After experimenting with code to add the ability to encode a delta
against part of the deltified file, it turns out that resulting packs
are _bigger_ than when this ability is not used. The raw delta output
might be smaller, but it doesn't compress as well using gzip with a
negative net saving on average.
Said bit would in fact be more useful to allow for encoding the copying
of chunks larger than 64KB providing more savings with large files.
This will correspond to packs version 3.
While the current code still produces packs version 2, it is made future
proof so pack versions 2 and 3 are accepted. Any pack version 2 are
compatible with version 3 since the redefined bit was never used before.
When enough time has passed, code to use that bit to produce version 3
packs could be added.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
At least pretty_print_commit() expects to get NUL-terminated commit data to
work properly. unpack_sha1_rest(), which reads objects from separate files,
and unpack_non_delta_entry(), which reads non-delta-compressed objects from
pack files, already add the NUL byte after the object data, but patch_delta()
did not do it, which caused problems with, e.g., git-rev-list --pretty when
there are delta-compressed commit objects.
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This is a wrap-up patch including all the cleanups I've done to the
delta code and its usage. The most important change is the
factorization of the delta header handling code.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Since the delta data format is not tied to any actual git object
anymore, now is the time to add a small improvement to the delta data
header as it is been done for packed object header. This patch allows
for reducing the delta header of about 2 bytes and makes for simpler
code.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds the basic library functions to create and replay delta
information. Also included is a test-delta utility to validate the
code.
diff-delta was based on LibXDiff written by Davide Libenzi
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
