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<h1 class="title">Introduction</h1>
<p class="para">
xdiff extension enables you to create and apply patch files containing
differences between different revisions of files.
</p>
<p class="para">
This extension supports two modes of operation - on strings and on files, as well
as two different patch formats - unified and binary. Unified patches are excellent
for text files as they are human-readable and easy to review. For binary files like
archives or images, binary patches will be adequate choice as they are binary safe and
handle non-printable characters well.
</p>
<p class="para">
Starting from version 1.5.0 there are two different sets of functions for generating
binary patches. New functions - <span class="function"><a href="function.xdiff-string-rabdiff.html" class="function">xdiff_string_rabdiff()</a></span> and
<span class="function"><a href="function.xdiff-file-rabdiff.html" class="function">xdiff_file_rabdiff()</a></span> generate output compatible with older functions
but are typically faster and generate smaller results. For more details about methods of
generating binary patches and differences between them, please check
<a href="http://www.xmailserver.org/xdiff-lib.html" class="link external">» libxdiff</a> website.
</p>
<p class="para">
This extension uses libxdiff to implement these functions. Please see
<a href="http://www.xmailserver.org/xdiff-lib.html" class="link external">» http://www.xmailserver.org/xdiff-lib.html</a> for more information.
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