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| -rw-r--r-- | development/bsdiff/README | 39 |
1 files changed, 21 insertions, 18 deletions
diff --git a/development/bsdiff/README b/development/bsdiff/README index 482944aaced8..33119f056977 100644 --- a/development/bsdiff/README +++ b/development/bsdiff/README @@ -1,24 +1,27 @@ bsdiff (binary diff/patch utility) -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). +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. +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 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. +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. +Providing that off_t is defined properly, bsdiff and bspatch support +files of up to 2^61-1 = 2Ei-1 bytes. |