diff options
author | Jay Berkenbilt <ejb@ql.org> | 2015-10-25 16:09:25 +0100 |
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committer | Jay Berkenbilt <ejb@ql.org> | 2015-10-31 23:56:42 +0100 |
commit | b8bdef0ad12883d72ced5eb443e6e34a93bbbb91 (patch) | |
tree | 473250ef5919bba535743c2381b86c64ebe810a8 /manual | |
parent | 607c39211224e0d3bc2ab7066f16ff4952851ee9 (diff) | |
download | qpdf-b8bdef0ad12883d72ced5eb443e6e34a93bbbb91.tar.zst |
Implement deterministic ID
For non-encrypted files, determinstic ID generation uses file contents
instead of timestamp and file name. At a small runtime cost, this
enables generation of the same /ID if the same inputs are converted in
the same way multiple times.
Diffstat (limited to 'manual')
-rw-r--r-- | manual/qpdf-manual.xml | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/manual/qpdf-manual.xml b/manual/qpdf-manual.xml index 3174e68a..093d5b5b 100644 --- a/manual/qpdf-manual.xml +++ b/manual/qpdf-manual.xml @@ -991,11 +991,30 @@ outfile.pdf</option> file should be given. The following options are available: <variablelist> <varlistentry> + <term><option>--deterministic-id</option></term> + <listitem> + <para> + Causes generation of a deterministic value for /ID. This + prevents use of timestamp and output file name information in + the /ID generation. Instead, at some slight additional runtime + cost, the /ID field is generated to include a digest of the + significant parts of the content of the output PDF file. This + means that a given qpdf operation should generate the same /ID + each time it is run, which can be useful when caching results + or for generation of some test data. Use of this flag is not + compatible with creation of encrypted files. + </para> + </listitem> + </varlistentry> + <varlistentry> <term><option>--static-id</option></term> <listitem> <para> - Causes generation of a fixed value for /ID. This is intended - for testing only. Never use it for production files. + Causes generation of a fixed value for /ID. This is intended + for testing only. Never use it for production files. If you + are trying to get the same /ID each time for a given file and + you are not generating encrypted files, consider using the + <option>--deterministic-id</option> option. </para> </listitem> </varlistentry> |