Fixed the ascii protocol handler
[m6w6/libmemcached] / libmemcached / hash.c
1 /* LibMemcached
2 * Copyright (C) 2006-2010 Brian Aker
3 * All rights reserved.
4 *
5 * Use and distribution licensed under the BSD license. See
6 * the COPYING file in the parent directory for full text.
7 *
8 * Summary:
9 *
10 */
11
12 #include "common.h"
13
14
15 uint32_t memcached_generate_hash_value(const char *key, size_t key_length, memcached_hash_t hash_algorithm)
16 {
17 return libhashkit_digest(key, key_length, (hashkit_hash_algorithm_t)hash_algorithm);
18 }
19
20 uint32_t generate_hash(memcached_st *ptr, const char *key, size_t key_length)
21 {
22 uint32_t hash= 1; /* Just here to remove compile warning */
23
24
25 WATCHPOINT_ASSERT(memcached_server_count(ptr));
26
27 if (memcached_server_count(ptr) == 1)
28 return 0;
29
30 hash= hashkit_digest(&ptr->hashkit, key, key_length);
31 WATCHPOINT_ASSERT(hash);
32
33 return hash;
34 }
35
36 static uint32_t dispatch_host(memcached_st *ptr, uint32_t hash)
37 {
38 switch (ptr->distribution)
39 {
40 case MEMCACHED_DISTRIBUTION_CONSISTENT:
41 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
42 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
43 {
44 uint32_t num= ptr->continuum_points_counter;
45 WATCHPOINT_ASSERT(ptr->continuum);
46
47 hash= hash;
48 memcached_continuum_item_st *begin, *end, *left, *right, *middle;
49 begin= left= ptr->continuum;
50 end= right= ptr->continuum + num;
51
52 while (left < right)
53 {
54 middle= left + (right - left) / 2;
55 if (middle->value < hash)
56 left= middle + 1;
57 else
58 right= middle;
59 }
60 if (right == end)
61 right= begin;
62 return right->index;
63 }
64 case MEMCACHED_DISTRIBUTION_MODULA:
65 return hash % memcached_server_count(ptr);
66 case MEMCACHED_DISTRIBUTION_RANDOM:
67 return (uint32_t) random() % memcached_server_count(ptr);
68 case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
69 default:
70 WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
71 return hash % memcached_server_count(ptr);
72 }
73 /* NOTREACHED */
74 }
75
76 /*
77 One day make this public, and have it return the actual memcached_server_st
78 to the calling application.
79 */
80 uint32_t memcached_generate_hash(memcached_st *ptr, const char *key, size_t key_length)
81 {
82 uint32_t hash= 1; /* Just here to remove compile warning */
83
84 WATCHPOINT_ASSERT(memcached_server_count(ptr));
85
86 if (memcached_server_count(ptr) == 1)
87 return 0;
88
89 if (ptr->flags.hash_with_prefix_key)
90 {
91 size_t temp_length= ptr->prefix_key_length + key_length;
92 char temp[temp_length];
93
94 if (temp_length > MEMCACHED_MAX_KEY -1)
95 return 0;
96
97 strncpy(temp, ptr->prefix_key, ptr->prefix_key_length);
98 strncpy(temp + ptr->prefix_key_length, key, key_length);
99 hash= generate_hash(ptr, temp, temp_length);
100 }
101 else
102 {
103 hash= generate_hash(ptr, key, key_length);
104 }
105
106 WATCHPOINT_ASSERT(hash);
107
108 if (memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS) && ptr->next_distribution_rebuild)
109 {
110 struct timeval now;
111
112 if (gettimeofday(&now, NULL) == 0 &&
113 now.tv_sec > ptr->next_distribution_rebuild)
114 {
115 run_distribution(ptr);
116 }
117 }
118
119 return dispatch_host(ptr, hash);
120 }
121
122 hashkit_st *memcached_get_hashkit(memcached_st *ptr)
123 {
124 return &ptr->hashkit;
125 }