Updating for 1.0.2 release
[awesomized/libmemcached] / libmemcached / virtual_bucket.c
1 /* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
2 *
3 * Libmemcached library
4 *
5 * Copyright (C) 2011 Data Differential, http://datadifferential.com/
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are
10 * met:
11 *
12 * * Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * * Redistributions in binary form must reproduce the above
16 * copyright notice, this list of conditions and the following disclaimer
17 * in the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * * The names of its contributors may not be used to endorse or
21 * promote products derived from this software without specific prior
22 * written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
27 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
28 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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34 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 *
36 */
37
38 #include <libmemcached/common.h>
39
40 struct bucket_t {
41 uint32_t master;
42 uint32_t forward;
43 };
44
45 struct memcached_virtual_bucket_t {
46 bool has_forward;
47 uint32_t size;
48 uint32_t replicas;
49 struct bucket_t buckets[];
50 };
51
52 memcached_return_t memcached_virtual_bucket_create(memcached_st *self,
53 const uint32_t *host_map,
54 const uint32_t *forward_map,
55 const uint32_t buckets,
56 const uint32_t replicas)
57 {
58 if (! self || ! host_map || ! buckets)
59 {
60 return MEMCACHED_INVALID_ARGUMENTS;
61 }
62
63 memcached_virtual_bucket_free(self);
64
65 struct memcached_virtual_bucket_t *virtual_bucket= (struct memcached_virtual_bucket_t *)malloc(sizeof(struct memcached_virtual_bucket_t) + sizeof(struct bucket_t) *buckets);
66
67 if (virtual_bucket == NULL)
68 {
69 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
70 }
71
72
73 virtual_bucket->size= buckets;
74 virtual_bucket->replicas= replicas;
75 self->virtual_bucket= virtual_bucket;
76
77 uint32_t x= 0;
78 for (; x < buckets; x++)
79 {
80 virtual_bucket->buckets[x].master= host_map[x];
81 if (forward_map)
82 {
83 virtual_bucket->buckets[x].forward= forward_map[x];
84 }
85 else
86 {
87 virtual_bucket->buckets[x].forward= 0;
88 }
89 }
90
91 return MEMCACHED_SUCCESS;
92 }
93
94 void memcached_virtual_bucket_free(memcached_st *self)
95 {
96 if (self == NULL)
97 {
98 return;
99 }
100
101 if (self->virtual_bucket == NULL)
102 {
103 return;
104 }
105
106 free(self->virtual_bucket);
107 self->virtual_bucket= NULL;
108 }
109
110 uint32_t memcached_virtual_bucket_get(const memcached_st *self, uint32_t digest)
111 {
112 if (self == NULL)
113 {
114 return 0;
115 }
116
117 if (self->virtual_bucket == NULL)
118 {
119 return 0;
120 }
121
122 if (self->virtual_bucket)
123 {
124 uint32_t result= (uint32_t) (digest & (self->virtual_bucket->size -1));
125 return self->virtual_bucket->buckets[result].master;
126 }
127
128 return (uint32_t) (digest & (self->number_of_hosts -1));
129 }