From ed11fe130b2a0e188c6982c2965f4a485930eafb Mon Sep 17 00:00:00 2001 From: Dale Weiler Date: Sat, 22 Dec 2012 07:33:11 +0000 Subject: [PATCH] Stick to one hash function (no platform optimized versions) --- util.c | 69 +++------------------------------------------------------- 1 file changed, 3 insertions(+), 66 deletions(-) diff --git a/util.c b/util.c index d277ae4..4861537 100644 --- a/util.c +++ b/util.c @@ -599,61 +599,11 @@ typedef struct hash_node_t { struct hash_node_t *next; /* next node (linked list) */ } hash_node_t; -/* - * x86 and x86_64 optimized murmur hash functions for the hashtable - * we have individual implementations for optimal performance. - * - * Forced inlined as we wrap these up in the actual utility function - * below. These should be autovectorized by gcc. - */ -#ifdef __x86_64__ -GMQCC_INLINE uint32_t util_hthashfunc(hash_table_t *ht, const char *key, size_t seed) { - const uint64_t mix = 0xC6A4A7935BD1E995; - const int rot = 47; - size_t size = strlen(key); - uint64_t hash = seed ^ (size - mix); - uint64_t alias = 0; - const uint64_t *beg = (const uint64_t*)key; - const uint64_t *end = beg + (size / 8); - const unsigned char *final = NULL; - - while (beg != end) { - alias = *beg++; - - alias *= mix; - alias ^= alias >> rot; - alias *= mix; - - hash ^= alias; - hash *= mix; - } - - final = (const unsigned char *)beg; - - switch (size & 7) { - case 7: hash ^= (uint64_t)(final[6]) << 48; - case 6: hash ^= (uint64_t)(final[5]) << 40; - case 5: hash ^= (uint64_t)(final[4]) << 32; - case 4: hash ^= (uint64_t)(final[3]) << 24; - case 3: hash ^= (uint64_t)(final[2]) << 16; - case 2: hash ^= (uint64_t)(final[1]) << 8; - case 1: hash ^= (uint64_t)(final[0]); - hash *= mix; - } - - hash ^= hash >> rot; - hash *= mix; - hash ^= hash >> rot; - - return (uint32_t)(hash % ht->size); -} - -#else -GMQCC_INLINE uint32_t util_hthashfunc(hash_table_t *ht, const char *key, size_t seed) { +GMQCC_INLINE size_t util_hthash(hash_table_t *ht, const char *key) { const uint32_t mix = 0x5BD1E995; const uint32_t rot = 24; size_t size = strlen(key); - uint32_t hash = seed ^ size; + uint32_t hash = util_crc32_table[10] ^ size; uint32_t alias = 0; const unsigned char *data = (const unsigned char*)key; @@ -682,20 +632,7 @@ GMQCC_INLINE uint32_t util_hthashfunc(hash_table_t *ht, const char *key, size_t hash *= mix; hash ^= hash >> 15; - return hash % ht->size; -} -#endif - -/* we use the crc table as seeds for the murmur hash :P */ -size_t util_hthash(hash_table_t *ht, const char *key) { - static size_t seed = 0; - register size_t hash = util_hthashfunc(ht, key, util_crc32_table[seed]); - - /* reset seed */ - if (seed >= sizeof(util_crc32_table) / sizeof(*util_crc32_table)) - seed = 0; - - return hash; + return (size_t) (hash % ht->size); } hash_node_t *_util_htnewpair(const char *key, void *value) { -- 2.39.2