char *buffer, int buffersize); - - int pcre_copy_substring(const char *subject, int *ovector, - int stringcount, int stringnumber, char *buffer, - int buffersize); - - int pcre_get_named_substring(const pcre *code, - const char *subject, int *ovector, - int stringcount, const char *stringname, - const char **stringptr); - - int pcre_get_stringnumber(const pcre *code, - const char *name); - - int pcre_get_substring(const char *subject, int *ovector, - int stringcount, int stringnumber, - const char **stringptr); - - int pcre_get_substring_list(const char *subject, - int *ovector, int stringcount, const char ***listptr); - - void pcre_free_substring(const char *stringptr); - - void pcre_free_substring_list(const char **stringptr); - - const unsigned char *pcre_maketables(void); - - int pcre_fullinfo(const pcre *code, const pcre_extra *extra, - int what, void *where); - - int pcre_info(const pcre *code, int *optptr, int *firstcharptr); - - int pcre_config(int what, void *where); - - char *pcre_version(void); - - void *(*pcre_malloc)(size_t); - - void (*pcre_free)(void *); - - void *(*pcre_stack_malloc)(size_t); - - void (*pcre_stack_free)(void *); - - int (*pcre_callout)(pcre_callout_block *); - - -PCRE API - - PCRE has its own native API, which is described in this document. There - is also a set of wrapper functions that correspond to the POSIX regular - expression API. These are described in the pcreposix documentation. - - The native API function prototypes are defined in the header file - pcre.h, and on Unix systems the library itself is called libpcre.a, so - can be accessed by adding -lpcre to the command for linking an applica- - tion which calls it. The header file defines the macros PCRE_MAJOR and - PCRE_MINOR to contain the major and minor release numbers for the - library. Applications can use these to include support for different - releases. - - The functions pcre_compile(), pcre_study(), and pcre_exec() are used - for compiling and matching regular expressions. A sample program that - demonstrates the simplest way of using them is given in the file pcre- - demo.c. The pcresample documentation describes how to run it. - - There are convenience functions for extracting captured substrings from - a matched subject string. They are: - - pcre_copy_substring() - pcre_copy_named_substring() - pcre_get_substring() - pcre_get_named_substring() - pcre_get_substring_list() - - pcre_free_substring() and pcre_free_substring_list() are also provided, - to free the memory used for extracted strings. - - The function pcre_maketables() is used (optionally) to build a set of - character tables in the current locale for passing to pcre_compile(). - - The function pcre_fullinfo() is used to find out information about a - compiled pattern; pcre_info() is an obsolete version which returns only - some of the available information, but is retained for backwards com- - patibility. The function pcre_version() returns a pointer to a string - containing the version of PCRE and its date of release. - - The global variables pcre_malloc and pcre_free initially contain the - entry points of the standard malloc() and free() functions respec- - tively. PCRE calls the memory management functions via these variables, - so a calling program can replace them if it wishes to intercept the - calls. This should be done before calling any PCRE functions. - - The global variables pcre_stack_malloc and pcre_stack_free are also - indirections to memory management functions. These special functions - are used only when PCRE is compiled to use the heap for remembering - data, instead of recursive function calls. This is a non-standard way - of building PCRE, for use in environments that have limited stacks. - Because of the greater use of memory management, it runs more slowly. - Separate functions are provided so that special-purpose external code - can be used for this case. When used, these functions are always called - in a stack-like manner (last obtained, first freed), and always for - memory blocks of the same size. - - The global variable pcre_callout initially contains NULL. It can be set - by the caller to a "callout" function, which PCRE will then call at - specified points during a matching operation. Details are given in the - pcrecallout documentation. - - -MULTITHREADING - - The PCRE functions can be used in multi-threading applications, with - the proviso that the memory management functions pointed to by - pcre_malloc, pcre_free, pcre_stack_malloc, and pcre_stack_free, and the - callout function pointed to by pcre_callout, are shared by all threads. - - The compiled form of a regular expression is not altered during match- - ing, so the same compiled pattern can safely be used by several threads - at once. - - -CHECKING BUILD-TIME OPTIONS - - int pcre_config(int what, void *where); - - The function pcre_config() makes it possible for a PCRE client to dis- - cover which optional features have been compiled into the PCRE library. - The pcrebuild documentation has more details about these optional fea- - tures. - - The first argument for pcre_config() is an integer, specifying which - information is required; the second argument is a pointer to a variable - into which the information is placed. The following information is - available: - - PCRE_CONFIG_UTF8 - - The output is an integer that is set to one if UTF-8 support is avail- - able; otherwise it is set to zero. - - PCRE_CONFIG_NEWLINE - - The output is an integer that is set to the value of the code that is - used for the newline character. It is either linefeed (10) or carriage - return (13), and should normally be the standard character for your - operating system. - - PCRE_CONFIG_LINK_SIZE - - The output is an integer that contains the number of bytes used for - internal linkage in compiled regular expressions. The value is 2, 3, or - 4. Larger values allow larger regular expressions to be compiled, at - the expense of slower matching. The default value of 2 is sufficient - for all but the most massive patterns, since it allows the compiled - pattern to be up to 64K in size. - - PCRE_CONFIG_POSIX_MALLOC_THRESHOLD - - The output is an integer that contains the threshold above which the - POSIX interface uses malloc() for output vectors. Further details are - given in the pcreposix documentation. - - PCRE_CONFIG_MATCH_LIMIT - - The output is an integer that gives the default limit for the number of - internal matching function calls in a pcre_exec() execution. Further - details are given with pcre_exec() below. - - PCRE_CONFIG_STACKRECURSE - - The output is an integer that is set to one if internal recursion is - implemented by recursive function calls that use the stack to remember - their state. This is the usual way that PCRE is compiled. The output is - zero if PCRE was compiled to use blocks of data on the heap instead of - recursive function calls. In this case, pcre_stack_malloc and - pcre_stack_free are called to manage memory blocks on the heap, thus - avoiding the use of the stack. - - -COMPILING A PATTERN - - pcre *pcre_compile(const char *pattern, int options, - const char **errptr, int *erroffset, - const unsigned char *tableptr); - - - The function pcre_compile() is called to compile a pattern into an - internal form. The pattern is a C string terminated by a binary zero, - and is passed in the argument pattern. A pointer to a single block of - memory that is obtained via pcre_malloc is returned. This contains the - compiled code and related data. The pcre type is defined for the - returned block; this is a typedef for a structure whose contents are - not externally defined. It is up to the caller to free the memory when - it is no longer required. - - Although the compiled code of a PCRE regex is relocatable, that is, it - does not depend on memory location, the complete pcre data block is not - fully relocatable, because it contains a copy of the tableptr argument, - which is an address (see below). - - The options argument contains independent bits that affect the compila- - tion. It should be zero if no options are required. Some of the - options, in particular, those that are compatible with Perl, can also - be set and unset from within the pattern (see the detailed description - of regular expressions in the pcrepattern documentation). For these - options, the contents of the options argument specifies their initial - settings at the start of compilation and execution. The PCRE_ANCHORED - option can be set at the time of matching as well as at compile time. - - If errptr is NULL, pcre_compile() returns NULL immediately. Otherwise, - if compilation of a pattern fails, pcre_compile() returns NULL, and - sets the variable pointed to by errptr to point to a textual error mes- - sage. The offset from the start of the pattern to the character where - the error was discovered is placed in the variable pointed to by - erroffset, which must not be NULL. If it is, an immediate error is - given. - - If the final argument, tableptr, is NULL, PCRE uses a default set of - character tables which are built when it is compiled, using the default - C locale. Otherwise, tableptr must be the result of a call to - pcre_maketables(). See the section on locale support below. - - This code fragment shows a typical straightforward call to pcre_com- - pile(): - - pcre *re; - const char *error; - int erroffset; - re = pcre_compile( - "^A.*Z", /* the pattern */ - 0, /* default options */ - &error, /* for error message */ - &erroffset, /* for error offset */ - NULL); /* use default character tables */ - - The following option bits are defined: - - PCRE_ANCHORED - - If this bit is set, the pattern is forced to be "anchored", that is, it - is constrained to match only at the first matching point in the string - which is being searched (the "subject string"). This effect can also be - achieved by appropriate constructs in the pattern itself, which is the - only way to do it in Perl. - - PCRE_CASELESS - - If this bit is set, letters in the pattern match both upper and lower - case letters. It is equivalent to Perl's /i option, and it can be - changed within a pattern by a (?i) option setting. - - PCRE_DOLLAR_ENDONLY - - If this bit is set, a dollar metacharacter in the pattern matches only - at the end of the subject string. Without this option, a dollar also - matches immediately before the final character if it is a newline (but - not before any other newlines). The PCRE_DOLLAR_ENDONLY option is - ignored if PCRE_MULTILINE is set. There is no equivalent to this option - in Perl, and no way to set it within a pattern. - - PCRE_DOTALL - - If this bit is set, a dot metacharater in the pattern matches all char- - acters, including newlines. Without it, newlines are excluded. This - option is equivalent to Perl's /s option, and it can be changed within - a pattern by a (?s) option setting. A negative class such as [^a] - always matches a newline character, independent of the setting of this - option. - - PCRE_EXTENDED - - If this bit is set, whitespace data characters in the pattern are - totally ignored except when escaped or inside a character class. - Whitespace does not include the VT character (code 11). In addition, - characters between an unescaped # outside a character class and the - next newline character, inclusive, are also ignored. This is equivalent - to Perl's /x option, and it can be changed within a pattern by a (?x) - option setting. - - This option makes it possible to include comments inside complicated - patterns. Note, however, that this applies only to data characters. - Whitespace characters may never appear within special character - sequences in a pattern, for example within the sequence (?( which - introduces a conditional subpattern. - - PCRE_EXTRA - - This option was invented in order to turn on additional functionality - of PCRE that is incompatible with Perl, but it is currently of very - little use. When set, any backslash in a pattern that is followed by a - letter that has no special meaning causes an error, thus reserving - these combinations for future expansion. By default, as in Perl, a - backslash followed by a letter with no special meaning is treated as a - literal. There are at present no other features controlled by this - option. It can also be set by a (?X) option setting within a pattern. - - PCRE_MULTILINE - - By default, PCRE treats the subject string as consisting of a single - "line" of characters (even if it actually contains several newlines). - The "start of line" metacharacter (^) matches only at the start of the - string, while the "end of line" metacharacter ($) matches only at the - end of the string, or before a terminating newline (unless PCRE_DOL- - LAR_ENDONLY is set). This is the same as Perl. - - When PCRE_MULTILINE it is set, the "start of line" and "end of line" - constructs match immediately following or immediately before any new- - line in the subject string, respectively, as well as at the very start - and end. This is equivalent to Perl's /m option, and it can be changed - within a pattern by a (?m) option setting. If there are no "\n" charac- - ters in a subject string, or no occurrences of ^ or $ in a pattern, - setting PCRE_MULTILINE has no effect. - - PCRE_NO_AUTO_CAPTURE - - If this option is set, it disables the use of numbered capturing paren- - theses in the pattern. Any opening parenthesis that is not followed by - ? behaves as if it were followed by ?: but named parentheses can still - be used for capturing (and they acquire numbers in the usual way). - There is no equivalent of this option in Perl. - - PCRE_UNGREEDY - - This option inverts the "greediness" of the quantifiers so that they - are not greedy by default, but become greedy if followed by "?". It is - not compatible with Perl. It can also be set by a (?U) option setting - within the pattern. - - PCRE_UTF8 - - This option causes PCRE to regard both the pattern and the subject as - strings of UTF-8 characters instead of single-byte character strings. - However, it is available only if PCRE has been built to include UTF-8 - support. If not, the use of this option provokes an error. Details of - how this option changes the behaviour of PCRE are given in the section - on UTF-8 support in the main pcre page. - - PCRE_NO_UTF8_CHECK - - When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is - automatically checked. If an invalid UTF-8 sequence of bytes is found, - pcre_compile() returns an error. If you already know that your pattern - is valid, and you want to skip this check for performance reasons, you - can set the PCRE_NO_UTF8_CHECK option. When it is set, the effect of - passing an invalid UTF-8 string as a pattern is undefined. It may cause - your program to crash. Note that there is a similar option for sup- - pressing the checking of subject strings passed to pcre_exec(). - - - -STUDYING A PATTERN - - pcre_extra *pcre_study(const pcre *code, int options, - const char **errptr); - - When a pattern is going to be used several times, it is worth spending - more time analyzing it in order to speed up the time taken for match- - ing. The function pcre_study() takes a pointer to a compiled pattern as - its first argument. If studing the pattern produces additional informa- - tion that will help speed up matching, pcre_study() returns a pointer - to a pcre_extra block, in which the study_data field points to the - results of the study. - - The returned value from a pcre_study() can be passed directly to - pcre_exec(). However, the pcre_extra block also contains other fields - that can be set by the caller before the block is passed; these are - described below. If studying the pattern does not produce any addi- - tional information, pcre_study() returns NULL. In that circumstance, if - the calling program wants to pass some of the other fields to - pcre_exec(), it must set up its own pcre_extra block. - - The second argument contains option bits. At present, no options are - defined for pcre_study(), and this argument should always be zero. - - The third argument for pcre_study() is a pointer for an error message. - If studying succeeds (even if no data is returned), the variable it - points to is set to NULL. Otherwise it points to a textual error mes- - sage. You should therefore test the error pointer for NULL after call- - ing pcre_study(), to be sure that it has run successfully. - - This is a typical call to pcre_study(): - - pcre_extra *pe; - pe = pcre_study( - re, /* result of pcre_compile() */ - 0, /* no options exist */ - &error); /* set to NULL or points to a message */ - - At present, studying a pattern is useful only for non-anchored patterns - that do not have a single fixed starting character. A bitmap of possi- - ble starting characters is created. - - -LOCALE SUPPORT - - PCRE handles caseless matching, and determines whether characters are - letters, digits, or whatever, by reference to a set of tables. When - running in UTF-8 mode, this applies only to characters with codes less - than 256. The library contains a default set of tables that is created - in the default C locale when PCRE is compiled. This is used when the - final argument of pcre_compile() is NULL, and is sufficient for many - applications. - - An alternative set of tables can, however, be supplied. Such tables are - built by calling the pcre_maketables() function, which has no argu- - ments, in the relevant locale. The result can then be passed to - pcre_compile() as often as necessary. For example, to build and use - tables that are appropriate for the French locale (where accented char- - acters with codes greater than 128 are treated as letters), the follow- - ing code could be used: - - setlocale(LC_CTYPE, "fr"); - tables = pcre_maketables(); - re = pcre_compile(..., tables); - - The tables are built in memory that is obtained via pcre_malloc. The - pointer that is passed to pcre_compile is saved with the compiled pat- - tern, and the same tables are used via this pointer by pcre_study() and - pcre_exec(). Thus, for any single pattern, compilation, studying and - matching all happen in the same locale, but different patterns can be - compiled in different locales. It is the caller's responsibility to - ensure that the memory containing the tables remains available for as - long as it is needed. - - -INFORMATION ABOUT A PATTERN - - int pcre_fullinfo(const pcre *code, const pcre_extra *extra, - int what, void *where); - - The pcre_fullinfo() function returns information about a compiled pat- - tern. It replaces the obsolete pcre_info() function, which is neverthe- - less retained for backwards compability (and is documented below). - - The first argument for pcre_fullinfo() is a pointer to the compiled - pattern. The second argument is the result of pcre_study(), or NULL if - the pattern was not studied. The third argument specifies which piece - of information is required, and the fourth argument is a pointer to a - variable to receive the data. The yield of the function is zero for - success, or one of the following negative numbers: - - PCRE_ERROR_NULL the argument code was NULL - the argument where was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - PCRE_ERROR_BADOPTION the value of what was invalid - - Here is a typical call of pcre_fullinfo(), to obtain the length of the - compiled pattern: - - int rc; - unsigned long int length; - rc = pcre_fullinfo( - re, /* result of pcre_compile() */ - pe, /* result of pcre_study(), or NULL */ - PCRE_INFO_SIZE, /* what is required */ - &length); /* where to put the data */ - - The possible values for the third argument are defined in pcre.h, and - are as follows: - - PCRE_INFO_BACKREFMAX - - Return the number of the highest back reference in the pattern. The - fourth argument should point to an int variable. Zero is returned if - there are no back references. - - PCRE_INFO_CAPTURECOUNT - - Return the number of capturing subpatterns in the pattern. The fourth - argument should point to an int variable. - - PCRE_INFO_FIRSTBYTE - - Return information about the first byte of any matched string, for a - non-anchored pattern. (This option used to be called - PCRE_INFO_FIRSTCHAR; the old name is still recognized for backwards - compatibility.) - - If there is a fixed first byte, e.g. from a pattern such as - (cat|cow|coyote), it is returned in the integer pointed to by where. - Otherwise, if either - - (a) the pattern was compiled with the PCRE_MULTILINE option, and every - branch starts with "^", or - - (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not - set (if it were set, the pattern would be anchored), - - -1 is returned, indicating that the pattern matches only at the start - of a subject string or after any newline within the string. Otherwise - -2 is returned. For anchored patterns, -2 is returned. - - PCRE_INFO_FIRSTTABLE - - If the pattern was studied, and this resulted in the construction of a - 256-bit table indicating a fixed set of bytes for the first byte in any - matching string, a pointer to the table is returned. Otherwise NULL is - returned. The fourth argument should point to an unsigned char * vari- - able. - - PCRE_INFO_LASTLITERAL - - Return the value of the rightmost literal byte that must exist in any - matched string, other than at its start, if such a byte has been - recorded. The fourth argument should point to an int variable. If there - is no such byte, -1 is returned. For anchored patterns, a last literal - byte is recorded only if it follows something of variable length. For - example, for the pattern /^a\d+z\d+/ the returned value is "z", but for - /^a\dz\d/ the returned value is -1. - - PCRE_INFO_NAMECOUNT - PCRE_INFO_NAMEENTRYSIZE - PCRE_INFO_NAMETABLE - - PCRE supports the use of named as well as numbered capturing parenthe- - ses. The names are just an additional way of identifying the parenthe- - ses, which still acquire a number. A caller that wants to extract data - from a named subpattern must convert the name to a number in order to - access the correct pointers in the output vector (described with - pcre_exec() below). In order to do this, it must first use these three - values to obtain the name-to-number mapping table for the pattern. - - The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT - gives the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size - of each entry; both of these return an int value. The entry size - depends on the length of the longest name. PCRE_INFO_NAMETABLE returns - a pointer to the first entry of the table (a pointer to char). The - first two bytes of each entry are the number of the capturing parenthe- - sis, most significant byte first. The rest of the entry is the corre- - sponding name, zero terminated. The names are in alphabetical order. - For example, consider the following pattern (assume PCRE_EXTENDED is - set, so white space - including newlines - is ignored): - - (?P<date> (?P<year>(\d\d)?\d\d) - - (?P<month>\d\d) - (?P<day>\d\d) ) - - There are four named subpatterns, so the table has four entries, and - each entry in the table is eight bytes long. The table is as follows, - with non-printing bytes shows in hex, and undefined bytes shown as ??: - - 00 01 d a t e 00 ?? - 00 05 d a y 00 ?? ?? - 00 04 m o n t h 00 - 00 02 y e a r 00 ?? - - When writing code to extract data from named subpatterns, remember that - the length of each entry may be different for each compiled pattern. - - PCRE_INFO_OPTIONS - - Return a copy of the options with which the pattern was compiled. The - fourth argument should point to an unsigned long int variable. These - option bits are those specified in the call to pcre_compile(), modified - by any top-level option settings within the pattern itself. - - A pattern is automatically anchored by PCRE if all of its top-level - alternatives begin with one of the following: - - ^ unless PCRE_MULTILINE is set - \A always - \G always - .* if PCRE_DOTALL is set and there are no back - references to the subpattern in which .* appears - - For such patterns, the PCRE_ANCHORED bit is set in the options returned - by pcre_fullinfo(). - - PCRE_INFO_SIZE - - Return the size of the compiled pattern, that is, the value that was - passed as the argument to pcre_malloc() when PCRE was getting memory in - which to place the compiled data. The fourth argument should point to a - size_t variable. - - PCRE_INFO_STUDYSIZE - - Returns the size of the data block pointed to by the study_data field - in a pcre_extra block. That is, it is the value that was passed to - pcre_malloc() when PCRE was getting memory into which to place the data - created by pcre_study(). The fourth argument should point to a size_t - variable. - - -OBSOLETE INFO FUNCTION - - int pcre_info(const pcre *code, int *optptr, int *firstcharptr); - - The pcre_info() function is now obsolete because its interface is too - restrictive to return all the available data about a compiled pattern. - New programs should use pcre_fullinfo() instead. The yield of - pcre_info() is the number of capturing subpatterns, or one of the fol- - lowing negative numbers: - - PCRE_ERROR_NULL the argument code was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - - If the optptr argument is not NULL, a copy of the options with which - the pattern was compiled is placed in the integer it points to (see - PCRE_INFO_OPTIONS above). - - If the pattern is not anchored and the firstcharptr argument is not - NULL, it is used to pass back information about the first character of - any matched string (see PCRE_INFO_FIRSTBYTE above). - - -MATCHING A PATTERN - - int pcre_exec(const pcre *code, const pcre_extra *extra, - const char *subject, int length, int startoffset, - int options, int *ovector, int ovecsize); - - The function pcre_exec() is called to match a subject string against a - pre-compiled pattern, which is passed in the code argument. If the pat- - tern has been studied, the result of the study should be passed in the - extra argument. - - Here is an example of a simple call to pcre_exec(): - - int rc; - int ovector[30]; - rc = pcre_exec( - re, /* result of pcre_compile() */ - NULL, /* we didn't study the pattern */ - "some string", /* the subject string */ - 11, /* the length of the subject string */ - 0, /* start at offset 0 in the subject */ - 0, /* default options */ - ovector, /* vector for substring information */ - 30); /* number of elements in the vector */ - - If the extra argument is not NULL, it must point to a pcre_extra data - block. The pcre_study() function returns such a block (when it doesn't - return NULL), but you can also create one for yourself, and pass addi- - tional information in it. The fields in the block are as follows: - - unsigned long int flags; - void *study_data; - unsigned long int match_limit; - void *callout_data; - - The flags field is a bitmap that specifies which of the other fields - are set. The flag bits are: - - PCRE_EXTRA_STUDY_DATA - PCRE_EXTRA_MATCH_LIMIT - PCRE_EXTRA_CALLOUT_DATA - - Other flag bits should be set to zero. The study_data field is set in - the pcre_extra block that is returned by pcre_study(), together with - the appropriate flag bit. You should not set this yourself, but you can - add to the block by setting the other fields. - - The match_limit field provides a means of preventing PCRE from using up - a vast amount of resources when running patterns that are not going to - match, but which have a very large number of possibilities in their - search trees. The classic example is the use of nested unlimited - repeats. Internally, PCRE uses a function called match() which it calls - repeatedly (sometimes recursively). The limit is imposed on the number - of times this function is called during a match, which has the effect - of limiting the amount of recursion and backtracking that can take - place. For patterns that are not anchored, the count starts from zero - for each position in the subject string. - - The default limit for the library can be set when PCRE is built; the - default default is 10 million, which handles all but the most extreme - cases. You can reduce the default by suppling pcre_exec() with a - pcre_extra block in which match_limit is set to a smaller value, and - PCRE_EXTRA_MATCH_LIMIT is set in the flags field. If the limit is - exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT. - - The pcre_callout field is used in conjunction with the "callout" fea- - ture, which is described in the pcrecallout documentation. - - The PCRE_ANCHORED option can be passed in the options argument, whose - unused bits must be zero. This limits pcre_exec() to matching at the - first matching position. However, if a pattern was compiled with - PCRE_ANCHORED, or turned out to be anchored by virtue of its contents, - it cannot be made unachored at matching time. - - When PCRE_UTF8 was set at compile time, the validity of the subject as - a UTF-8 string is automatically checked, and the value of startoffset - is also checked to ensure that it points to the start of a UTF-8 char- - acter. If an invalid UTF-8 sequence of bytes is found, pcre_exec() - returns the error PCRE_ERROR_BADUTF8. If startoffset contains an - invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned. - - If you already know that your subject is valid, and you want to skip - these checks for performance reasons, you can set the - PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might want to - do this for the second and subsequent calls to pcre_exec() if you are - making repeated calls to find all the matches in a single subject - string. However, you should be sure that the value of startoffset - points to the start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is - set, the effect of passing an invalid UTF-8 string as a subject, or a - value of startoffset that does not point to the start of a UTF-8 char- - acter, is undefined. Your program may crash. - - There are also three further options that can be set only at matching - time: - - PCRE_NOTBOL - - The first character of the string is not the beginning of a line, so - the circumflex metacharacter should not match before it. Setting this - without PCRE_MULTILINE (at compile time) causes circumflex never to - match. - - PCRE_NOTEOL - - The end of the string is not the end of a line, so the dollar metachar- - acter should not match it nor (except in multiline mode) a newline - immediately before it. Setting this without PCRE_MULTILINE (at compile - time) causes dollar never to match. - - PCRE_NOTEMPTY - - An empty string is not considered to be a valid match if this option is - set. If there are alternatives in the pattern, they are tried. If all - the alternatives match the empty string, the entire match fails. For - example, if the pattern - - a?b? - - is applied to a string not beginning with "a" or "b", it matches the - empty string at the start of the subject. With PCRE_NOTEMPTY set, this - match is not valid, so PCRE searches further into the string for occur- - rences of "a" or "b". - - Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe- - cial case of a pattern match of the empty string within its split() - function, and when using the /g modifier. It is possible to emulate - Perl's behaviour after matching a null string by first trying the match - again at the same offset with PCRE_NOTEMPTY set, and then if that fails - by advancing the starting offset (see below) and trying an ordinary - match again. - - The subject string is passed to pcre_exec() as a pointer in subject, a - length in length, and a starting byte offset in startoffset. Unlike the - pattern string, the subject may contain binary zero bytes. When the - starting offset is zero, the search for a match starts at the beginning - of the subject, and this is by far the most common case. - - If the pattern was compiled with the PCRE_UTF8 option, the subject must - be a sequence of bytes that is a valid UTF-8 string, and the starting - offset must point to the beginning of a UTF-8 character. If an invalid - UTF-8 string or offset is passed, an error (either PCRE_ERROR_BADUTF8 - or PCRE_ERROR_BADUTF8_OFFSET) is returned, unless the option - PCRE_NO_UTF8_CHECK is set, in which case PCRE's behaviour is not - defined. - - A non-zero starting offset is useful when searching for another match - in the same subject by calling pcre_exec() again after a previous suc- - cess. Setting startoffset differs from just passing over a shortened - string and setting PCRE_NOTBOL in the case of a pattern that begins - with any kind of lookbehind. For example, consider the pattern - - \Biss\B - - which finds occurrences of "iss" in the middle of words. (\B matches - only if the current position in the subject is not a word boundary.) - When applied to the string "Mississipi" the first call to pcre_exec() - finds the first occurrence. If pcre_exec() is called again with just - the remainder of the subject, namely "issipi", it does not match, - because \B is always false at the start of the subject, which is deemed - to be a word boundary. However, if pcre_exec() is passed the entire - string again, but with startoffset set to 4, it finds the second - occurrence of "iss" because it is able to look behind the starting - point to discover that it is preceded by a letter. - - If a non-zero starting offset is passed when the pattern is anchored, - one attempt to match at the given offset is tried. This can only suc- - ceed if the pattern does not require the match to be at the start of - the subject. - - In general, a pattern matches a certain portion of the subject, and in - addition, further substrings from the subject may be picked out by - parts of the pattern. Following the usage in Jeffrey Friedl's book, - this is called "capturing" in what follows, and the phrase "capturing - subpattern" is used for a fragment of a pattern that picks out a sub- - string. PCRE supports several other kinds of parenthesized subpattern - that do not cause substrings to be captured. - - Captured substrings are returned to the caller via a vector of integer - offsets whose address is passed in ovector. The number of elements in - the vector is passed in ovecsize. The first two-thirds of the vector is - used to pass back captured substrings, each substring using a pair of - integers. The remaining third of the vector is used as workspace by - pcre_exec() while matching capturing subpatterns, and is not available - for passing back information. The length passed in ovecsize should - always be a multiple of three. If it is not, it is rounded down. - - When a match has been successful, information about captured substrings - is returned in pairs of integers, starting at the beginning of ovector, - and continuing up to two-thirds of its length at the most. The first - element of a pair is set to the offset of the first character in a sub- - string, and the second is set to the offset of the first character - after the end of a substring. The first pair, ovector[0] and ovec- - tor[1], identify the portion of the subject string matched by the - entire pattern. The next pair is used for the first capturing subpat- - tern, and so on. The value returned by pcre_exec() is the number of - pairs that have been set. If there are no capturing subpatterns, the - return value from a successful match is 1, indicating that just the - first pair of offsets has been set. - - Some convenience functions are provided for extracting the captured - substrings as separate strings. These are described in the following - section. - - It is possible for an capturing subpattern number n+1 to match some - part of the subject when subpattern n has not been used at all. For - example, if the string "abc" is matched against the pattern (a|(z))(bc) - subpatterns 1 and 3 are matched, but 2 is not. When this happens, both - offset values corresponding to the unused subpattern are set to -1. - - If a capturing subpattern is matched repeatedly, it is the last portion - of the string that it matched that gets returned. - - If the vector is too small to hold all the captured substrings, it is - used as far as possible (up to two-thirds of its length), and the func- - tion returns a value of zero. In particular, if the substring offsets - are not of interest, pcre_exec() may be called with ovector passed as - NULL and ovecsize as zero. However, if the pattern contains back refer- - ences and the ovector isn't big enough to remember the related sub- - strings, PCRE has to get additional memory for use during matching. - Thus it is usually advisable to supply an ovector. - - Note that pcre_info() can be used to find out how many capturing sub- - patterns there are in a compiled pattern. The smallest size for ovector - that will allow for n captured substrings, in addition to the offsets - of the substring matched by the whole pattern, is (n+1)*3. - - If pcre_exec() fails, it returns a negative number. The following are - defined in the header file: - - PCRE_ERROR_NOMATCH (-1) - - The subject string did not match the pattern. - - PCRE_ERROR_NULL (-2) - - Either code or subject was passed as NULL, or ovector was NULL and - ovecsize was not zero. - - PCRE_ERROR_BADOPTION (-3) - - An unrecognized bit was set in the options argument. - - PCRE_ERROR_BADMAGIC (-4) - - PCRE stores a 4-byte "magic number" at the start of the compiled code, - to catch the case when it is passed a junk pointer. This is the error - it gives when the magic number isn't present. - - PCRE_ERROR_UNKNOWN_NODE (-5) - - While running the pattern match, an unknown item was encountered in the - compiled pattern. This error could be caused by a bug in PCRE or by - overwriting of the compiled pattern. - - PCRE_ERROR_NOMEMORY (-6) - - If a pattern contains back references, but the ovector that is passed - to pcre_exec() is not big enough to remember the referenced substrings, - PCRE gets a block of memory at the start of matching to use for this - purpose. If the call via pcre_malloc() fails, this error is given. The - memory is freed at the end of matching. - - PCRE_ERROR_NOSUBSTRING (-7) - - This error is used by the pcre_copy_substring(), pcre_get_substring(), - and pcre_get_substring_list() functions (see below). It is never - returned by pcre_exec(). - - PCRE_ERROR_MATCHLIMIT (-8) - - The recursion and backtracking limit, as specified by the match_limit - field in a pcre_extra structure (or defaulted) was reached. See the - description above. - - PCRE_ERROR_CALLOUT (-9) - - This error is never generated by pcre_exec() itself. It is provided for - use by callout functions that want to yield a distinctive error code. - See the pcrecallout documentation for details. - - PCRE_ERROR_BADUTF8 (-10) - - A string that contains an invalid UTF-8 byte sequence was passed as a - subject. - - PCRE_ERROR_BADUTF8_OFFSET (-11) - - The UTF-8 byte sequence that was passed as a subject was valid, but the - value of startoffset did not point to the beginning of a UTF-8 charac- - ter. - - -EXTRACTING CAPTURED SUBSTRINGS BY NUMBER - - int pcre_copy_substring(const char *subject, int *ovector, - int stringcount, int stringnumber, char *buffer, - int buffersize); - - int pcre_get_substring(const char *subject, int *ovector, - int stringcount, int stringnumber, - const char **stringptr); - - int pcre_get_substring_list(const char *subject, - int *ovector, int stringcount, const char ***listptr); - - Captured substrings can be accessed directly by using the offsets - returned by pcre_exec() in ovector. For convenience, the functions - pcre_copy_substring(), pcre_get_substring(), and pcre_get_sub- - string_list() are provided for extracting captured substrings as new, - separate, zero-terminated strings. These functions identify substrings - by number. The next section describes functions for extracting named - substrings. A substring that contains a binary zero is correctly - extracted and has a further zero added on the end, but the result is - not, of course, a C string. - - The first three arguments are the same for all three of these func- - tions: subject is the subject string which has just been successfully - matched, ovector is a pointer to the vector of integer offsets that was - passed to pcre_exec(), and stringcount is the number of substrings that - were captured by the match, including the substring that matched the - entire regular expression. This is the value returned by pcre_exec if - it is greater than zero. If pcre_exec() returned zero, indicating that - it ran out of space in ovector, the value passed as stringcount should - be the size of the vector divided by three. - - The functions pcre_copy_substring() and pcre_get_substring() extract a - single substring, whose number is given as stringnumber. A value of - zero extracts the substring that matched the entire pattern, while - higher values extract the captured substrings. For pcre_copy_sub- - string(), the string is placed in buffer, whose length is given by - buffersize, while for pcre_get_substring() a new block of memory is - obtained via pcre_malloc, and its address is returned via stringptr. - The yield of the function is the length of the string, not including - the terminating zero, or one of - - PCRE_ERROR_NOMEMORY (-6) - - The buffer was too small for pcre_copy_substring(), or the attempt to - get memory failed for pcre_get_substring(). - - PCRE_ERROR_NOSUBSTRING (-7) - - There is no substring whose number is stringnumber. - - The pcre_get_substring_list() function extracts all available sub- - strings and builds a list of pointers to them. All this is done in a - single block of memory which is obtained via pcre_malloc. The address - of the memory block is returned via listptr, which is also the start of - the list of string pointers. The end of the list is marked by a NULL - pointer. The yield of the function is zero if all went well, or - - PCRE_ERROR_NOMEMORY (-6) - - if the attempt to get the memory block failed. - - When any of these functions encounter a substring that is unset, which - can happen when capturing subpattern number n+1 matches some part of - the subject, but subpattern n has not been used at all, they return an - empty string. This can be distinguished from a genuine zero-length sub- - string by inspecting the appropriate offset in ovector, which is nega- - tive for unset substrings. - - The two convenience functions pcre_free_substring() and - pcre_free_substring_list() can be used to free the memory returned by a - previous call of pcre_get_substring() or pcre_get_substring_list(), - respectively. They do nothing more than call the function pointed to by - pcre_free, which of course could be called directly from a C program. - However, PCRE is used in some situations where it is linked via a spe- - cial interface to another programming language which cannot use - pcre_free directly; it is for these cases that the functions are pro- - vided. - - -EXTRACTING CAPTURED SUBSTRINGS BY NAME - - int pcre_copy_named_substring(const pcre *code, - const char *subject, int *ovector, - int stringcount, const char *stringname, - char *buffer, int buffersize); - - int pcre_get_stringnumber(const pcre *code, - const char *name); - - int pcre_get_named_substring(const pcre *code, - const char *subject, int *ovector, - int stringcount, const char *stringname, - const char **stringptr); - - To extract a substring by name, you first have to find associated num- - ber. This can be done by calling pcre_get_stringnumber(). The first - argument is the compiled pattern, and the second is the name. For exam- - ple, for this pattern - - ab(?<xxx>\d+)... - - the number of the subpattern called "xxx" is 1. Given the number, you - can then extract the substring directly, or use one of the functions - described in the previous section. For convenience, there are also two - functions that do the whole job. - - Most of the arguments of pcre_copy_named_substring() and - pcre_get_named_substring() are the same as those for the functions that - extract by number, and so are not re-described here. There are just two - differences. - - First, instead of a substring number, a substring name is given. Sec- - ond, there is an extra argument, given at the start, which is a pointer - to the compiled pattern. This is needed in order to gain access to the - name-to-number translation table. - - These functions call pcre_get_stringnumber(), and if it succeeds, they - then call pcre_copy_substring() or pcre_get_substring(), as appropri- - ate. - -Last updated: 09 December 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -PCRE CALLOUTS - - int (*pcre_callout)(pcre_callout_block *); - - PCRE provides a feature called "callout", which is a means of temporar- - ily passing control to the caller of PCRE in the middle of pattern - matching. The caller of PCRE provides an external function by putting - its entry point in the global variable pcre_callout. By default, this - variable contains NULL, which disables all calling out. - - Within a regular expression, (?C) indicates the points at which the - external function is to be called. Different callout points can be - identified by putting a number less than 256 after the letter C. The - default value is zero. For example, this pattern has two callout - points: - - (?C1)abc(?C2)def - - During matching, when PCRE reaches a callout point (and pcre_callout is - set), the external function is called. Its only argument is a pointer - to a pcre_callout block. This contains the following variables: - - int version; - int callout_number; - int *offset_vector; - const char *subject; - int subject_length; - int start_match; - int current_position; - int capture_top; - int capture_last; - void *callout_data; - - The version field is an integer containing the version number of the - block format. The current version is zero. The version number may - change in future if additional fields are added, but the intention is - never to remove any of the existing fields. - - The callout_number field contains the number of the callout, as com- - piled into the pattern (that is, the number after ?C). - - The offset_vector field is a pointer to the vector of offsets that was - passed by the caller to pcre_exec(). The contents can be inspected in - order to extract substrings that have been matched so far, in the same - way as for extracting substrings after a match has completed. - - The subject and subject_length fields contain copies the values that - were passed to pcre_exec(). - - The start_match field contains the offset within the subject at which - the current match attempt started. If the pattern is not anchored, the - callout function may be called several times for different starting - points. - - The current_position field contains the offset within the subject of - the current match pointer. - - The capture_top field contains one more than the number of the highest - numbered captured substring so far. If no substrings have been - captured, the value of capture_top is one. - - The capture_last field contains the number of the most recently cap- - tured substring. - - The callout_data field contains a value that is passed to pcre_exec() - by the caller specifically so that it can be passed back in callouts. - It is passed in the pcre_callout field of the pcre_extra data struc- - ture. If no such data was passed, the value of callout_data in a - pcre_callout block is NULL. There is a description of the pcre_extra - structure in the pcreapi documentation. - - - -RETURN VALUES - - The callout function returns an integer. If the value is zero, matching - proceeds as normal. If the value is greater than zero, matching fails - at the current point, but backtracking to test other possibilities goes - ahead, just as if a lookahead assertion had failed. If the value is - less than zero, the match is abandoned, and pcre_exec() returns the - value. - - Negative values should normally be chosen from the set of - PCRE_ERROR_xxx values. In particular, PCRE_ERROR_NOMATCH forces a stan- - dard "no match" failure. The error number PCRE_ERROR_CALLOUT is - reserved for use by callout functions; it will never be used by PCRE - itself. - -Last updated: 21 January 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -DIFFERENCES FROM PERL - - This document describes the differences in the ways that PCRE and Perl - handle regular expressions. The differences described here are with - respect to Perl 5.8. - - 1. PCRE does not have full UTF-8 support. Details of what it does have - are given in the section on UTF-8 support in the main pcre page. - - 2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl - permits them, but they do not mean what you might think. For example, - (?!a){3} does not assert that the next three characters are not "a". It - just asserts that the next character is not "a" three times. - - 3. Capturing subpatterns that occur inside negative lookahead asser- - tions are counted, but their entries in the offsets vector are never - set. Perl sets its numerical variables from any such patterns that are - matched before the assertion fails to match something (thereby succeed- - ing), but only if the negative lookahead assertion contains just one - branch. - - 4. Though binary zero characters are supported in the subject string, - they are not allowed in a pattern string because it is passed as a nor- - mal C string, terminated by zero. The escape sequence "\0" can be used - in the pattern to represent a binary zero. - - 5. The following Perl escape sequences are not supported: \l, \u, \L, - \U, \P, \p, \N, and \X. In fact these are implemented by Perl's general - string-handling and are not part of its pattern matching engine. If any - of these are encountered by PCRE, an error is generated. - - 6. PCRE does support the \Q...\E escape for quoting substrings. Charac- - ters in between are treated as literals. This is slightly different - from Perl in that $ and @ are also handled as literals inside the - quotes. In Perl, they cause variable interpolation (but of course PCRE - does not have variables). Note the following examples: - - Pattern PCRE matches Perl matches - - \Qabc$xyz\E abc$xyz abc followed by the - contents of $xyz - \Qabc\$xyz\E abc\$xyz abc\$xyz - \Qabc\E\$\Qxyz\E abc$xyz abc$xyz - - The \Q...\E sequence is recognized both inside and outside character - classes. - - 7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code}) - constructions. However, there is some experimental support for recur- - sive patterns using the non-Perl items (?R), (?number) and (?P>name). - Also, the PCRE "callout" feature allows an external function to be - called during pattern matching. - - 8. There are some differences that are concerned with the settings of - captured strings when part of a pattern is repeated. For example, - matching "aba" against the pattern /^(a(b)?)+$/ in Perl leaves $2 - unset, but in PCRE it is set to "b". - - 9. PCRE provides some extensions to the Perl regular expression - facilities: - - (a) Although lookbehind assertions must match fixed length strings, - each alternative branch of a lookbehind assertion can match a different - length of string. Perl requires them all to have the same length. - - (b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ - meta-character matches only at the very end of the string. - - (c) If PCRE_EXTRA is set, a backslash followed by a letter with no spe- - cial meaning is faulted. - - (d) If PCRE_UNGREEDY is set, the greediness of the repetition quanti- - fiers is inverted, that is, by default they are not greedy, but if fol- - lowed by a question mark they are. - - (e) PCRE_ANCHORED can be used to force a pattern to be tried only at - the first matching position in the subject string. - - (f) The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAP- - TURE options for pcre_exec() have no Perl equivalents. - - (g) The (?R), (?number), and (?P>name) constructs allows for recursive - pattern matching (Perl can do this using the (?p{code}) construct, - which PCRE cannot support.) - - (h) PCRE supports named capturing substrings, using the Python syntax. - - (i) PCRE supports the possessive quantifier "++" syntax, taken from - Sun's Java package. - - (j) The (R) condition, for testing recursion, is a PCRE extension. - - (k) The callout facility is PCRE-specific. - -Last updated: 09 December 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -PCRE REGULAR EXPRESSION DETAILS - - The syntax and semantics of the regular expressions supported by PCRE - are described below. Regular expressions are also described in the Perl - documentation and in a number of other books, some of which have copi- - ous examples. Jeffrey Friedl's "Mastering Regular Expressions", pub- - lished by O'Reilly, covers them in great detail. The description here - is intended as reference documentation. - - The basic operation of PCRE is on strings of bytes. However, there is - also support for UTF-8 character strings. To use this support you must - build PCRE to include UTF-8 support, and then call pcre_compile() with - the PCRE_UTF8 option. How this affects the pattern matching is men- - tioned in several places below. There is also a summary of UTF-8 fea- - tures in the section on UTF-8 support in the main pcre page. - - A regular expression is a pattern that is matched against a subject - string from left to right. Most characters stand for themselves in a - pattern, and match the corresponding characters in the subject. As a - trivial example, the pattern - - The quick brown fox - - matches a portion of a subject string that is identical to itself. The - power of regular expressions comes from the ability to include alterna- - tives and repetitions in the pattern. These are encoded in the pattern - by the use of meta-characters, which do not stand for themselves but - instead are interpreted in some special way. - - There are two different sets of meta-characters: those that are recog- - nized anywhere in the pattern except within square brackets, and those - that are recognized in square brackets. Outside square brackets, the - meta-characters are as follows: - - \ general escape character with several uses - ^ assert start of string (or line, in multiline mode) - $ assert end of string (or line, in multiline mode) - . match any character except newline (by default) - [ start character class definition - | start of alternative branch - ( start subpattern - ) end subpattern - ? extends the meaning of ( - also 0 or 1 quantifier - also quantifier minimizer - * 0 or more quantifier - + 1 or more quantifier - also "possessive quantifier" - { start min/max quantifier - - Part of a pattern that is in square brackets is called a "character - class". In a character class the only meta-characters are: - - \ general escape character - ^ negate the class, but only if the first character - - indicates character range - [ POSIX character class (only if followed by POSIX - syntax) - ] terminates the character class - - The following sections describe the use of each of the meta-characters. - - -BACKSLASH - - The backslash character has several uses. Firstly, if it is followed by - a non-alphameric character, it takes away any special meaning that - character may have. This use of backslash as an escape character - applies both inside and outside character classes. - - For example, if you want to match a * character, you write \* in the - pattern. This escaping action applies whether or not the following - character would otherwise be interpreted as a meta-character, so it is - always safe to precede a non-alphameric with backslash to specify that - it stands for itself. In particular, if you want to match a backslash, - you write \\. - - If a pattern is compiled with the PCRE_EXTENDED option, whitespace in - the pattern (other than in a character class) and characters between a - # outside a character class and the next newline character are ignored. - An escaping backslash can be used to include a whitespace or # charac- - ter as part of the pattern. - - If you want to remove the special meaning from a sequence of charac- - ters, you can do so by putting them between \Q and \E. This is differ- - ent from Perl in that $ and @ are handled as literals in \Q...\E - sequences in PCRE, whereas in Perl, $ and @ cause variable interpola- - tion. Note the following examples: - - Pattern PCRE matches Perl matches - - \Qabc$xyz\E abc$xyz abc followed by the - contents of $xyz - \Qabc\$xyz\E abc\$xyz abc\$xyz - \Qabc\E\$\Qxyz\E abc$xyz abc$xyz - - The \Q...\E sequence is recognized both inside and outside character - classes. - - A second use of backslash provides a way of encoding non-printing char- - acters in patterns in a visible manner. There is no restriction on the - appearance of non-printing characters, apart from the binary zero that - terminates a pattern, but when a pattern is being prepared by text - editing, it is usually easier to use one of the following escape - sequences than the binary character it represents: - - \a alarm, that is, the BEL character (hex 07) - \cx "control-x", where x is any character - \e escape (hex 1B) - \f formfeed (hex 0C) - \n newline (hex 0A) - \r carriage return (hex 0D) - \t tab (hex 09) - \ddd character with octal code ddd, or backreference - \xhh character with hex code hh - \x{hhh..} character with hex code hhh... (UTF-8 mode only) - - The precise effect of \cx is as follows: if x is a lower case letter, - it is converted to upper case. Then bit 6 of the character (hex 40) is - inverted. Thus \cz becomes hex 1A, but \c{ becomes hex 3B, while \c; - becomes hex 7B. - - After \x, from zero to two hexadecimal digits are read (letters can be - in upper or lower case). In UTF-8 mode, any number of hexadecimal dig- - its may appear between \x{ and }, but the value of the character code - must be less than 2**31 (that is, the maximum hexadecimal value is - 7FFFFFFF). If characters other than hexadecimal digits appear between - \x{ and }, or if there is no terminating }, this form of escape is not - recognized. Instead, the initial \x will be interpreted as a basic hex- - adecimal escape, with no following digits, giving a byte whose value is - zero. - - Characters whose value is less than 256 can be defined by either of the - two syntaxes for \x when PCRE is in UTF-8 mode. There is no difference - in the way they are handled. For example, \xdc is exactly the same as - \x{dc}. - - After \0 up to two further octal digits are read. In both cases, if - there are fewer than two digits, just those that are present are used. - Thus the sequence \0\x\07 specifies two binary zeros followed by a BEL - character (code value 7). Make sure you supply two digits after the - initial zero if the character that follows is itself an octal digit. - - The handling of a backslash followed by a digit other than 0 is compli- - cated. Outside a character class, PCRE reads it and any following dig- - its as a decimal number. If the number is less than 10, or if there - have been at least that many previous capturing left parentheses in the - expression, the entire sequence is taken as a back reference. A - description of how this works is given later, following the discussion - of parenthesized subpatterns. - - Inside a character class, or if the decimal number is greater than 9 - and there have not been that many capturing subpatterns, PCRE re-reads - up to three octal digits following the backslash, and generates a sin- - gle byte from the least significant 8 bits of the value. Any subsequent - digits stand for themselves. For example: - - \040 is another way of writing a space - \40 is the same, provided there are fewer than 40 - previous capturing subpatterns - \7 is always a back reference - \11 might be a back reference, or another way of - writing a tab - \011 is always a tab - \0113 is a tab followed by the character "3" - \113 might be a back reference, otherwise the - character with octal code 113 - \377 might be a back reference, otherwise - the byte consisting entirely of 1 bits - \81 is either a back reference, or a binary zero - followed by the two characters "8" and "1" - - Note that octal values of 100 or greater must not be introduced by a - leading zero, because no more than three octal digits are ever read. - - All the sequences that define a single byte value or a single UTF-8 - character (in UTF-8 mode) can be used both inside and outside character - classes. In addition, inside a character class, the sequence \b is - interpreted as the backspace character (hex 08). Outside a character - class it has a different meaning (see below). - - The third use of backslash is for specifying generic character types: - - \d any decimal digit - \D any character that is not a decimal digit - \s any whitespace character - \S any character that is not a whitespace character - \w any "word" character - \W any "non-word" character - - Each pair of escape sequences partitions the complete set of characters - into two disjoint sets. Any given character matches one, and only one, - of each pair. - - In UTF-8 mode, characters with values greater than 255 never match \d, - \s, or \w, and always match \D, \S, and \W. - - For compatibility with Perl, \s does not match the VT character (code - 11). This makes it different from the the POSIX "space" class. The \s - characters are HT (9), LF (10), FF (12), CR (13), and space (32). - - A "word" character is any letter or digit or the underscore character, - that is, any character which can be part of a Perl "word". The defini- - tion of letters and digits is controlled by PCRE's character tables, - and may vary if locale- specific matching is taking place (see "Locale - support" in the pcreapi page). For example, in the "fr" (French) - locale, some character codes greater than 128 are used for accented - letters, and these are matched by \w. - - These character type sequences can appear both inside and outside char- - acter classes. They each match one character of the appropriate type. - If the current matching point is at the end of the subject string, all - of them fail, since there is no character to match. - - The fourth use of backslash is for certain simple assertions. An asser- - tion specifies a condition that has to be met at a particular point in - a match, without consuming any characters from the subject string. The - use of subpatterns for more complicated assertions is described below. - The backslashed assertions are - - \b matches at a word boundary - \B matches when not at a word boundary - \A matches at start of subject - \Z matches at end of subject or before newline at end - \z matches at end of subject - \G matches at first matching position in subject - - These assertions may not appear in character classes (but note that \b - has a different meaning, namely the backspace character, inside a char- - acter class). - - A word boundary is a position in the subject string where the current - character and the previous character do not both match \w or \W (i.e. - one matches \w and the other matches \W), or the start or end of the - string if the first or last character matches \w, respectively. - - The \A, \Z, and \z assertions differ from the traditional circumflex - and dollar (described below) in that they only ever match at the very - start and end of the subject string, whatever options are set. Thus, - they are independent of multiline mode. - - They are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options. If the - startoffset argument of pcre_exec() is non-zero, indicating that match- - ing is to start at a point other than the beginning of the subject, \A - can never match. The difference between \Z and \z is that \Z matches - before a newline that is the last character of the string as well as at - the end of the string, whereas \z matches only at the end. - - The \G assertion is true only when the current matching position is at - the start point of the match, as specified by the startoffset argument - of pcre_exec(). It differs from \A when the value of startoffset is - non-zero. By calling pcre_exec() multiple times with appropriate argu- - ments, you can mimic Perl's /g option, and it is in this kind of imple- - mentation where \G can be useful. - - Note, however, that PCRE's interpretation of \G, as the start of the - current match, is subtly different from Perl's, which defines it as the - end of the previous match. In Perl, these can be different when the - previously matched string was empty. Because PCRE does just one match - at a time, it cannot reproduce this behaviour. - - If all the alternatives of a pattern begin with \G, the expression is - anchored to the starting match position, and the "anchored" flag is set - in the compiled regular expression. - - -CIRCUMFLEX AND DOLLAR - - Outside a character class, in the default matching mode, the circumflex - character is an assertion which is true only if the current matching - point is at the start of the subject string. If the startoffset argu- - ment of pcre_exec() is non-zero, circumflex can never match if the - PCRE_MULTILINE option is unset. Inside a character class, circumflex - has an entirely different meaning (see below). - - Circumflex need not be the first character of the pattern if a number - of alternatives are involved, but it should be the first thing in each - alternative in which it appears if the pattern is ever to match that - branch. If all possible alternatives start with a circumflex, that is, - if the pattern is constrained to match only at the start of the sub- - ject, it is said to be an "anchored" pattern. (There are also other - constructs that can cause a pattern to be anchored.) - - A dollar character is an assertion which is true only if the current - matching point is at the end of the subject string, or immediately - before a newline character that is the last character in the string (by - default). Dollar need not be the last character of the pattern if a - number of alternatives are involved, but it should be the last item in - any branch in which it appears. Dollar has no special meaning in a - character class. - - The meaning of dollar can be changed so that it matches only at the - very end of the string, by setting the PCRE_DOLLAR_ENDONLY option at - compile time. This does not affect the \Z assertion. - - The meanings of the circumflex and dollar characters are changed if the - PCRE_MULTILINE option is set. When this is the case, they match immedi- - ately after and immediately before an internal newline character, - respectively, in addition to matching at the start and end of the sub- - ject string. For example, the pattern /^abc$/ matches the subject - string "def\nabc" in multiline mode, but not otherwise. Consequently, - patterns that are anchored in single line mode because all branches - start with ^ are not anchored in multiline mode, and a match for cir- - cumflex is possible when the startoffset argument of pcre_exec() is - non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE - is set. - - Note that the sequences \A, \Z, and \z can be used to match the start - and end of the subject in both modes, and if all branches of a pattern - start with \A it is always anchored, whether PCRE_MULTILINE is set or - not. - - -FULL STOP (PERIOD, DOT) - - Outside a character class, a dot in the pattern matches any one charac- - ter in the subject, including a non-printing character, but not (by - default) newline. In UTF-8 mode, a dot matches any UTF-8 character, - which might be more than one byte long, except (by default) for new- - line. If the PCRE_DOTALL option is set, dots match newlines as well. - The handling of dot is entirely independent of the handling of circum- - flex and dollar, the only relationship being that they both involve - newline characters. Dot has no special meaning in a character class. - - -MATCHING A SINGLE BYTE - - Outside a character class, the escape sequence \C matches any one byte, - both in and out of UTF-8 mode. Unlike a dot, it always matches a new- - line. The feature is provided in Perl in order to match individual - bytes in UTF-8 mode. Because it breaks up UTF-8 characters into indi- - vidual bytes, what remains in the string may be a malformed UTF-8 - string. For this reason it is best avoided. - - PCRE does not allow \C to appear in lookbehind assertions (see below), - because in UTF-8 mode it makes it impossible to calculate the length of - the lookbehind. - - -SQUARE BRACKETS - - An opening square bracket introduces a character class, terminated by a - closing square bracket. A closing square bracket on its own is not spe- - cial. If a closing square bracket is required as a member of the class, - it should be the first data character in the class (after an initial - circumflex, if present) or escaped with a backslash. - - A character class matches a single character in the subject. In UTF-8 - mode, the character may occupy more than one byte. A matched character - must be in the set of characters defined by the class, unless the first - character in the class definition is a circumflex, in which case the - subject character must not be in the set defined by the class. If a - circumflex is actually required as a member of the class, ensure it is - not the first character, or escape it with a backslash. - - For example, the character class [aeiou] matches any lower case vowel, - while [^aeiou] matches any character that is not a lower case vowel. - Note that a circumflex is just a convenient notation for specifying the - characters which are in the class by enumerating those that are not. It - is not an assertion: it still consumes a character from the subject - string, and fails if the current pointer is at the end of the string. - - In UTF-8 mode, characters with values greater than 255 can be included - in a class as a literal string of bytes, or by using the \x{ escaping - mechanism. - - When caseless matching is set, any letters in a class represent both - their upper case and lower case versions, so for example, a caseless - [aeiou] matches "A" as well as "a", and a caseless [^aeiou] does not - match "A", whereas a caseful version would. PCRE does not support the - concept of case for characters with values greater than 255. - - The newline character is never treated in any special way in character - classes, whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE - options is. A class such as [^a] will always match a newline. - - The minus (hyphen) character can be used to specify a range of charac- - ters in a character class. For example, [d-m] matches any letter - between d and m, inclusive. If a minus character is required in a - class, it must be escaped with a backslash or appear in a position - where it cannot be interpreted as indicating a range, typically as the - first or last character in the class. - - It is not possible to have the literal character "]" as the end charac- - ter of a range. A pattern such as [W-]46] is interpreted as a class of - two characters ("W" and "-") followed by a literal string "46]", so it - would match "W46]" or "-46]". However, if the "]" is escaped with a - backslash it is interpreted as the end of range, so [W-\]46] is inter- - preted as a single class containing a range followed by two separate - characters. The octal or hexadecimal representation of "]" can also be - used to end a range. - - Ranges operate in the collating sequence of character values. They can - also be used for characters specified numerically, for example - [\000-\037]. In UTF-8 mode, ranges can include characters whose values - are greater than 255, for example [\x{100}-\x{2ff}]. - - If a range that includes letters is used when caseless matching is set, - it matches the letters in either case. For example, [W-c] is equivalent - to [][\^_`wxyzabc], matched caselessly, and if character tables for the - "fr" locale are in use, [\xc8-\xcb] matches accented E characters in - both cases. - - The character types \d, \D, \s, \S, \w, and \W may also appear in a - character class, and add the characters that they match to the class. - For example, [\dABCDEF] matches any hexadecimal digit. A circumflex can - conveniently be used with the upper case character types to specify a - more restricted set of characters than the matching lower case type. - For example, the class [^\W_] matches any letter or digit, but not - underscore. - - All non-alphameric characters other than \, -, ^ (at the start) and the - terminating ] are non-special in character classes, but it does no harm - if they are escaped. - - -POSIX CHARACTER CLASSES - - Perl supports the POSIX notation for character classes, which uses - names enclosed by [: and :] within the enclosing square brackets. PCRE - also supports this notation. For example, - - [01[:alpha:]%] - - matches "0", "1", any alphabetic character, or "%". The supported class - names are - - alnum letters and digits - alpha letters - ascii character codes 0 - 127 - blank space or tab only - cntrl control characters - digit decimal digits (same as \d) - graph printing characters, excluding space - lower lower case letters - print printing characters, including space - punct printing characters, excluding letters and digits - space white space (not quite the same as \s) - upper upper case letters - word "word" characters (same as \w) - xdigit hexadecimal digits - - The "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13), - and space (32). Notice that this list includes the VT character (code - 11). This makes "space" different to \s, which does not include VT (for - Perl compatibility). - - The name "word" is a Perl extension, and "blank" is a GNU extension - from Perl 5.8. Another Perl extension is negation, which is indicated - by a ^ character after the colon. For example, - - [12[:^digit:]] - - matches "1", "2", or any non-digit. PCRE (and Perl) also recognize the - POSIX syntax [.ch.] and [=ch=] where "ch" is a "collating element", but - these are not supported, and an error is given if they are encountered. - - In UTF-8 mode, characters with values greater than 255 do not match any - of the POSIX character classes. - - -VERTICAL BAR - - Vertical bar characters are used to separate alternative patterns. For - example, the pattern - - gilbert|sullivan - - matches either "gilbert" or "sullivan". Any number of alternatives may - appear, and an empty alternative is permitted (matching the empty - string). The matching process tries each alternative in turn, from - left to right, and the first one that succeeds is used. If the alterna- - tives are within a subpattern (defined below), "succeeds" means match- - ing the rest of the main pattern as well as the alternative in the sub- - pattern. - - -INTERNAL OPTION SETTING - - The settings of the PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and - PCRE_EXTENDED options can be changed from within the pattern by a - sequence of Perl option letters enclosed between "(?" and ")". The - option letters are - - i for PCRE_CASELESS - m for PCRE_MULTILINE - s for PCRE_DOTALL - x for PCRE_EXTENDED - - For example, (?im) sets caseless, multiline matching. It is also possi- - ble to unset these options by preceding the letter with a hyphen, and a - combined setting and unsetting such as (?im-sx), which sets PCRE_CASE- - LESS and PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, - is also permitted. If a letter appears both before and after the - hyphen, the option is unset. - - When an option change occurs at top level (that is, not inside subpat- - tern parentheses), the change applies to the remainder of the pattern - that follows. If the change is placed right at the start of a pattern, - PCRE extracts it into the global options (and it will therefore show up - in data extracted by the pcre_fullinfo() function). - - An option change within a subpattern affects only that part of the cur- - rent pattern that follows it, so - - (a(?i)b)c - - matches abc and aBc and no other strings (assuming PCRE_CASELESS is not - used). By this means, options can be made to have different settings - in different parts of the pattern. Any changes made in one alternative - do carry on into subsequent branches within the same subpattern. For - example, - - (a(?i)b|c) - - matches "ab", "aB", "c", and "C", even though when matching "C" the - first branch is abandoned before the option setting. This is because - the effects of option settings happen at compile time. There would be - some very weird behaviour otherwise. - - The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed - in the same way as the Perl-compatible options by using the characters - U and X respectively. The (?X) flag setting is special in that it must - always occur earlier in the pattern than any of the additional features - it turns on, even when it is at top level. It is best put at the start. - - -SUBPATTERNS - - Subpatterns are delimited by parentheses (round brackets), which can be - nested. Marking part of a pattern as a subpattern does two things: - - 1. It localizes a set of alternatives. For example, the pattern - - cat(aract|erpillar|) - - matches one of the words "cat", "cataract", or "caterpillar". Without - the parentheses, it would match "cataract", "erpillar" or the empty - string. - - 2. It sets up the subpattern as a capturing subpattern (as defined - above). When the whole pattern matches, that portion of the subject - string that matched the subpattern is passed back to the caller via the - ovector argument of pcre_exec(). Opening parentheses are counted from - left to right (starting from 1) to obtain the numbers of the capturing - subpatterns. - - For example, if the string "the red king" is matched against the pat- - tern - - the ((red|white) (king|queen)) - - the captured substrings are "red king", "red", and "king", and are num- - bered 1, 2, and 3, respectively. - - The fact that plain parentheses fulfil two functions is not always - helpful. There are often times when a grouping subpattern is required - without a capturing requirement. If an opening parenthesis is followed - by a question mark and a colon, the subpattern does not do any captur- - ing, and is not counted when computing the number of any subsequent - capturing subpatterns. For example, if the string "the white queen" is - matched against the pattern - - the ((?:red|white) (king|queen)) - - the captured substrings are "white queen" and "queen", and are numbered - 1 and 2. The maximum number of capturing subpatterns is 65535, and the - maximum depth of nesting of all subpatterns, both capturing and non- - capturing, is 200. - - As a convenient shorthand, if any option settings are required at the - start of a non-capturing subpattern, the option letters may appear - between the "?" and the ":". Thus the two patterns - - (?i:saturday|sunday) - (?:(?i)saturday|sunday) - - match exactly the same set of strings. Because alternative branches are - tried from left to right, and options are not reset until the end of - the subpattern is reached, an option setting in one branch does affect - subsequent branches, so the above patterns match "SUNDAY" as well as - "Saturday". - - -NAMED SUBPATTERNS - - Identifying capturing parentheses by number is simple, but it can be - very hard to keep track of the numbers in complicated regular expres- - sions. Furthermore, if an expression is modified, the numbers may - change. To help with the difficulty, PCRE supports the naming of sub- - patterns, something that Perl does not provide. The Python syntax - (?P<name>...) is used. Names consist of alphanumeric characters and - underscores, and must be unique within a pattern. - - Named capturing parentheses are still allocated numbers as well as - names. The PCRE API provides function calls for extracting the name-to- - number translation table from a compiled pattern. For further details - see the pcreapi documentation. - - -REPETITION - - Repetition is specified by quantifiers, which can follow any of the - following items: - - a literal data character - the . metacharacter - the \C escape sequence - escapes such as \d that match single characters - a character class - a back reference (see next section) - a parenthesized subpattern (unless it is an assertion) - - The general repetition quantifier specifies a minimum and maximum num- - ber of permitted matches, by giving the two numbers in curly brackets - (braces), separated by a comma. The numbers must be less than 65536, - and the first must be less than or equal to the second. For example: - - z{2,4} - - matches "zz", "zzz", or "zzzz". A closing brace on its own is not a - special character. If the second number is omitted, but the comma is - present, there is no upper limit; if the second number and the comma - are both omitted, the quantifier specifies an exact number of required - matches. Thus - - [aeiou]{3,} - - matches at least 3 successive vowels, but may match many more, while - - \d{8} - - matches exactly 8 digits. An opening curly bracket that appears in a - position where a quantifier is not allowed, or one that does not match - the syntax of a quantifier, is taken as a literal character. For exam- - ple, {,6} is not a quantifier, but a literal string of four characters. - - In UTF-8 mode, quantifiers apply to UTF-8 characters rather than to - individual bytes. Thus, for example, \x{100}{2} matches two UTF-8 char- - acters, each of which is represented by a two-byte sequence. - - The quantifier {0} is permitted, causing the expression to behave as if - the previous item and the quantifier were not present. - - For convenience (and historical compatibility) the three most common - quantifiers have single-character abbreviations: - - * is equivalent to {0,} - + is equivalent to {1,} - ? is equivalent to {0,1} - - It is possible to construct infinite loops by following a subpattern - that can match no characters with a quantifier that has no upper limit, - for example: - - (a?)* - - Earlier versions of Perl and PCRE used to give an error at compile time - for such patterns. However, because there are cases where this can be - useful, such patterns are now accepted, but if any repetition of the - subpattern does in fact match no characters, the loop is forcibly bro- - ken. - - By default, the quantifiers are "greedy", that is, they match as much - as possible (up to the maximum number of permitted times), without - causing the rest of the pattern to fail. The classic example of where - this gives problems is in trying to match comments in C programs. These - appear between the sequences /* and */ and within the sequence, indi- - vidual * and / characters may appear. An attempt to match C comments by - applying the pattern - - /\*.*\*/ - - to the string - - /* first command */ not comment /* second comment */ - - fails, because it matches the entire string owing to the greediness of - the .* item. - - However, if a quantifier is followed by a question mark, it ceases to - be greedy, and instead matches the minimum number of times possible, so - the pattern - - /\*.*?\*/ - - does the right thing with the C comments. The meaning of the various - quantifiers is not otherwise changed, just the preferred number of - matches. Do not confuse this use of question mark with its use as a - quantifier in its own right. Because it has two uses, it can sometimes - appear doubled, as in - - \d??\d - - which matches one digit by preference, but can match two if that is the - only way the rest of the pattern matches. - - If the PCRE_UNGREEDY option is set (an option which is not available in - Perl), the quantifiers are not greedy by default, but individual ones - can be made greedy by following them with a question mark. In other - words, it inverts the default behaviour. - - When a parenthesized subpattern is quantified with a minimum repeat - count that is greater than 1 or with a limited maximum, more store is - required for the compiled pattern, in proportion to the size of the - minimum or maximum. - - If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equiv- - alent to Perl's /s) is set, thus allowing the . to match newlines, the - pattern is implicitly anchored, because whatever follows will be tried - against every character position in the subject string, so there is no - point in retrying the overall match at any position after the first. - PCRE normally treats such a pattern as though it were preceded by \A. - - In cases where it is known that the subject string contains no new- - lines, it is worth setting PCRE_DOTALL in order to obtain this opti- - mization, or alternatively using ^ to indicate anchoring explicitly. - - However, there is one situation where the optimization cannot be used. - When .* is inside capturing parentheses that are the subject of a - backreference elsewhere in the pattern, a match at the start may fail, - and a later one succeed. Consider, for example: - - (.*)abc\1 - - If the subject is "xyz123abc123" the match point is the fourth charac- - ter. For this reason, such a pattern is not implicitly anchored. - - When a capturing subpattern is repeated, the value captured is the sub- - string that matched the final iteration. For example, after - - (tweedle[dume]{3}\s*)+ - - has matched "tweedledum tweedledee" the value of the captured substring - is "tweedledee". However, if there are nested capturing subpatterns, - the corresponding captured values may have been set in previous itera- - tions. For example, after - - /(a|(b))+/ - - matches "aba" the value of the second captured substring is "b". - - -ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS - - With both maximizing and minimizing repetition, failure of what follows - normally causes the repeated item to be re-evaluated to see if a dif- - ferent number of repeats allows the rest of the pattern to match. Some- - times it is useful to prevent this, either to change the nature of the - match, or to cause it fail earlier than it otherwise might, when the - author of the pattern knows there is no point in carrying on. - - Consider, for example, the pattern \d+foo when applied to the subject - line - - 123456bar - - After matching all 6 digits and then failing to match "foo", the normal - action of the matcher is to try again with only 5 digits matching the - \d+ item, and then with 4, and so on, before ultimately failing. - "Atomic grouping" (a term taken from Jeffrey Friedl's book) provides - the means for specifying that once a subpattern has matched, it is not - to be re-evaluated in this way. - - If we use atomic grouping for the previous example, the matcher would - give up immediately on failing to match "foo" the first time. The nota- - tion is a kind of special parenthesis, starting with (?> as in this - example: - - (?>\d+)foo - - This kind of parenthesis "locks up" the part of the pattern it con- - tains once it has matched, and a failure further into the pattern is - prevented from backtracking into it. Backtracking past it to previous - items, however, works as normal. - - An alternative description is that a subpattern of this type matches - the string of characters that an identical standalone pattern would - match, if anchored at the current point in the subject string. - - Atomic grouping subpatterns are not capturing subpatterns. Simple cases - such as the above example can be thought of as a maximizing repeat that - must swallow everything it can. So, while both \d+ and \d+? are pre- - pared to adjust the number of digits they match in order to make the - rest of the pattern match, (?>\d+) can only match an entire sequence of - digits. - - Atomic groups in general can of course contain arbitrarily complicated - subpatterns, and can be nested. However, when the subpattern for an - atomic group is just a single repeated item, as in the example above, a - simpler notation, called a "possessive quantifier" can be used. This - consists of an additional + character following a quantifier. Using - this notation, the previous example can be rewritten as - - \d++bar - - Possessive quantifiers are always greedy; the setting of the - PCRE_UNGREEDY option is ignored. They are a convenient notation for the - simpler forms of atomic group. However, there is no difference in the - meaning or processing of a possessive quantifier and the equivalent - atomic group. - - The possessive quantifier syntax is an extension to the Perl syntax. It - originates in Sun's Java package. - - When a pattern contains an unlimited repeat inside a subpattern that - can itself be repeated an unlimited number of times, the use of an - atomic group is the only way to avoid some failing matches taking a - very long time indeed. The pattern - - (\D+|<\d+>)*[!?] - - matches an unlimited number of substrings that either consist of non- - digits, or digits enclosed in <>, followed by either ! or ?. When it - matches, it runs quickly. However, if it is applied to - - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa - - it takes a long time before reporting failure. This is because the - string can be divided between the two repeats in a large number of - ways, and all have to be tried. (The example used [!?] rather than a - single character at the end, because both PCRE and Perl have an opti- - mization that allows for fast failure when a single character is used. - They remember the last single character that is required for a match, - and fail early if it is not present in the string.) If the pattern is - changed to - - ((?>\D+)|<\d+>)*[!?] - - sequences of non-digits cannot be broken, and failure happens quickly. - - -BACK REFERENCES - - Outside a character class, a backslash followed by a digit greater than - 0 (and possibly further digits) is a back reference to a capturing sub- - pattern earlier (that is, to its left) in the pattern, provided there - have been that many previous capturing left parentheses. - - However, if the decimal number following the backslash is less than 10, - it is always taken as a back reference, and causes an error only if - there are not that many capturing left parentheses in the entire pat- - tern. In other words, the parentheses that are referenced need not be - to the left of the reference for numbers less than 10. See the section - entitled "Backslash" above for further details of the handling of dig- - its following a backslash. - - A back reference matches whatever actually matched the capturing sub- - pattern in the current subject string, rather than anything matching - the subpattern itself (see "Subpatterns as subroutines" below for a way - of doing that). So the pattern - - (sens|respons)e and \1ibility - - matches "sense and sensibility" and "response and responsibility", but - not "sense and responsibility". If caseful matching is in force at the - time of the back reference, the case of letters is relevant. For exam- - ple, - - ((?i)rah)\s+\1 - - matches "rah rah" and "RAH RAH", but not "RAH rah", even though the - original capturing subpattern is matched caselessly. - - Back references to named subpatterns use the Python syntax (?P=name). - We could rewrite the above example as follows: - - (?<p1>(?i)rah)\s+(?P=p1) - - There may be more than one back reference to the same subpattern. If a - subpattern has not actually been used in a particular match, any back - references to it always fail. For example, the pattern - - (a|(bc))\2 - - always fails if it starts to match "a" rather than "bc". Because there - may be many capturing parentheses in a pattern, all digits following - the backslash are taken as part of a potential back reference number. - If the pattern continues with a digit character, some delimiter must be - used to terminate the back reference. If the PCRE_EXTENDED option is - set, this can be whitespace. Otherwise an empty comment can be used. - - A back reference that occurs inside the parentheses to which it refers - fails when the subpattern is first used, so, for example, (a\1) never - matches. However, such references can be useful inside repeated sub- - patterns. For example, the pattern - - (a|b\1)+ - - matches any number of "a"s and also "aba", "ababbaa" etc. At each iter- - ation of the subpattern, the back reference matches the character - string corresponding to the previous iteration. In order for this to - work, the pattern must be such that the first iteration does not need - to match the back reference. This can be done using alternation, as in - the example above, or by a quantifier with a minimum of zero. - - -ASSERTIONS - - An assertion is a test on the characters following or preceding the - current matching point that does not actually consume any characters. - The simple assertions coded as \b, \B, \A, \G, \Z, \z, ^ and $ are - described above. More complicated assertions are coded as subpatterns. - There are two kinds: those that look ahead of the current position in - the subject string, and those that look behind it. - - An assertion subpattern is matched in the normal way, except that it - does not cause the current matching position to be changed. Lookahead - assertions start with (?= for positive assertions and (?! for negative - assertions. For example, - - \w+(?=;) - - matches a word followed by a semicolon, but does not include the semi- - colon in the match, and - - foo(?!bar) - - matches any occurrence of "foo" that is not followed by "bar". Note - that the apparently similar pattern - - (?!foo)bar - - does not find an occurrence of "bar" that is preceded by something - other than "foo"; it finds any occurrence of "bar" whatsoever, because - the assertion (?!foo) is always true when the next three characters are - "bar". A lookbehind assertion is needed to achieve this effect. - - If you want to force a matching failure at some point in a pattern, the - most convenient way to do it is with (?!) because an empty string - always matches, so an assertion that requires there not to be an empty - string must always fail. - - Lookbehind assertions start with (?<= for positive assertions and (?<! - for negative assertions. For example, - - (?<!foo)bar - - does find an occurrence of "bar" that is not preceded by "foo". The - contents of a lookbehind assertion are restricted such that all the - strings it matches must have a fixed length. However, if there are sev- - eral alternatives, they do not all have to have the same fixed length. - Thus - - (?<=bullock|donkey) - - is permitted, but - - (?<!dogs?|cats?) - - causes an error at compile time. Branches that match different length - strings are permitted only at the top level of a lookbehind assertion. - This is an extension compared with Perl (at least for 5.8), which - requires all branches to match the same length of string. An assertion - such as - - (?<=ab(c|de)) - - is not permitted, because its single top-level branch can match two - different lengths, but it is acceptable if rewritten to use two top- - level branches: - - (?<=abc|abde) - - The implementation of lookbehind assertions is, for each alternative, - to temporarily move the current position back by the fixed width and - then try to match. If there are insufficient characters before the cur- - rent position, the match is deemed to fail. - - PCRE does not allow the \C escape (which matches a single byte in UTF-8 - mode) to appear in lookbehind assertions, because it makes it impossi- - ble to calculate the length of the lookbehind. - - Atomic groups can be used in conjunction with lookbehind assertions to - specify efficient matching at the end of the subject string. Consider a - simple pattern such as - - abcd$ - - when applied to a long string that does not match. Because matching - proceeds from left to right, PCRE will look for each "a" in the subject - and then see if what follows matches the rest of the pattern. If the - pattern is specified as - - ^.*abcd$ - - the initial .* matches the entire string at first, but when this fails - (because there is no following "a"), it backtracks to match all but the - last character, then all but the last two characters, and so on. Once - again the search for "a" covers the entire string, from right to left, - so we are no better off. However, if the pattern is written as - - ^(?>.*)(?<=abcd) - - or, equivalently, - - ^.*+(?<=abcd) - - there can be no backtracking for the .* item; it can match only the - entire string. The subsequent lookbehind assertion does a single test - on the last four characters. If it fails, the match fails immediately. - For long strings, this approach makes a significant difference to the - processing time. - - Several assertions (of any sort) may occur in succession. For example, - - (?<=\d{3})(?<!999)foo - - matches "foo" preceded by three digits that are not "999". Notice that - each of the assertions is applied independently at the same point in - the subject string. First there is a check that the previous three - characters are all digits, and then there is a check that the same - three characters are not "999". This pattern does not match "foo" pre- - ceded by six characters, the first of which are digits and the last - three of which are not "999". For example, it doesn't match "123abc- - foo". A pattern to do that is - - (?<=\d{3}...)(?<!999)foo - - This time the first assertion looks at the preceding six characters, - checking that the first three are digits, and then the second assertion - checks that the preceding three characters are not "999". - - Assertions can be nested in any combination. For example, - - (?<=(?<!foo)bar)baz - - matches an occurrence of "baz" that is preceded by "bar" which in turn - is not preceded by "foo", while - - (?<=\d{3}(?!999)...)foo - - is another pattern which matches "foo" preceded by three digits and any - three characters that are not "999". - - Assertion subpatterns are not capturing subpatterns, and may not be - repeated, because it makes no sense to assert the same thing several - times. If any kind of assertion contains capturing subpatterns within - it, these are counted for the purposes of numbering the capturing sub- - patterns in the whole pattern. However, substring capturing is carried - out only for positive assertions, because it does not make sense for - negative assertions. - - -CONDITIONAL SUBPATTERNS - - It is possible to cause the matching process to obey a subpattern con- - ditionally or to choose between two alternative subpatterns, depending - on the result of an assertion, or whether a previous capturing - subpattern matched or not. The two possible forms of conditional sub- - pattern are - - (?(condition)yes-pattern) - (?(condition)yes-pattern|no-pattern) - - If the condition is satisfied, the yes-pattern is used; otherwise the - no-pattern (if present) is used. If there are more than two alterna- - tives in the subpattern, a compile-time error occurs. - - There are three kinds of condition. If the text between the parentheses - consists of a sequence of digits, the condition is satisfied if the - capturing subpattern of that number has previously matched. The number - must be greater than zero. Consider the following pattern, which con- - tains non-significant white space to make it more readable (assume the - PCRE_EXTENDED option) and to divide it into three parts for ease of - discussion: - - ( \( )? [^()]+ (?(1) \) ) - - The first part matches an optional opening parenthesis, and if that - character is present, sets it as the first captured substring. The sec- - ond part matches one or more characters that are not parentheses. The - third part is a conditional subpattern that tests whether the first set - of parentheses matched or not. If they did, that is, if subject started - with an opening parenthesis, the condition is true, and so the yes-pat- - tern is executed and a closing parenthesis is required. Otherwise, - since no-pattern is not present, the subpattern matches nothing. In - other words, this pattern matches a sequence of non-parentheses, - optionally enclosed in parentheses. - - If the condition is the string (R), it is satisfied if a recursive call - to the pattern or subpattern has been made. At "top level", the condi- - tion is false. This is a PCRE extension. Recursive patterns are - described in the next section. - - If the condition is not a sequence of digits or (R), it must be an - assertion. This may be a positive or negative lookahead or lookbehind - assertion. Consider this pattern, again containing non-significant - white space, and with the two alternatives on the second line: - - (?(?=[^a-z]*[a-z]) - \d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} ) - - The condition is a positive lookahead assertion that matches an - optional sequence of non-letters followed by a letter. In other words, - it tests for the presence of at least one letter in the subject. If a - letter is found, the subject is matched against the first alternative; - otherwise it is matched against the second. This pattern matches - strings in one of the two forms dd-aaa-dd or dd-dd-dd, where aaa are - letters and dd are digits. - - -COMMENTS - - The sequence (?# marks the start of a comment which continues up to the - next closing parenthesis. Nested parentheses are not permitted. The - characters that make up a comment play no part in the pattern matching - at all. - - If the PCRE_EXTENDED option is set, an unescaped # character outside a - character class introduces a comment that continues up to the next new- - line character in the pattern. - - -RECURSIVE PATTERNS - - Consider the problem of matching a string in parentheses, allowing for - unlimited nested parentheses. Without the use of recursion, the best - that can be done is to use a pattern that matches up to some fixed - depth of nesting. It is not possible to handle an arbitrary nesting - depth. Perl has provided an experimental facility that allows regular - expressions to recurse (amongst other things). It does this by interpo- - lating Perl code in the expression at run time, and the code can refer - to the expression itself. A Perl pattern to solve the parentheses prob- - lem can be created like this: - - $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x; - - The (?p{...}) item interpolates Perl code at run time, and in this case - refers recursively to the pattern in which it appears. Obviously, PCRE - cannot support the interpolation of Perl code. Instead, it supports - some special syntax for recursion of the entire pattern, and also for - individual subpattern recursion. - - The special item that consists of (? followed by a number greater than - zero and a closing parenthesis is a recursive call of the subpattern of - the given number, provided that it occurs inside that subpattern. (If - not, it is a "subroutine" call, which is described in the next sec- - tion.) The special item (?R) is a recursive call of the entire regular - expression. - - For example, this PCRE pattern solves the nested parentheses problem - (assume the PCRE_EXTENDED option is set so that white space is - ignored): - - \( ( (?>[^()]+) | (?R) )* \) - - First it matches an opening parenthesis. Then it matches any number of - substrings which can either be a sequence of non-parentheses, or a - recursive match of the pattern itself (that is a correctly parenthe- - sized substring). Finally there is a closing parenthesis. - - If this were part of a larger pattern, you would not want to recurse - the entire pattern, so instead you could use this: - - ( \( ( (?>[^()]+) | (?1) )* \) ) - - We have put the pattern into parentheses, and caused the recursion to - refer to them instead of the whole pattern. In a larger pattern, keep- - ing track of parenthesis numbers can be tricky. It may be more conve- - nient to use named parentheses instead. For this, PCRE uses (?P>name), - which is an extension to the Python syntax that PCRE uses for named - parentheses (Perl does not provide named parentheses). We could rewrite - the above example as follows: - - (?P<pn> \( ( (?>[^()]+) | (?P>pn) )* \) ) - - This particular example pattern contains nested unlimited repeats, and - so the use of atomic grouping for matching strings of non-parentheses - is important when applying the pattern to strings that do not match. - For example, when this pattern is applied to - - (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() - - it yields "no match" quickly. However, if atomic grouping is not used, - the match runs for a very long time indeed because there are so many - different ways the + and * repeats can carve up the subject, and all - have to be tested before failure can be reported. - - At the end of a match, the values set for any capturing subpatterns are - those from the outermost level of the recursion at which the subpattern - value is set. If you want to obtain intermediate values, a callout - function can be used (see below and the pcrecallout documentation). If - the pattern above is matched against - - (ab(cd)ef) - - the value for the capturing parentheses is "ef", which is the last - value taken on at the top level. If additional parentheses are added, - giving - - \( ( ( (?>[^()]+) | (?R) )* ) \) - ^ ^ - ^ ^ - - the string they capture is "ab(cd)ef", the contents of the top level - parentheses. If there are more than 15 capturing parentheses in a pat- - tern, PCRE has to obtain extra memory to store data during a recursion, - which it does by using pcre_malloc, freeing it via pcre_free after- - wards. If no memory can be obtained, the match fails with the - PCRE_ERROR_NOMEMORY error. - - Do not confuse the (?R) item with the condition (R), which tests for - recursion. Consider this pattern, which matches text in angle brack- - ets, allowing for arbitrary nesting. Only digits are allowed in nested - brackets (that is, when recursing), whereas any characters are permit- - ted at the outer level. - - < (?: (?(R) \d++ | [^<>]*+) | (?R)) * > - - In this pattern, (?(R) is the start of a conditional subpattern, with - two different alternatives for the recursive and non-recursive cases. - The (?R) item is the actual recursive call. - - -SUBPATTERNS AS SUBROUTINES - - If the syntax for a recursive subpattern reference (either by number or - by name) is used outside the parentheses to which it refers, it oper- - ates like a subroutine in a programming language. An earlier example - pointed out that the pattern - - (sens|respons)e and \1ibility - - matches "sense and sensibility" and "response and responsibility", but - not "sense and responsibility". If instead the pattern - - (sens|respons)e and (?1)ibility - - is used, it does match "sense and responsibility" as well as the other - two strings. Such references must, however, follow the subpattern to - which they refer. - - -CALLOUTS - - Perl has a feature whereby using the sequence (?{...}) causes arbitrary - Perl code to be obeyed in the middle of matching a regular expression. - This makes it possible, amongst other things, to extract different sub- - strings that match the same pair of parentheses when there is a repeti- - tion. - - PCRE provides a similar feature, but of course it cannot obey arbitrary - Perl code. The feature is called "callout". The caller of PCRE provides - an external function by putting its entry point in the global variable - pcre_callout. By default, this variable contains NULL, which disables - all calling out. - - Within a regular expression, (?C) indicates the points at which the - external function is to be called. If you want to identify different - callout points, you can put a number less than 256 after the letter C. - The default value is zero. For example, this pattern has two callout - points: - - (?C1)abc(?C2)def - - During matching, when PCRE reaches a callout point (and pcre_callout is - set), the external function is called. It is provided with the number - of the callout, and, optionally, one item of data originally supplied - by the caller of pcre_exec(). The callout function may cause matching - to backtrack, or to fail altogether. A complete description of the - interface to the callout function is given in the pcrecallout documen- - tation. - -Last updated: 03 February 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -PCRE PERFORMANCE - - Certain items that may appear in regular expression patterns are more - efficient than others. It is more efficient to use a character class - like [aeiou] than a set of alternatives such as (a|e|i|o|u). In gen- - eral, the simplest construction that provides the required behaviour is - usually the most efficient. Jeffrey Friedl's book contains a lot of - discussion about optimizing regular expressions for efficient perfor- - mance. - - When a pattern begins with .* not in parentheses, or in parentheses - that are not the subject of a backreference, and the PCRE_DOTALL option - is set, the pattern is implicitly anchored by PCRE, since it can match - only at the start of a subject string. However, if PCRE_DOTALL is not - set, PCRE cannot make this optimization, because the . metacharacter - does not then match a newline, and if the subject string contains new- - lines, the pattern may match from the character immediately following - one of them instead of from the very start. For example, the pattern - - .*second - - matches the subject "first\nand second" (where \n stands for a newline - character), with the match starting at the seventh character. In order - to do this, PCRE has to retry the match starting after every newline in - the subject. - - If you are using such a pattern with subject strings that do not con- - tain newlines, the best performance is obtained by setting PCRE_DOTALL, - or starting the pattern with ^.* to indicate explicit anchoring. That - saves PCRE from having to scan along the subject looking for a newline - to restart at. - - Beware of patterns that contain nested indefinite repeats. These can - take a long time to run when applied to a string that does not match. - Consider the pattern fragment - - (a+)* - - This can match "aaaa" in 33 different ways, and this number increases - very rapidly as the string gets longer. (The * repeat can match 0, 1, - 2, 3, or 4 times, and for each of those cases other than 0, the + - repeats can match different numbers of times.) When the remainder of - the pattern is such that the entire match is going to fail, PCRE has in - principle to try every possible variation, and this can take an - extremely long time. - - An optimization catches some of the more simple cases such as - - (a+)*b - - where a literal character follows. Before embarking on the standard - matching procedure, PCRE checks that there is a "b" later in the sub- - ject string, and if there is not, it fails the match immediately. How- - ever, when there is no following literal this optimization cannot be - used. You can see the difference by comparing the behaviour of - - (a+)*\d - - with the pattern above. The former gives a failure almost instantly - when applied to a whole line of "a" characters, whereas the latter - takes an appreciable time with strings longer than about 20 characters. - -Last updated: 03 February 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions. - -SYNOPSIS OF POSIX API - #include <pcreposix.h> - - int regcomp(regex_t *preg, const char *pattern, - int cflags); - - int regexec(regex_t *preg, const char *string, - size_t nmatch, regmatch_t pmatch[], int eflags); - - size_t regerror(int errcode, const regex_t *preg, - char *errbuf, size_t errbuf_size); - - void regfree(regex_t *preg); - - -DESCRIPTION - - This set of functions provides a POSIX-style API to the PCRE regular - expression package. See the pcreapi documentation for a description of - the native API, which contains additional functionality. - - The functions described here are just wrapper functions that ultimately - call the PCRE native API. Their prototypes are defined in the - pcreposix.h header file, and on Unix systems the library itself is - called pcreposix.a, so can be accessed by adding -lpcreposix to the - command for linking an application which uses them. Because the POSIX - functions call the native ones, it is also necessary to add -lpcre. - - I have implemented only those option bits that can be reasonably mapped - to PCRE native options. In addition, the options REG_EXTENDED and - REG_NOSUB are defined with the value zero. They have no effect, but - since programs that are written to the POSIX interface often use them, - this makes it easier to slot in PCRE as a replacement library. Other - POSIX options are not even defined. - - When PCRE is called via these functions, it is only the API that is - POSIX-like in style. The syntax and semantics of the regular expres- - sions themselves are still those of Perl, subject to the setting of - various PCRE options, as described below. "POSIX-like in style" means - that the API approximates to the POSIX definition; it is not fully - POSIX-compatible, and in multi-byte encoding domains it is probably - even less compatible. - - The header for these functions is supplied as pcreposix.h to avoid any - potential clash with other POSIX libraries. It can, of course, be - renamed or aliased as regex.h, which is the "correct" name. It provides - two structure types, regex_t for compiled internal forms, and reg- - match_t for returning captured substrings. It also defines some con- - stants whose names start with "REG_"; these are used for setting - options and identifying error codes. - - -COMPILING A PATTERN - - The function regcomp() is called to compile a pattern into an internal - form. The pattern is a C string terminated by a binary zero, and is - passed in the argument pattern. The preg argument is a pointer to a - regex_t structure which is used as a base for storing information about - the compiled expression. - - The argument cflags is either zero, or contains one or more of the bits - defined by the following macros: - - REG_ICASE - - The PCRE_CASELESS option is set when the expression is passed for com- - pilation to the native function. - - REG_NEWLINE - - The PCRE_MULTILINE option is set when the expression is passed for com- - pilation to the native function. Note that this does not mimic the - defined POSIX behaviour for REG_NEWLINE (see the following section). - - In the absence of these flags, no options are passed to the native - function. This means the the regex is compiled with PCRE default - semantics. In particular, the way it handles newline characters in the - subject string is the Perl way, not the POSIX way. Note that setting - PCRE_MULTILINE has only some of the effects specified for REG_NEWLINE. - It does not affect the way newlines are matched by . (they aren't) or - by a negative class such as [^a] (they are). - - The yield of regcomp() is zero on success, and non-zero otherwise. The - preg structure is filled in on success, and one member of the structure - is public: re_nsub contains the number of capturing subpatterns in the - regular expression. Various error codes are defined in the header file. - - -MATCHING NEWLINE CHARACTERS - - This area is not simple, because POSIX and Perl take different views of - things. It is not possible to get PCRE to obey POSIX semantics, but - then PCRE was never intended to be a POSIX engine. The following table - lists the different possibilities for matching newline characters in - PCRE: - - Default Change with - - . matches newline no PCRE_DOTALL - newline matches [^a] yes not changeable - $ matches \n at end yes PCRE_DOLLARENDONLY - $ matches \n in middle no PCRE_MULTILINE - ^ matches \n in middle no PCRE_MULTILINE - - This is the equivalent table for POSIX: - - Default Change with - - . matches newline yes REG_NEWLINE - newline matches [^a] yes REG_NEWLINE - $ matches \n at end no REG_NEWLINE - $ matches \n in middle no REG_NEWLINE - ^ matches \n in middle no REG_NEWLINE - - PCRE's behaviour is the same as Perl's, except that there is no equiva- - lent for PCRE_DOLLARENDONLY in Perl. In both PCRE and Perl, there is no - way to stop newline from matching [^a]. - - The default POSIX newline handling can be obtained by setting - PCRE_DOTALL and PCRE_DOLLARENDONLY, but there is no way to make PCRE - behave exactly as for the REG_NEWLINE action. - - -MATCHING A PATTERN - - The function regexec() is called to match a pre-compiled pattern preg - against a given string, which is terminated by a zero byte, subject to - the options in eflags. These can be: - - REG_NOTBOL - - The PCRE_NOTBOL option is set when calling the underlying PCRE matching - function. - - REG_NOTEOL - - The PCRE_NOTEOL option is set when calling the underlying PCRE matching - function. - - The portion of the string that was matched, and also any captured sub- - strings, are returned via the pmatch argument, which points to an array - of nmatch structures of type regmatch_t, containing the members rm_so - and rm_eo. These contain the offset to the first character of each sub- - string and the offset to the first character after the end of each sub- - string, respectively. The 0th element of the vector relates to the - entire portion of string that was matched; subsequent elements relate - to the capturing subpatterns of the regular expression. Unused entries - in the array have both structure members set to -1. - - A successful match yields a zero return; various error codes are - defined in the header file, of which REG_NOMATCH is the "expected" - failure code. - - -ERROR MESSAGES - - The regerror() function maps a non-zero errorcode from either regcomp() - or regexec() to a printable message. If preg is not NULL, the error - should have arisen from the use of that structure. A message terminated - by a binary zero is placed in errbuf. The length of the message, - including the zero, is limited to errbuf_size. The yield of the func- - tion is the size of buffer needed to hold the whole message. - - -STORAGE - - Compiling a regular expression causes memory to be allocated and asso- - ciated with the preg structure. The function regfree() frees all such - memory, after which preg may no longer be used as a compiled expres- - sion. - - -AUTHOR - - Philip Hazel <ph10@cam.ac.uk> - University Computing Service, - Cambridge CB2 3QG, England. - -Last updated: 03 February 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - -PCRE(3) PCRE(3) - - - -NAME - PCRE - Perl-compatible regular expressions - -PCRE SAMPLE PROGRAM - - A simple, complete demonstration program, to get you started with using - PCRE, is supplied in the file pcredemo.c in the PCRE distribution. - - The program compiles the regular expression that is its first argument, - and matches it against the subject string in its second argument. No - PCRE options are set, and default character tables are used. If match- - ing succeeds, the program outputs the portion of the subject that - matched, together with the contents of any captured substrings. - - If the -g option is given on the command line, the program then goes on - to check for further matches of the same regular expression in the same - subject string. The logic is a little bit tricky because of the possi- - bility of matching an empty string. Comments in the code explain what - is going on. - - On a Unix system that has PCRE installed in /usr/local, you can compile - the demonstration program using a command like this: - - gcc -o pcredemo pcredemo.c -I/usr/local/include \ - -L/usr/local/lib -lpcre - - Then you can run simple tests like this: - - ./pcredemo 'cat|dog' 'the cat sat on the mat' - ./pcredemo -g 'cat|dog' 'the dog sat on the cat' - - Note that there is a much more comprehensive test program, called - pcretest, which supports many more facilities for testing regular - expressions and the PCRE library. The pcredemo program is provided as a - simple coding example. - - On some operating systems (e.g. Solaris) you may get an error like this - when you try to run pcredemo: - - ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or - directory - - This is caused by the way shared library support works on those sys- - tems. You need to add - - -R/usr/local/lib - - to the compile command to get round this problem. - -Last updated: 28 January 2003 -Copyright (c) 1997-2003 University of Cambridge. ------------------------------------------------------------------------------ - diff --git a/external-libs/pcre/doc/pcre_compile.3 b/external-libs/pcre/doc/pcre_compile.3 deleted file mode 100644 index a8273151..00000000 --- a/external-libs/pcre/doc/pcre_compile.3 +++ /dev/null @@ -1,59 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B pcre *pcre_compile(const char *\fIpattern\fR, int \fIoptions\fR, -.ti +5n -.B const char **\fIerrptr\fR, int *\fIerroffset\fR, -.ti +5n -.B const unsigned char *\fItableptr\fR); - -.SH DESCRIPTION -.rs -.sp -This function compiles a regular expression into an internal form. Its -arguments are: - - \fIpattern\fR A zero-terminated string containing the - regular expression to be compiled - \fIoptions\fR Zero or more option bits - \fIerrptr\fR Where to put an error message - \fIerroffset\fR Offset in pattern where error was found - \fItableptr\fR Pointer to character tables, or NULL to - use the built-in default - -The option bits are: - - PCRE_ANCHORED Force pattern anchoring - PCRE_CASELESS Do caseless matching - PCRE_DOLLAR_ENDONLY $ not to match newline at end - PCRE_DOTALL . matches anything including NL - PCRE_EXTENDED Ignore whitespace and # comments - PCRE_EXTRA PCRE extra features - (not much use currently) - PCRE_MULTILINE ^ and $ match newlines within data - PCRE_NO_AUTO_CAPTURE Disable numbered capturing paren- - theses (named ones available) - PCRE_UNGREEDY Invert greediness of quantifiers - PCRE_UTF8 Run in UTF-8 mode - PCRE_NO_UTF8_CHECK Do not check the pattern for UTF-8 - validity (only relevant if - PCRE_UTF8 is set) - -PCRE must be compiled with UTF-8 support in order to use PCRE_UTF8 -(or PCRE_NO_UTF8_CHECK). - -The yield of the function is a pointer to a private data structure that -contains the compiled pattern, or NULL if an error was detected. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_config.3 b/external-libs/pcre/doc/pcre_config.3 deleted file mode 100644 index 3a0e6998..00000000 --- a/external-libs/pcre/doc/pcre_config.3 +++ /dev/null @@ -1,45 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_config(int \fIwhat\fR, void *\fIwhere\fR); - -.SH DESCRIPTION -.rs -.sp -This function makes it possible for a client program to find out which optional -features are available in the version of the PCRE library it is using. Its -arguments are as follows: - - \fIwhat\fR A code specifying what information is required - \fIwhere\fR Points to where to put the data - -The available codes are: - - PCRE_CONFIG_LINK_SIZE Internal link size: 2, 3, or 4 - PCRE_CONFIG_MATCH_LIMIT Internal resource limit - PCRE_CONFIG_NEWLINE Value of the newline character - PCRE_CONFIG_POSIX_MALLOC_THRESHOLD - Threshold of return slots, above - which \fBmalloc()\fR is used by - the POSIX API - PCRE_CONFIG_STACKRECURSE Recursion implementation (1=stack 0=heap) - PCRE_CONFIG_UTF8 Availability of UTF-8 support (1=yes 0=no) - -The function yields 0 on success or PCRE_ERROR_BADOPTION otherwise. - -There is a complete description of the PCRE native API in the -.\" HREF -\fBpcreapi\fR -.\" -page, and a description of the POSIX API in the -.\" HREF -\fBpcreposix\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_copy_named_substring.3 b/external-libs/pcre/doc/pcre_copy_named_substring.3 deleted file mode 100644 index 915bd0a5..00000000 --- a/external-libs/pcre/doc/pcre_copy_named_substring.3 +++ /dev/null @@ -1,40 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_copy_named_substring(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, const char *\fIstringname\fR, -.ti +5n -.B char *\fIbuffer\fR, int \fIbuffersize\fR); - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for extracting a captured substring, identified -by name, into a given buffer. The arguments are: - - \fIcode\fR Pattern that was successfully matched - \fIsubject\fR Subject that has been successfully matched - \fIovector\fR Offset vector that \fBpcre_exec()\fR used - \fIstringcount\fR Value returned by \fBpcre_exec()\fR - \fIstringname\fR Name of the required substring - \fIbuffer\fR Buffer to receive the string - \fIbuffersize\fR Size of buffer - -The yield is the length of the substring, PCRE_ERROR_NOMEMORY if the buffer was -too small, or PCRE_ERROR_NOSUBSTRING if the string name is invalid. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_copy_substring.3 b/external-libs/pcre/doc/pcre_copy_substring.3 deleted file mode 100644 index d61b99bf..00000000 --- a/external-libs/pcre/doc/pcre_copy_substring.3 +++ /dev/null @@ -1,37 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_copy_substring(const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, int \fIstringnumber\fR, char *\fIbuffer\fR, -.ti +5n -.B int \fIbuffersize\fR); - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for extracting a captured substring into a given -buffer. The arguments are: - - \fIsubject\fR Subject that has been successfully matched - \fIovector\fR Offset vector that \fBpcre_exec()\fR used - \fIstringcount\fR Value returned by \fBpcre_exec()\fR - \fIstringnumber\fR Number of the required substring - \fIbuffer\fR Buffer to receive the string - \fIbuffersize\fR Size of buffer - -The yield is the legnth of the string, PCRE_ERROR_NOMEMORY if the buffer was -too small, or PCRE_ERROR_NOSUBSTRING if the string number is invalid. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_exec.3 b/external-libs/pcre/doc/pcre_exec.3 deleted file mode 100644 index 0d6c3805..00000000 --- a/external-libs/pcre/doc/pcre_exec.3 +++ /dev/null @@ -1,48 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_exec(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," -.ti +5n -.B "const char *\fIsubject\fR," int \fIlength\fR, int \fIstartoffset\fR, -.ti +5n -.B int \fIoptions\fR, int *\fIovector\fR, int \fIovecsize\fR); - -.SH DESCRIPTION -.rs -.sp -This function matches a compiled regular expression against a given subject -string, and returns offsets to capturing subexpressions. Its arguments are: - - \fIcode\fR Points to the compiled pattern - \fIextra\fR Points to an associated \fBpcre_extra\fR structure, - or is NULL - \fIsubject\fR Points to the subject string - \fIlength\fR Length of the subject string, in bytes - \fIstartoffset\fR Offset in bytes in the subject at which to - start matching - \fIoptions\fR Option bits - \fIovector\fR Points to a vector of ints for result offsets - \fIovecsize\fR Size of the vector (a multiple of 3) - -The options are: - - PCRE_ANCHORED Match only at the first position - PCRE_NOTBOL Subject is not the beginning of a line - PCRE_NOTEOL Subject is not the end of a line - PCRE_NOTEMPTY An empty string is not a valid match - PCRE_NO_UTF8_CHECK Do not check the subject for UTF-8 - validity (only relevant if PCRE_UTF8 - was set at compile time) - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_free_substring.3 b/external-libs/pcre/doc/pcre_free_substring.3 deleted file mode 100644 index 3fcaf117..00000000 --- a/external-libs/pcre/doc/pcre_free_substring.3 +++ /dev/null @@ -1,24 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B void pcre_free_substring(const char *\fIstringptr\fR); - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for freeing the store obtained by a previous -call to \fBpcre_get_substring()\fR or \fBpcre_get_named_substring()\fR. Its -only argument is a pointer to the string. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_free_substring_list.3 b/external-libs/pcre/doc/pcre_free_substring_list.3 deleted file mode 100644 index 73d5993d..00000000 --- a/external-libs/pcre/doc/pcre_free_substring_list.3 +++ /dev/null @@ -1,24 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B void pcre_free_substring_list(const char **\fIstringptr\fR); - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for freeing the store obtained by a previous -call to \fBpcre_get_substring_list()\fR. Its only argument is a pointer to the -list of string pointers. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_fullinfo.3 b/external-libs/pcre/doc/pcre_fullinfo.3 deleted file mode 100644 index 06de985f..00000000 --- a/external-libs/pcre/doc/pcre_fullinfo.3 +++ /dev/null @@ -1,53 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_fullinfo(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," -.ti +5n -.B int \fIwhat\fR, void *\fIwhere\fR); - -.SH DESCRIPTION -.rs -.sp -This function returns information about a compiled pattern. Its arguments are: - - \fIcode\fR Compiled regular expression - \fIextra\fR Result of \fBpcre_study()\fR or NULL - \fIwhat\fR What information is required - \fIwhere\fR Where to put the information - -The following information is available: - - PCRE_INFO_BACKREFMAX Number of highest back reference - PCRE_INFO_CAPTURECOUNT Number of capturing subpatterns - PCRE_INFO_FIRSTBYTE Fixed first byte for a match, or - -1 for start of string - or after newline, or - -2 otherwise - PCRE_INFO_FIRSTTABLE Table of first bytes - (after studying) - PCRE_INFO_LASTLITERAL Literal last byte required - PCRE_INFO_NAMECOUNT Number of named subpatterns - PCRE_INFO_NAMEENTRYSIZE Size of name table entry - PCRE_INFO_NAMETABLE Pointer to name table - PCRE_INFO_OPTIONS Options used for compilation - PCRE_INFO_SIZE Size of compiled pattern - -The yield of the function is zero on success or: - - PCRE_ERROR_NULL the argument \fIcode\fR was NULL - the argument \fIwhere\fR was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - PCRE_ERROR_BADOPTION the value of \fIwhat\fR was invalid - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_get_named_substring.3 b/external-libs/pcre/doc/pcre_get_named_substring.3 deleted file mode 100644 index 6d3f80ea..00000000 --- a/external-libs/pcre/doc/pcre_get_named_substring.3 +++ /dev/null @@ -1,40 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_get_named_substring(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, const char *\fIstringname\fR, -.ti +5n -.B const char **\fIstringptr\fR); - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for extracting a captured substring by name. The -arguments are: - - \fIcode\fR Compiled pattern - \fIsubject\fR Subject that has been successfully matched - \fIovector\fR Offset vector that \fBpcre_exec()\fR used - \fIstringcount\fR Value returned by \fBpcre_exec()\fR - \fIstringname\fR Name of the required substring - \fIstringptr\fR Where to put the string pointer - -The yield is the length of the extracted substring, PCRE_ERROR_NOMEMORY if -sufficient memory could not be obtained, or PCRE_ERROR_NOSUBSTRING if the -string name is invalid. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_get_stringnumber.3 b/external-libs/pcre/doc/pcre_get_stringnumber.3 deleted file mode 100644 index f6c9357f..00000000 --- a/external-libs/pcre/doc/pcre_get_stringnumber.3 +++ /dev/null @@ -1,31 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_get_stringnumber(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIname\fR); - -.SH DESCRIPTION -.rs -.sp -This convenience function finds the number of a named substring capturing -parenthesis in a compiled pattern. Its arguments are: - - \fIcode\fR Compiled regular expression - \fIname\fR Name whose number is required - -The yield of the function is the number of the parenthesis if the name is -found, or PCRE_ERROR_NOSUBSTRING otherwise. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_get_substring.3 b/external-libs/pcre/doc/pcre_get_substring.3 deleted file mode 100644 index 4c92c9c5..00000000 --- a/external-libs/pcre/doc/pcre_get_substring.3 +++ /dev/null @@ -1,37 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_get_substring(const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, int \fIstringnumber\fR, -.ti +5n -.B const char **\fIstringptr\fR); - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for extracting a captured substring. The -arguments are: - - \fIsubject\fR Subject that has been successfully matched - \fIovector\fR Offset vector that \fBpcre_exec()\fR used - \fIstringcount\fR Value returned by \fBpcre_exec()\fR - \fIstringnumber\fR Number of the required substring - \fIstringptr\fR Where to put the string pointer - -The yield is the length of the substring, PCRE_ERROR_NOMEMORY if sufficient -memory could not be obtained, or PCRE_ERROR_NOSUBSTRING if the string number is -invalid. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_get_substring_list.3 b/external-libs/pcre/doc/pcre_get_substring_list.3 deleted file mode 100644 index 69090e1b..00000000 --- a/external-libs/pcre/doc/pcre_get_substring_list.3 +++ /dev/null @@ -1,33 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_get_substring_list(const char *\fIsubject\fR, -.ti +5n -.B int *\fIovector\fR, int \fIstringcount\fR, "const char ***\fIlistptr\fR);" - -.SH DESCRIPTION -.rs -.sp -This is a convenience function for extracting a list of all the captured -substrings. The arguments are: - - \fIsubject\fR Subject that has been successfully matched - \fIovector\fR Offset vector that \fBpcre_exec\fR used - \fIstringcount\fR Value returned by \fBpcre_exec\fR - \fIlistptr\fR Where to put a pointer to the list - -The yield is zero on success or PCRE_ERROR_NOMEMORY if sufficient memory could -not be obtained. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_info.3 b/external-libs/pcre/doc/pcre_info.3 deleted file mode 100644 index c4970764..00000000 --- a/external-libs/pcre/doc/pcre_info.3 +++ /dev/null @@ -1,23 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B int pcre_info(const pcre *\fIcode\fR, int *\fIoptptr\fR, int -.B *\fIfirstcharptr\fR); - -.SH DESCRIPTION -.rs -.sp -This function is obsolete. You should be using \fBpcre_fullinfo()\fR instead. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_maketables.3 b/external-libs/pcre/doc/pcre_maketables.3 deleted file mode 100644 index 7d459ed4..00000000 --- a/external-libs/pcre/doc/pcre_maketables.3 +++ /dev/null @@ -1,26 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B const unsigned char *pcre_maketables(void); - -.SH DESCRIPTION -.rs -.sp -This function builds a set of character tables which can be passed to -\fBpcre_compile()\fR to override PCRE's internal, built-in tables (which were -made by \fBpcre_maketables()\fR when PCRE was compiled). You might want to do -this if you are using a non-standard locale. The function yields a pointer to -the tables. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_study.3 b/external-libs/pcre/doc/pcre_study.3 deleted file mode 100644 index 69ff20e4..00000000 --- a/external-libs/pcre/doc/pcre_study.3 +++ /dev/null @@ -1,36 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B pcre_extra *pcre_study(const pcre *\fIcode\fR, int \fIoptions\fR, -.ti +5n -.B const char **\fIerrptr\fR); - -.SH DESCRIPTION -.rs -.sp -This function studies a compiled pattern, to see if additional information can -be extracted that might speed up matching. Its arguments are: - - \fIcode\fR A compiled regular expression - \fIoptions\fR Options for \fBpcre_study()\fR - \fIerrptr\fR Where to put an error message - -If the function returns NULL, either it could not find any additional -information, or there was an error. You can tell the difference by looking at -the error value. It is NULL in first case. - -There are currently no options defined; the value of the second argument should -always be zero. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcre_version.3 b/external-libs/pcre/doc/pcre_version.3 deleted file mode 100644 index 6f981224..00000000 --- a/external-libs/pcre/doc/pcre_version.3 +++ /dev/null @@ -1,23 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B char *pcre_version(void); - -.SH DESCRIPTION -.rs -.sp -This function returns a character string that gives the version number of the -PCRE library, and its date of release. - -There is a complete description of the PCRE API in the -.\" HREF -\fBpcreapi\fR -.\" -page. diff --git a/external-libs/pcre/doc/pcreapi.3 b/external-libs/pcre/doc/pcreapi.3 deleted file mode 100644 index 4c7d43c3..00000000 --- a/external-libs/pcre/doc/pcreapi.3 +++ /dev/null @@ -1,1082 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH SYNOPSIS OF PCRE API -.rs -.sp -.B #include <pcre.h> -.PP -.SM -.br -.B pcre *pcre_compile(const char *\fIpattern\fR, int \fIoptions\fR, -.ti +5n -.B const char **\fIerrptr\fR, int *\fIerroffset\fR, -.ti +5n -.B const unsigned char *\fItableptr\fR); -.PP -.br -.B pcre_extra *pcre_study(const pcre *\fIcode\fR, int \fIoptions\fR, -.ti +5n -.B const char **\fIerrptr\fR); -.PP -.br -.B int pcre_exec(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," -.ti +5n -.B "const char *\fIsubject\fR," int \fIlength\fR, int \fIstartoffset\fR, -.ti +5n -.B int \fIoptions\fR, int *\fIovector\fR, int \fIovecsize\fR); -.PP -.br -.B int pcre_copy_named_substring(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, const char *\fIstringname\fR, -.ti +5n -.B char *\fIbuffer\fR, int \fIbuffersize\fR); -.PP -.br -.B int pcre_copy_substring(const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, int \fIstringnumber\fR, char *\fIbuffer\fR, -.ti +5n -.B int \fIbuffersize\fR); -.PP -.br -.B int pcre_get_named_substring(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, const char *\fIstringname\fR, -.ti +5n -.B const char **\fIstringptr\fR); -.PP -.br -.B int pcre_get_stringnumber(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIname\fR); -.PP -.br -.B int pcre_get_substring(const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, int \fIstringnumber\fR, -.ti +5n -.B const char **\fIstringptr\fR); -.PP -.br -.B int pcre_get_substring_list(const char *\fIsubject\fR, -.ti +5n -.B int *\fIovector\fR, int \fIstringcount\fR, "const char ***\fIlistptr\fR);" -.PP -.br -.B void pcre_free_substring(const char *\fIstringptr\fR); -.PP -.br -.B void pcre_free_substring_list(const char **\fIstringptr\fR); -.PP -.br -.B const unsigned char *pcre_maketables(void); -.PP -.br -.B int pcre_fullinfo(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," -.ti +5n -.B int \fIwhat\fR, void *\fIwhere\fR); -.PP -.br -.B int pcre_info(const pcre *\fIcode\fR, int *\fIoptptr\fR, int -.B *\fIfirstcharptr\fR); -.PP -.br -.B int pcre_config(int \fIwhat\fR, void *\fIwhere\fR); -.PP -.br -.B char *pcre_version(void); -.PP -.br -.B void *(*pcre_malloc)(size_t); -.PP -.br -.B void (*pcre_free)(void *); -.PP -.br -.B void *(*pcre_stack_malloc)(size_t); -.PP -.br -.B void (*pcre_stack_free)(void *); -.PP -.br -.B int (*pcre_callout)(pcre_callout_block *); - -.SH PCRE API -.rs -.sp -PCRE has its own native API, which is described in this document. There is also -a set of wrapper functions that correspond to the POSIX regular expression API. -These are described in the \fBpcreposix\fR documentation. - -The native API function prototypes are defined in the header file \fBpcre.h\fR, -and on Unix systems the library itself is called \fBlibpcre.a\fR, so can be -accessed by adding \fB-lpcre\fR to the command for linking an application which -calls it. The header file defines the macros PCRE_MAJOR and PCRE_MINOR to -contain the major and minor release numbers for the library. Applications can -use these to include support for different releases. - -The functions \fBpcre_compile()\fR, \fBpcre_study()\fR, and \fBpcre_exec()\fR -are used for compiling and matching regular expressions. A sample program that -demonstrates the simplest way of using them is given in the file -\fIpcredemo.c\fR. The \fBpcresample\fR documentation describes how to run it. - -There are convenience functions for extracting captured substrings from a -matched subject string. They are: - - \fBpcre_copy_substring()\fR - \fBpcre_copy_named_substring()\fR - \fBpcre_get_substring()\fR - \fBpcre_get_named_substring()\fR - \fBpcre_get_substring_list()\fR - -\fBpcre_free_substring()\fR and \fBpcre_free_substring_list()\fR are also -provided, to free the memory used for extracted strings. - -The function \fBpcre_maketables()\fR is used (optionally) to build a set of -character tables in the current locale for passing to \fBpcre_compile()\fR. - -The function \fBpcre_fullinfo()\fR is used to find out information about a -compiled pattern; \fBpcre_info()\fR is an obsolete version which returns only -some of the available information, but is retained for backwards compatibility. -The function \fBpcre_version()\fR returns a pointer to a string containing the -version of PCRE and its date of release. - -The global variables \fBpcre_malloc\fR and \fBpcre_free\fR initially contain -the entry points of the standard \fBmalloc()\fR and \fBfree()\fR functions -respectively. PCRE calls the memory management functions via these variables, -so a calling program can replace them if it wishes to intercept the calls. This -should be done before calling any PCRE functions. - -The global variables \fBpcre_stack_malloc\fR and \fBpcre_stack_free\fR are also -indirections to memory management functions. These special functions are used -only when PCRE is compiled to use the heap for remembering data, instead of -recursive function calls. This is a non-standard way of building PCRE, for use -in environments that have limited stacks. Because of the greater use of memory -management, it runs more slowly. Separate functions are provided so that -special-purpose external code can be used for this case. When used, these -functions are always called in a stack-like manner (last obtained, first -freed), and always for memory blocks of the same size. - -The global variable \fBpcre_callout\fR initially contains NULL. It can be set -by the caller to a "callout" function, which PCRE will then call at specified -points during a matching operation. Details are given in the \fBpcrecallout\fR -documentation. - -.SH MULTITHREADING -.rs -.sp -The PCRE functions can be used in multi-threading applications, with the -proviso that the memory management functions pointed to by \fBpcre_malloc\fR, -\fBpcre_free\fR, \fBpcre_stack_malloc\fR, and \fBpcre_stack_free\fR, and the -callout function pointed to by \fBpcre_callout\fR, are shared by all threads. - -The compiled form of a regular expression is not altered during matching, so -the same compiled pattern can safely be used by several threads at once. - -.SH CHECKING BUILD-TIME OPTIONS -.rs -.sp -.B int pcre_config(int \fIwhat\fR, void *\fIwhere\fR); -.PP -The function \fBpcre_config()\fR makes it possible for a PCRE client to -discover which optional features have been compiled into the PCRE library. The -.\" HREF -\fBpcrebuild\fR -.\" -documentation has more details about these optional features. - -The first argument for \fBpcre_config()\fR is an integer, specifying which -information is required; the second argument is a pointer to a variable into -which the information is placed. The following information is available: - - PCRE_CONFIG_UTF8 - -The output is an integer that is set to one if UTF-8 support is available; -otherwise it is set to zero. - - PCRE_CONFIG_NEWLINE - -The output is an integer that is set to the value of the code that is used for -the newline character. It is either linefeed (10) or carriage return (13), and -should normally be the standard character for your operating system. - - PCRE_CONFIG_LINK_SIZE - -The output is an integer that contains the number of bytes used for internal -linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values -allow larger regular expressions to be compiled, at the expense of slower -matching. The default value of 2 is sufficient for all but the most massive -patterns, since it allows the compiled pattern to be up to 64K in size. - - PCRE_CONFIG_POSIX_MALLOC_THRESHOLD - -The output is an integer that contains the threshold above which the POSIX -interface uses \fBmalloc()\fR for output vectors. Further details are given in -the \fBpcreposix\fR documentation. - - PCRE_CONFIG_MATCH_LIMIT - -The output is an integer that gives the default limit for the number of -internal matching function calls in a \fBpcre_exec()\fR execution. Further -details are given with \fBpcre_exec()\fR below. - - PCRE_CONFIG_STACKRECURSE - -The output is an integer that is set to one if internal recursion is -implemented by recursive function calls that use the stack to remember their -state. This is the usual way that PCRE is compiled. The output is zero if PCRE -was compiled to use blocks of data on the heap instead of recursive function -calls. In this case, \fBpcre_stack_malloc\fR and \fBpcre_stack_free\fR are -called to manage memory blocks on the heap, thus avoiding the use of the stack. - -.SH COMPILING A PATTERN -.rs -.sp -.B pcre *pcre_compile(const char *\fIpattern\fR, int \fIoptions\fR, -.ti +5n -.B const char **\fIerrptr\fR, int *\fIerroffset\fR, -.ti +5n -.B const unsigned char *\fItableptr\fR); -.PP - -The function \fBpcre_compile()\fR is called to compile a pattern into an -internal form. The pattern is a C string terminated by a binary zero, and -is passed in the argument \fIpattern\fR. A pointer to a single block of memory -that is obtained via \fBpcre_malloc\fR is returned. This contains the compiled -code and related data. The \fBpcre\fR type is defined for the returned block; -this is a typedef for a structure whose contents are not externally defined. It -is up to the caller to free the memory when it is no longer required. - -Although the compiled code of a PCRE regex is relocatable, that is, it does not -depend on memory location, the complete \fBpcre\fR data block is not -fully relocatable, because it contains a copy of the \fItableptr\fR argument, -which is an address (see below). - -The \fIoptions\fR argument contains independent bits that affect the -compilation. It should be zero if no options are required. Some of the options, -in particular, those that are compatible with Perl, can also be set and unset -from within the pattern (see the detailed description of regular expressions -in the \fBpcrepattern\fR documentation). For these options, the contents of the -\fIoptions\fR argument specifies their initial settings at the start of -compilation and execution. The PCRE_ANCHORED option can be set at the time of -matching as well as at compile time. - -If \fIerrptr\fR is NULL, \fBpcre_compile()\fR returns NULL immediately. -Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fR returns -NULL, and sets the variable pointed to by \fIerrptr\fR to point to a textual -error message. The offset from the start of the pattern to the character where -the error was discovered is placed in the variable pointed to by -\fIerroffset\fR, which must not be NULL. If it is, an immediate error is given. - -If the final argument, \fItableptr\fR, is NULL, PCRE uses a default set of -character tables which are built when it is compiled, using the default C -locale. Otherwise, \fItableptr\fR must be the result of a call to -\fBpcre_maketables()\fR. See the section on locale support below. - -This code fragment shows a typical straightforward call to \fBpcre_compile()\fR: - - pcre *re; - const char *error; - int erroffset; - re = pcre_compile( - "^A.*Z", /* the pattern */ - 0, /* default options */ - &error, /* for error message */ - &erroffset, /* for error offset */ - NULL); /* use default character tables */ - -The following option bits are defined: - - PCRE_ANCHORED - -If this bit is set, the pattern is forced to be "anchored", that is, it is -constrained to match only at the first matching point in the string which is -being searched (the "subject string"). This effect can also be achieved by -appropriate constructs in the pattern itself, which is the only way to do it in -Perl. - - PCRE_CASELESS - -If this bit is set, letters in the pattern match both upper and lower case -letters. It is equivalent to Perl's /i option, and it can be changed within a -pattern by a (?i) option setting. - - PCRE_DOLLAR_ENDONLY - -If this bit is set, a dollar metacharacter in the pattern matches only at the -end of the subject string. Without this option, a dollar also matches -immediately before the final character if it is a newline (but not before any -other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is -set. There is no equivalent to this option in Perl, and no way to set it within -a pattern. - - PCRE_DOTALL - -If this bit is set, a dot metacharater in the pattern matches all characters, -including newlines. Without it, newlines are excluded. This option is -equivalent to Perl's /s option, and it can be changed within a pattern by a -(?s) option setting. A negative class such as [^a] always matches a newline -character, independent of the setting of this option. - - PCRE_EXTENDED - -If this bit is set, whitespace data characters in the pattern are totally -ignored except when escaped or inside a character class. Whitespace does not -include the VT character (code 11). In addition, characters between an -unescaped # outside a character class and the next newline character, -inclusive, are also ignored. This is equivalent to Perl's /x option, and it can -be changed within a pattern by a (?x) option setting. - -This option makes it possible to include comments inside complicated patterns. -Note, however, that this applies only to data characters. Whitespace characters -may never appear within special character sequences in a pattern, for example -within the sequence (?( which introduces a conditional subpattern. - - PCRE_EXTRA - -This option was invented in order to turn on additional functionality of PCRE -that is incompatible with Perl, but it is currently of very little use. When -set, any backslash in a pattern that is followed by a letter that has no -special meaning causes an error, thus reserving these combinations for future -expansion. By default, as in Perl, a backslash followed by a letter with no -special meaning is treated as a literal. There are at present no other features -controlled by this option. It can also be set by a (?X) option setting within a -pattern. - - PCRE_MULTILINE - -By default, PCRE treats the subject string as consisting of a single "line" of -characters (even if it actually contains several newlines). The "start of line" -metacharacter (^) matches only at the start of the string, while the "end of -line" metacharacter ($) matches only at the end of the string, or before a -terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as -Perl. - -When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs -match immediately following or immediately before any newline in the subject -string, respectively, as well as at the very start and end. This is equivalent -to Perl's /m option, and it can be changed within a pattern by a (?m) option -setting. If there are no "\\n" characters in a subject string, or no -occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect. - - PCRE_NO_AUTO_CAPTURE - -If this option is set, it disables the use of numbered capturing parentheses in -the pattern. Any opening parenthesis that is not followed by ? behaves as if it -were followed by ?: but named parentheses can still be used for capturing (and -they acquire numbers in the usual way). There is no equivalent of this option -in Perl. - - PCRE_UNGREEDY - -This option inverts the "greediness" of the quantifiers so that they are not -greedy by default, but become greedy if followed by "?". It is not compatible -with Perl. It can also be set by a (?U) option setting within the pattern. - - PCRE_UTF8 - -This option causes PCRE to regard both the pattern and the subject as strings -of UTF-8 characters instead of single-byte character strings. However, it is -available only if PCRE has been built to include UTF-8 support. If not, the use -of this option provokes an error. Details of how this option changes the -behaviour of PCRE are given in the -.\" HTML <a href="pcre.html#utf8support"> -.\" </a> -section on UTF-8 support -.\" -in the main -.\" HREF -\fBpcre\fR -.\" -page. - - PCRE_NO_UTF8_CHECK - -When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is -automatically checked. If an invalid UTF-8 sequence of bytes is found, -\fBpcre_compile()\fR returns an error. If you already know that your pattern is -valid, and you want to skip this check for performance reasons, you can set the -PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid -UTF-8 string as a pattern is undefined. It may cause your program to crash. -Note that there is a similar option for suppressing the checking of subject -strings passed to \fBpcre_exec()\fR. - - -.SH STUDYING A PATTERN -.rs -.sp -.B pcre_extra *pcre_study(const pcre *\fIcode\fR, int \fIoptions\fR, -.ti +5n -.B const char **\fIerrptr\fR); -.PP -When a pattern is going to be used several times, it is worth spending more -time analyzing it in order to speed up the time taken for matching. The -function \fBpcre_study()\fR takes a pointer to a compiled pattern as its first -argument. If studing the pattern produces additional information that will help -speed up matching, \fBpcre_study()\fR returns a pointer to a \fBpcre_extra\fR -block, in which the \fIstudy_data\fR field points to the results of the study. - -The returned value from a \fBpcre_study()\fR can be passed directly to -\fBpcre_exec()\fR. However, the \fBpcre_extra\fR block also contains other -fields that can be set by the caller before the block is passed; these are -described below. If studying the pattern does not produce any additional -information, \fBpcre_study()\fR returns NULL. In that circumstance, if the -calling program wants to pass some of the other fields to \fBpcre_exec()\fR, it -must set up its own \fBpcre_extra\fR block. - -The second argument contains option bits. At present, no options are defined -for \fBpcre_study()\fR, and this argument should always be zero. - -The third argument for \fBpcre_study()\fR is a pointer for an error message. If -studying succeeds (even if no data is returned), the variable it points to is -set to NULL. Otherwise it points to a textual error message. You should -therefore test the error pointer for NULL after calling \fBpcre_study()\fR, to -be sure that it has run successfully. - -This is a typical call to \fBpcre_study\fR(): - - pcre_extra *pe; - pe = pcre_study( - re, /* result of pcre_compile() */ - 0, /* no options exist */ - &error); /* set to NULL or points to a message */ - -At present, studying a pattern is useful only for non-anchored patterns that do -not have a single fixed starting character. A bitmap of possible starting -characters is created. - -.\" HTML <a name="localesupport"></a> -.SH LOCALE SUPPORT -.rs -.sp -PCRE handles caseless matching, and determines whether characters are letters, -digits, or whatever, by reference to a set of tables. When running in UTF-8 -mode, this applies only to characters with codes less than 256. The library -contains a default set of tables that is created in the default C locale when -PCRE is compiled. This is used when the final argument of \fBpcre_compile()\fR -is NULL, and is sufficient for many applications. - -An alternative set of tables can, however, be supplied. Such tables are built -by calling the \fBpcre_maketables()\fR function, which has no arguments, in the -relevant locale. The result can then be passed to \fBpcre_compile()\fR as often -as necessary. For example, to build and use tables that are appropriate for the -French locale (where accented characters with codes greater than 128 are -treated as letters), the following code could be used: - - setlocale(LC_CTYPE, "fr"); - tables = pcre_maketables(); - re = pcre_compile(..., tables); - -The tables are built in memory that is obtained via \fBpcre_malloc\fR. The -pointer that is passed to \fBpcre_compile\fR is saved with the compiled -pattern, and the same tables are used via this pointer by \fBpcre_study()\fR -and \fBpcre_exec()\fR. Thus, for any single pattern, compilation, studying and -matching all happen in the same locale, but different patterns can be compiled -in different locales. It is the caller's responsibility to ensure that the -memory containing the tables remains available for as long as it is needed. - -.SH INFORMATION ABOUT A PATTERN -.rs -.sp -.B int pcre_fullinfo(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," -.ti +5n -.B int \fIwhat\fR, void *\fIwhere\fR); -.PP -The \fBpcre_fullinfo()\fR function returns information about a compiled -pattern. It replaces the obsolete \fBpcre_info()\fR function, which is -nevertheless retained for backwards compability (and is documented below). - -The first argument for \fBpcre_fullinfo()\fR is a pointer to the compiled -pattern. The second argument is the result of \fBpcre_study()\fR, or NULL if -the pattern was not studied. The third argument specifies which piece of -information is required, and the fourth argument is a pointer to a variable -to receive the data. The yield of the function is zero for success, or one of -the following negative numbers: - - PCRE_ERROR_NULL the argument \fIcode\fR was NULL - the argument \fIwhere\fR was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - PCRE_ERROR_BADOPTION the value of \fIwhat\fR was invalid - -Here is a typical call of \fBpcre_fullinfo()\fR, to obtain the length of the -compiled pattern: - - int rc; - unsigned long int length; - rc = pcre_fullinfo( - re, /* result of pcre_compile() */ - pe, /* result of pcre_study(), or NULL */ - PCRE_INFO_SIZE, /* what is required */ - &length); /* where to put the data */ - -The possible values for the third argument are defined in \fBpcre.h\fR, and are -as follows: - - PCRE_INFO_BACKREFMAX - -Return the number of the highest back reference in the pattern. The fourth -argument should point to an \fBint\fR variable. Zero is returned if there are -no back references. - - PCRE_INFO_CAPTURECOUNT - -Return the number of capturing subpatterns in the pattern. The fourth argument -should point to an \fbint\fR variable. - - PCRE_INFO_FIRSTBYTE - -Return information about the first byte of any matched string, for a -non-anchored pattern. (This option used to be called PCRE_INFO_FIRSTCHAR; the -old name is still recognized for backwards compatibility.) - -If there is a fixed first byte, e.g. from a pattern such as (cat|cow|coyote), -it is returned in the integer pointed to by \fIwhere\fR. Otherwise, if either - -(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch -starts with "^", or - -(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set -(if it were set, the pattern would be anchored), - --1 is returned, indicating that the pattern matches only at the start of a -subject string or after any newline within the string. Otherwise -2 is -returned. For anchored patterns, -2 is returned. - - PCRE_INFO_FIRSTTABLE - -If the pattern was studied, and this resulted in the construction of a 256-bit -table indicating a fixed set of bytes for the first byte in any matching -string, a pointer to the table is returned. Otherwise NULL is returned. The -fourth argument should point to an \fBunsigned char *\fR variable. - - PCRE_INFO_LASTLITERAL - -Return the value of the rightmost literal byte that must exist in any matched -string, other than at its start, if such a byte has been recorded. The fourth -argument should point to an \fBint\fR variable. If there is no such byte, -1 is -returned. For anchored patterns, a last literal byte is recorded only if it -follows something of variable length. For example, for the pattern -/^a\\d+z\\d+/ the returned value is "z", but for /^a\\dz\\d/ the returned value -is -1. - - PCRE_INFO_NAMECOUNT - PCRE_INFO_NAMEENTRYSIZE - PCRE_INFO_NAMETABLE - -PCRE supports the use of named as well as numbered capturing parentheses. The -names are just an additional way of identifying the parentheses, which still -acquire a number. A caller that wants to extract data from a named subpattern -must convert the name to a number in order to access the correct pointers in -the output vector (described with \fBpcre_exec()\fR below). In order to do -this, it must first use these three values to obtain the name-to-number mapping -table for the pattern. - -The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives -the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each -entry; both of these return an \fBint\fR value. The entry size depends on the -length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first -entry of the table (a pointer to \fBchar\fR). The first two bytes of each entry -are the number of the capturing parenthesis, most significant byte first. The -rest of the entry is the corresponding name, zero terminated. The names are in -alphabetical order. For example, consider the following pattern (assume -PCRE_EXTENDED is set, so white space - including newlines - is ignored): - - (?P<date> (?P<year>(\\d\\d)?\\d\\d) - - (?P<month>\\d\\d) - (?P<day>\\d\\d) ) - -There are four named subpatterns, so the table has four entries, and each entry -in the table is eight bytes long. The table is as follows, with non-printing -bytes shows in hex, and undefined bytes shown as ??: - - 00 01 d a t e 00 ?? - 00 05 d a y 00 ?? ?? - 00 04 m o n t h 00 - 00 02 y e a r 00 ?? - -When writing code to extract data from named subpatterns, remember that the -length of each entry may be different for each compiled pattern. - - PCRE_INFO_OPTIONS - -Return a copy of the options with which the pattern was compiled. The fourth -argument should point to an \fBunsigned long int\fR variable. These option bits -are those specified in the call to \fBpcre_compile()\fR, modified by any -top-level option settings within the pattern itself. - -A pattern is automatically anchored by PCRE if all of its top-level -alternatives begin with one of the following: - - ^ unless PCRE_MULTILINE is set - \\A always - \\G always - .* if PCRE_DOTALL is set and there are no back - references to the subpattern in which .* appears - -For such patterns, the PCRE_ANCHORED bit is set in the options returned by -\fBpcre_fullinfo()\fR. - - PCRE_INFO_SIZE - -Return the size of the compiled pattern, that is, the value that was passed as -the argument to \fBpcre_malloc()\fR when PCRE was getting memory in which to -place the compiled data. The fourth argument should point to a \fBsize_t\fR -variable. - - PCRE_INFO_STUDYSIZE - -Returns the size of the data block pointed to by the \fIstudy_data\fR field in -a \fBpcre_extra\fR block. That is, it is the value that was passed to -\fBpcre_malloc()\fR when PCRE was getting memory into which to place the data -created by \fBpcre_study()\fR. The fourth argument should point to a -\fBsize_t\fR variable. - -.SH OBSOLETE INFO FUNCTION -.rs -.sp -.B int pcre_info(const pcre *\fIcode\fR, int *\fIoptptr\fR, int -.B *\fIfirstcharptr\fR); -.PP -The \fBpcre_info()\fR function is now obsolete because its interface is too -restrictive to return all the available data about a compiled pattern. New -programs should use \fBpcre_fullinfo()\fR instead. The yield of -\fBpcre_info()\fR is the number of capturing subpatterns, or one of the -following negative numbers: - - PCRE_ERROR_NULL the argument \fIcode\fR was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found - -If the \fIoptptr\fR argument is not NULL, a copy of the options with which the -pattern was compiled is placed in the integer it points to (see -PCRE_INFO_OPTIONS above). - -If the pattern is not anchored and the \fIfirstcharptr\fR argument is not NULL, -it is used to pass back information about the first character of any matched -string (see PCRE_INFO_FIRSTBYTE above). - -.SH MATCHING A PATTERN -.rs -.sp -.B int pcre_exec(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," -.ti +5n -.B "const char *\fIsubject\fR," int \fIlength\fR, int \fIstartoffset\fR, -.ti +5n -.B int \fIoptions\fR, int *\fIovector\fR, int \fIovecsize\fR); -.PP -The function \fBpcre_exec()\fR is called to match a subject string against a -pre-compiled pattern, which is passed in the \fIcode\fR argument. If the -pattern has been studied, the result of the study should be passed in the -\fIextra\fR argument. - -Here is an example of a simple call to \fBpcre_exec()\fR: - - int rc; - int ovector[30]; - rc = pcre_exec( - re, /* result of pcre_compile() */ - NULL, /* we didn't study the pattern */ - "some string", /* the subject string */ - 11, /* the length of the subject string */ - 0, /* start at offset 0 in the subject */ - 0, /* default options */ - ovector, /* vector for substring information */ - 30); /* number of elements in the vector */ - -If the \fIextra\fR argument is not NULL, it must point to a \fBpcre_extra\fR -data block. The \fBpcre_study()\fR function returns such a block (when it -doesn't return NULL), but you can also create one for yourself, and pass -additional information in it. The fields in the block are as follows: - - unsigned long int \fIflags\fR; - void *\fIstudy_data\fR; - unsigned long int \fImatch_limit\fR; - void *\fIcallout_data\fR; - -The \fIflags\fR field is a bitmap that specifies which of the other fields -are set. The flag bits are: - - PCRE_EXTRA_STUDY_DATA - PCRE_EXTRA_MATCH_LIMIT - PCRE_EXTRA_CALLOUT_DATA - -Other flag bits should be set to zero. The \fIstudy_data\fR field is set in the -\fBpcre_extra\fR block that is returned by \fBpcre_study()\fR, together with -the appropriate flag bit. You should not set this yourself, but you can add to -the block by setting the other fields. - -The \fImatch_limit\fR field provides a means of preventing PCRE from using up a -vast amount of resources when running patterns that are not going to match, -but which have a very large number of possibilities in their search trees. The -classic example is the use of nested unlimited repeats. Internally, PCRE uses a -function called \fBmatch()\fR which it calls repeatedly (sometimes -recursively). The limit is imposed on the number of times this function is -called during a match, which has the effect of limiting the amount of recursion -and backtracking that can take place. For patterns that are not anchored, the -count starts from zero for each position in the subject string. - -The default limit for the library can be set when PCRE is built; the default -default is 10 million, which handles all but the most extreme cases. You can -reduce the default by suppling \fBpcre_exec()\fR with a \fRpcre_extra\fR block -in which \fImatch_limit\fR is set to a smaller value, and -PCRE_EXTRA_MATCH_LIMIT is set in the \fIflags\fR field. If the limit is -exceeded, \fBpcre_exec()\fR returns PCRE_ERROR_MATCHLIMIT. - -The \fIpcre_callout\fR field is used in conjunction with the "callout" feature, -which is described in the \fBpcrecallout\fR documentation. - -The PCRE_ANCHORED option can be passed in the \fIoptions\fR argument, whose -unused bits must be zero. This limits \fBpcre_exec()\fR to matching at the -first matching position. However, if a pattern was compiled with PCRE_ANCHORED, -or turned out to be anchored by virtue of its contents, it cannot be made -unachored at matching time. - -When PCRE_UTF8 was set at compile time, the validity of the subject as a UTF-8 -string is automatically checked, and the value of \fIstartoffset\fR is also -checked to ensure that it points to the start of a UTF-8 character. If an -invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fR returns the error -PCRE_ERROR_BADUTF8. If \fIstartoffset\fR contains an invalid value, -PCRE_ERROR_BADUTF8_OFFSET is returned. - -If you already know that your subject is valid, and you want to skip these -checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when -calling \fBpcre_exec()\fR. You might want to do this for the second and -subsequent calls to \fBpcre_exec()\fR if you are making repeated calls to find -all the matches in a single subject string. However, you should be sure that -the value of \fIstartoffset\fR points to the start of a UTF-8 character. When -PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a -subject, or a value of \fIstartoffset\fR that does not point to the start of a -UTF-8 character, is undefined. Your program may crash. - -There are also three further options that can be set only at matching time: - - PCRE_NOTBOL - -The first character of the string is not the beginning of a line, so the -circumflex metacharacter should not match before it. Setting this without -PCRE_MULTILINE (at compile time) causes circumflex never to match. - - PCRE_NOTEOL - -The end of the string is not the end of a line, so the dollar metacharacter -should not match it nor (except in multiline mode) a newline immediately before -it. Setting this without PCRE_MULTILINE (at compile time) causes dollar never -to match. - - PCRE_NOTEMPTY - -An empty string is not considered to be a valid match if this option is set. If -there are alternatives in the pattern, they are tried. If all the alternatives -match the empty string, the entire match fails. For example, if the pattern - - a?b? - -is applied to a string not beginning with "a" or "b", it matches the empty -string at the start of the subject. With PCRE_NOTEMPTY set, this match is not -valid, so PCRE searches further into the string for occurrences of "a" or "b". - -Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case -of a pattern match of the empty string within its \fBsplit()\fR function, and -when using the /g modifier. It is possible to emulate Perl's behaviour after -matching a null string by first trying the match again at the same offset with -PCRE_NOTEMPTY set, and then if that fails by advancing the starting offset (see -below) and trying an ordinary match again. - -The subject string is passed to \fBpcre_exec()\fR as a pointer in -\fIsubject\fR, a length in \fIlength\fR, and a starting byte offset in -\fIstartoffset\fR. Unlike the pattern string, the subject may contain binary -zero bytes. When the starting offset is zero, the search for a match starts at -the beginning of the subject, and this is by far the most common case. - -If the pattern was compiled with the PCRE_UTF8 option, the subject must be a -sequence of bytes that is a valid UTF-8 string, and the starting offset must -point to the beginning of a UTF-8 character. If an invalid UTF-8 string or -offset is passed, an error (either PCRE_ERROR_BADUTF8 or -PCRE_ERROR_BADUTF8_OFFSET) is returned, unless the option PCRE_NO_UTF8_CHECK is -set, in which case PCRE's behaviour is not defined. - -A non-zero starting offset is useful when searching for another match in the -same subject by calling \fBpcre_exec()\fR again after a previous success. -Setting \fIstartoffset\fR differs from just passing over a shortened string and -setting PCRE_NOTBOL in the case of a pattern that begins with any kind of -lookbehind. For example, consider the pattern - - \\Biss\\B - -which finds occurrences of "iss" in the middle of words. (\\B matches only if -the current position in the subject is not a word boundary.) When applied to -the string "Mississipi" the first call to \fBpcre_exec()\fR finds the first -occurrence. If \fBpcre_exec()\fR is called again with just the remainder of the -subject, namely "issipi", it does not match, because \\B is always false at the -start of the subject, which is deemed to be a word boundary. However, if -\fBpcre_exec()\fR is passed the entire string again, but with \fIstartoffset\fR -set to 4, it finds the second occurrence of "iss" because it is able to look -behind the starting point to discover that it is preceded by a letter. - -If a non-zero starting offset is passed when the pattern is anchored, one -attempt to match at the given offset is tried. This can only succeed if the -pattern does not require the match to be at the start of the subject. - -In general, a pattern matches a certain portion of the subject, and in -addition, further substrings from the subject may be picked out by parts of the -pattern. Following the usage in Jeffrey Friedl's book, this is called -"capturing" in what follows, and the phrase "capturing subpattern" is used for -a fragment of a pattern that picks out a substring. PCRE supports several other -kinds of parenthesized subpattern that do not cause substrings to be captured. - -Captured substrings are returned to the caller via a vector of integer offsets -whose address is passed in \fIovector\fR. The number of elements in the vector -is passed in \fIovecsize\fR. The first two-thirds of the vector is used to pass -back captured substrings, each substring using a pair of integers. The -remaining third of the vector is used as workspace by \fBpcre_exec()\fR while -matching capturing subpatterns, and is not available for passing back -information. The length passed in \fIovecsize\fR should always be a multiple of -three. If it is not, it is rounded down. - -When a match has been successful, information about captured substrings is -returned in pairs of integers, starting at the beginning of \fIovector\fR, and -continuing up to two-thirds of its length at the most. The first element of a -pair is set to the offset of the first character in a substring, and the second -is set to the offset of the first character after the end of a substring. The -first pair, \fIovector[0]\fR and \fIovector[1]\fR, identify the portion of the -subject string matched by the entire pattern. The next pair is used for the -first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fR -is the number of pairs that have been set. If there are no capturing -subpatterns, the return value from a successful match is 1, indicating that -just the first pair of offsets has been set. - -Some convenience functions are provided for extracting the captured substrings -as separate strings. These are described in the following section. - -It is possible for an capturing subpattern number \fIn+1\fR to match some -part of the subject when subpattern \fIn\fR has not been used at all. For -example, if the string "abc" is matched against the pattern (a|(z))(bc) -subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset -values corresponding to the unused subpattern are set to -1. - -If a capturing subpattern is matched repeatedly, it is the last portion of the -string that it matched that gets returned. - -If the vector is too small to hold all the captured substrings, it is used as -far as possible (up to two-thirds of its length), and the function returns a -value of zero. In particular, if the substring offsets are not of interest, -\fBpcre_exec()\fR may be called with \fIovector\fR passed as NULL and -\fIovecsize\fR as zero. However, if the pattern contains back references and -the \fIovector\fR isn't big enough to remember the related substrings, PCRE has -to get additional memory for use during matching. Thus it is usually advisable -to supply an \fIovector\fR. - -Note that \fBpcre_info()\fR can be used to find out how many capturing -subpatterns there are in a compiled pattern. The smallest size for -\fIovector\fR that will allow for \fIn\fR captured substrings, in addition to -the offsets of the substring matched by the whole pattern, is (\fIn\fR+1)*3. - -If \fBpcre_exec()\fR fails, it returns a negative number. The following are -defined in the header file: - - PCRE_ERROR_NOMATCH (-1) - -The subject string did not match the pattern. - - PCRE_ERROR_NULL (-2) - -Either \fIcode\fR or \fIsubject\fR was passed as NULL, or \fIovector\fR was -NULL and \fIovecsize\fR was not zero. - - PCRE_ERROR_BADOPTION (-3) - -An unrecognized bit was set in the \fIoptions\fR argument. - - PCRE_ERROR_BADMAGIC (-4) - -PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch -the case when it is passed a junk pointer. This is the error it gives when the -magic number isn't present. - - PCRE_ERROR_UNKNOWN_NODE (-5) - -While running the pattern match, an unknown item was encountered in the -compiled pattern. This error could be caused by a bug in PCRE or by overwriting -of the compiled pattern. - - PCRE_ERROR_NOMEMORY (-6) - -If a pattern contains back references, but the \fIovector\fR that is passed to -\fBpcre_exec()\fR is not big enough to remember the referenced substrings, PCRE -gets a block of memory at the start of matching to use for this purpose. If the -call via \fBpcre_malloc()\fR fails, this error is given. The memory is freed at -the end of matching. - - PCRE_ERROR_NOSUBSTRING (-7) - -This error is used by the \fBpcre_copy_substring()\fR, -\fBpcre_get_substring()\fR, and \fBpcre_get_substring_list()\fR functions (see -below). It is never returned by \fBpcre_exec()\fR. - - PCRE_ERROR_MATCHLIMIT (-8) - -The recursion and backtracking limit, as specified by the \fImatch_limit\fR -field in a \fBpcre_extra\fR structure (or defaulted) was reached. See the -description above. - - PCRE_ERROR_CALLOUT (-9) - -This error is never generated by \fBpcre_exec()\fR itself. It is provided for -use by callout functions that want to yield a distinctive error code. See the -\fBpcrecallout\fR documentation for details. - - PCRE_ERROR_BADUTF8 (-10) - -A string that contains an invalid UTF-8 byte sequence was passed as a subject. - - PCRE_ERROR_BADUTF8_OFFSET (-11) - -The UTF-8 byte sequence that was passed as a subject was valid, but the value -of \fIstartoffset\fR did not point to the beginning of a UTF-8 character. - -.SH EXTRACTING CAPTURED SUBSTRINGS BY NUMBER -.rs -.sp -.B int pcre_copy_substring(const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, int \fIstringnumber\fR, char *\fIbuffer\fR, -.ti +5n -.B int \fIbuffersize\fR); -.PP -.br -.B int pcre_get_substring(const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, int \fIstringnumber\fR, -.ti +5n -.B const char **\fIstringptr\fR); -.PP -.br -.B int pcre_get_substring_list(const char *\fIsubject\fR, -.ti +5n -.B int *\fIovector\fR, int \fIstringcount\fR, "const char ***\fIlistptr\fR);" -.PP -Captured substrings can be accessed directly by using the offsets returned by -\fBpcre_exec()\fR in \fIovector\fR. For convenience, the functions -\fBpcre_copy_substring()\fR, \fBpcre_get_substring()\fR, and -\fBpcre_get_substring_list()\fR are provided for extracting captured substrings -as new, separate, zero-terminated strings. These functions identify substrings -by number. The next section describes functions for extracting named -substrings. A substring that contains a binary zero is correctly extracted and -has a further zero added on the end, but the result is not, of course, -a C string. - -The first three arguments are the same for all three of these functions: -\fIsubject\fR is the subject string which has just been successfully matched, -\fIovector\fR is a pointer to the vector of integer offsets that was passed to -\fBpcre_exec()\fR, and \fIstringcount\fR is the number of substrings that were -captured by the match, including the substring that matched the entire regular -expression. This is the value returned by \fBpcre_exec\fR if it is greater than -zero. If \fBpcre_exec()\fR returned zero, indicating that it ran out of space -in \fIovector\fR, the value passed as \fIstringcount\fR should be the size of -the vector divided by three. - -The functions \fBpcre_copy_substring()\fR and \fBpcre_get_substring()\fR -extract a single substring, whose number is given as \fIstringnumber\fR. A -value of zero extracts the substring that matched the entire pattern, while -higher values extract the captured substrings. For \fBpcre_copy_substring()\fR, -the string is placed in \fIbuffer\fR, whose length is given by -\fIbuffersize\fR, while for \fBpcre_get_substring()\fR a new block of memory is -obtained via \fBpcre_malloc\fR, and its address is returned via -\fIstringptr\fR. The yield of the function is the length of the string, not -including the terminating zero, or one of - - PCRE_ERROR_NOMEMORY (-6) - -The buffer was too small for \fBpcre_copy_substring()\fR, or the attempt to get -memory failed for \fBpcre_get_substring()\fR. - - PCRE_ERROR_NOSUBSTRING (-7) - -There is no substring whose number is \fIstringnumber\fR. - -The \fBpcre_get_substring_list()\fR function extracts all available substrings -and builds a list of pointers to them. All this is done in a single block of -memory which is obtained via \fBpcre_malloc\fR. The address of the memory block -is returned via \fIlistptr\fR, which is also the start of the list of string -pointers. The end of the list is marked by a NULL pointer. The yield of the -function is zero if all went well, or - - PCRE_ERROR_NOMEMORY (-6) - -if the attempt to get the memory block failed. - -When any of these functions encounter a substring that is unset, which can -happen when capturing subpattern number \fIn+1\fR matches some part of the -subject, but subpattern \fIn\fR has not been used at all, they return an empty -string. This can be distinguished from a genuine zero-length substring by -inspecting the appropriate offset in \fIovector\fR, which is negative for unset -substrings. - -The two convenience functions \fBpcre_free_substring()\fR and -\fBpcre_free_substring_list()\fR can be used to free the memory returned by -a previous call of \fBpcre_get_substring()\fR or -\fBpcre_get_substring_list()\fR, respectively. They do nothing more than call -the function pointed to by \fBpcre_free\fR, which of course could be called -directly from a C program. However, PCRE is used in some situations where it is -linked via a special interface to another programming language which cannot use -\fBpcre_free\fR directly; it is for these cases that the functions are -provided. - -.SH EXTRACTING CAPTURED SUBSTRINGS BY NAME -.rs -.sp -.B int pcre_copy_named_substring(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, const char *\fIstringname\fR, -.ti +5n -.B char *\fIbuffer\fR, int \fIbuffersize\fR); -.PP -.br -.B int pcre_get_stringnumber(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIname\fR); -.PP -.br -.B int pcre_get_named_substring(const pcre *\fIcode\fR, -.ti +5n -.B const char *\fIsubject\fR, int *\fIovector\fR, -.ti +5n -.B int \fIstringcount\fR, const char *\fIstringname\fR, -.ti +5n -.B const char **\fIstringptr\fR); -.PP -To extract a substring by name, you first have to find associated number. This -can be done by calling \fBpcre_get_stringnumber()\fR. The first argument is the -compiled pattern, and the second is the name. For example, for this pattern - - ab(?<xxx>\\d+)... - -the number of the subpattern called "xxx" is 1. Given the number, you can then -extract the substring directly, or use one of the functions described in the -previous section. For convenience, there are also two functions that do the -whole job. - -Most of the arguments of \fIpcre_copy_named_substring()\fR and -\fIpcre_get_named_substring()\fR are the same as those for the functions that -extract by number, and so are not re-described here. There are just two -differences. - -First, instead of a substring number, a substring name is given. Second, there -is an extra argument, given at the start, which is a pointer to the compiled -pattern. This is needed in order to gain access to the name-to-number -translation table. - -These functions call \fBpcre_get_stringnumber()\fR, and if it succeeds, they -then call \fIpcre_copy_substring()\fR or \fIpcre_get_substring()\fR, as -appropriate. - -.in 0 -Last updated: 09 December 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcrebuild.3 b/external-libs/pcre/doc/pcrebuild.3 deleted file mode 100644 index a91782c0..00000000 --- a/external-libs/pcre/doc/pcrebuild.3 +++ /dev/null @@ -1,145 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH PCRE BUILD-TIME OPTIONS -.rs -.sp -This document describes the optional features of PCRE that can be selected when -the library is compiled. They are all selected, or deselected, by providing -options to the \fBconfigure\fR script which is run before the \fBmake\fR -command. The complete list of options for \fBconfigure\fR (which includes the -standard ones such as the selection of the installation directory) can be -obtained by running - - ./configure --help - -The following sections describe certain options whose names begin with --enable -or --disable. These settings specify changes to the defaults for the -\fBconfigure\fR command. Because of the way that \fBconfigure\fR works, ---enable and --disable always come in pairs, so the complementary option always -exists as well, but as it specifies the default, it is not described. - -.SH UTF-8 SUPPORT -.rs -.sp -To build PCRE with support for UTF-8 character strings, add - - --enable-utf8 - -to the \fBconfigure\fR command. Of itself, this does not make PCRE treat -strings as UTF-8. As well as compiling PCRE with this option, you also have -have to set the PCRE_UTF8 option when you call the \fBpcre_compile()\fR -function. - -.SH CODE VALUE OF NEWLINE -.rs -.sp -By default, PCRE treats character 10 (linefeed) as the newline character. This -is the normal newline character on Unix-like systems. You can compile PCRE to -use character 13 (carriage return) instead by adding - - --enable-newline-is-cr - -to the \fBconfigure\fR command. For completeness there is also a ---enable-newline-is-lf option, which explicitly specifies linefeed as the -newline character. - -.SH BUILDING SHARED AND STATIC LIBRARIES -.rs -.sp -The PCRE building process uses \fBlibtool\fR to build both shared and static -Unix libraries by default. You can suppress one of these by adding one of - - --disable-shared - --disable-static - -to the \fBconfigure\fR command, as required. - -.SH POSIX MALLOC USAGE -.rs -.sp -When PCRE is called through the POSIX interface (see the \fBpcreposix\fR -documentation), additional working storage is required for holding the pointers -to capturing substrings because PCRE requires three integers per substring, -whereas the POSIX interface provides only two. If the number of expected -substrings is small, the wrapper function uses space on the stack, because this -is faster than using \fBmalloc()\fR for each call. The default threshold above -which the stack is no longer used is 10; it can be changed by adding a setting -such as - - --with-posix-malloc-threshold=20 - -to the \fBconfigure\fR command. - -.SH LIMITING PCRE RESOURCE USAGE -.rs -.sp -Internally, PCRE has a function called \fBmatch()\fR which it calls repeatedly -(possibly recursively) when performing a matching operation. By limiting the -number of times this function may be called, a limit can be placed on the -resources used by a single call to \fBpcre_exec()\fR. The limit can be changed -at run time, as described in the \fBpcreapi\fR documentation. The default is 10 -million, but this can be changed by adding a setting such as - - --with-match-limit=500000 - -to the \fBconfigure\fR command. - -.SH HANDLING VERY LARGE PATTERNS -.rs -.sp -Within a compiled pattern, offset values are used to point from one part to -another (for example, from an opening parenthesis to an alternation -metacharacter). By default two-byte values are used for these offsets, leading -to a maximum size for a compiled pattern of around 64K. This is sufficient to -handle all but the most gigantic patterns. Nevertheless, some people do want to -process enormous patterns, so it is possible to compile PCRE to use three-byte -or four-byte offsets by adding a setting such as - - --with-link-size=3 - -to the \fBconfigure\fR command. The value given must be 2, 3, or 4. Using -longer offsets slows down the operation of PCRE because it has to load -additional bytes when handling them. - -If you build PCRE with an increased link size, test 2 (and test 5 if you are -using UTF-8) will fail. Part of the output of these tests is a representation -of the compiled pattern, and this changes with the link size. - -.SH AVOIDING EXCESSIVE STACK USAGE -.rs -.sp -PCRE implements backtracking while matching by making recursive calls to an -internal function called \fBmatch()\fR. In environments where the size of the -stack is limited, this can severely limit PCRE's operation. (The Unix -environment does not usually suffer from this problem.) An alternative approach -that uses memory from the heap to remember data, instead of using recursive -function calls, has been implemented to work round this problem. If you want to -build a version of PCRE that works this way, add - - --disable-stack-for-recursion - -to the \fBconfigure\fR command. With this configuration, PCRE will use the -\fBpcre_stack_malloc\fR and \fBpcre_stack_free\fR variables to call memory -management functions. Separate functions are provided because the usage is very -predictable: the block sizes requested are always the same, and the blocks are -always freed in reverse order. A calling program might be able to implement -optimized functions that perform better than the standard \fBmalloc()\fR and -\fBfree()\fR functions. PCRE runs noticeably more slowly when built in this -way. - -.SH USING EBCDIC CODE -.rs -.sp -PCRE assumes by default that it will run in an environment where the character -code is ASCII (or UTF-8, which is a superset of ASCII). PCRE can, however, be -compiled to run in an EBCDIC environment by adding - - --enable-ebcdic - -to the \fBconfigure\fR command. - -.in 0 -Last updated: 09 December 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcrecallout.3 b/external-libs/pcre/doc/pcrecallout.3 deleted file mode 100644 index bfbb66b2..00000000 --- a/external-libs/pcre/doc/pcrecallout.3 +++ /dev/null @@ -1,92 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH PCRE CALLOUTS -.rs -.sp -.B int (*pcre_callout)(pcre_callout_block *); -.PP -PCRE provides a feature called "callout", which is a means of temporarily -passing control to the caller of PCRE in the middle of pattern matching. The -caller of PCRE provides an external function by putting its entry point in the -global variable \fIpcre_callout\fR. By default, this variable contains NULL, -which disables all calling out. - -Within a regular expression, (?C) indicates the points at which the external -function is to be called. Different callout points can be identified by putting -a number less than 256 after the letter C. The default value is zero. -For example, this pattern has two callout points: - - (?C1)\dabc(?C2)def - -During matching, when PCRE reaches a callout point (and \fIpcre_callout\fR is -set), the external function is called. Its only argument is a pointer to a -\fBpcre_callout\fR block. This contains the following variables: - - int \fIversion\fR; - int \fIcallout_number\fR; - int *\fIoffset_vector\fR; - const char *\fIsubject\fR; - int \fIsubject_length\fR; - int \fIstart_match\fR; - int \fIcurrent_position\fR; - int \fIcapture_top\fR; - int \fIcapture_last\fR; - void *\fIcallout_data\fR; - -The \fIversion\fR field is an integer containing the version number of the -block format. The current version is zero. The version number may change in -future if additional fields are added, but the intention is never to remove any -of the existing fields. - -The \fIcallout_number\fR field contains the number of the callout, as compiled -into the pattern (that is, the number after ?C). - -The \fIoffset_vector\fR field is a pointer to the vector of offsets that was -passed by the caller to \fBpcre_exec()\fR. The contents can be inspected in -order to extract substrings that have been matched so far, in the same way as -for extracting substrings after a match has completed. - -The \fIsubject\fR and \fIsubject_length\fR fields contain copies the values -that were passed to \fBpcre_exec()\fR. - -The \fIstart_match\fR field contains the offset within the subject at which the -current match attempt started. If the pattern is not anchored, the callout -function may be called several times for different starting points. - -The \fIcurrent_position\fR field contains the offset within the subject of the -current match pointer. - -The \fIcapture_top\fR field contains one more than the number of the highest -numbered captured substring so far. If no substrings have been captured, -the value of \fIcapture_top\fR is one. - -The \fIcapture_last\fR field contains the number of the most recently captured -substring. - -The \fIcallout_data\fR field contains a value that is passed to -\fBpcre_exec()\fR by the caller specifically so that it can be passed back in -callouts. It is passed in the \fIpcre_callout\fR field of the \fBpcre_extra\fR -data structure. If no such data was passed, the value of \fIcallout_data\fR in -a \fBpcre_callout\fR block is NULL. There is a description of the -\fBpcre_extra\fR structure in the \fBpcreapi\fR documentation. - - -.SH RETURN VALUES -.rs -.sp -The callout function returns an integer. If the value is zero, matching -proceeds as normal. If the value is greater than zero, matching fails at the -current point, but backtracking to test other possibilities goes ahead, just as -if a lookahead assertion had failed. If the value is less than zero, the match -is abandoned, and \fBpcre_exec()\fR returns the value. - -Negative values should normally be chosen from the set of PCRE_ERROR_xxx -values. In particular, PCRE_ERROR_NOMATCH forces a standard "no match" failure. -The error number PCRE_ERROR_CALLOUT is reserved for use by callout functions; -it will never be used by PCRE itself. - -.in 0 -Last updated: 21 January 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcrecompat.3 b/external-libs/pcre/doc/pcrecompat.3 deleted file mode 100644 index e358f607..00000000 --- a/external-libs/pcre/doc/pcrecompat.3 +++ /dev/null @@ -1,107 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH DIFFERENCES FROM PERL -.rs -.sp -This document describes the differences in the ways that PCRE and Perl handle -regular expressions. The differences described here are with respect to Perl -5.8. - -1. PCRE does not have full UTF-8 support. Details of what it does have are -given in the -.\" HTML <a href="pcre.html#utf8support"> -.\" </a> -section on UTF-8 support -.\" -in the main -.\" HREF -\fBpcre\fR -.\" -page. - -2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl permits -them, but they do not mean what you might think. For example, (?!a){3} does -not assert that the next three characters are not "a". It just asserts that the -next character is not "a" three times. - -3. Capturing subpatterns that occur inside negative lookahead assertions are -counted, but their entries in the offsets vector are never set. Perl sets its -numerical variables from any such patterns that are matched before the -assertion fails to match something (thereby succeeding), but only if the -negative lookahead assertion contains just one branch. - -4. Though binary zero characters are supported in the subject string, they are -not allowed in a pattern string because it is passed as a normal C string, -terminated by zero. The escape sequence "\\0" can be used in the pattern to -represent a binary zero. - -5. The following Perl escape sequences are not supported: \\l, \\u, \\L, -\\U, \\P, \\p, \\N, and \\X. In fact these are implemented by Perl's general -string-handling and are not part of its pattern matching engine. If any of -these are encountered by PCRE, an error is generated. - -6. PCRE does support the \\Q...\\E escape for quoting substrings. Characters in -between are treated as literals. This is slightly different from Perl in that $ -and @ are also handled as literals inside the quotes. In Perl, they cause -variable interpolation (but of course PCRE does not have variables). Note the -following examples: - - Pattern PCRE matches Perl matches - - \\Qabc$xyz\\E abc$xyz abc followed by the - contents of $xyz - \\Qabc\\$xyz\\E abc\\$xyz abc\\$xyz - \\Qabc\\E\\$\\Qxyz\\E abc$xyz abc$xyz - -The \\Q...\\E sequence is recognized both inside and outside character classes. - -7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code}) -constructions. However, there is some experimental support for recursive -patterns using the non-Perl items (?R), (?number) and (?P>name). Also, the PCRE -"callout" feature allows an external function to be called during pattern -matching. - -8. There are some differences that are concerned with the settings of captured -strings when part of a pattern is repeated. For example, matching "aba" against -the pattern /^(a(b)?)+$/ in Perl leaves $2 unset, but in PCRE it is set to "b". - -9. PCRE provides some extensions to the Perl regular expression facilities: - -(a) Although lookbehind assertions must match fixed length strings, each -alternative branch of a lookbehind assertion can match a different length of -string. Perl requires them all to have the same length. - -(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ -meta-character matches only at the very end of the string. - -(c) If PCRE_EXTRA is set, a backslash followed by a letter with no special -meaning is faulted. - -(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is -inverted, that is, by default they are not greedy, but if followed by a -question mark they are. - -(e) PCRE_ANCHORED can be used to force a pattern to be tried only at the first -matching position in the subject string. - -(f) The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAPTURE -options for \fBpcre_exec()\fR have no Perl equivalents. - -(g) The (?R), (?number), and (?P>name) constructs allows for recursive pattern -matching (Perl can do this using the (?p{code}) construct, which PCRE cannot -support.) - -(h) PCRE supports named capturing substrings, using the Python syntax. - -(i) PCRE supports the possessive quantifier "++" syntax, taken from Sun's Java -package. - -(j) The (R) condition, for testing recursion, is a PCRE extension. - -(k) The callout facility is PCRE-specific. - -.in 0 -Last updated: 09 December 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcregrep.1 b/external-libs/pcre/doc/pcregrep.1 deleted file mode 100644 index c40dc054..00000000 --- a/external-libs/pcre/doc/pcregrep.1 +++ /dev/null @@ -1,130 +0,0 @@ -.TH PCREGREP 1 -.SH NAME -pcregrep - a grep with Perl-compatible regular expressions. -.SH SYNOPSIS -.B pcregrep [-Vcfhilnrsuvx] [long options] [pattern] [file1 file2 ...] - -.SH DESCRIPTION -.rs -.sp -\fBpcregrep\fR searches files for character patterns, in the same way as other -grep commands do, but it uses the PCRE regular expression library to support -patterns that are compatible with the regular expressions of Perl 5. See -.\" HREF -\fBpcrepattern\fR -.\" -for a full description of syntax and semantics of the regular expressions that -PCRE supports. - -A pattern must be specified on the command line unless the \fB-f\fR option is -used (see below). - -If no files are specified, \fBpcregrep\fR reads the standard input. By default, -each line that matches the pattern is copied to the standard output, and if -there is more than one file, the file name is printed before each line of -output. However, there are options that can change how \fBpcregrep\fR behaves. - -Lines are limited to BUFSIZ characters. BUFSIZ is defined in \fB<stdio.h>\fR. -The newline character is removed from the end of each line before it is matched -against the pattern. - -.SH OPTIONS -.rs -.sp -.TP 10 -\fB-V\fR -Write the version number of the PCRE library being used to the standard error -stream. -.TP -\fB-c\fR -Do not print individual lines; instead just print a count of the number of -lines that would otherwise have been printed. If several files are given, a -count is printed for each of them. -.TP -\fB-f\fR\fIfilename\fR -Read a number of patterns from the file, one per line, and match all of them -against each line of input. A line is output if any of the patterns match it. -When \fB-f\fR is used, no pattern is taken from the command line; all arguments -are treated as file names. There is a maximum of 100 patterns. Trailing white -space is removed, and blank lines are ignored. An empty file contains no -patterns and therefore matches nothing. -.TP -\fB-h\fR -Suppress printing of filenames when searching multiple files. -.TP -\fB-i\fR -Ignore upper/lower case distinctions during comparisons. -.TP -\fB-l\fR -Instead of printing lines from the files, just print the names of the files -containing lines that would have been printed. Each file name is printed -once, on a separate line. -.TP -\fB-n\fR -Precede each line by its line number in the file. -.TP -\fB-r\fR -If any file is a directory, recursively scan the files it contains. Without -\fB-r\fR a directory is scanned as a normal file. -.TP -\fB-s\fR -Work silently, that is, display nothing except error messages. -The exit status indicates whether any matches were found. -.TP -\fB-u\fR -Operate in UTF-8 mode. This option is available only if PCRE has been compiled -with UTF-8 support. Both the pattern and each subject line are assumed to be -valid strings of UTF-8 characters. -.TP -\fB-v\fR -Invert the sense of the match, so that lines which do \fInot\fR match the -pattern are now the ones that are found. -.TP -\fB-x\fR -Force the pattern to be anchored (it must start matching at the beginning of -the line) and in addition, require it to match the entire line. This is -equivalent to having ^ and $ characters at the start and end of each -alternative branch in the regular expression. - -.SH LONG OPTIONS -.rs -.sp -Long forms of all the options are available, as in GNU grep. They are shown in -the following table: - - -c --count - -h --no-filename - -i --ignore-case - -l --files-with-matches - -n --line-number - -r --recursive - -s --no-messages - -u --utf-8 - -V --version - -v --invert-match - -x --line-regex - -x --line-regexp - -In addition, --file=\fIfilename\fR is equivalent to -f\fIfilename\fR, and ---help shows the list of options and then exits. - -.SH DIAGNOSTICS -.rs -.sp -Exit status is 0 if any matches were found, 1 if no matches were found, and 2 -for syntax errors or inacessible files (even if matches were found). - - -.SH AUTHOR -.rs -.sp -Philip Hazel <ph10@cam.ac.uk> -.br -University Computing Service -.br -Cambridge CB2 3QG, England. - -.in 0 -Last updated: 03 February 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcregrep.txt b/external-libs/pcre/doc/pcregrep.txt deleted file mode 100644 index aae8928f..00000000 --- a/external-libs/pcre/doc/pcregrep.txt +++ /dev/null @@ -1,124 +0,0 @@ -PCREGREP(1) PCREGREP(1) - - - -NAME - pcregrep - a grep with Perl-compatible regular expressions. - -SYNOPSIS - pcregrep [-Vcfhilnrsuvx] [long options] [pattern] [file1 file2 ...] - - -DESCRIPTION - - pcregrep searches files for character patterns, in the same way as - other grep commands do, but it uses the PCRE regular expression library - to support patterns that are compatible with the regular expressions of - Perl 5. See pcrepattern for a full description of syntax and semantics - of the regular expressions that PCRE supports. - - A pattern must be specified on the command line unless the -f option is - used (see below). - - If no files are specified, pcregrep reads the standard input. By - default, each line that matches the pattern is copied to the standard - output, and if there is more than one file, the file name is printed - before each line of output. However, there are options that can change - how pcregrep behaves. - - Lines are limited to BUFSIZ characters. BUFSIZ is defined in <stdio.h>. - The newline character is removed from the end of each line before it is - matched against the pattern. - - -OPTIONS - - - -V Write the version number of the PCRE library being used to - the standard error stream. - - -c Do not print individual lines; instead just print a count of - the number of lines that would otherwise have been printed. - If several files are given, a count is printed for each of - them. - - -ffilename - Read a number of patterns from the file, one per line, and - match all of them against each line of input. A line is out- - put if any of the patterns match it. When -f is used, no - pattern is taken from the command line; all arguments are - treated as file names. There is a maximum of 100 patterns. - Trailing white space is removed, and blank lines are ignored. - An empty file contains no patterns and therefore matches - nothing. - - -h Suppress printing of filenames when searching multiple files. - - -i Ignore upper/lower case distinctions during comparisons. - - -l Instead of printing lines from the files, just print the - names of the files containing lines that would have been - printed. Each file name is printed once, on a separate line. - - -n Precede each line by its line number in the file. - - -r If any file is a directory, recursively scan the files it - contains. Without -r a directory is scanned as a normal file. - - -s Work silently, that is, display nothing except error mes- - sages. The exit status indicates whether any matches were - found. - - -u Operate in UTF-8 mode. This option is available only if PCRE - has been compiled with UTF-8 support. Both the pattern and - each subject line are assumed to be valid strings of UTF-8 - characters. - - -v Invert the sense of the match, so that lines which do not - match the pattern are now the ones that are found. - - -x Force the pattern to be anchored (it must start matching at - the beginning of the line) and in addition, require it to - match the entire line. This is equivalent to having ^ and $ - characters at the start and end of each alternative branch in - the regular expression. - - -LONG OPTIONS - - Long forms of all the options are available, as in GNU grep. They are - shown in the following table: - - -c --count - -h --no-filename - -i --ignore-case - -l --files-with-matches - -n --line-number - -r --recursive - -s --no-messages - -u --utf-8 - -V --version - -v --invert-match - -x --line-regex - -x --line-regexp - - In addition, --file=filename is equivalent to -ffilename, and --help - shows the list of options and then exits. - - -DIAGNOSTICS - - Exit status is 0 if any matches were found, 1 if no matches were found, - and 2 for syntax errors or inacessible files (even if matches were - found). - - - -AUTHOR - - Philip Hazel <ph10@cam.ac.uk> - University Computing Service - Cambridge CB2 3QG, England. - -Last updated: 03 February 2003 -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcrepattern.3 b/external-libs/pcre/doc/pcrepattern.3 deleted file mode 100644 index 101aa311..00000000 --- a/external-libs/pcre/doc/pcrepattern.3 +++ /dev/null @@ -1,1231 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH PCRE REGULAR EXPRESSION DETAILS -.rs -.sp -The syntax and semantics of the regular expressions supported by PCRE are -described below. Regular expressions are also described in the Perl -documentation and in a number of other books, some of which have copious -examples. Jeffrey Friedl's "Mastering Regular Expressions", published by -O'Reilly, covers them in great detail. The description here is intended as -reference documentation. - -The basic operation of PCRE is on strings of bytes. However, there is also -support for UTF-8 character strings. To use this support you must build PCRE to -include UTF-8 support, and then call \fBpcre_compile()\fR with the PCRE_UTF8 -option. How this affects the pattern matching is mentioned in several places -below. There is also a summary of UTF-8 features in the -.\" HTML <a href="pcre.html#utf8support"> -.\" </a> -section on UTF-8 support -.\" -in the main -.\" HREF -\fBpcre\fR -.\" -page. - -A regular expression is a pattern that is matched against a subject string from -left to right. Most characters stand for themselves in a pattern, and match the -corresponding characters in the subject. As a trivial example, the pattern - - The quick brown fox - -matches a portion of a subject string that is identical to itself. The power of -regular expressions comes from the ability to include alternatives and -repetitions in the pattern. These are encoded in the pattern by the use of -\fImeta-characters\fR, which do not stand for themselves but instead are -interpreted in some special way. - -There are two different sets of meta-characters: those that are recognized -anywhere in the pattern except within square brackets, and those that are -recognized in square brackets. Outside square brackets, the meta-characters are -as follows: - - \\ general escape character with several uses - ^ assert start of string (or line, in multiline mode) - $ assert end of string (or line, in multiline mode) - . match any character except newline (by default) - [ start character class definition - | start of alternative branch - ( start subpattern - ) end subpattern - ? extends the meaning of ( - also 0 or 1 quantifier - also quantifier minimizer - * 0 or more quantifier - + 1 or more quantifier - also "possessive quantifier" - { start min/max quantifier - -Part of a pattern that is in square brackets is called a "character class". In -a character class the only meta-characters are: - - \\ general escape character - ^ negate the class, but only if the first character - - indicates character range - [ POSIX character class (only if followed by POSIX - syntax) - ] terminates the character class - -The following sections describe the use of each of the meta-characters. - -.SH BACKSLASH -.rs -.sp -The backslash character has several uses. Firstly, if it is followed by a -non-alphameric character, it takes away any special meaning that character may -have. This use of backslash as an escape character applies both inside and -outside character classes. - -For example, if you want to match a * character, you write \\* in the pattern. -This escaping action applies whether or not the following character would -otherwise be interpreted as a meta-character, so it is always safe to precede a -non-alphameric with backslash to specify that it stands for itself. In -particular, if you want to match a backslash, you write \\\\. - -If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the -pattern (other than in a character class) and characters between a # outside -a character class and the next newline character are ignored. An escaping -backslash can be used to include a whitespace or # character as part of the -pattern. - -If you want to remove the special meaning from a sequence of characters, you -can do so by putting them between \\Q and \\E. This is different from Perl in -that $ and @ are handled as literals in \\Q...\\E sequences in PCRE, whereas in -Perl, $ and @ cause variable interpolation. Note the following examples: - - Pattern PCRE matches Perl matches - - \\Qabc$xyz\\E abc$xyz abc followed by the - contents of $xyz - \\Qabc\\$xyz\\E abc\\$xyz abc\\$xyz - \\Qabc\\E\\$\\Qxyz\\E abc$xyz abc$xyz - -The \\Q...\\E sequence is recognized both inside and outside character classes. - -A second use of backslash provides a way of encoding non-printing characters -in patterns in a visible manner. There is no restriction on the appearance of -non-printing characters, apart from the binary zero that terminates a pattern, -but when a pattern is being prepared by text editing, it is usually easier to -use one of the following escape sequences than the binary character it -represents: - - \\a alarm, that is, the BEL character (hex 07) - \\cx "control-x", where x is any character - \\e escape (hex 1B) - \\f formfeed (hex 0C) - \\n newline (hex 0A) - \\r carriage return (hex 0D) - \\t tab (hex 09) - \\ddd character with octal code ddd, or backreference - \\xhh character with hex code hh - \\x{hhh..} character with hex code hhh... (UTF-8 mode only) - -The precise effect of \\cx is as follows: if x is a lower case letter, it -is converted to upper case. Then bit 6 of the character (hex 40) is inverted. -Thus \\cz becomes hex 1A, but \\c{ becomes hex 3B, while \\c; becomes hex -7B. - -After \\x, from zero to two hexadecimal digits are read (letters can be in -upper or lower case). In UTF-8 mode, any number of hexadecimal digits may -appear between \\x{ and }, but the value of the character code must be less -than 2**31 (that is, the maximum hexadecimal value is 7FFFFFFF). If characters -other than hexadecimal digits appear between \\x{ and }, or if there is no -terminating }, this form of escape is not recognized. Instead, the initial -\\x will be interpreted as a basic hexadecimal escape, with no following -digits, giving a byte whose value is zero. - -Characters whose value is less than 256 can be defined by either of the two -syntaxes for \\x when PCRE is in UTF-8 mode. There is no difference in the -way they are handled. For example, \\xdc is exactly the same as \\x{dc}. - -After \\0 up to two further octal digits are read. In both cases, if there -are fewer than two digits, just those that are present are used. Thus the -sequence \\0\\x\\07 specifies two binary zeros followed by a BEL character -(code value 7). Make sure you supply two digits after the initial zero if the -character that follows is itself an octal digit. - -The handling of a backslash followed by a digit other than 0 is complicated. -Outside a character class, PCRE reads it and any following digits as a decimal -number. If the number is less than 10, or if there have been at least that many -previous capturing left parentheses in the expression, the entire sequence is -taken as a \fIback reference\fR. A description of how this works is given -later, following the discussion of parenthesized subpatterns. - -Inside a character class, or if the decimal number is greater than 9 and there -have not been that many capturing subpatterns, PCRE re-reads up to three octal -digits following the backslash, and generates a single byte from the least -significant 8 bits of the value. Any subsequent digits stand for themselves. -For example: - - \\040 is another way of writing a space - \\40 is the same, provided there are fewer than 40 - previous capturing subpatterns - \\7 is always a back reference - \\11 might be a back reference, or another way of - writing a tab - \\011 is always a tab - \\0113 is a tab followed by the character "3" - \\113 might be a back reference, otherwise the - character with octal code 113 - \\377 might be a back reference, otherwise - the byte consisting entirely of 1 bits - \\81 is either a back reference, or a binary zero - followed by the two characters "8" and "1" - -Note that octal values of 100 or greater must not be introduced by a leading -zero, because no more than three octal digits are ever read. - -All the sequences that define a single byte value or a single UTF-8 character -(in UTF-8 mode) can be used both inside and outside character classes. In -addition, inside a character class, the sequence \\b is interpreted as the -backspace character (hex 08). Outside a character class it has a different -meaning (see below). - -The third use of backslash is for specifying generic character types: - - \\d any decimal digit - \\D any character that is not a decimal digit - \\s any whitespace character - \\S any character that is not a whitespace character - \\w any "word" character - \\W any "non-word" character - -Each pair of escape sequences partitions the complete set of characters into -two disjoint sets. Any given character matches one, and only one, of each pair. - -In UTF-8 mode, characters with values greater than 255 never match \\d, \\s, or -\\w, and always match \\D, \\S, and \\W. - -For compatibility with Perl, \\s does not match the VT character (code 11). -This makes it different from the the POSIX "space" class. The \\s characters -are HT (9), LF (10), FF (12), CR (13), and space (32). - -A "word" character is any letter or digit or the underscore character, that is, -any character which can be part of a Perl "word". The definition of letters and -digits is controlled by PCRE's character tables, and may vary if locale- -specific matching is taking place (see -.\" HTML <a href="pcreapi.html#localesupport"> -.\" </a> -"Locale support" -.\" -in the -.\" HREF -\fBpcreapi\fR -.\" -page). For example, in the "fr" (French) locale, some character codes greater -than 128 are used for accented letters, and these are matched by \\w. - -These character type sequences can appear both inside and outside character -classes. They each match one character of the appropriate type. If the current -matching point is at the end of the subject string, all of them fail, since -there is no character to match. - -The fourth use of backslash is for certain simple assertions. An assertion -specifies a condition that has to be met at a particular point in a match, -without consuming any characters from the subject string. The use of -subpatterns for more complicated assertions is described below. The backslashed -assertions are - - \\b matches at a word boundary - \\B matches when not at a word boundary - \\A matches at start of subject - \\Z matches at end of subject or before newline at end - \\z matches at end of subject - \\G matches at first matching position in subject - -These assertions may not appear in character classes (but note that \\b has a -different meaning, namely the backspace character, inside a character class). - -A word boundary is a position in the subject string where the current character -and the previous character do not both match \\w or \\W (i.e. one matches -\\w and the other matches \\W), or the start or end of the string if the -first or last character matches \\w, respectively. - -The \\A, \\Z, and \\z assertions differ from the traditional circumflex and -dollar (described below) in that they only ever match at the very start and end -of the subject string, whatever options are set. Thus, they are independent of -multiline mode. - -They are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options. If the -\fIstartoffset\fR argument of \fBpcre_exec()\fR is non-zero, indicating that -matching is to start at a point other than the beginning of the subject, \\A -can never match. The difference between \\Z and \\z is that \\Z matches before -a newline that is the last character of the string as well as at the end of the -string, whereas \\z matches only at the end. - -The \\G assertion is true only when the current matching position is at the -start point of the match, as specified by the \fIstartoffset\fR argument of -\fBpcre_exec()\fR. It differs from \\A when the value of \fIstartoffset\fR is -non-zero. By calling \fBpcre_exec()\fR multiple times with appropriate -arguments, you can mimic Perl's /g option, and it is in this kind of -implementation where \\G can be useful. - -Note, however, that PCRE's interpretation of \\G, as the start of the current -match, is subtly different from Perl's, which defines it as the end of the -previous match. In Perl, these can be different when the previously matched -string was empty. Because PCRE does just one match at a time, it cannot -reproduce this behaviour. - -If all the alternatives of a pattern begin with \\G, the expression is anchored -to the starting match position, and the "anchored" flag is set in the compiled -regular expression. - -.SH CIRCUMFLEX AND DOLLAR -.rs -.sp -Outside a character class, in the default matching mode, the circumflex -character is an assertion which is true only if the current matching point is -at the start of the subject string. If the \fIstartoffset\fR argument of -\fBpcre_exec()\fR is non-zero, circumflex can never match if the PCRE_MULTILINE -option is unset. Inside a character class, circumflex has an entirely different -meaning (see below). - -Circumflex need not be the first character of the pattern if a number of -alternatives are involved, but it should be the first thing in each alternative -in which it appears if the pattern is ever to match that branch. If all -possible alternatives start with a circumflex, that is, if the pattern is -constrained to match only at the start of the subject, it is said to be an -"anchored" pattern. (There are also other constructs that can cause a pattern -to be anchored.) - -A dollar character is an assertion which is true only if the current matching -point is at the end of the subject string, or immediately before a newline -character that is the last character in the string (by default). Dollar need -not be the last character of the pattern if a number of alternatives are -involved, but it should be the last item in any branch in which it appears. -Dollar has no special meaning in a character class. - -The meaning of dollar can be changed so that it matches only at the very end of -the string, by setting the PCRE_DOLLAR_ENDONLY option at compile time. This -does not affect the \\Z assertion. - -The meanings of the circumflex and dollar characters are changed if the -PCRE_MULTILINE option is set. When this is the case, they match immediately -after and immediately before an internal newline character, respectively, in -addition to matching at the start and end of the subject string. For example, -the pattern /^abc$/ matches the subject string "def\\nabc" in multiline mode, -but not otherwise. Consequently, patterns that are anchored in single line mode -because all branches start with ^ are not anchored in multiline mode, and a -match for circumflex is possible when the \fIstartoffset\fR argument of -\fBpcre_exec()\fR is non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if -PCRE_MULTILINE is set. - -Note that the sequences \\A, \\Z, and \\z can be used to match the start and -end of the subject in both modes, and if all branches of a pattern start with -\\A it is always anchored, whether PCRE_MULTILINE is set or not. - -.SH FULL STOP (PERIOD, DOT) -.rs -.sp -Outside a character class, a dot in the pattern matches any one character in -the subject, including a non-printing character, but not (by default) newline. -In UTF-8 mode, a dot matches any UTF-8 character, which might be more than one -byte long, except (by default) for newline. If the PCRE_DOTALL option is set, -dots match newlines as well. The handling of dot is entirely independent of the -handling of circumflex and dollar, the only relationship being that they both -involve newline characters. Dot has no special meaning in a character class. - -.SH MATCHING A SINGLE BYTE -.rs -.sp -Outside a character class, the escape sequence \\C matches any one byte, both -in and out of UTF-8 mode. Unlike a dot, it always matches a newline. The -feature is provided in Perl in order to match individual bytes in UTF-8 mode. -Because it breaks up UTF-8 characters into individual bytes, what remains in -the string may be a malformed UTF-8 string. For this reason it is best avoided. - -PCRE does not allow \\C to appear in lookbehind assertions (see below), because -in UTF-8 mode it makes it impossible to calculate the length of the lookbehind. - -.SH SQUARE BRACKETS -.rs -.sp -An opening square bracket introduces a character class, terminated by a closing -square bracket. A closing square bracket on its own is not special. If a -closing square bracket is required as a member of the class, it should be the -first data character in the class (after an initial circumflex, if present) or -escaped with a backslash. - -A character class matches a single character in the subject. In UTF-8 mode, the -character may occupy more than one byte. A matched character must be in the set -of characters defined by the class, unless the first character in the class -definition is a circumflex, in which case the subject character must not be in -the set defined by the class. If a circumflex is actually required as a member -of the class, ensure it is not the first character, or escape it with a -backslash. - -For example, the character class [aeiou] matches any lower case vowel, while -[^aeiou] matches any character that is not a lower case vowel. Note that a -circumflex is just a convenient notation for specifying the characters which -are in the class by enumerating those that are not. It is not an assertion: it -still consumes a character from the subject string, and fails if the current -pointer is at the end of the string. - -In UTF-8 mode, characters with values greater than 255 can be included in a -class as a literal string of bytes, or by using the \\x{ escaping mechanism. - -When caseless matching is set, any letters in a class represent both their -upper case and lower case versions, so for example, a caseless [aeiou] matches -"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a -caseful version would. PCRE does not support the concept of case for characters -with values greater than 255. - -The newline character is never treated in any special way in character classes, -whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE options is. A class -such as [^a] will always match a newline. - -The minus (hyphen) character can be used to specify a range of characters in a -character class. For example, [d-m] matches any letter between d and m, -inclusive. If a minus character is required in a class, it must be escaped with -a backslash or appear in a position where it cannot be interpreted as -indicating a range, typically as the first or last character in the class. - -It is not possible to have the literal character "]" as the end character of a -range. A pattern such as [W-]46] is interpreted as a class of two characters -("W" and "-") followed by a literal string "46]", so it would match "W46]" or -"-46]". However, if the "]" is escaped with a backslash it is interpreted as -the end of range, so [W-\\]46] is interpreted as a single class containing a -range followed by two separate characters. The octal or hexadecimal -representation of "]" can also be used to end a range. - -Ranges operate in the collating sequence of character values. They can also be -used for characters specified numerically, for example [\\000-\\037]. In UTF-8 -mode, ranges can include characters whose values are greater than 255, for -example [\\x{100}-\\x{2ff}]. - -If a range that includes letters is used when caseless matching is set, it -matches the letters in either case. For example, [W-c] is equivalent to -[][\\^_`wxyzabc], matched caselessly, and if character tables for the "fr" -locale are in use, [\\xc8-\\xcb] matches accented E characters in both cases. - -The character types \\d, \\D, \\s, \\S, \\w, and \\W may also appear in a -character class, and add the characters that they match to the class. For -example, [\\dABCDEF] matches any hexadecimal digit. A circumflex can -conveniently be used with the upper case character types to specify a more -restricted set of characters than the matching lower case type. For example, -the class [^\\W_] matches any letter or digit, but not underscore. - -All non-alphameric characters other than \\, -, ^ (at the start) and the -terminating ] are non-special in character classes, but it does no harm if they -are escaped. - -.SH POSIX CHARACTER CLASSES -.rs -.sp -Perl supports the POSIX notation for character classes, which uses names -enclosed by [: and :] within the enclosing square brackets. PCRE also supports -this notation. For example, - - [01[:alpha:]%] - -matches "0", "1", any alphabetic character, or "%". The supported class names -are - - alnum letters and digits - alpha letters - ascii character codes 0 - 127 - blank space or tab only - cntrl control characters - digit decimal digits (same as \\d) - graph printing characters, excluding space - lower lower case letters - print printing characters, including space - punct printing characters, excluding letters and digits - space white space (not quite the same as \\s) - upper upper case letters - word "word" characters (same as \\w) - xdigit hexadecimal digits - -The "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13), and -space (32). Notice that this list includes the VT character (code 11). This -makes "space" different to \\s, which does not include VT (for Perl -compatibility). - -The name "word" is a Perl extension, and "blank" is a GNU extension from Perl -5.8. Another Perl extension is negation, which is indicated by a ^ character -after the colon. For example, - - [12[:^digit:]] - -matches "1", "2", or any non-digit. PCRE (and Perl) also recognize the POSIX -syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not -supported, and an error is given if they are encountered. - -In UTF-8 mode, characters with values greater than 255 do not match any of -the POSIX character classes. - -.SH VERTICAL BAR -.rs -.sp -Vertical bar characters are used to separate alternative patterns. For example, -the pattern - - gilbert|sullivan - -matches either "gilbert" or "sullivan". Any number of alternatives may appear, -and an empty alternative is permitted (matching the empty string). -The matching process tries each alternative in turn, from left to right, -and the first one that succeeds is used. If the alternatives are within a -subpattern (defined below), "succeeds" means matching the rest of the main -pattern as well as the alternative in the subpattern. - -.SH INTERNAL OPTION SETTING -.rs -.sp -The settings of the PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and -PCRE_EXTENDED options can be changed from within the pattern by a sequence of -Perl option letters enclosed between "(?" and ")". The option letters are - - i for PCRE_CASELESS - m for PCRE_MULTILINE - s for PCRE_DOTALL - x for PCRE_EXTENDED - -For example, (?im) sets caseless, multiline matching. It is also possible to -unset these options by preceding the letter with a hyphen, and a combined -setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and -PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also -permitted. If a letter appears both before and after the hyphen, the option is -unset. - -When an option change occurs at top level (that is, not inside subpattern -parentheses), the change applies to the remainder of the pattern that follows. -If the change is placed right at the start of a pattern, PCRE extracts it into -the global options (and it will therefore show up in data extracted by the -\fBpcre_fullinfo()\fR function). - -An option change within a subpattern affects only that part of the current -pattern that follows it, so - - (a(?i)b)c - -matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used). -By this means, options can be made to have different settings in different -parts of the pattern. Any changes made in one alternative do carry on -into subsequent branches within the same subpattern. For example, - - (a(?i)b|c) - -matches "ab", "aB", "c", and "C", even though when matching "C" the first -branch is abandoned before the option setting. This is because the effects of -option settings happen at compile time. There would be some very weird -behaviour otherwise. - -The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed in the -same way as the Perl-compatible options by using the characters U and X -respectively. The (?X) flag setting is special in that it must always occur -earlier in the pattern than any of the additional features it turns on, even -when it is at top level. It is best put at the start. - -.SH SUBPATTERNS -.rs -.sp -Subpatterns are delimited by parentheses (round brackets), which can be nested. -Marking part of a pattern as a subpattern does two things: - -1. It localizes a set of alternatives. For example, the pattern - - cat(aract|erpillar|) - -matches one of the words "cat", "cataract", or "caterpillar". Without the -parentheses, it would match "cataract", "erpillar" or the empty string. - -2. It sets up the subpattern as a capturing subpattern (as defined above). -When the whole pattern matches, that portion of the subject string that matched -the subpattern is passed back to the caller via the \fIovector\fR argument of -\fBpcre_exec()\fR. Opening parentheses are counted from left to right (starting -from 1) to obtain the numbers of the capturing subpatterns. - -For example, if the string "the red king" is matched against the pattern - - the ((red|white) (king|queen)) - -the captured substrings are "red king", "red", and "king", and are numbered 1, -2, and 3, respectively. - -The fact that plain parentheses fulfil two functions is not always helpful. -There are often times when a grouping subpattern is required without a -capturing requirement. If an opening parenthesis is followed by a question mark -and a colon, the subpattern does not do any capturing, and is not counted when -computing the number of any subsequent capturing subpatterns. For example, if -the string "the white queen" is matched against the pattern - - the ((?:red|white) (king|queen)) - -the captured substrings are "white queen" and "queen", and are numbered 1 and -2. The maximum number of capturing subpatterns is 65535, and the maximum depth -of nesting of all subpatterns, both capturing and non-capturing, is 200. - -As a convenient shorthand, if any option settings are required at the start of -a non-capturing subpattern, the option letters may appear between the "?" and -the ":". Thus the two patterns - - (?i:saturday|sunday) - (?:(?i)saturday|sunday) - -match exactly the same set of strings. Because alternative branches are tried -from left to right, and options are not reset until the end of the subpattern -is reached, an option setting in one branch does affect subsequent branches, so -the above patterns match "SUNDAY" as well as "Saturday". - -.SH NAMED SUBPATTERNS -.rs -.sp -Identifying capturing parentheses by number is simple, but it can be very hard -to keep track of the numbers in complicated regular expressions. Furthermore, -if an expression is modified, the numbers may change. To help with the -difficulty, PCRE supports the naming of subpatterns, something that Perl does -not provide. The Python syntax (?P<name>...) is used. Names consist of -alphanumeric characters and underscores, and must be unique within a pattern. - -Named capturing parentheses are still allocated numbers as well as names. The -PCRE API provides function calls for extracting the name-to-number translation -table from a compiled pattern. For further details see the -.\" HREF -\fBpcreapi\fR -.\" -documentation. - -.SH REPETITION -.rs -.sp -Repetition is specified by quantifiers, which can follow any of the following -items: - - a literal data character - the . metacharacter - the \\C escape sequence - escapes such as \\d that match single characters - a character class - a back reference (see next section) - a parenthesized subpattern (unless it is an assertion) - -The general repetition quantifier specifies a minimum and maximum number of -permitted matches, by giving the two numbers in curly brackets (braces), -separated by a comma. The numbers must be less than 65536, and the first must -be less than or equal to the second. For example: - - z{2,4} - -matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special -character. If the second number is omitted, but the comma is present, there is -no upper limit; if the second number and the comma are both omitted, the -quantifier specifies an exact number of required matches. Thus - - [aeiou]{3,} - -matches at least 3 successive vowels, but may match many more, while - - \\d{8} - -matches exactly 8 digits. An opening curly bracket that appears in a position -where a quantifier is not allowed, or one that does not match the syntax of a -quantifier, is taken as a literal character. For example, {,6} is not a -quantifier, but a literal string of four characters. - -In UTF-8 mode, quantifiers apply to UTF-8 characters rather than to individual -bytes. Thus, for example, \\x{100}{2} matches two UTF-8 characters, each of -which is represented by a two-byte sequence. - -The quantifier {0} is permitted, causing the expression to behave as if the -previous item and the quantifier were not present. - -For convenience (and historical compatibility) the three most common -quantifiers have single-character abbreviations: - - * is equivalent to {0,} - + is equivalent to {1,} - ? is equivalent to {0,1} - -It is possible to construct infinite loops by following a subpattern that can -match no characters with a quantifier that has no upper limit, for example: - - (a?)* - -Earlier versions of Perl and PCRE used to give an error at compile time for -such patterns. However, because there are cases where this can be useful, such -patterns are now accepted, but if any repetition of the subpattern does in fact -match no characters, the loop is forcibly broken. - -By default, the quantifiers are "greedy", that is, they match as much as -possible (up to the maximum number of permitted times), without causing the -rest of the pattern to fail. The classic example of where this gives problems -is in trying to match comments in C programs. These appear between the -sequences /* and */ and within the sequence, individual * and / characters may -appear. An attempt to match C comments by applying the pattern - - /\\*.*\\*/ - -to the string - - /* first command */ not comment /* second comment */ - -fails, because it matches the entire string owing to the greediness of the .* -item. - -However, if a quantifier is followed by a question mark, it ceases to be -greedy, and instead matches the minimum number of times possible, so the -pattern - - /\\*.*?\\*/ - -does the right thing with the C comments. The meaning of the various -quantifiers is not otherwise changed, just the preferred number of matches. -Do not confuse this use of question mark with its use as a quantifier in its -own right. Because it has two uses, it can sometimes appear doubled, as in - - \\d??\\d - -which matches one digit by preference, but can match two if that is the only -way the rest of the pattern matches. - -If the PCRE_UNGREEDY option is set (an option which is not available in Perl), -the quantifiers are not greedy by default, but individual ones can be made -greedy by following them with a question mark. In other words, it inverts the -default behaviour. - -When a parenthesized subpattern is quantified with a minimum repeat count that -is greater than 1 or with a limited maximum, more store is required for the -compiled pattern, in proportion to the size of the minimum or maximum. - -If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent -to Perl's /s) is set, thus allowing the . to match newlines, the pattern is -implicitly anchored, because whatever follows will be tried against every -character position in the subject string, so there is no point in retrying the -overall match at any position after the first. PCRE normally treats such a -pattern as though it were preceded by \\A. - -In cases where it is known that the subject string contains no newlines, it is -worth setting PCRE_DOTALL in order to obtain this optimization, or -alternatively using ^ to indicate anchoring explicitly. - -However, there is one situation where the optimization cannot be used. When .* -is inside capturing parentheses that are the subject of a backreference -elsewhere in the pattern, a match at the start may fail, and a later one -succeed. Consider, for example: - - (.*)abc\\1 - -If the subject is "xyz123abc123" the match point is the fourth character. For -this reason, such a pattern is not implicitly anchored. - -When a capturing subpattern is repeated, the value captured is the substring -that matched the final iteration. For example, after - - (tweedle[dume]{3}\\s*)+ - -has matched "tweedledum tweedledee" the value of the captured substring is -"tweedledee". However, if there are nested capturing subpatterns, the -corresponding captured values may have been set in previous iterations. For -example, after - - /(a|(b))+/ - -matches "aba" the value of the second captured substring is "b". - -.SH ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS -.rs -.sp -With both maximizing and minimizing repetition, failure of what follows -normally causes the repeated item to be re-evaluated to see if a different -number of repeats allows the rest of the pattern to match. Sometimes it is -useful to prevent this, either to change the nature of the match, or to cause -it fail earlier than it otherwise might, when the author of the pattern knows -there is no point in carrying on. - -Consider, for example, the pattern \\d+foo when applied to the subject line - - 123456bar - -After matching all 6 digits and then failing to match "foo", the normal -action of the matcher is to try again with only 5 digits matching the \\d+ -item, and then with 4, and so on, before ultimately failing. "Atomic grouping" -(a term taken from Jeffrey Friedl's book) provides the means for specifying -that once a subpattern has matched, it is not to be re-evaluated in this way. - -If we use atomic grouping for the previous example, the matcher would give up -immediately on failing to match "foo" the first time. The notation is a kind of -special parenthesis, starting with (?> as in this example: - - (?>\\d+)foo - -This kind of parenthesis "locks up" the part of the pattern it contains once -it has matched, and a failure further into the pattern is prevented from -backtracking into it. Backtracking past it to previous items, however, works as -normal. - -An alternative description is that a subpattern of this type matches the string -of characters that an identical standalone pattern would match, if anchored at -the current point in the subject string. - -Atomic grouping subpatterns are not capturing subpatterns. Simple cases such as -the above example can be thought of as a maximizing repeat that must swallow -everything it can. So, while both \\d+ and \\d+? are prepared to adjust the -number of digits they match in order to make the rest of the pattern match, -(?>\\d+) can only match an entire sequence of digits. - -Atomic groups in general can of course contain arbitrarily complicated -subpatterns, and can be nested. However, when the subpattern for an atomic -group is just a single repeated item, as in the example above, a simpler -notation, called a "possessive quantifier" can be used. This consists of an -additional + character following a quantifier. Using this notation, the -previous example can be rewritten as - - \\d++bar - -Possessive quantifiers are always greedy; the setting of the PCRE_UNGREEDY -option is ignored. They are a convenient notation for the simpler forms of -atomic group. However, there is no difference in the meaning or processing of a -possessive quantifier and the equivalent atomic group. - -The possessive quantifier syntax is an extension to the Perl syntax. It -originates in Sun's Java package. - -When a pattern contains an unlimited repeat inside a subpattern that can itself -be repeated an unlimited number of times, the use of an atomic group is the -only way to avoid some failing matches taking a very long time indeed. The -pattern - - (\\D+|<\\d+>)*[!?] - -matches an unlimited number of substrings that either consist of non-digits, or -digits enclosed in <>, followed by either ! or ?. When it matches, it runs -quickly. However, if it is applied to - - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa - -it takes a long time before reporting failure. This is because the string can -be divided between the two repeats in a large number of ways, and all have to -be tried. (The example used [!?] rather than a single character at the end, -because both PCRE and Perl have an optimization that allows for fast failure -when a single character is used. They remember the last single character that -is required for a match, and fail early if it is not present in the string.) -If the pattern is changed to - - ((?>\\D+)|<\\d+>)*[!?] - -sequences of non-digits cannot be broken, and failure happens quickly. - -.SH BACK REFERENCES -.rs -.sp -Outside a character class, a backslash followed by a digit greater than 0 (and -possibly further digits) is a back reference to a capturing subpattern earlier -(that is, to its left) in the pattern, provided there have been that many -previous capturing left parentheses. - -However, if the decimal number following the backslash is less than 10, it is -always taken as a back reference, and causes an error only if there are not -that many capturing left parentheses in the entire pattern. In other words, the -parentheses that are referenced need not be to the left of the reference for -numbers less than 10. See the section entitled "Backslash" above for further -details of the handling of digits following a backslash. - -A back reference matches whatever actually matched the capturing subpattern in -the current subject string, rather than anything matching the subpattern -itself (see -.\" HTML <a href="#subpatternsassubroutines"> -.\" </a> -"Subpatterns as subroutines" -.\" -below for a way of doing that). So the pattern - - (sens|respons)e and \\1ibility - -matches "sense and sensibility" and "response and responsibility", but not -"sense and responsibility". If caseful matching is in force at the time of the -back reference, the case of letters is relevant. For example, - - ((?i)rah)\\s+\\1 - -matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original -capturing subpattern is matched caselessly. - -Back references to named subpatterns use the Python syntax (?P=name). We could -rewrite the above example as follows: - - (?<p1>(?i)rah)\\s+(?P=p1) - -There may be more than one back reference to the same subpattern. If a -subpattern has not actually been used in a particular match, any back -references to it always fail. For example, the pattern - - (a|(bc))\\2 - -always fails if it starts to match "a" rather than "bc". Because there may be -many capturing parentheses in a pattern, all digits following the backslash are -taken as part of a potential back reference number. If the pattern continues -with a digit character, some delimiter must be used to terminate the back -reference. If the PCRE_EXTENDED option is set, this can be whitespace. -Otherwise an empty comment can be used. - -A back reference that occurs inside the parentheses to which it refers fails -when the subpattern is first used, so, for example, (a\\1) never matches. -However, such references can be useful inside repeated subpatterns. For -example, the pattern - - (a|b\\1)+ - -matches any number of "a"s and also "aba", "ababbaa" etc. At each iteration of -the subpattern, the back reference matches the character string corresponding -to the previous iteration. In order for this to work, the pattern must be such -that the first iteration does not need to match the back reference. This can be -done using alternation, as in the example above, or by a quantifier with a -minimum of zero. - -.SH ASSERTIONS -.rs -.sp -An assertion is a test on the characters following or preceding the current -matching point that does not actually consume any characters. The simple -assertions coded as \\b, \\B, \\A, \\G, \\Z, \\z, ^ and $ are described above. -More complicated assertions are coded as subpatterns. There are two kinds: -those that look ahead of the current position in the subject string, and those -that look behind it. - -An assertion subpattern is matched in the normal way, except that it does not -cause the current matching position to be changed. Lookahead assertions start -with (?= for positive assertions and (?! for negative assertions. For example, - - \\w+(?=;) - -matches a word followed by a semicolon, but does not include the semicolon in -the match, and - - foo(?!bar) - -matches any occurrence of "foo" that is not followed by "bar". Note that the -apparently similar pattern - - (?!foo)bar - -does not find an occurrence of "bar" that is preceded by something other than -"foo"; it finds any occurrence of "bar" whatsoever, because the assertion -(?!foo) is always true when the next three characters are "bar". A -lookbehind assertion is needed to achieve this effect. - -If you want to force a matching failure at some point in a pattern, the most -convenient way to do it is with (?!) because an empty string always matches, so -an assertion that requires there not to be an empty string must always fail. - -Lookbehind assertions start with (?<= for positive assertions and (?<! for -negative assertions. For example, - - (?<!foo)bar - -does find an occurrence of "bar" that is not preceded by "foo". The contents of -a lookbehind assertion are restricted such that all the strings it matches must -have a fixed length. However, if there are several alternatives, they do not -all have to have the same fixed length. Thus - - (?<=bullock|donkey) - -is permitted, but - - (?<!dogs?|cats?) - -causes an error at compile time. Branches that match different length strings -are permitted only at the top level of a lookbehind assertion. This is an -extension compared with Perl (at least for 5.8), which requires all branches to -match the same length of string. An assertion such as - - (?<=ab(c|de)) - -is not permitted, because its single top-level branch can match two different -lengths, but it is acceptable if rewritten to use two top-level branches: - - (?<=abc|abde) - -The implementation of lookbehind assertions is, for each alternative, to -temporarily move the current position back by the fixed width and then try to -match. If there are insufficient characters before the current position, the -match is deemed to fail. - -PCRE does not allow the \\C escape (which matches a single byte in UTF-8 mode) -to appear in lookbehind assertions, because it makes it impossible to calculate -the length of the lookbehind. - -Atomic groups can be used in conjunction with lookbehind assertions to specify -efficient matching at the end of the subject string. Consider a simple pattern -such as - - abcd$ - -when applied to a long string that does not match. Because matching proceeds -from left to right, PCRE will look for each "a" in the subject and then see if -what follows matches the rest of the pattern. If the pattern is specified as - - ^.*abcd$ - -the initial .* matches the entire string at first, but when this fails (because -there is no following "a"), it backtracks to match all but the last character, -then all but the last two characters, and so on. Once again the search for "a" -covers the entire string, from right to left, so we are no better off. However, -if the pattern is written as - - ^(?>.*)(?<=abcd) - -or, equivalently, - - ^.*+(?<=abcd) - -there can be no backtracking for the .* item; it can match only the entire -string. The subsequent lookbehind assertion does a single test on the last four -characters. If it fails, the match fails immediately. For long strings, this -approach makes a significant difference to the processing time. - -Several assertions (of any sort) may occur in succession. For example, - - (?<=\\d{3})(?<!999)foo - -matches "foo" preceded by three digits that are not "999". Notice that each of -the assertions is applied independently at the same point in the subject -string. First there is a check that the previous three characters are all -digits, and then there is a check that the same three characters are not "999". -This pattern does \fInot\fR match "foo" preceded by six characters, the first -of which are digits and the last three of which are not "999". For example, it -doesn't match "123abcfoo". A pattern to do that is - - (?<=\\d{3}...)(?<!999)foo - -This time the first assertion looks at the preceding six characters, checking -that the first three are digits, and then the second assertion checks that the -preceding three characters are not "999". - -Assertions can be nested in any combination. For example, - - (?<=(?<!foo)bar)baz - -matches an occurrence of "baz" that is preceded by "bar" which in turn is not -preceded by "foo", while - - (?<=\\d{3}(?!999)...)foo - -is another pattern which matches "foo" preceded by three digits and any three -characters that are not "999". - -Assertion subpatterns are not capturing subpatterns, and may not be repeated, -because it makes no sense to assert the same thing several times. If any kind -of assertion contains capturing subpatterns within it, these are counted for -the purposes of numbering the capturing subpatterns in the whole pattern. -However, substring capturing is carried out only for positive assertions, -because it does not make sense for negative assertions. - -.SH CONDITIONAL SUBPATTERNS -.rs -.sp -It is possible to cause the matching process to obey a subpattern -conditionally or to choose between two alternative subpatterns, depending on -the result of an assertion, or whether a previous capturing subpattern matched -or not. The two possible forms of conditional subpattern are - - (?(condition)yes-pattern) - (?(condition)yes-pattern|no-pattern) - -If the condition is satisfied, the yes-pattern is used; otherwise the -no-pattern (if present) is used. If there are more than two alternatives in the -subpattern, a compile-time error occurs. - -There are three kinds of condition. If the text between the parentheses -consists of a sequence of digits, the condition is satisfied if the capturing -subpattern of that number has previously matched. The number must be greater -than zero. Consider the following pattern, which contains non-significant white -space to make it more readable (assume the PCRE_EXTENDED option) and to divide -it into three parts for ease of discussion: - - ( \\( )? [^()]+ (?(1) \\) ) - -The first part matches an optional opening parenthesis, and if that -character is present, sets it as the first captured substring. The second part -matches one or more characters that are not parentheses. The third part is a -conditional subpattern that tests whether the first set of parentheses matched -or not. If they did, that is, if subject started with an opening parenthesis, -the condition is true, and so the yes-pattern is executed and a closing -parenthesis is required. Otherwise, since no-pattern is not present, the -subpattern matches nothing. In other words, this pattern matches a sequence of -non-parentheses, optionally enclosed in parentheses. - -If the condition is the string (R), it is satisfied if a recursive call to the -pattern or subpattern has been made. At "top level", the condition is false. -This is a PCRE extension. Recursive patterns are described in the next section. - -If the condition is not a sequence of digits or (R), it must be an assertion. -This may be a positive or negative lookahead or lookbehind assertion. Consider -this pattern, again containing non-significant white space, and with the two -alternatives on the second line: - - (?(?=[^a-z]*[a-z]) - \\d{2}-[a-z]{3}-\\d{2} | \\d{2}-\\d{2}-\\d{2} ) - -The condition is a positive lookahead assertion that matches an optional -sequence of non-letters followed by a letter. In other words, it tests for the -presence of at least one letter in the subject. If a letter is found, the -subject is matched against the first alternative; otherwise it is matched -against the second. This pattern matches strings in one of the two forms -dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits. - -.SH COMMENTS -.rs -.sp -The sequence (?# marks the start of a comment which continues up to the next -closing parenthesis. Nested parentheses are not permitted. The characters -that make up a comment play no part in the pattern matching at all. - -If the PCRE_EXTENDED option is set, an unescaped # character outside a -character class introduces a comment that continues up to the next newline -character in the pattern. - -.SH RECURSIVE PATTERNS -.rs -.sp -Consider the problem of matching a string in parentheses, allowing for -unlimited nested parentheses. Without the use of recursion, the best that can -be done is to use a pattern that matches up to some fixed depth of nesting. It -is not possible to handle an arbitrary nesting depth. Perl has provided an -experimental facility that allows regular expressions to recurse (amongst other -things). It does this by interpolating Perl code in the expression at run time, -and the code can refer to the expression itself. A Perl pattern to solve the -parentheses problem can be created like this: - - $re = qr{\\( (?: (?>[^()]+) | (?p{$re}) )* \\)}x; - -The (?p{...}) item interpolates Perl code at run time, and in this case refers -recursively to the pattern in which it appears. Obviously, PCRE cannot support -the interpolation of Perl code. Instead, it supports some special syntax for -recursion of the entire pattern, and also for individual subpattern recursion. - -The special item that consists of (? followed by a number greater than zero and -a closing parenthesis is a recursive call of the subpattern of the given -number, provided that it occurs inside that subpattern. (If not, it is a -"subroutine" call, which is described in the next section.) The special item -(?R) is a recursive call of the entire regular expression. - -For example, this PCRE pattern solves the nested parentheses problem (assume -the PCRE_EXTENDED option is set so that white space is ignored): - - \\( ( (?>[^()]+) | (?R) )* \\) - -First it matches an opening parenthesis. Then it matches any number of -substrings which can either be a sequence of non-parentheses, or a recursive -match of the pattern itself (that is a correctly parenthesized substring). -Finally there is a closing parenthesis. - -If this were part of a larger pattern, you would not want to recurse the entire -pattern, so instead you could use this: - - ( \\( ( (?>[^()]+) | (?1) )* \\) ) - -We have put the pattern into parentheses, and caused the recursion to refer to -them instead of the whole pattern. In a larger pattern, keeping track of -parenthesis numbers can be tricky. It may be more convenient to use named -parentheses instead. For this, PCRE uses (?P>name), which is an extension to -the Python syntax that PCRE uses for named parentheses (Perl does not provide -named parentheses). We could rewrite the above example as follows: - - (?P<pn> \\( ( (?>[^()]+) | (?P>pn) )* \\) ) - -This particular example pattern contains nested unlimited repeats, and so the -use of atomic grouping for matching strings of non-parentheses is important -when applying the pattern to strings that do not match. For example, when this -pattern is applied to - - (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() - -it yields "no match" quickly. However, if atomic grouping is not used, -the match runs for a very long time indeed because there are so many different -ways the + and * repeats can carve up the subject, and all have to be tested -before failure can be reported. - -At the end of a match, the values set for any capturing subpatterns are those -from the outermost level of the recursion at which the subpattern value is set. -If you want to obtain intermediate values, a callout function can be used (see -below and the -.\" HREF -\fBpcrecallout\fR -.\" -documentation). If the pattern above is matched against - - (ab(cd)ef) - -the value for the capturing parentheses is "ef", which is the last value taken -on at the top level. If additional parentheses are added, giving - - \\( ( ( (?>[^()]+) | (?R) )* ) \\) - ^ ^ - ^ ^ - -the string they capture is "ab(cd)ef", the contents of the top level -parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE -has to obtain extra memory to store data during a recursion, which it does by -using \fBpcre_malloc\fR, freeing it via \fBpcre_free\fR afterwards. If no -memory can be obtained, the match fails with the PCRE_ERROR_NOMEMORY error. - -Do not confuse the (?R) item with the condition (R), which tests for recursion. -Consider this pattern, which matches text in angle brackets, allowing for -arbitrary nesting. Only digits are allowed in nested brackets (that is, when -recursing), whereas any characters are permitted at the outer level. - - < (?: (?(R) \\d++ | [^<>]*+) | (?R)) * > - -In this pattern, (?(R) is the start of a conditional subpattern, with two -different alternatives for the recursive and non-recursive cases. The (?R) item -is the actual recursive call. - -.\" HTML <a name="subpatternsassubroutines"></a> -.SH SUBPATTERNS AS SUBROUTINES -.rs -.sp -If the syntax for a recursive subpattern reference (either by number or by -name) is used outside the parentheses to which it refers, it operates like a -subroutine in a programming language. An earlier example pointed out that the -pattern - - (sens|respons)e and \\1ibility - -matches "sense and sensibility" and "response and responsibility", but not -"sense and responsibility". If instead the pattern - - (sens|respons)e and (?1)ibility - -is used, it does match "sense and responsibility" as well as the other two -strings. Such references must, however, follow the subpattern to which they -refer. - -.SH CALLOUTS -.rs -.sp -Perl has a feature whereby using the sequence (?{...}) causes arbitrary Perl -code to be obeyed in the middle of matching a regular expression. This makes it -possible, amongst other things, to extract different substrings that match the -same pair of parentheses when there is a repetition. - -PCRE provides a similar feature, but of course it cannot obey arbitrary Perl -code. The feature is called "callout". The caller of PCRE provides an external -function by putting its entry point in the global variable \fIpcre_callout\fR. -By default, this variable contains NULL, which disables all calling out. - -Within a regular expression, (?C) indicates the points at which the external -function is to be called. If you want to identify different callout points, you -can put a number less than 256 after the letter C. The default value is zero. -For example, this pattern has two callout points: - - (?C1)\dabc(?C2)def - -During matching, when PCRE reaches a callout point (and \fIpcre_callout\fR is -set), the external function is called. It is provided with the number of the -callout, and, optionally, one item of data originally supplied by the caller of -\fBpcre_exec()\fR. The callout function may cause matching to backtrack, or to -fail altogether. A complete description of the interface to the callout -function is given in the -.\" HREF -\fBpcrecallout\fR -.\" -documentation. - -.in 0 -Last updated: 03 February 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcreperform.3 b/external-libs/pcre/doc/pcreperform.3 deleted file mode 100644 index 52a332fc..00000000 --- a/external-libs/pcre/doc/pcreperform.3 +++ /dev/null @@ -1,66 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH PCRE PERFORMANCE -.rs -.sp -Certain items that may appear in regular expression patterns are more efficient -than others. It is more efficient to use a character class like [aeiou] than a -set of alternatives such as (a|e|i|o|u). In general, the simplest construction -that provides the required behaviour is usually the most efficient. Jeffrey -Friedl's book contains a lot of discussion about optimizing regular expressions -for efficient performance. - -When a pattern begins with .* not in parentheses, or in parentheses that are -not the subject of a backreference, and the PCRE_DOTALL option is set, the -pattern is implicitly anchored by PCRE, since it can match only at the start of -a subject string. However, if PCRE_DOTALL is not set, PCRE cannot make this -optimization, because the . metacharacter does not then match a newline, and if -the subject string contains newlines, the pattern may match from the character -immediately following one of them instead of from the very start. For example, -the pattern - - .*second - -matches the subject "first\\nand second" (where \\n stands for a newline -character), with the match starting at the seventh character. In order to do -this, PCRE has to retry the match starting after every newline in the subject. - -If you are using such a pattern with subject strings that do not contain -newlines, the best performance is obtained by setting PCRE_DOTALL, or starting -the pattern with ^.* to indicate explicit anchoring. That saves PCRE from -having to scan along the subject looking for a newline to restart at. - -Beware of patterns that contain nested indefinite repeats. These can take a -long time to run when applied to a string that does not match. Consider the -pattern fragment - - (a+)* - -This can match "aaaa" in 33 different ways, and this number increases very -rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4 -times, and for each of those cases other than 0, the + repeats can match -different numbers of times.) When the remainder of the pattern is such that the -entire match is going to fail, PCRE has in principle to try every possible -variation, and this can take an extremely long time. - -An optimization catches some of the more simple cases such as - - (a+)*b - -where a literal character follows. Before embarking on the standard matching -procedure, PCRE checks that there is a "b" later in the subject string, and if -there is not, it fails the match immediately. However, when there is no -following literal this optimization cannot be used. You can see the difference -by comparing the behaviour of - - (a+)*\\d - -with the pattern above. The former gives a failure almost instantly when -applied to a whole line of "a" characters, whereas the latter takes an -appreciable time with strings longer than about 20 characters. - -.in 0 -Last updated: 03 February 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcreposix.3 b/external-libs/pcre/doc/pcreposix.3 deleted file mode 100644 index 5198630f..00000000 --- a/external-libs/pcre/doc/pcreposix.3 +++ /dev/null @@ -1,194 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions. -.SH SYNOPSIS OF POSIX API -.B #include <pcreposix.h> -.PP -.SM -.br -.B int regcomp(regex_t *\fIpreg\fR, const char *\fIpattern\fR, -.ti +5n -.B int \fIcflags\fR); -.PP -.br -.B int regexec(regex_t *\fIpreg\fR, const char *\fIstring\fR, -.ti +5n -.B size_t \fInmatch\fR, regmatch_t \fIpmatch\fR[], int \fIeflags\fR); -.PP -.br -.B size_t regerror(int \fIerrcode\fR, const regex_t *\fIpreg\fR, -.ti +5n -.B char *\fIerrbuf\fR, size_t \fIerrbuf_size\fR); -.PP -.br -.B void regfree(regex_t *\fIpreg\fR); - -.SH DESCRIPTION -.rs -.sp -This set of functions provides a POSIX-style API to the PCRE regular expression -package. See the -.\" HREF -\fBpcreapi\fR -.\" -documentation for a description of the native API, which contains additional -functionality. - -The functions described here are just wrapper functions that ultimately call -the PCRE native API. Their prototypes are defined in the \fBpcreposix.h\fR -header file, and on Unix systems the library itself is called -\fBpcreposix.a\fR, so can be accessed by adding \fB-lpcreposix\fR to the -command for linking an application which uses them. Because the POSIX functions -call the native ones, it is also necessary to add \fR-lpcre\fR. - -I have implemented only those option bits that can be reasonably mapped to PCRE -native options. In addition, the options REG_EXTENDED and REG_NOSUB are defined -with the value zero. They have no effect, but since programs that are written -to the POSIX interface often use them, this makes it easier to slot in PCRE as -a replacement library. Other POSIX options are not even defined. - -When PCRE is called via these functions, it is only the API that is POSIX-like -in style. The syntax and semantics of the regular expressions themselves are -still those of Perl, subject to the setting of various PCRE options, as -described below. "POSIX-like in style" means that the API approximates to the -POSIX definition; it is not fully POSIX-compatible, and in multi-byte encoding -domains it is probably even less compatible. - -The header for these functions is supplied as \fBpcreposix.h\fR to avoid any -potential clash with other POSIX libraries. It can, of course, be renamed or -aliased as \fBregex.h\fR, which is the "correct" name. It provides two -structure types, \fIregex_t\fR for compiled internal forms, and -\fIregmatch_t\fR for returning captured substrings. It also defines some -constants whose names start with "REG_"; these are used for setting options and -identifying error codes. - -.SH COMPILING A PATTERN -.rs -.sp -The function \fBregcomp()\fR is called to compile a pattern into an -internal form. The pattern is a C string terminated by a binary zero, and -is passed in the argument \fIpattern\fR. The \fIpreg\fR argument is a pointer -to a regex_t structure which is used as a base for storing information about -the compiled expression. - -The argument \fIcflags\fR is either zero, or contains one or more of the bits -defined by the following macros: - - REG_ICASE - -The PCRE_CASELESS option is set when the expression is passed for compilation -to the native function. - - REG_NEWLINE - -The PCRE_MULTILINE option is set when the expression is passed for compilation -to the native function. Note that this does \fInot\fR mimic the defined POSIX -behaviour for REG_NEWLINE (see the following section). - -In the absence of these flags, no options are passed to the native function. -This means the the regex is compiled with PCRE default semantics. In -particular, the way it handles newline characters in the subject string is the -Perl way, not the POSIX way. Note that setting PCRE_MULTILINE has only -\fIsome\fR of the effects specified for REG_NEWLINE. It does not affect the way -newlines are matched by . (they aren't) or by a negative class such as [^a] -(they are). - -The yield of \fBregcomp()\fR is zero on success, and non-zero otherwise. The -\fIpreg\fR structure is filled in on success, and one member of the structure -is public: \fIre_nsub\fR contains the number of capturing subpatterns in -the regular expression. Various error codes are defined in the header file. - -.SH MATCHING NEWLINE CHARACTERS -.rs -.sp -This area is not simple, because POSIX and Perl take different views of things. -It is not possible to get PCRE to obey POSIX semantics, but then PCRE was never -intended to be a POSIX engine. The following table lists the different -possibilities for matching newline characters in PCRE: - - Default Change with - - . matches newline no PCRE_DOTALL - newline matches [^a] yes not changeable - $ matches \\n at end yes PCRE_DOLLARENDONLY - $ matches \\n in middle no PCRE_MULTILINE - ^ matches \\n in middle no PCRE_MULTILINE - -This is the equivalent table for POSIX: - - Default Change with - - . matches newline yes REG_NEWLINE - newline matches [^a] yes REG_NEWLINE - $ matches \\n at end no REG_NEWLINE - $ matches \\n in middle no REG_NEWLINE - ^ matches \\n in middle no REG_NEWLINE - -PCRE's behaviour is the same as Perl's, except that there is no equivalent for -PCRE_DOLLARENDONLY in Perl. In both PCRE and Perl, there is no way to stop -newline from matching [^a]. - -The default POSIX newline handling can be obtained by setting PCRE_DOTALL and -PCRE_DOLLARENDONLY, but there is no way to make PCRE behave exactly as for the -REG_NEWLINE action. - -.SH MATCHING A PATTERN -.rs -.sp -The function \fBregexec()\fR is called to match a pre-compiled pattern -\fIpreg\fR against a given \fIstring\fR, which is terminated by a zero byte, -subject to the options in \fIeflags\fR. These can be: - - REG_NOTBOL - -The PCRE_NOTBOL option is set when calling the underlying PCRE matching -function. - - REG_NOTEOL - -The PCRE_NOTEOL option is set when calling the underlying PCRE matching -function. - -The portion of the string that was matched, and also any captured substrings, -are returned via the \fIpmatch\fR argument, which points to an array of -\fInmatch\fR structures of type \fIregmatch_t\fR, containing the members -\fIrm_so\fR and \fIrm_eo\fR. These contain the offset to the first character of -each substring and the offset to the first character after the end of each -substring, respectively. The 0th element of the vector relates to the entire -portion of \fIstring\fR that was matched; subsequent elements relate to the -capturing subpatterns of the regular expression. Unused entries in the array -have both structure members set to -1. - -A successful match yields a zero return; various error codes are defined in the -header file, of which REG_NOMATCH is the "expected" failure code. - -.SH ERROR MESSAGES -.rs -.sp -The \fBregerror()\fR function maps a non-zero errorcode from either -\fBregcomp()\fR or \fBregexec()\fR to a printable message. If \fIpreg\fR is not -NULL, the error should have arisen from the use of that structure. A message -terminated by a binary zero is placed in \fIerrbuf\fR. The length of the -message, including the zero, is limited to \fIerrbuf_size\fR. The yield of the -function is the size of buffer needed to hold the whole message. - -.SH STORAGE -.rs -.sp -Compiling a regular expression causes memory to be allocated and associated -with the \fIpreg\fR structure. The function \fBregfree()\fR frees all such -memory, after which \fIpreg\fR may no longer be used as a compiled expression. - -.SH AUTHOR -.rs -.sp -Philip Hazel <ph10@cam.ac.uk> -.br -University Computing Service, -.br -Cambridge CB2 3QG, England. - -.in 0 -Last updated: 03 February 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcresample.3 b/external-libs/pcre/doc/pcresample.3 deleted file mode 100644 index 02a7a548..00000000 --- a/external-libs/pcre/doc/pcresample.3 +++ /dev/null @@ -1,52 +0,0 @@ -.TH PCRE 3 -.SH NAME -PCRE - Perl-compatible regular expressions -.SH PCRE SAMPLE PROGRAM -.rs -.sp -A simple, complete demonstration program, to get you started with using PCRE, -is supplied in the file \fIpcredemo.c\fR in the PCRE distribution. - -The program compiles the regular expression that is its first argument, and -matches it against the subject string in its second argument. No PCRE options -are set, and default character tables are used. If matching succeeds, the -program outputs the portion of the subject that matched, together with the -contents of any captured substrings. - -If the -g option is given on the command line, the program then goes on to -check for further matches of the same regular expression in the same subject -string. The logic is a little bit tricky because of the possibility of matching -an empty string. Comments in the code explain what is going on. - -On a Unix system that has PCRE installed in \fI/usr/local\fR, you can compile -the demonstration program using a command like this: - - gcc -o pcredemo pcredemo.c -I/usr/local/include \\ - -L/usr/local/lib -lpcre - -Then you can run simple tests like this: - - ./pcredemo 'cat|dog' 'the cat sat on the mat' - ./pcredemo -g 'cat|dog' 'the dog sat on the cat' - -Note that there is a much more comprehensive test program, called -\fBpcretest\fR, which supports many more facilities for testing regular -expressions and the PCRE library. The \fBpcredemo\fR program is provided as a -simple coding example. - -On some operating systems (e.g. Solaris) you may get an error like this when -you try to run \fBpcredemo\fR: - - ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory - -This is caused by the way shared library support works on those systems. You -need to add - - -R/usr/local/lib - -to the compile command to get round this problem. - -.in 0 -Last updated: 28 January 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcretest.1 b/external-libs/pcre/doc/pcretest.1 deleted file mode 100644 index f3d69c83..00000000 --- a/external-libs/pcre/doc/pcretest.1 +++ /dev/null @@ -1,364 +0,0 @@ -.TH PCRETEST 1 -.SH NAME -pcretest - a program for testing Perl-compatible regular expressions. -.SH SYNOPSIS -.B pcretest "[-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]" - -\fBpcretest\fR was written as a test program for the PCRE regular expression -library itself, but it can also be used for experimenting with regular -expressions. This document describes the features of the test program; for -details of the regular expressions themselves, see the -.\" HREF -\fBpcrepattern\fR -.\" -documentation. For details of PCRE and its options, see the -.\" HREF -\fBpcreapi\fR -.\" -documentation. - -.SH OPTIONS -.rs -.sp -.TP 10 -\fB-C\fR -Output the version number of the PCRE library, and all available information -about the optional features that are included, and then exit. -.TP 10 -\fB-d\fR -Behave as if each regex had the \fB/D\fR modifier (see below); the internal -form is output after compilation. -.TP 10 -\fB-i\fR -Behave as if each regex had the \fB/I\fR modifier; information about the -compiled pattern is given after compilation. -.TP 10 -\fB-m\fR -Output the size of each compiled pattern after it has been compiled. This is -equivalent to adding /M to each regular expression. For compatibility with -earlier versions of pcretest, \fB-s\fR is a synonym for \fB-m\fR. -.TP 10 -\fB-o\fR \fIosize\fR -Set the number of elements in the output vector that is used when calling PCRE -to be \fIosize\fR. The default value is 45, which is enough for 14 capturing -subexpressions. The vector size can be changed for individual matching calls by -including \\O in the data line (see below). -.TP 10 -\fB-p\fR -Behave as if each regex has \fB/P\fR modifier; the POSIX wrapper API is used -to call PCRE. None of the other options has any effect when \fB-p\fR is set. -.TP 10 -\fB-t\fR -Run each compile, study, and match many times with a timer, and output -resulting time per compile or match (in milliseconds). Do not set \fB-t\fR with -\fB-m\fR, because you will then get the size output 20000 times and the timing -will be distorted. - -.SH DESCRIPTION -.rs -.sp -If \fBpcretest\fR is given two filename arguments, it reads from the first and -writes to the second. If it is given only one filename argument, it reads from -that file and writes to stdout. Otherwise, it reads from stdin and writes to -stdout, and prompts for each line of input, using "re>" to prompt for regular -expressions, and "data>" to prompt for data lines. - -The program handles any number of sets of input on a single input file. Each -set starts with a regular expression, and continues with any number of data -lines to be matched against the pattern. - -Each line is matched separately and independently. If you want to do -multiple-line matches, you have to use the \\n escape sequence in a single line -of input to encode the newline characters. The maximum length of data line is -30,000 characters. - -An empty line signals the end of the data lines, at which point a new regular -expression is read. The regular expressions are given enclosed in any -non-alphameric delimiters other than backslash, for example - - /(a|bc)x+yz/ - -White space before the initial delimiter is ignored. A regular expression may -be continued over several input lines, in which case the newline characters are -included within it. It is possible to include the delimiter within the pattern -by escaping it, for example - - /abc\\/def/ - -If you do so, the escape and the delimiter form part of the pattern, but since -delimiters are always non-alphameric, this does not affect its interpretation. -If the terminating delimiter is immediately followed by a backslash, for -example, - - /abc/\\ - -then a backslash is added to the end of the pattern. This is done to provide a -way of testing the error condition that arises if a pattern finishes with a -backslash, because - - /abc\\/ - -is interpreted as the first line of a pattern that starts with "abc/", causing -pcretest to read the next line as a continuation of the regular expression. - -.SH PATTERN MODIFIERS -.rs -.sp -The pattern may be followed by \fBi\fR, \fBm\fR, \fBs\fR, or \fBx\fR to set the -PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, -respectively. For example: - - /caseless/i - -These modifier letters have the same effect as they do in Perl. There are -others that set PCRE options that do not correspond to anything in Perl: -\fB/A\fR, \fB/E\fR, \fB/N\fR, \fB/U\fR, and \fB/X\fR set PCRE_ANCHORED, -PCRE_DOLLAR_ENDONLY, PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA -respectively. - -Searching for all possible matches within each subject string can be requested -by the \fB/g\fR or \fB/G\fR modifier. After finding a match, PCRE is called -again to search the remainder of the subject string. The difference between -\fB/g\fR and \fB/G\fR is that the former uses the \fIstartoffset\fR argument to -\fBpcre_exec()\fR to start searching at a new point within the entire string -(which is in effect what Perl does), whereas the latter passes over a shortened -substring. This makes a difference to the matching process if the pattern -begins with a lookbehind assertion (including \\b or \\B). - -If any call to \fBpcre_exec()\fR in a \fB/g\fR or \fB/G\fR sequence matches an -empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED -flags set in order to search for another, non-empty, match at the same point. -If this second match fails, the start offset is advanced by one, and the normal -match is retried. This imitates the way Perl handles such cases when using the -\fB/g\fR modifier or the \fBsplit()\fR function. - -There are a number of other modifiers for controlling the way \fBpcretest\fR -operates. - -The \fB/+\fR modifier requests that as well as outputting the substring that -matched the entire pattern, pcretest should in addition output the remainder of -the subject string. This is useful for tests where the subject contains -multiple copies of the same substring. - -The \fB/L\fR modifier must be followed directly by the name of a locale, for -example, - - /pattern/Lfr - -For this reason, it must be the last modifier letter. The given locale is set, -\fBpcre_maketables()\fR is called to build a set of character tables for the -locale, and this is then passed to \fBpcre_compile()\fR when compiling the -regular expression. Without an \fB/L\fR modifier, NULL is passed as the tables -pointer; that is, \fB/L\fR applies only to the expression on which it appears. - -The \fB/I\fR modifier requests that \fBpcretest\fR output information about the -compiled expression (whether it is anchored, has a fixed first character, and -so on). It does this by calling \fBpcre_fullinfo()\fR after compiling an -expression, and outputting the information it gets back. If the pattern is -studied, the results of that are also output. - -The \fB/D\fR modifier is a PCRE debugging feature, which also assumes \fB/I\fR. -It causes the internal form of compiled regular expressions to be output after -compilation. If the pattern was studied, the information returned is also -output. - -The \fB/S\fR modifier causes \fBpcre_study()\fR to be called after the -expression has been compiled, and the results used when the expression is -matched. - -The \fB/M\fR modifier causes the size of memory block used to hold the compiled -pattern to be output. - -The \fB/P\fR modifier causes \fBpcretest\fR to call PCRE via the POSIX wrapper -API rather than its native API. When this is done, all other modifiers except -\fB/i\fR, \fB/m\fR, and \fB/+\fR are ignored. REG_ICASE is set if \fB/i\fR is -present, and REG_NEWLINE is set if \fB/m\fR is present. The wrapper functions -force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. - -The \fB/8\fR modifier causes \fBpcretest\fR to call PCRE with the PCRE_UTF8 -option set. This turns on support for UTF-8 character handling in PCRE, -provided that it was compiled with this support enabled. This modifier also -causes any non-printing characters in output strings to be printed using the -\\x{hh...} notation if they are valid UTF-8 sequences. - -If the \fB/?\fR modifier is used with \fB/8\fR, it causes \fBpcretest\fR to -call \fBpcre_compile()\fR with the PCRE_NO_UTF8_CHECK option, to suppress the -checking of the string for UTF-8 validity. - -.SH CALLOUTS -.rs -.sp -If the pattern contains any callout requests, \fBpcretest\fR's callout function -will be called. By default, it displays the callout number, and the start and -current positions in the text at the callout time. For example, the output - - --->pqrabcdef - 0 ^ ^ - -indicates that callout number 0 occurred for a match attempt starting at the -fourth character of the subject string, when the pointer was at the seventh -character. The callout function returns zero (carry on matching) by default. - -Inserting callouts may be helpful when using \fBpcretest\fR to check -complicated regular expressions. For further information about callouts, see -the -.\" HREF -\fBpcrecallout\fR -.\" -documentation. - -For testing the PCRE library, additional control of callout behaviour is -available via escape sequences in the data, as described in the following -section. In particular, it is possible to pass in a number as callout data (the -default is zero). If the callout function receives a non-zero number, it -returns that value instead of zero. - -.SH DATA LINES -.rs -.sp -Before each data line is passed to \fBpcre_exec()\fR, leading and trailing -whitespace is removed, and it is then scanned for \\ escapes. Some of these are -pretty esoteric features, intended for checking out some of the more -complicated features of PCRE. If you are just testing "ordinary" regular -expressions, you probably don't need any of these. The following escapes are -recognized: - - \\a alarm (= BEL) - \\b backspace - \\e escape - \\f formfeed - \\n newline - \\r carriage return - \\t tab - \\v vertical tab - \\nnn octal character (up to 3 octal digits) - \\xhh hexadecimal character (up to 2 hex digits) - \\x{hh...} hexadecimal character, any number of digits - in UTF-8 mode - \\A pass the PCRE_ANCHORED option to \fBpcre_exec()\fR - \\B pass the PCRE_NOTBOL option to \fBpcre_exec()\fR - \\Cdd call pcre_copy_substring() for substring dd - after a successful match (any decimal number - less than 32) - \\Cname call pcre_copy_named_substring() for substring - "name" after a successful match (name termin- - ated by next non alphanumeric character) - \\C+ show the current captured substrings at callout - time - \\C- do not supply a callout function - \\C!n return 1 instead of 0 when callout number n is - reached - \\C!n!m return 1 instead of 0 when callout number n is - reached for the nth time - \\C*n pass the number n (may be negative) as callout - data - \\Gdd call pcre_get_substring() for substring dd - after a successful match (any decimal number - less than 32) - \\Gname call pcre_get_named_substring() for substring - "name" after a successful match (name termin- - ated by next non-alphanumeric character) - \\L call pcre_get_substringlist() after a - successful match - \\M discover the minimum MATCH_LIMIT setting - \\N pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fR - \\Odd set the size of the output vector passed to - \fBpcre_exec()\fR to dd (any number of decimal - digits) - \\S output details of memory get/free calls during matching - \\Z pass the PCRE_NOTEOL option to \fBpcre_exec()\fR - \\? pass the PCRE_NO_UTF8_CHECK option to - \fBpcre_exec()\fR - -If \\M is present, \fBpcretest\fR calls \fBpcre_exec()\fR several times, with -different values in the \fImatch_limit\fR field of the \fBpcre_extra\fR data -structure, until it finds the minimum number that is needed for -\fBpcre_exec()\fR to complete. This number is a measure of the amount of -recursion and backtracking that takes place, and checking it out can be -instructive. For most simple matches, the number is quite small, but for -patterns with very large numbers of matching possibilities, it can become large -very quickly with increasing length of subject string. - -When \\O is used, it may be higher or lower than the size set by the \fB-O\fR -option (or defaulted to 45); \\O applies only to the call of \fBpcre_exec()\fR -for the line in which it appears. - -A backslash followed by anything else just escapes the anything else. If the -very last character is a backslash, it is ignored. This gives a way of passing -an empty line as data, since a real empty line terminates the data input. - -If \fB/P\fR was present on the regex, causing the POSIX wrapper API to be used, -only \fB\B\fR, and \fB\Z\fR have any effect, causing REG_NOTBOL and REG_NOTEOL -to be passed to \fBregexec()\fR respectively. - -The use of \\x{hh...} to represent UTF-8 characters is not dependent on the use -of the \fB/8\fR modifier on the pattern. It is recognized always. There may be -any number of hexadecimal digits inside the braces. The result is from one to -six bytes, encoded according to the UTF-8 rules. - -.SH OUTPUT FROM PCRETEST -.rs -.sp -When a match succeeds, pcretest outputs the list of captured substrings that -\fBpcre_exec()\fR returns, starting with number 0 for the string that matched -the whole pattern. Here is an example of an interactive pcretest run. - - $ pcretest - PCRE version 4.00 08-Jan-2003 - - re> /^abc(\\d+)/ - data> abc123 - 0: abc123 - 1: 123 - data> xyz - No match - -If the strings contain any non-printing characters, they are output as \\0x -escapes, or as \\x{...} escapes if the \fB/8\fR modifier was present on the -pattern. If the pattern has the \fB/+\fR modifier, then the output for -substring 0 is followed by the the rest of the subject string, identified by -"0+" like this: - - re> /cat/+ - data> cataract - 0: cat - 0+ aract - -If the pattern has the \fB/g\fR or \fB/G\fR modifier, the results of successive -matching attempts are output in sequence, like this: - - re> /\\Bi(\\w\\w)/g - data> Mississippi - 0: iss - 1: ss - 0: iss - 1: ss - 0: ipp - 1: pp - -"No match" is output only if the first match attempt fails. - -If any of the sequences \fB\\C\fR, \fB\\G\fR, or \fB\\L\fR are present in a -data line that is successfully matched, the substrings extracted by the -convenience functions are output with C, G, or L after the string number -instead of a colon. This is in addition to the normal full list. The string -length (that is, the return from the extraction function) is given in -parentheses after each string for \fB\\C\fR and \fB\\G\fR. - -Note that while patterns can be continued over several lines (a plain ">" -prompt is used for continuations), data lines may not. However newlines can be -included in data by means of the \\n escape. - -.SH AUTHOR -.rs -.sp -Philip Hazel <ph10@cam.ac.uk> -.br -University Computing Service, -.br -Cambridge CB2 3QG, England. - -.in 0 -Last updated: 09 December 2003 -.br -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/pcretest.txt b/external-libs/pcre/doc/pcretest.txt deleted file mode 100644 index 0e9cd138..00000000 --- a/external-libs/pcre/doc/pcretest.txt +++ /dev/null @@ -1,357 +0,0 @@ -PCRETEST(1) PCRETEST(1) - - - -NAME - pcretest - a program for testing Perl-compatible regular expressions. - -SYNOPSIS - pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination] - - pcretest was written as a test program for the PCRE regular expression - library itself, but it can also be used for experimenting with regular - expressions. This document describes the features of the test program; - for details of the regular expressions themselves, see the pcrepattern - documentation. For details of PCRE and its options, see the pcreapi - documentation. - - -OPTIONS - - - -C Output the version number of the PCRE library, and all avail- - able information about the optional features that are - included, and then exit. - - -d Behave as if each regex had the /D modifier (see below); the - internal form is output after compilation. - - -i Behave as if each regex had the /I modifier; information - about the compiled pattern is given after compilation. - - -m Output the size of each compiled pattern after it has been - compiled. This is equivalent to adding /M to each regular - expression. For compatibility with earlier versions of - pcretest, -s is a synonym for -m. - - -o osize Set the number of elements in the output vector that is used - when calling PCRE to be osize. The default value is 45, which - is enough for 14 capturing subexpressions. The vector size - can be changed for individual matching calls by including \O - in the data line (see below). - - -p Behave as if each regex has /P modifier; the POSIX wrapper - API is used to call PCRE. None of the other options has any - effect when -p is set. - - -t Run each compile, study, and match many times with a timer, - and output resulting time per compile or match (in millisec- - onds). Do not set -t with -m, because you will then get the - size output 20000 times and the timing will be distorted. - - -DESCRIPTION - - If pcretest is given two filename arguments, it reads from the first - and writes to the second. If it is given only one filename argument, it - reads from that file and writes to stdout. Otherwise, it reads from - stdin and writes to stdout, and prompts for each line of input, using - "re>" to prompt for regular expressions, and "data>" to prompt for data - lines. - - The program handles any number of sets of input on a single input file. - Each set starts with a regular expression, and continues with any num- - ber of data lines to be matched against the pattern. - - Each line is matched separately and independently. If you want to do - multiple-line matches, you have to use the \n escape sequence in a sin- - gle line of input to encode the newline characters. The maximum length - of data line is 30,000 characters. - - An empty line signals the end of the data lines, at which point a new - regular expression is read. The regular expressions are given enclosed - in any non-alphameric delimiters other than backslash, for example - - /(a|bc)x+yz/ - - White space before the initial delimiter is ignored. A regular expres- - sion may be continued over several input lines, in which case the new- - line characters are included within it. It is possible to include the - delimiter within the pattern by escaping it, for example - - /abc\/def/ - - If you do so, the escape and the delimiter form part of the pattern, - but since delimiters are always non-alphameric, this does not affect - its interpretation. If the terminating delimiter is immediately fol- - lowed by a backslash, for example, - - /abc/\ - - then a backslash is added to the end of the pattern. This is done to - provide a way of testing the error condition that arises if a pattern - finishes with a backslash, because - - /abc\/ - - is interpreted as the first line of a pattern that starts with "abc/", - causing pcretest to read the next line as a continuation of the regular - expression. - - -PATTERN MODIFIERS - - The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS, - PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. - For example: - - /caseless/i - - These modifier letters have the same effect as they do in Perl. There - are others that set PCRE options that do not correspond to anything in - Perl: /A, /E, /N, /U, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, - PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA respectively. - - Searching for all possible matches within each subject string can be - requested by the /g or /G modifier. After finding a match, PCRE is - called again to search the remainder of the subject string. The differ- - ence between /g and /G is that the former uses the startoffset argument - to pcre_exec() to start searching at a new point within the entire - string (which is in effect what Perl does), whereas the latter passes - over a shortened substring. This makes a difference to the matching - process if the pattern begins with a lookbehind assertion (including \b - or \B). - - If any call to pcre_exec() in a /g or /G sequence matches an empty - string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED - flags set in order to search for another, non-empty, match at the same - point. If this second match fails, the start offset is advanced by - one, and the normal match is retried. This imitates the way Perl han- - dles such cases when using the /g modifier or the split() function. - - There are a number of other modifiers for controlling the way pcretest - operates. - - The /+ modifier requests that as well as outputting the substring that - matched the entire pattern, pcretest should in addition output the - remainder of the subject string. This is useful for tests where the - subject contains multiple copies of the same substring. - - The /L modifier must be followed directly by the name of a locale, for - example, - - /pattern/Lfr - - For this reason, it must be the last modifier letter. The given locale - is set, pcre_maketables() is called to build a set of character tables - for the locale, and this is then passed to pcre_compile() when compil- - ing the regular expression. Without an /L modifier, NULL is passed as - the tables pointer; that is, /L applies only to the expression on which - it appears. - - The /I modifier requests that pcretest output information about the - compiled expression (whether it is anchored, has a fixed first charac- - ter, and so on). It does this by calling pcre_fullinfo() after compil- - ing an expression, and outputting the information it gets back. If the - pattern is studied, the results of that are also output. - - The /D modifier is a PCRE debugging feature, which also assumes /I. It - causes the internal form of compiled regular expressions to be output - after compilation. If the pattern was studied, the information returned - is also output. - - The /S modifier causes pcre_study() to be called after the expression - has been compiled, and the results used when the expression is matched. - - The /M modifier causes the size of memory block used to hold the com- - piled pattern to be output. - - The /P modifier causes pcretest to call PCRE via the POSIX wrapper API - rather than its native API. When this is done, all other modifiers - except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present, - and REG_NEWLINE is set if /m is present. The wrapper functions force - PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. - - The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option - set. This turns on support for UTF-8 character handling in PCRE, pro- - vided that it was compiled with this support enabled. This modifier - also causes any non-printing characters in output strings to be printed - using the \x{hh...} notation if they are valid UTF-8 sequences. - - If the /? modifier is used with /8, it causes pcretest to call - pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the - checking of the string for UTF-8 validity. - - -CALLOUTS - - If the pattern contains any callout requests, pcretest's callout func- - tion will be called. By default, it displays the callout number, and - the start and current positions in the text at the callout time. For - example, the output - - --->pqrabcdef - 0 ^ ^ - - indicates that callout number 0 occurred for a match attempt starting - at the fourth character of the subject string, when the pointer was at - the seventh character. The callout function returns zero (carry on - matching) by default. - - Inserting callouts may be helpful when using pcretest to check compli- - cated regular expressions. For further information about callouts, see - the pcrecallout documentation. - - For testing the PCRE library, additional control of callout behaviour - is available via escape sequences in the data, as described in the fol- - lowing section. In particular, it is possible to pass in a number as - callout data (the default is zero). If the callout function receives a - non-zero number, it returns that value instead of zero. - - -DATA LINES - - Before each data line is passed to pcre_exec(), leading and trailing - whitespace is removed, and it is then scanned for \ escapes. Some of - these are pretty esoteric features, intended for checking out some of - the more complicated features of PCRE. If you are just testing "ordi- - nary" regular expressions, you probably don't need any of these. The - following escapes are recognized: - - \a alarm (= BEL) - \b backspace - \e escape - \f formfeed - \n newline - \r carriage return - \t tab - \v vertical tab - \nnn octal character (up to 3 octal digits) - \xhh hexadecimal character (up to 2 hex digits) - \x{hh...} hexadecimal character, any number of digits - in UTF-8 mode - \A pass the PCRE_ANCHORED option to pcre_exec() - \B pass the PCRE_NOTBOL option to pcre_exec() - \Cdd call pcre_copy_substring() for substring dd - after a successful match (any decimal number - less than 32) - \Cname call pcre_copy_named_substring() for substring - "name" after a successful match (name termin- - ated by next non alphanumeric character) - \C+ show the current captured substrings at callout - time - \C- do not supply a callout function - \C!n return 1 instead of 0 when callout number n is - reached - \C!n!m return 1 instead of 0 when callout number n is - reached for the nth time - \C*n pass the number n (may be negative) as callout - data - \Gdd call pcre_get_substring() for substring dd - after a successful match (any decimal number - less than 32) - \Gname call pcre_get_named_substring() for substring - "name" after a successful match (name termin- - ated by next non-alphanumeric character) - \L call pcre_get_substringlist() after a - successful match - \M discover the minimum MATCH_LIMIT setting - \N pass the PCRE_NOTEMPTY option to pcre_exec() - \Odd set the size of the output vector passed to - pcre_exec() to dd (any number of decimal - digits) - \S output details of memory get/free calls during matching - \Z pass the PCRE_NOTEOL option to pcre_exec() - \? pass the PCRE_NO_UTF8_CHECK option to - pcre_exec() - - If \M is present, pcretest calls pcre_exec() several times, with dif- - ferent values in the match_limit field of the pcre_extra data struc- - ture, until it finds the minimum number that is needed for pcre_exec() - to complete. This number is a measure of the amount of recursion and - backtracking that takes place, and checking it out can be instructive. - For most simple matches, the number is quite small, but for patterns - with very large numbers of matching possibilities, it can become large - very quickly with increasing length of subject string. - - When \O is used, it may be higher or lower than the size set by the -O - option (or defaulted to 45); \O applies only to the call of pcre_exec() - for the line in which it appears. - - A backslash followed by anything else just escapes the anything else. - If the very last character is a backslash, it is ignored. This gives a - way of passing an empty line as data, since a real empty line termi- - nates the data input. - - If /P was present on the regex, causing the POSIX wrapper API to be - used, only 0 causing REG_NOTBOL and REG_NOTEOL to be passed to - regexec() respectively. - - The use of \x{hh...} to represent UTF-8 characters is not dependent on - the use of the /8 modifier on the pattern. It is recognized always. - There may be any number of hexadecimal digits inside the braces. The - result is from one to six bytes, encoded according to the UTF-8 rules. - - -OUTPUT FROM PCRETEST - - When a match succeeds, pcretest outputs the list of captured substrings - that pcre_exec() returns, starting with number 0 for the string that - matched the whole pattern. Here is an example of an interactive - pcretest run. - - $ pcretest - PCRE version 4.00 08-Jan-2003 - - re> /^abc(\d+)/ - data> abc123 - 0: abc123 - 1: 123 - data> xyz - No match - - If the strings contain any non-printing characters, they are output as - \0x escapes, or as \x{...} escapes if the /8 modifier was present on - the pattern. If the pattern has the /+ modifier, then the output for - substring 0 is followed by the the rest of the subject string, identi- - fied by "0+" like this: - - re> /cat/+ - data> cataract - 0: cat - 0+ aract - - If the pattern has the /g or /G modifier, the results of successive - matching attempts are output in sequence, like this: - - re> /\Bi(\w\w)/g - data> Mississippi - 0: iss - 1: ss - 0: iss - 1: ss - 0: ipp - 1: pp - - "No match" is output only if the first match attempt fails. - - If any of the sequences \C, \G, or \L are present in a data line that - is successfully matched, the substrings extracted by the convenience - functions are output with C, G, or L after the string number instead of - a colon. This is in addition to the normal full list. The string length - (that is, the return from the extraction function) is given in paren- - theses after each string for \C and \G. - - Note that while patterns can be continued over several lines (a plain - ">" prompt is used for continuations), data lines may not. However new- - lines can be included in data by means of the \n escape. - - -AUTHOR - - Philip Hazel <ph10@cam.ac.uk> - University Computing Service, - Cambridge CB2 3QG, England. - -Last updated: 09 December 2003 -Copyright (c) 1997-2003 University of Cambridge. diff --git a/external-libs/pcre/doc/perltest.txt b/external-libs/pcre/doc/perltest.txt deleted file mode 100644 index 9ea9d932..00000000 --- a/external-libs/pcre/doc/perltest.txt +++ /dev/null @@ -1,34 +0,0 @@ -The perltest program --------------------- - -The perltest program tests Perl's regular expressions; it has the same -specification as pcretest, and so can be given identical input, except that -input patterns can be followed only by Perl's lower case modifiers and /+ (as -used by pcretest), which is recognized and handled by the program. - -The data lines are processed as Perl double-quoted strings, so if they contain -" \ $ or @ characters, these have to be escaped. For this reason, all such -characters in testinput1 and testinput3 are escaped so that they can be used -for perltest as well as for pcretest, and the special upper case modifiers such -as /A that pcretest recognizes are not used in these files. The output should -be identical, apart from the initial identifying banner. - -The perltest script can also test UTF-8 features. It works as is for Perl 5.8 -or higher. It recognizes the special modifier /8 that pcretest uses to invoke -UTF-8 functionality. The testinput5 file can be fed to perltest to run UTF-8 -tests. - -For Perl 5.6, perltest won't work unmodified for the UTF-8 tests. You need to -uncomment the "use utf8" lines that it contains. It is best to do this on a -copy of the script, because for non-UTF-8 tests, these lines should remain -commented out. - -The testinput2 and testinput4 files are not suitable for feeding to perltest, -since they do make use of the special upper case modifiers and escapes that -pcretest uses to test some features of PCRE. The first of these files also -contains malformed regular expressions, in order to check that PCRE diagnoses -them correctly. Similarly, testinput6 tests UTF-8 features that do not relate -to Perl. - -Philip Hazel <ph10@cam.ac.uk> -August 2002 |