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2007-03-07Cast 64 bit off_t to 32 bit size_tLibravatar Shawn O. Pearce1-1/+1
Some systems have sizeof(off_t) == 8 while sizeof(size_t) == 4. This implies that we are able to access and work on files whose maximum length is around 2^63-1 bytes, but we can only malloc or mmap somewhat less than 2^32-1 bytes of memory. On such a system an implicit conversion of off_t to size_t can cause the size_t to wrap, resulting in unexpected and exciting behavior. Right now we are working around all gcc warnings generated by the -Wshorten-64-to-32 option by passing the off_t through xsize_t(). In the future we should make xsize_t on such problematic platforms detect the wrapping and die if such a file is accessed. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-17Do not use memcmp(sha1_1, sha1_2, 20) with hardcoded length.Libravatar David Rientjes1-1/+1
Introduces global inline: hashcmp(const unsigned char *sha1, const unsigned char *sha2) Uses memcmp for comparison and returns the result based on the length of the hash name (a future runtime decision). Acked-by: Alex Riesen <raa.lkml@gmail.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-12diffcore-rename: somewhat optimized.Libravatar Junio C Hamano1-0/+1
This changes diffcore-rename to reuse statistics information gathered during similarity estimation, and updates the hashtable implementation used to keep track of the statistics to be denser. This seems to give better performance. Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-04diffcore-break: similarity estimator fix.Libravatar Junio C Hamano1-19/+26
This is a companion patch to the previous fix to diffcore-rename. The merging-back process should use a logic similar to what is used there. Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-02-28diffcore-rename: split out the delta counting code.Libravatar Junio C Hamano1-16/+5
This is to rework diffcore break/rename/copy detection code so that it does not affected when deltifier code gets improved. Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-02-28diffcore-break: micro-optimize by avoiding delta between identical files.Libravatar Junio C Hamano1-0/+4
We did not check if we have the same file on both sides when computing break score. This is usually not a problem, but if the user said --find-copies-harde with -B, we ended up trying a delta between the same data even when we know the SHA1 hash of both sides match. Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-12-12diffcore-break: do not break too small filepair.Libravatar Junio C Hamano1-2/+3
Somehow we checked only one side and not the other. By checking the filesize upfront, we can bypass generating delta unnecessarily. Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-12-12diffcore-break.c: check diff_delta() return value.Libravatar Junio C Hamano1-0/+2
This bug caused Darrin Thompson to notice that our deltifier was half broken and punting on an empty blob. Signed-off-by: Junio C Hamano <junio@twinsun.com>
2005-09-14Revert "[PATCH] plug memory leak in diff.c::diff_free_filepair()"Libravatar Junio C Hamano1-2/+2
This reverts 068eac91ce04b9aca163acb1927c3878c45d1a07 commit.
2005-08-13[PATCH] plug memory leak in diff.c::diff_free_filepair()Libravatar Yasushi SHOJI1-2/+2
When I run git-diff-tree on big change, it seems the command eats so much memory. so I just put git under valgrind to see what's going on. diff_free_filespec_data() doesn't free diff_filespec itself. [jc: I ended up doing things slightly differently from Yasushi's patch. The original idea was to use free_filespec_data() only to free the data portion and keep useing the filespec itself, but no existing code seems to do things that way, so I just yanked that part out.] Signed-off-by: Yasushi SHOJI <yashi@atmark-techno.com> Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-06-29[PATCH] Fixlets on top of Nico's clean-up.Libravatar Junio C Hamano1-1/+1
If we prefer 0 as maxsize for diff_delta() to say "unlimited", let's be consistent about it. This patch also fixes type mismatch in a call to get_delta_hdr_size() from packed_delta_info(). Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25Add a "max_size" parameter to diff_delta()Libravatar Linus Torvalds1-1/+1
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.
2005-06-19[PATCH] Rework -B output.Libravatar Junio C Hamano1-4/+3
Patch for a completely rewritten file detected by the -B flag was shown as a pair of creation followed by deletion in earlier versions. This was an misguided attempt to make reviewing such a complete rewrite easier, and unnecessarily ended up confusing git-apply. Instead, show the entire contents of old version prefixed with '-', followed by the entire contents of new version prefixed with '+'. This gives the same easy-to-review for human consumer while keeping it a single, regular modification patch for machine consumption, something that even GNU patch can grok. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-05[PATCH] diffcore-break.c: various fixes.Libravatar Junio C Hamano1-14/+8
This fixes three bugs in the -B heuristics. - Although it was advertised that the initial break criteria used was the same as what diffcore-rename uses, it was using something different. Instead of using smaller of src and dst size to compare with "edit" size, (insertion and deletion), it was using larger of src and dst, unlike the rename/copy detection logic. This caused the parameter to -B to mean something different from the one to -M and -C. To compensate for this change, the default break score is also changed to match that of the default for rename/copy. - The code would have crashed with division by zero when trying to break an originally empty file. - Contrary to what the comment said, the algorithm was breaking small files, only to later merge them together. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-03[PATCH] diff: Update -B heuristics.Libravatar Junio C Hamano1-41/+197
As Linus pointed out on the mailing list discussion, -B should break a files that has many inserts even if it still keeps enough of the original contents, so that the broken pieces can later be matched with other files by -M or -C. However, if such a broken pair does not get picked up by -M or -C, we would want to apply different criteria; namely, regardless of the amount of new material in the result, the determination of "rewrite" should be done by looking at the amount of original material still left in the result. If you still have the original 97 lines from a 100-line document, it does not matter if you add your own 13 lines to make a 110-line document, or if you add 903 lines to make a 1000-line document. It is not a rewrite but an in-place edit. On the other hand, if you did lose 97 lines from the original, it does not matter if you added 27 lines to make a 30-line document or if you added 997 lines to make a 1000-line document. You did a complete rewrite in either case. This patch introduces a post-processing phase that runs after diffcore-rename matches up broken pairs diffcore-break creates. The purpose of this post-processing is to pick up these broken pieces and merge them back into in-place modifications. For this, the score parameter -B option takes is changed into a pair of numbers, and it takes "-B99/80" format when fully spelled out. The first number is the minimum amount of "edit" (same definition as what diffcore-rename uses, which is "sum of deletion and insertion") that a modification needs to have to be broken, and the second number is the minimum amount of "delete" a surviving broken pair must have to avoid being merged back together. It can be abbreviated to "-B" to use default for both, "-B9" or "-B9/" to use 90% for "edit" but default (80%) for merge avoidance, or "-B/75" to use default (99%) "edit" and 75% for merge avoidance. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-03[PATCH] Tweak count-delta interfaceLibravatar Junio C Hamano1-4/+11
Make it return copied source and insertion separately, so that later implementation of heuristics can use them more flexibly. This does not change the heuristics implemented in diffcore-rename nor diffcore-break in any way. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-30[PATCH] Add -B flag to diff-* brothers.Libravatar Junio C Hamano1-0/+127
A new diffcore transformation, diffcore-break.c, is introduced. When the -B flag is given, a patch that represents a complete rewrite is broken into a deletion followed by a creation. This makes it easier to review such a complete rewrite patch. The -B flag takes the same syntax as the -M and -C flags to specify the minimum amount of non-source material the resulting file needs to have to be considered a complete rewrite, and defaults to 99% if not specified. As the new test t4008-diff-break-rewrite.sh demonstrates, if a file is a complete rewrite, it is broken into a delete/create pair, which can further be subjected to the usual rename detection if -M or -C is used. For example, if file0 gets completely rewritten to make it as if it were rather based on file1 which itself disappeared, the following happens: The original change looks like this: file0 --> file0' (quite different from file0) file1 --> /dev/null After diffcore-break runs, it would become this: file0 --> /dev/null /dev/null --> file0' file1 --> /dev/null Then diffcore-rename matches them up: file1 --> file0' The internal score values are finer grained now. Earlier maximum of 10000 has been raised to 60000; there is no user visible changes but there is no reason to waste available bits. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>