#include "common.h"
+/* Defines */
+static uint64_t FNV_64_INIT= 0xcbf29ce484222325LL;
+static uint64_t FNV_64_PRIME= 0x100000001b3LL;
+
+static uint32_t FNV_32_INIT= 2166136261UL;
+static uint32_t FNV_32_PRIME= 16777619;
+
/* Prototypes */
-static unsigned int internal_generate_hash(char *key, size_t key_length);
+static uint32_t internal_generate_hash(char *key, size_t key_length);
+static uint32_t internal_generate_md5(char *key, size_t key_length);
+static uint32_t internal_generate_ketama_md5(char *key, size_t key_length);
unsigned int memcached_generate_hash(memcached_st *ptr, char *key, size_t key_length)
{
- unsigned int hash;
+ uint32_t hash= 1; /* Just here to remove compile warning */
+ unsigned int x;
- if (ptr->flags & MEM_USE_MD5)
- {
- unsigned char results[16];
+ WATCHPOINT_ASSERT(ptr->number_of_hosts);
- md5_signature((unsigned char*)key, (unsigned int)key_length, results);
+ if (ptr->number_of_hosts == 1)
+ return 0;
- hash= (unsigned int)(( results[3] << 24 )
- | ( results[2] << 16 )
- | ( results[1] << 8 )
- | results[0] );
- }
- else
+ switch (ptr->hash)
+ {
+ case MEMCACHED_HASH_DEFAULT:
hash= internal_generate_hash(key, key_length);
+ break;
+ case MEMCACHED_HASH_MD5:
+ hash= internal_generate_md5(key, key_length);
+ break;
+ case MEMCACHED_HASH_CRC:
+ hash= ((hash_crc32(key, key_length) >> 16) & 0x7fff);
+ if (hash == 0)
+ hash= 1;
+ break;
+ /* FNV hash'es lifted from Dustin Sallings work */
+ case MEMCACHED_HASH_FNV1_64:
+ {
+ /* Thanks to pierre@demartines.com for the pointer */
+ uint64_t temp_hash;
- if (ptr->flags & MEM_USE_KETAMA)
+ temp_hash= FNV_64_INIT;
+ for (x= 0; x < key_length; x++)
+ {
+ temp_hash *= FNV_64_PRIME;
+ temp_hash ^= key[x];
+ }
+ hash= (uint32_t)temp_hash;
+ }
+ break;
+ case MEMCACHED_HASH_FNV1A_64:
+ {
+ hash= FNV_64_INIT;
+ for (x= 0; x < key_length; x++)
+ {
+ hash ^= key[x];
+ hash *= FNV_64_PRIME;
+ }
+ }
+ break;
+ case MEMCACHED_HASH_FNV1_32:
+ {
+ hash= FNV_32_INIT;
+ for (x= 0; x < key_length; x++)
+ {
+ hash *= FNV_32_PRIME;
+ hash ^= key[x];
+ }
+ }
+ break;
+ case MEMCACHED_HASH_FNV1A_32:
+ {
+ hash= FNV_32_INIT;
+ for (x= 0; x < key_length; x++)
+ {
+ hash ^= key[x];
+ hash *= FNV_32_PRIME;
+ }
+ }
+ break;
+ case MEMCACHED_HASH_KETAMA:
+ {
+ hash= internal_generate_ketama_md5(key, key_length);
+ break;
+ }
+ case MEMCACHED_HASH_HSIEH:
+ {
+ hash= hsieh_hash(key, key_length);
+ break;
+ }
+ case MEMCACHED_HASH_MURMUR:
+ {
+ hash= murmur_hash(key, key_length);
+ break;
+ }
+ }
+
+ WATCHPOINT_ASSERT(hash);
+
+ if (ptr->distribution == MEMCACHED_DISTRIBUTION_MODULA)
{
- WATCHPOINT_ASSERT(0);
- return 0;
+ return hash % ptr->number_of_hosts;
}
else
- return hash % ptr->number_of_hosts;
+ {
+ unsigned int server_key;
+
+ server_key= hash % MEMCACHED_WHEEL_SIZE;
+
+ return ptr->wheel[server_key];
+ }
}
-static unsigned int internal_generate_hash(char *key, size_t key_length)
+static uint32_t internal_generate_hash(char *key, size_t key_length)
{
char *ptr= key;
- unsigned int value= 0;
+ uint32_t value= 0;
while (--key_length)
{
return value == 0 ? 1 : value;
}
+
+static uint32_t internal_generate_md5(char *key, size_t key_length)
+{
+ unsigned char results[16];
+
+ md5_signature((unsigned char*)key, (unsigned int)key_length, results);
+
+ return (uint32_t)(( results[3] << 24 )
+ | ( results[2] << 16 )
+ | ( results[1] << 8 )
+ | results[0] );
+}
+
+static uint32_t internal_generate_ketama_md5(char *key, size_t key_length)
+{
+ unsigned char results[16];
+
+ md5_signature((unsigned char*)key, (unsigned int)key_length, results);
+
+ return ((uint32_t) (results[3] & 0xFF) << 24)
+ | ((uint32_t) (results[2] & 0xFF) << 16)
+ | ((uint32_t) (results[1] & 0xFF) << 8)
+ | (results[0] & 0xFF);
+}