On 4/28/11 2:59 PM, Erik Faye-Lund wrote:
So my preference is still something like this. Call me conservative ;)
diff --git a/cache.h b/cache.h
index c730c58..8bc03c6 100644
--- a/cache.h
+++ b/cache.h
@@ -681,13 +681,17 @@ extern char *sha1_pack_name(const unsigned char *sha1);
extern char *sha1_pack_index_name(const unsigned char *sha1);
extern const char *find_unique_abbrev(const unsigned char *sha1, int);
extern const unsigned char null_sha1[20];
-static inline int is_null_sha1(const unsigned char *sha1)
+static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
{
- return !memcmp(sha1, null_sha1, 20);
+ /* early out for fast mis-match */
+ if (*sha1 != *sha2)
+ return *sha1 - *sha2;
+
+ return memcmp(sha1 + 1, sha2 + 1, 19);
}
-static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
+static inline int is_null_sha1(const unsigned char *sha1)
{
- return memcmp(sha1, sha2, 20);
+ return !hashcmp(sha1, null_sha1);
}
static inline void hashcpy(unsigned char *sha_dst, const unsigned
char *sha_src)
{
Yup, might be the most reasonable thing to do if it still speeds things up.
Pekka
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