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authorKarsten Blees <karsten.blees@gmail.com>2014-07-03 00:20:20 +0200
committerJunio C Hamano <gitster@pobox.com>2014-07-07 13:56:24 -0700
commit039dc71a7cb824300e242f8abc0fcb19dac93641 (patch)
tree9c38bb8655e0314cfe122b7355922c2413533825 /hashmap.h
parent6f92e5ff3cdc813de8ef5327fd4bad492fb7d6c9 (diff)
downloadgit-039dc71a7cb824300e242f8abc0fcb19dac93641.tar.gz
git-039dc71a7cb824300e242f8abc0fcb19dac93641.tar.xz
hashmap: factor out getting a hash code from a SHA1
Copying the first bytes of a SHA1 is duplicated in six places, however, the implications (the actual value would depend on the endianness of the platform) is documented only once. Add a properly documented API for this. Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'hashmap.h')
-rw-r--r--hashmap.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/hashmap.h b/hashmap.h
index a816ad47b..c51fd0abf 100644
--- a/hashmap.h
+++ b/hashmap.h
@@ -13,6 +13,17 @@ extern unsigned int strihash(const char *buf);
extern unsigned int memhash(const void *buf, size_t len);
extern unsigned int memihash(const void *buf, size_t len);
+static inline unsigned int sha1hash(const unsigned char *sha1)
+{
+ /*
+ * Equivalent to 'return *(unsigned int *)sha1;', but safe on
+ * platforms that don't support unaligned reads.
+ */
+ unsigned int hash;
+ memcpy(&hash, sha1, sizeof(hash));
+ return hash;
+}
+
/* data structures */
struct hashmap_entry {