1 /**************************************************************************
2 *
3 * Copyright 2007 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 /**
29 * @file
30 * Hash table implementation.
31 *
32 * This file provides a hash implementation that is capable of dealing
33 * with collisions. It stores colliding entries in linked list. All
34 * functions operating on the hash return an iterator. The iterator
35 * itself points to the collision list. If there wasn't any collision
36 * the list will have just one entry, otherwise client code should
37 * iterate over the entries to find the exact entry among ones that
38 * had the same key (e.g. memcmp could be used on the data to check
39 * that)
40 *
41 * @author Zack Rusin <zackr@vmware.com>
42 */
43
44 #ifndef CSO_HASH_H
45 #define CSO_HASH_H
46
47 #include "pipe/p_compiler.h"
48
49 #ifdef __cplusplus
50 extern "C" {
51 #endif
52
53
54 struct cso_node {
55 struct cso_node *next;
56 void *value;
57 unsigned key;
58 };
59
60 struct cso_hash_iter {
61 struct cso_hash *hash;
62 struct cso_node *node;
63 };
64
65 struct cso_hash {
66 struct cso_node *fakeNext;
67 struct cso_node **buckets;
68 struct cso_node *end;
69 int size;
70 short userNumBits;
71 short numBits;
72 int numBuckets;
73 };
74
75 void cso_hash_init(struct cso_hash *hash);
76 void cso_hash_deinit(struct cso_hash *hash);
77
78
79 int cso_hash_size(struct cso_hash *hash);
80
81
82 /**
83 * Adds a data with the given key to the hash. If entry with the given
84 * key is already in the hash, this current entry is instered before it
85 * in the collision list.
86 * Function returns iterator pointing to the inserted item in the hash.
87 */
88 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash, unsigned key,
89 void *data);
90 /**
91 * Removes the item pointed to by the current iterator from the hash.
92 * Note that the data itself is not erased and if it was a malloc'ed pointer
93 * it will have to be freed after calling this function by the callee.
94 * Function returns iterator pointing to the item after the removed one in
95 * the hash.
96 */
97 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter);
98
99 void *cso_hash_take(struct cso_hash *hash, unsigned key);
100
101
102
103 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash);
104
105 /**
106 * Returns true if a value with the given key exists in the hash
107 */
108 bool cso_hash_contains(struct cso_hash *hash, unsigned key);
109
110
111 unsigned cso_hash_iter_key(struct cso_hash_iter iter);
112
113
114 /**
115 * Convenience routine to iterate over the collision list while doing a memory
116 * comparison to see which entry in the list is a direct copy of our template
117 * and returns that entry.
118 */
119 void *cso_hash_find_data_from_template(struct cso_hash *hash,
120 unsigned hash_key,
121 void *templ,
122 int size);
123
124 struct cso_node *cso_hash_data_next(struct cso_node *node);
125
126 static inline bool
cso_hash_iter_is_null(struct cso_hash_iter iter)127 cso_hash_iter_is_null(struct cso_hash_iter iter)
128 {
129 return !iter.node || iter.node == iter.hash->end;
130 }
131
132 static inline void *
cso_hash_iter_data(struct cso_hash_iter iter)133 cso_hash_iter_data(struct cso_hash_iter iter)
134 {
135 if (!iter.node || iter.hash->end == iter.node)
136 return NULL;
137 return iter.node->value;
138 }
139
140 static inline struct cso_node **
cso_hash_find_node(struct cso_hash * hash,unsigned akey)141 cso_hash_find_node(struct cso_hash *hash, unsigned akey)
142 {
143 struct cso_node **node;
144
145 if (hash->numBuckets) {
146 node = &hash->buckets[akey % hash->numBuckets];
147 assert(*node == hash->end || (*node)->next);
148 while (*node != hash->end && (*node)->key != akey)
149 node = &(*node)->next;
150 } else {
151 node = &hash->end;
152 }
153 return node;
154 }
155
156 /**
157 * Return an iterator pointing to the first entry in the collision list.
158 */
159 static inline struct cso_hash_iter
cso_hash_find(struct cso_hash * hash,unsigned key)160 cso_hash_find(struct cso_hash *hash, unsigned key)
161 {
162 struct cso_node **nextNode = cso_hash_find_node(hash, key);
163 struct cso_hash_iter iter = {hash, *nextNode};
164 return iter;
165 }
166
167 static inline struct cso_hash_iter
cso_hash_iter_next(struct cso_hash_iter iter)168 cso_hash_iter_next(struct cso_hash_iter iter)
169 {
170 struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
171 return next;
172 }
173
174 #ifdef __cplusplus
175 }
176 #endif
177
178 #endif
179