Description:

XDelta (X for XCF: the eXperimental Computing Facility at Berkeley) is
a library interface and binary delta generator (like a diff program
for binaries) and an RCS. These changes (deltas) are similar to the
output of the "diff" program in that they may be used to store and
transmit only the changes between files. However, unlike diff, the
output of XDelta is not expressed in a human-readable format - XDelta
can also also apply these deltas to a copy of the original file(s).
XDelta uses a fast, linear algorithm and performs well on both binary
and text files. XDelta typically outperforms GNU diff in both time and
generated-delta-size, even for plain text files. XDelta also includes
a simple implementation of the Rsync algorithm and several advanced
features for implementing RCS-like file-archival with.

The XDelta library performs its work independently of the actual
format used to encode the file and is intended to be used by various
higher-level programs such as XCF's Project Revision Control System
(PRCS). PRCS is a front end for a version control toolset. Xdelta uses
a binary file delta algorithm to replace the standard diff program
used by RCS.