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Stick to one hash function (no platform optimized versions)

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Dale Weiler 2012-12-22 07:33:11 +00:00
parent 7753e19ba8
commit ed11fe130b
1 changed files with 3 additions and 66 deletions
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69
util.c
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@ -599,61 +599,11 @@ typedef struct hash_node_t {
struct hash_node_t *next; /* next node (linked list) */ struct hash_node_t *next; /* next node (linked list) */
} hash_node_t; } hash_node_t;
/* GMQCC_INLINE size_t util_hthash(hash_table_t *ht, const char *key) {
* 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) {
const uint32_t mix = 0x5BD1E995; const uint32_t mix = 0x5BD1E995;
const uint32_t rot = 24; const uint32_t rot = 24;
size_t size = strlen(key); size_t size = strlen(key);
uint32_t hash = seed ^ size; uint32_t hash = util_crc32_table[10] ^ size;
uint32_t alias = 0; uint32_t alias = 0;
const unsigned char *data = (const unsigned char*)key; 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 *= mix;
hash ^= hash >> 15; hash ^= hash >> 15;
return hash % ht->size; return (size_t) (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;
} }
hash_node_t *_util_htnewpair(const char *key, void *value) { hash_node_t *_util_htnewpair(const char *key, void *value) {