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19 Commits

Author SHA1 Message Date
Nguyễn Thái Ngọc Duy b78ea5fc35 diff.c: reduce implicit dependency on the_index
diff and textconv code has so widespread use that it's hard to simply
update their api and all call sites at once because it would result in
a big patch. For now reduce the_index references to two places:
diff_setup() and fill_textconv().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-21 09:48:10 -07:00
Brandon Williams 94a5c5d5b0 diffcore-delta: rename 'new' variables
Rename C++ keyword in order to bring the codebase closer to being able
to be compiled with a C++ compiler.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-22 10:08:05 -08:00
Junio C Hamano 6d40812e4b Merge branch 'tk/diffcore-delta-remove-unused'
Code cleanup.

* tk/diffcore-delta-remove-unused:
  diffcore-delta: remove unused parameter to diffcore_count_changes()
2016-11-17 13:45:22 -08:00
Tobias Klauser 974e0044d6 diffcore-delta: remove unused parameter to diffcore_count_changes()
The delta_limit parameter to diffcore_count_changes() has been unused
since commit ba23bbc8e ("diffcore-delta: make change counter to byte
oriented again.", 2006-03-04).

Remove the parameter and adjust all callers.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-11-14 09:24:04 -08:00
René Scharfe 9ed0d8d6e6 use QSORT
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code
base, replacing calls of qsort(3) with QSORT.  The resulting code is
shorter and supports empty arrays with NULL pointers.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-29 15:42:18 -07:00
Jeff King 50a6c8efa2 use st_add and st_mult for allocation size computation
If our size computation overflows size_t, we may allocate a
much smaller buffer than we expected and overflow it. It's
probably impossible to trigger an overflow in most of these
sites in practice, but it is easy enough convert their
additions and multiplications into overflow-checking
variants. This may be fixing real bugs, and it makes
auditing the code easier.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00
Linus Torvalds 77cd6ab621 Fix diff -B/--dirstat miscounting of newly added contents
What used to happen is that diffcore_count_changes() simply ignored any
hashes in the destination that didn't match hashes in the source. EXCEPT
if the source hash didn't exist at all, in which case it would count _one_
destination hash that happened to have the "next" hash value.  As a
consequence, newly added material was often undercounted, making output
from --dirstat and "complete rewrite" detection used by -B unrelialble.

This changes it so that:

 - whenever it bypasses a destination hash (because it doesn't match a
   source), it counts the bytes associated with that as "literal added"

 - at the end (once we have used up all the source hashes), we do the same
   thing with the remaining destination hashes.

 - when hashes do match, and we use the difference in counts as a value,
   we also use up that destination hash entry (the 'd++').

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-12-05 10:54:17 -08:00
Linus Torvalds eb4d0e3f45 optimize diffcore-delta by sorting hash entries.
Here's a test-patch. I don't guarantee anything, except that when I did
the timings I also did a "wc" on the result, and they matched..

Before:
	[torvalds@woody linux]$ time git diff -l0 --stat -C v2.6.22.. | wc
	   7104   28574  438020

	real    0m10.526s
	user    0m10.401s
	sys     0m0.136s

After:
	[torvalds@woody linux]$ time ~/git/git diff -l0 --stat -C v2.6.22.. | wc
	   7104   28574  438020

	real    0m8.876s
	user    0m8.761s
	sys     0m0.128s

but the diff is fairly simple, so if somebody will go over it and say
whether it's likely to be *correct* too, that 15% may well be worth it.

[ Side note, without rename detection, that diff takes just under three
  seconds for me, so in that sense the improvement to the rename detection
  itself is larger than the overall 15% - it brings the cost of just
  rename detection from 7.5s to 5.9s, which would be on the order of just
  over a 20% performance improvement. ]

Hmm. The patch depends on half-way subtle issues like the fact that the
hashtables are guaranteed to not be full => we're guaranteed to have zero
counts at the end => we don't need to do any steenking iterator count in
the loop. A few comments might in order.

		Linus
2007-10-04 00:05:36 -07:00
Junio C Hamano 29a3eefde1 Introduce diff_filespec_is_binary()
This replaces an explicit initialization of filespec->is_binary
field used for rename/break followed by direct access to that
field with a wrapper function that lazily iniaitlizes and
accesses the field.  We would add more attribute accesses for
the use of diff routines, and it would be better to make this
abstraction earlier.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-07-06 00:21:41 -07:00
Junio C Hamano b9905fed7a diffcore-delta.c: Ignore CR in CRLF for text files
This ignores CR byte in CRLF sequence in text file when
computing similarity of two blobs.

Usually this should not matter as nobody sane would be checking
in a file with CRLF line endings to the repository (they would
use autocrlf so that the repository copy would have LF line
endings).

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-30 20:51:31 -07:00
Junio C Hamano af3abef94a diffcore-delta.c: update the comment on the algorithm.
The comment at the top of the file described an old algorithm
that was neutral to text/binary differences (it hashed sliding
window of N-byte sequences and counted overlaps), but long time
ago we switched to a new heuristics that are more suitable for
line oriented (read: text) files that are much faster.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-30 20:51:31 -07:00
Junio C Hamano d8c3d03a0b diffcore_count_changes: pass diffcore_filespec
We may want to use richer information on the data we are dealing
with in this function, so instead of passing a buffer address
and length, just pass the diffcore_filespec structure.  Existing
callers always call this function with parameters taken from a
filespec anyway, so there is no functionality changes.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-30 20:51:31 -07:00
Linus Torvalds e31c9f241a diffcore-delta: 64-byte-or-EOL ultrafast replacement (hash fix).
The rotating 64-bit number was not really rotating, and worse
yet ulong was longer than 64-bit on 64-bit architectures X-<.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-15 13:19:27 -08:00
Linus Torvalds 3c7ceba4f1 diffcore-delta: 64-byte-or-EOL ultrafast replacement.
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-15 00:37:57 -08:00
Junio C Hamano fc66d213f8 diffcore-delta: tweak hashbase value.
This tweaks the maximum hashvalue we use to hash the string into
without making the maximum size of the hashtable can grow from
the current limit.  With this, the renames detected becomes a
bit more precise without incurring additional paging cost.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-12 20:42:12 -08:00
Junio C Hamano 2821104db7 diffcore-delta: make the hash a bit denser.
To reduce wasted memory, wait until the hash fills up more
densely before we rehash.  This reduces the working set size a
bit further.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-12 17:26:32 -08:00
Junio C Hamano c06c79667c diffcore-rename: somewhat optimized.
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>
2006-03-12 03:22:10 -08:00
Junio C Hamano ba23bbc8ef diffcore-delta: make change counter to byte oriented again.
The textual line oriented change counter was fun but was not
very effective.  It tended to overcount the changes.  This one
changes it to a simple N-letter substring based implementation.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-04 13:34:50 -08:00
Junio C Hamano 65416758cd diffcore-rename: split out the delta counting code.
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>
2006-02-28 20:20:04 -08:00