mirror of
https://github.com/Ponce/slackbuilds
synced 2024-11-26 22:06:35 +01:00
23 lines
1.2 KiB
Text
23 lines
1.2 KiB
Text
|
bsdiff and bspatch are tools for building and applying patches to binary
|
||
|
|
files. By using suffix sorting (specifically, Larsson and Sadakane's qsufsort)
|
||
|
|
and taking advantage of how executable files change, bsdiff routinely produces
|
||
|
|
binary patches 50-80% smaller than those produced by Xdelta, and 15% smaller
|
||
|
|
than those produced by .RTPatch (a $2750/seat commercial patch tool).
|
||
|
|
|
||
|
|
These programs were originally named bdiff and bpatch, but the large number of
|
||
|
|
other programs using those names lead to confusion; I'm not sure if the "bs"
|
||
|
|
in refers to "binary software" (because bsdiff produces exceptionally small
|
||
|
|
patches for executable files) or "bytewise subtraction" (which is the key to
|
||
|
|
how well it performs). Feel free to offer other suggestions.
|
||
|
|
|
||
|
|
bsdiff is quite memory-hungry. It requires max(17*n,9*n+m)+O(1) bytes of
|
||
|
|
memory, where n is the size of the old file and m is the size of the new
|
||
|
|
file. bspatch requires n+m+O(1) bytes.
|
||
|
|
|
||
|
|
bsdiff runs in O((n+m) log n) time; on a 200MHz Pentium Pro, building a binary
|
||
|
|
patch for a 4MB file takes about 90 seconds. bspatch runs in O(n+m) time; on
|
||
|
|
the same machine, applying that patch takes about two seconds.
|
||
|
|
|
||
|
|
Providing that off_t is defined properly, bsdiff and bspatch support files of
|
||
|
|
up to 2^61-1 = 2Ei-1 bytes.
|