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authorJunio C Hamano <junkio@cox.net>2005-06-03 01:36:03 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-03 11:23:03 -0700
commit355e76a4a3c5e49ae15a642806457bce10fe2ef4 (patch)
tree61d1a1313ab1732458e47f55e14d6c1c7f1225ea /count-delta.c
parent5b86040679626e36c12345039f6df62f4622aef2 (diff)
downloadgit-355e76a4a3c5e49ae15a642806457bce10fe2ef4.tar.gz
git-355e76a4a3c5e49ae15a642806457bce10fe2ef4.tar.xz
[PATCH] Tweak count-delta interface
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>
Diffstat (limited to 'count-delta.c')
-rw-r--r--count-delta.c30
1 files changed, 16 insertions, 14 deletions
diff --git a/count-delta.c b/count-delta.c
index e10c832a7..c7f376788 100644
--- a/count-delta.c
+++ b/count-delta.c
@@ -29,15 +29,18 @@ static unsigned long get_hdr_size(const unsigned char **datap)
/*
* NOTE. We do not _interpret_ delta fully. As an approximation, we
* just count the number of bytes that are copied from the source, and
- * the number of literal data bytes that are inserted. Number of
- * bytes that are _not_ copied from the source is deletion, and number
- * of inserted literal bytes are addition, so sum of them is what we
- * return. xdelta can express an edit that copies data inside of the
- * destination which originally came from the source. We do not count
- * that in the following routine, so we are undercounting the source
- * material that remains in the final output that way.
+ * the number of literal data bytes that are inserted.
+ *
+ * Number of bytes that are _not_ copied from the source is deletion,
+ * and number of inserted literal bytes are addition, so sum of them
+ * is the extent of damage. xdelta can express an edit that copies
+ * data inside of the destination which originally came from the
+ * source. We do not count that in the following routine, so we are
+ * undercounting the source material that remains in the final output
+ * that way.
*/
-unsigned long count_delta(void *delta_buf, unsigned long delta_size)
+int count_delta(void *delta_buf, unsigned long delta_size,
+ unsigned long *src_copied, unsigned long *literal_added)
{
unsigned long copied_from_source, added_literal;
const unsigned char *data, *top;
@@ -46,7 +49,7 @@ unsigned long count_delta(void *delta_buf, unsigned long delta_size)
/* the smallest delta size possible is 6 bytes */
if (delta_size < 6)
- return UINT_MAX;
+ return -1;
data = delta_buf;
top = delta_buf + delta_size;
@@ -83,13 +86,12 @@ unsigned long count_delta(void *delta_buf, unsigned long delta_size)
/* sanity check */
if (data != top || out != dst_size)
- return UINT_MAX;
+ return -1;
/* delete size is what was _not_ copied from source.
* edit size is that and literal additions.
*/
- if (src_size + added_literal < copied_from_source)
- /* we ended up overcounting and underflowed */
- return 0;
- return (src_size - copied_from_source) + added_literal;
+ *src_copied = copied_from_source;
+ *literal_added = added_literal;
+ return 0;
}