kernel/git - git - PowerEL Git System

Commit Graph

Author	SHA1	Message	Date
Linus Torvalds	48fb7deb5b	Fix big left-shifts of unsigned char Shifting 'unsigned char' or 'unsigned short' left can result in sign extension errors, since the C integer promotion rules means that the unsigned char/short will get implicitly promoted to a signed 'int' due to the shift (or due to other operations). This normally doesn't matter, but if you shift things up sufficiently, it will now set the sign bit in 'int', and a subsequent cast to a bigger type (eg 'long' or 'unsigned long') will now sign-extend the value despite the original expression being unsigned. One example of this would be something like unsigned long size; unsigned char c; size += c << 24; where despite all the variables being unsigned, 'c << 24' ends up being a signed entity, and will get sign-extended when then doing the addition in an 'unsigned long' type. Since git uses 'unsigned char' pointers extensively, we actually have this bug in a couple of places. I may have missed some, but this is the result of looking at git grep '[^0-9 ][ ]<<[ ][a-z]' -- '.c' '.h' git grep '<<[ ]24' which catches at least the common byte cases (shifting variables by a variable amount, and shifting by 24 bits). I also grepped for just 'unsigned char' variables in general, and converted the ones that most obviously ended up getting implicitly cast immediately anyway (eg hash_name(), encode_85()). In addition to just avoiding 'unsigned char', this patch also tries to use a common idiom for the delta header size thing. We had three different variations on it: "& 0x7fUL" in one place (getting the sign extension right), and "& ~0x80" and "& 0x7f" in two other places (not getting it right). Apart from making them all just avoid using "unsigned char" at all, I also unified them to then use a simple "& 0x7f". I considered making a sparse extension which warns about doing implicit casts from unsigned types to signed types, but it gets rather complex very quickly, so this is just a hack. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>	16 years ago
Brian Downing	11779e7907	Support fetching the memory usage of a delta index Delta indices, at least on 64-bit platforms, tend to be larger than the actual uncompressed data. As such, keeping track of this storage is important if you want to successfully limit the memory size of your pack window. Squirrel away the total allocation size inside the delta_index struct, and add an accessor "sizeof_delta_index" to access it. Signed-off-by: Brian Downing <bdowning@lavos.net> Acked-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>	18 years ago
Nicolas Pitre	ff45715ce5	pack-object: slightly more efficient Avoid creating a delta index for objects with maximum depth since they are not going to be used as delta base anyway. This also reduce peak memory usage slightly as the current object's delta index is not useful until the next object in the loop is considered for deltification. This saves a bit more than 1% on CPU usage. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	ac4c758adc	delta: stricter constness Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Nicolas Pitre	08abe669c0	split the diff-delta interface This patch splits the diff-delta interface into index creation and delta generation. A wrapper is provided to preserve the diff-delta() call. This will allow for an optimization in pack-objects.c where the source object could be fixed and a full window of objects tentatively tried against that same source object without recomputing the source index each time. This patch only restructure things, plus a couple cleanups for good measure. There is no performance change yet. Signed-off-by: Nicolas Pitre <nico@cam.org>	19 years ago
Nicolas Pitre	8960844a78	check patch_delta bounds more carefully Let's avoid going south with invalid delta data. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Nicolas Pitre	38fd0721d0	diff-delta: allow reusing of the reference buffer index When a reference buffer is used multiple times then its index can be computed only once and reused multiple times. This patch adds an extra pointer to a pointer argument (from_index) to diff_delta() for this. If from_index is NULL then everything is like before. If from_index is non NULL and from_index is NULL then the index is created and its location stored to from_index. In this case the caller has the responsibility to free the memory pointed to by from_index. If from_index and from_index are non NULL then the index is reused as is. This currently saves about 10% of CPU time to repack the git archive. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Nicolas Pitre	39556fbdad	delta micro optimization My kernel work habit made me look at the generated assembly for the delta code, and one obvious albeit small improvement is this patch. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Junio C Hamano	c7a45bd20e	Revert "diff-delta.c: allow delta with empty blob." This reverts `962537a3eb` commit to play safe.	19 years ago
Junio C Hamano	962537a3eb	diff-delta.c: allow delta with empty blob. Delta computation with an empty blob used to punt and returned NULL. This commit allows creation with empty blob; all combination of empty->empty, empty->something, and something->empty are allowed. Signed-off-by: Junio C Hamano <junkio@cox.net>	19 years ago
Nicolas Pitre	dcde55bc58	[PATCH] assorted delta code cleanup 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>	20 years ago
Junio C Hamano	c4584ae3fd	[PATCH] Remove "delta" object representation. Packed delta files created by git-pack-objects seems to be the way to go, and existing "delta" object handling code has exposed the object representation details to too many places. Remove it while we refactor code to come up with a proper interface in sha1_file.c. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>	20 years ago
Linus Torvalds	75c42d8cc3	Add a "max_size" parameter to diff_delta() Anything that generates a delta to see if two objects are close usually isn't interested in the delta ends up being bigger than some specified size, and this allows us to stop delta generation early when that happens.	20 years ago
Jason McMullan	5d6ccf5ce7	[PATCH] Anal retentive 'const unsigned char *sha1' Make 'sha1' parameters const where possible Signed-off-by: Jason McMullan <jason.mcmullan@timesys.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>	20 years ago
Nicolas Pitre	d1af002dc6	[PATCH] delta check This adds knowledge of delta objects to fsck-cache and various object parsing code. A new switch to git-fsck-cache is provided to display the maximum delta depth found in a repository. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>	20 years ago
Nicolas Pitre	a310d43494	[PATCH] Deltification library work by Nicolas Pitre. 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>	20 years ago

12 Commits (2c1d2d818895d896f706835142a75978aabdbdc9)