xdiff extension enables you to create and apply patch files containing differences between different revisions of files.
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.
Starting from version 1.5.0 there are two different sets of functions for generating binary patches. New functions - xdiff_string_rabdiff() and xdiff_file_rabdiff() 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 » libxdiff website.
This extension uses libxdiff to implement these functions. Please see » http://www.xmailserver.org/xdiff-lib.html for more informations.