xdelta

Users want speed, especially video gamers. I tested with some of your data: Unreal tournament and Wesnoth patches. These patches save 50-100MB per download.

Xdelta1 remains popular today because of speed, and xdelta3 until now hasn't been as fast (debdev has tests). Xdelta-3.0o has improved compression levels (download).

Over my sample data, the new default compression level (same as the command-line flag -1) is a little faster than, with compression roughly the same as Xdelta-1.x. Compression levels -3, -6, and -9 are also improved.

This release also features Swig support, e.g.,

import xdelta3

# memory interface
source = 'source source input0 source source'
target = 'source source target source source'

result1, patch = xdelta3.xd3_encode_memory(target, source, len(target))
result2, target1 = xdelta3.xd3_decode_memory(patch, source, len(target))

assert result1 == 0
assert result2 == 0
assert target1 == target
assert len(patch) < len(target)

# command-line interface

source_file = ...
target_file = ...
command_args = ['xdelta3', '-f', '-s', source_file, target_file, output_file]

xdelta3.xd3_main_cmdline(command_args)