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| author | Ben Pfaff <blp@nicira.com> | 2012-12-14 13:43:54 -0800 |
|---|---|---|
| committer | Ben Pfaff <blp@nicira.com> | 2013-01-22 13:40:50 -0800 |
| commit | b2a52eedaa406bacfa53d2b2a3d4236e46042bcd (patch) | |
| tree | f83085b1efd7bf817e51a160a26ac56ca9e4b668 /lib/hash.h | |
| parent | 432fca235c375c1d56bd6d3049b0b24ce2cb2958 (diff) | |
| download | openvswitch-b2a52eedaa406bacfa53d2b2a3d4236e46042bcd.tar.gz | |
hash: Correct implementation of mhash_finish().
With rotates instead of shifts, the upper and lower 16 bits of the returned
hash are always the same.
I noticed this while working on replacing Jenkins hash by murmurhash,
because some of the database unit tests started failing, e.g. "row
hashing (scalars)".
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>
Diffstat (limited to 'lib/hash.h')
| -rw-r--r-- | lib/hash.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/lib/hash.h b/lib/hash.h index 701e6866e..96866c42a 100644 --- a/lib/hash.h +++ b/lib/hash.h @@ -152,11 +152,11 @@ static inline uint32_t mhash_add(uint32_t hash, uint32_t data) static inline uint32_t mhash_finish(uint32_t hash, size_t n) { hash ^= n * 4; - hash ^= hash_rot(hash, 16); + hash ^= hash >> 16; hash *= 0x85ebca6b; - hash ^= hash_rot(hash, 13); + hash ^= hash >> 13; hash *= 0xc2b2ae35; - hash ^= hash_rot(hash, 16); + hash ^= hash >> 16; return hash; } |