From 296b679d6e3217cc112b7ed19b363b82356615ef Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sun, 6 Aug 2017 08:42:01 -0400
Subject: Implement findFirst and findLast in InputSource

Preparing to refactor some pattern searching code to use these instead
of their own memchr loops. This should simplify the code that replaces
PCRE.
---
 include/qpdf/BufferInputSource.hh | 10 ++++++++++
 include/qpdf/FileInputSource.hh   | 11 +++++++++++
 include/qpdf/InputSource.hh       | 35 +++++++++++++++++++++++++++++++++++
 include/qpdf/QPDF.hh              | 21 +++++++++++++++++++++
 4 files changed, 77 insertions(+)

(limited to 'include')

diff --git a/include/qpdf/BufferInputSource.hh b/include/qpdf/BufferInputSource.hh
index 64ee4605..db055783 100644
--- a/include/qpdf/BufferInputSource.hh
+++ b/include/qpdf/BufferInputSource.hh
@@ -15,17 +15,27 @@
 class BufferInputSource: public InputSource
 {
   public:
+    QPDF_DLL
     BufferInputSource(std::string const& description, Buffer* buf,
                       bool own_memory = false);
+    QPDF_DLL
     BufferInputSource(std::string const& description,
                       std::string const& contents);
+    QPDF_DLL
     virtual ~BufferInputSource();
+    QPDF_DLL
     virtual qpdf_offset_t findAndSkipNextEOL();
+    QPDF_DLL
     virtual std::string const& getName() const;
+    QPDF_DLL
     virtual qpdf_offset_t tell();
+    QPDF_DLL
     virtual void seek(qpdf_offset_t offset, int whence);
+    QPDF_DLL
     virtual void rewind();
+    QPDF_DLL
     virtual size_t read(char* buffer, size_t length);
+    QPDF_DLL
     virtual void unreadCh(char ch);
 
   private:
diff --git a/include/qpdf/FileInputSource.hh b/include/qpdf/FileInputSource.hh
index 64457365..3f0c05a9 100644
--- a/include/qpdf/FileInputSource.hh
+++ b/include/qpdf/FileInputSource.hh
@@ -14,16 +14,27 @@
 class FileInputSource: public InputSource
 {
   public:
+    QPDF_DLL
     FileInputSource();
+    QPDF_DLL
     void setFilename(char const* filename);
+    QPDF_DLL
     void setFile(char const* description, FILE* filep, bool close_file);
+    QPDF_DLL
     virtual ~FileInputSource();
+    QPDF_DLL
     virtual qpdf_offset_t findAndSkipNextEOL();
+    QPDF_DLL
     virtual std::string const& getName() const;
+    QPDF_DLL
     virtual qpdf_offset_t tell();
+    QPDF_DLL
     virtual void seek(qpdf_offset_t offset, int whence);
+    QPDF_DLL
     virtual void rewind();
+    QPDF_DLL
     virtual size_t read(char* buffer, size_t length);
+    QPDF_DLL
     virtual void unreadCh(char ch);
 
   private:
diff --git a/include/qpdf/InputSource.hh b/include/qpdf/InputSource.hh
index a731918e..c20e5076 100644
--- a/include/qpdf/InputSource.hh
+++ b/include/qpdf/InputSource.hh
@@ -9,6 +9,7 @@
 #ifndef __QPDF_INPUTSOURCE_HH__
 #define __QPDF_INPUTSOURCE_HH__
 
+#include <qpdf/DLL.h>
 #include <qpdf/Types.h>
 #include <stdio.h>
 #include <string>
@@ -16,18 +17,52 @@
 class InputSource
 {
   public:
+    QPDF_DLL
     InputSource() :
         last_offset(0)
     {
     }
+    QPDF_DLL
     virtual ~InputSource()
     {
     }
 
+    class Finder
+    {
+      public:
+        Finder()
+        {
+        }
+        virtual ~Finder()
+        {
+        }
+
+        virtual bool check() = 0;
+    };
+
+    QPDF_DLL
     void setLastOffset(qpdf_offset_t);
+    QPDF_DLL
     qpdf_offset_t getLastOffset() const;
+    QPDF_DLL
     std::string readLine(size_t max_line_length);
 
+    // Find first or last occurrence of a sequence of characters
+    // starting within the range defined by offset and len such that,
+    // when the input source is positioned at the beginning of that
+    // sequence, finder.check() returns true. If len is 0, the search
+    // proceeds until EOF. If a qualifying pattern these methods
+    // return true and leave the input source positioned wherever
+    // check() left it at the end of the matching pattern.
+    QPDF_DLL
+    bool findFirst(char const* start_chars,
+                   qpdf_offset_t offset, size_t len,
+                   Finder& finder);
+    QPDF_DLL
+    bool findLast(char const* start_chars,
+                  qpdf_offset_t offset, size_t len,
+                  Finder& finder);
+
     virtual qpdf_offset_t findAndSkipNextEOL() = 0;
     virtual std::string const& getName() const = 0;
     virtual qpdf_offset_t tell() = 0;
diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index f57789a0..c9d120b4 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -1006,6 +1006,27 @@ class QPDF
 	std::string key;	// if ou_trailer_key or ou_root_key
     };
 
+    class PatternFinder: public InputSource::Finder
+    {
+      public:
+        PatternFinder(QPDF& qpdf, bool (QPDF::*checker)()) :
+            qpdf(qpdf),
+            checker(checker)
+        {
+        }
+        virtual ~PatternFinder()
+        {
+        }
+        virtual bool check()
+        {
+            return (this->qpdf.*checker)();
+        }
+
+      private:
+        QPDF& qpdf;
+        bool (QPDF::*checker)();
+    };
+
     // methods to support linearization checking -- implemented in
     // QPDF_linearization.cc
     void readLinearizationData();
-- 
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