librsync is a library for calculating and applying network deltas, with an
interface designed to ease integration into diverse network applications.
librsync encapsulates the core algorithms of the rsync protocol, which help
with efficient calculation of the differences between two files. The rsync
algorithm is different from most differencing algorithms because it does not
require the presence of the two files to calculate the delta. Instead, it
requires a set of checksums of each block of one file, which together form a
signature for that file. Blocks at any in the other file which have the same
checksum are likely to be identical, and whatever remains is the difference.
