diff options
Diffstat (limited to 'hv.h')
| -rw-r--r-- | hv.h | 14 |
1 files changed, 11 insertions, 3 deletions
@@ -43,14 +43,22 @@ struct xpvhv { }; /* hash a key */ +/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins */ +/* from requirements by Colin Plumb. */ +/* (http://burtleburtle.net/bob/hash/doobs.html) */ #define PERL_HASH(hash,str,len) \ STMT_START { \ register const char *s_PeRlHaSh = str; \ register I32 i_PeRlHaSh = len; \ register U32 hash_PeRlHaSh = 0; \ - while (i_PeRlHaSh--) \ - hash_PeRlHaSh = hash_PeRlHaSh * 33 + *s_PeRlHaSh++; \ - (hash) = hash_PeRlHaSh + (hash_PeRlHaSh>>5); \ + while (i_PeRlHaSh--) { \ + hash_PeRlHaSh += *s_PeRlHaSh++; \ + hash_PeRlHaSh += (hash_PeRlHaSh << 10); \ + hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \ + } \ + hash_PeRlHaSh += (hash_PeRlHaSh << 3); \ + hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \ + (hash) = (hash_PeRlHaSh += (hash_PeRlHaSh << 15)); \ } STMT_END /* |