src/gallium/auxiliary/cso_cache/cso_hash.h

   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    unsigned key;
  57    void *value;
  58 };
  59
  60 struct cso_hash {
  61    union {
  62       struct cso_hash_data *d;
  63       struct cso_node      *e;
  64    } data;
  65 };
  66
  67 struct cso_hash_iter {
  68    struct cso_hash *hash;
  69    struct cso_node  *node;
  70 };
  71
  72 struct cso_hash_data {
  73    struct cso_node *fakeNext;
  74    struct cso_node **buckets;
  75    int size;
  76    short userNumBits;
  77    short numBits;
  78    int numBuckets;
  79 };
  80
  81 bool cso_hash_init(struct cso_hash *hash);
  82 void cso_hash_deinit(struct cso_hash *hash);
  83
  84
  85 int              cso_hash_size(struct cso_hash *hash);
  86
  87
  88 /**
  89  * Adds a data with the given key to the hash. If entry with the given
  90  * key is already in the hash, this current entry is instered before it
  91  * in the collision list.
  92  * Function returns iterator pointing to the inserted item in the hash.
  93  */
  94 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash, unsigned key,
  95                                      void *data);
  96 /**
  97  * Removes the item pointed to by the current iterator from the hash.
  98  * Note that the data itself is not erased and if it was a malloc'ed pointer
  99  * it will have to be freed after calling this function by the callee.
 100  * Function returns iterator pointing to the item after the removed one in
 101  * the hash.
 102  */
 103 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter);
 104
 105 void  *cso_hash_take(struct cso_hash *hash, unsigned key);
 106
 107
 108
 109 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash);
 110
 111 /**
 112  * Returns true if a value with the given key exists in the hash
 113  */
 114 boolean   cso_hash_contains(struct cso_hash *hash, unsigned key);
 115
 116
 117 unsigned  cso_hash_iter_key(struct cso_hash_iter iter);
 118
 119
 120 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter);
 121
 122
 123 /**
 124  * Convenience routine to iterate over the collision list while doing a memory
 125  * comparison to see which entry in the list is a direct copy of our template
 126  * and returns that entry.
 127  */
 128 void *cso_hash_find_data_from_template( struct cso_hash *hash,
 129                                         unsigned hash_key,
 130                                         void *templ,
 131                                         int size );
 132
 133 struct cso_node *cso_hash_data_next(struct cso_node *node);
 134
 135 static inline int
 136 cso_hash_iter_is_null(struct cso_hash_iter iter)
 137 {
 138    if (!iter.node || iter.node == iter.hash->data.e)
 139       return 1;
 140    return 0;
 141 }
 142
 143 static inline void *
 144 cso_hash_iter_data(struct cso_hash_iter iter)
 145 {
 146    if (!iter.node || iter.hash->data.e == iter.node)
 147       return 0;
 148    return iter.node->value;
 149 }
 150
 151 static inline struct cso_node **
 152 cso_hash_find_node(struct cso_hash *hash, unsigned akey)
 153 {
 154    struct cso_node **node;
 155
 156    if (hash->data.d->numBuckets) {
 157       node = (struct cso_node **)(&hash->data.d->buckets[akey % hash->data.d->numBuckets]);
 158       assert(*node == hash->data.e || (*node)->next);
 159       while (*node != hash->data.e && (*node)->key != akey)
 160          node = &(*node)->next;
 161    } else {
 162       node = (struct cso_node **)((const struct cso_node * const *)(&hash->data.e));
 163    }
 164    return node;
 165 }
 166
 167 /**
 168  * Return an iterator pointing to the first entry in the collision list.
 169  */
 170 static inline struct cso_hash_iter
 171 cso_hash_find(struct cso_hash *hash, unsigned key)
 172 {
 173    struct cso_node **nextNode = cso_hash_find_node(hash, key);
 174    struct cso_hash_iter iter = {hash, *nextNode};
 175    return iter;
 176 }
 177
 178 static inline struct cso_hash_iter
 179 cso_hash_iter_next(struct cso_hash_iter iter)
 180 {
 181    struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
 182    return next;
 183 }
 184
 185 #ifdef  __cplusplus
 186 }
 187 #endif
 188
 189 #endif