Merge up for version.
[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,
29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
34 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 *
36 */
37
38 #include <config.h>
39 #include <libmemcached/memcached.h>
40 #include <libmemcached/virtual_bucket.h>
41
42 struct bucket_t {
43 uint32_t master;
44 uint32_t forward;
45 };
46
47 struct memcached_virtual_bucket_t {
48 bool has_forward;
49 uint32_t size;
50 uint32_t replicas;
51 struct bucket_t buckets[];
52 };
53
54 memcached_return_t memcached_virtual_bucket_create(memcached_st *self,
55 const uint32_t *host_map,
56 const uint32_t *forward_map,
57 const uint32_t buckets,
58 const uint32_t replicas)
59 {
60 if (! self || ! host_map || ! buckets)
61 return MEMCACHED_INVALID_ARGUMENTS;
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)
68 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
69
70 virtual_bucket->size= buckets;
71 virtual_bucket->replicas= replicas;
72 self->virtual_bucket= virtual_bucket;
73
74 for (uint32_t x=0; x < buckets; x++)
75 {
76 virtual_bucket->buckets[x].master= host_map[x];
77 if (forward_map)
78 {
79 virtual_bucket->buckets[x].forward= forward_map[x];
80 }
81 else
82 {
83 virtual_bucket->buckets[x].forward= 0;
84 }
85 }
86
87
88 return MEMCACHED_SUCCESS;
89 }
90
91 void memcached_virtual_bucket_free(memcached_st *self)
92 {
93 if (! self)
94 return;
95
96 if (! self->virtual_bucket)
97 return;
98
99 free(self->virtual_bucket);
100 self->virtual_bucket= NULL;
101 }
102
103 uint32_t memcached_virtual_bucket_get(const memcached_st *self, uint32_t digest)
104 {
105 if (! self)
106 return 0;
107
108 if (! self->virtual_bucket)
109 return 0;
110
111 if (self->virtual_bucket)
112 {
113 uint32_t result= (uint32_t) (digest & (self->virtual_bucket->size -1));
114 return self->virtual_bucket->buckets[result].master;
115 }
116
117 return (uint32_t) (digest & (self->number_of_hosts -1));
118 }