4 static uint64_t FNV_64_INIT
= 0xcbf29ce484222325LL
;
5 static uint64_t FNV_64_PRIME
= 0x100000001b3LL
;
7 static uint32_t FNV_32_INIT
= 2166136261UL;
8 static uint32_t FNV_32_PRIME
= 16777619;
11 static uint32_t internal_generate_hash(char *key
, size_t key_length
);
12 static uint32_t internal_generate_md5(char *key
, size_t key_length
);
13 static uint32_t internal_generate_ketama_md5(char *key
, size_t key_length
);
15 uint32_t generate_hash(memcached_st
*ptr
, char *key
, size_t key_length
)
17 uint32_t hash
= 1; /* Just here to remove compile warning */
21 WATCHPOINT_ASSERT(ptr
->number_of_hosts
);
23 if (ptr
->number_of_hosts
== 1)
28 case MEMCACHED_HASH_DEFAULT
:
29 hash
= internal_generate_hash(key
, key_length
);
31 case MEMCACHED_HASH_MD5
:
32 hash
= internal_generate_md5(key
, key_length
);
34 case MEMCACHED_HASH_CRC
:
35 hash
= ((hash_crc32(key
, key_length
) >> 16) & 0x7fff);
39 /* FNV hash'es lifted from Dustin Sallings work */
40 case MEMCACHED_HASH_FNV1_64
:
42 /* Thanks to pierre@demartines.com for the pointer */
45 temp_hash
= FNV_64_INIT
;
46 for (x
= 0; x
< key_length
; x
++)
48 temp_hash
*= FNV_64_PRIME
;
51 hash
= (uint32_t)temp_hash
;
54 case MEMCACHED_HASH_FNV1A_64
:
57 for (x
= 0; x
< key_length
; x
++)
64 case MEMCACHED_HASH_FNV1_32
:
67 for (x
= 0; x
< key_length
; x
++)
74 case MEMCACHED_HASH_FNV1A_32
:
77 for (x
= 0; x
< key_length
; x
++)
84 case MEMCACHED_HASH_KETAMA
:
86 hash
= internal_generate_ketama_md5(key
, key_length
);
89 case MEMCACHED_HASH_HSIEH
:
91 hash
= hsieh_hash(key
, key_length
);
94 case MEMCACHED_HASH_MURMUR
:
96 hash
= murmur_hash(key
, key_length
);
101 WATCHPOINT_ASSERT(hash
);
105 unsigned int dispatch_host(memcached_st
*ptr
, uint32_t hash
)
107 switch (ptr
->distribution
)
109 case MEMCACHED_DISTRIBUTION_CONSISTENT
:
110 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA
:
112 int num
= ptr
->number_of_hosts
* MEMCACHED_POINTS_PER_SERVER
;
113 WATCHPOINT_ASSERT(ptr
->continuum
);
116 memcached_continuum_item_st
*begin
, *end
, *left
, *right
, *middle
;
117 begin
= left
= ptr
->continuum
;
118 end
= right
= ptr
->continuum
+ (num
- 1);
122 memcached_continuum_item_st
*rmiddle
;
124 middle
= left
+ (right
- left
) / 2;
134 if (hash
<rmiddle
->value
&& hash
>=middle
->value
)
135 return middle
->index
;
137 if (middle
->value
< hash
)
139 else if (middle
->value
> hash
)
147 case MEMCACHED_DISTRIBUTION_CONSISTENT_WHEEL
:
149 unsigned int server_key
;
151 server_key
= hash
% MEMCACHED_WHEEL_SIZE
;
153 return ptr
->wheel
[server_key
];
155 case MEMCACHED_DISTRIBUTION_MODULA
:
156 return hash
% ptr
->number_of_hosts
;
158 WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
159 return hash
% ptr
->number_of_hosts
;
162 if (ptr
->distribution
== MEMCACHED_DISTRIBUTION_MODULA
)
164 return hash
% ptr
->number_of_hosts
;
166 else if (ptr
->distribution
== MEMCACHED_DISTRIBUTION_CONSISTENT
)
168 unsigned int server_key
;
170 server_key
= hash
% MEMCACHED_WHEEL_SIZE
;
172 return ptr
->wheel
[server_key
];
174 else if (ptr
->distribution
== MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA
)
176 int num
= ptr
->number_of_hosts
* MEMCACHED_POINTS_PER_SERVER
;
179 memcached_continuum_item_st
*begin
, *end
, *left
, *right
, *middle
;
180 begin
= left
= ptr
->continuum
;
181 end
= right
= ptr
->continuum
+ (num
- 1);
184 middle
= left
+ (right
- left
) / 2;
193 memcached_continuum_item_st
*rmiddle
= middle
+1;
194 if(hash
<rmiddle
->value
&& hash
>=middle
->value
)
195 return middle
->index
;
197 if(middle
->value
< hash
) {
199 }else if(middle
->value
> hash
) {
209 WATCHPOINT_ASSERT(0);
213 unsigned int memcached_generate_hash(memcached_st
*ptr
, char *key
, size_t key_length
)
215 uint32_t hash
= 1; /* Just here to remove compile warning */
217 WATCHPOINT_ASSERT(ptr
->number_of_hosts
);
219 if (ptr
->number_of_hosts
== 1)
222 hash
= generate_hash(ptr
, key
, key_length
);
224 WATCHPOINT_ASSERT(hash
);
225 return dispatch_host(ptr
, hash
);
228 static uint32_t internal_generate_hash(char *key
, size_t key_length
)
236 value
+= (value
<< 10);
237 value
^= (value
>> 6);
239 value
+= (value
<< 3);
240 value
^= (value
>> 11);
241 value
+= (value
<< 15);
243 return value
== 0 ? 1 : value
;
246 static uint32_t internal_generate_md5(char *key
, size_t key_length
)
248 unsigned char results
[16];
250 md5_signature((unsigned char*)key
, (unsigned int)key_length
, results
);
252 return (uint32_t)(( results
[3] << 24 )
253 | ( results
[2] << 16 )
254 | ( results
[1] << 8 )
258 static uint32_t internal_generate_ketama_md5(char *key
, size_t key_length
)
260 unsigned char results
[16];
262 md5_signature((unsigned char*)key
, (unsigned int)key_length
, results
);
264 return ((uint32_t) (results
[3] & 0xFF) << 24)
265 | ((uint32_t) (results
[2] & 0xFF) << 16)
266 | ((uint32_t) (results
[1] & 0xFF) << 8)
267 | (results
[0] & 0xFF);