src/gallium/auxiliary/cso_cache/cso_hash.h

   1 /**************************************************************************
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   3  * Copyright 2007 VMware, Inc.
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  11  * permit persons to whom the Software is furnished to do so, subject to
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  16  * of the Software.
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  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    int nodeSize;
  77    short userNumBits;
  78    short numBits;
  79    int numBuckets;
  80 };
  81
  82 struct cso_hash *cso_hash_create(void);
  83 void             cso_hash_delete(struct cso_hash *hash);
  84
  85
  86 int              cso_hash_size(struct cso_hash *hash);
  87
  88
  89 /**
  90  * Adds a data with the given key to the hash. If entry with the given
  91  * key is already in the hash, this current entry is instered before it
  92  * in the collision list.
  93  * Function returns iterator pointing to the inserted item in the hash.
  94  */
  95 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash, unsigned key,
  96                                      void *data);
  97 /**
  98  * Removes the item pointed to by the current iterator from the hash.
  99  * Note that the data itself is not erased and if it was a malloc'ed pointer
 100  * it will have to be freed after calling this function by the callee.
 101  * Function returns iterator pointing to the item after the removed one in
 102  * the hash.
 103  */
 104 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter);
 105
 106 void  *cso_hash_take(struct cso_hash *hash, unsigned key);
 107
 108
 109
 110 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash);
 111
 112 /**
 113  * Returns true if a value with the given key exists in the hash
 114  */
 115 boolean   cso_hash_contains(struct cso_hash *hash, unsigned key);
 116
 117
 118 unsigned  cso_hash_iter_key(struct cso_hash_iter iter);
 119
 120
 121 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter);
 122
 123
 124 /**
 125  * Convenience routine to iterate over the collision list while doing a memory
 126  * comparison to see which entry in the list is a direct copy of our template
 127  * and returns that entry.
 128  */
 129 void *cso_hash_find_data_from_template( struct cso_hash *hash,
 130                                         unsigned hash_key,
 131                                         void *templ,
 132                                         int size );
 133
 134 struct cso_node *cso_hash_data_next(struct cso_node *node);
 135
 136 static inline int
 137 cso_hash_iter_is_null(struct cso_hash_iter iter)
 138 {
 139    if (!iter.node || iter.node == iter.hash->data.e)
 140       return 1;
 141    return 0;
 142 }
 143
 144 static inline void *
 145 cso_hash_iter_data(struct cso_hash_iter iter)
 146 {
 147    if (!iter.node || iter.hash->data.e == iter.node)
 148       return 0;
 149    return iter.node->value;
 150 }
 151
 152 static inline struct cso_node **
 153 cso_hash_find_node(struct cso_hash *hash, unsigned akey)
 154 {
 155    struct cso_node **node;
 156
 157    if (hash->data.d->numBuckets) {
 158       node = (struct cso_node **)(&hash->data.d->buckets[akey % hash->data.d->numBuckets]);
 159       assert(*node == hash->data.e || (*node)->next);
 160       while (*node != hash->data.e && (*node)->key != akey)
 161          node = &(*node)->next;
 162    } else {
 163       node = (struct cso_node **)((const struct cso_node * const *)(&hash->data.e));
 164    }
 165    return node;
 166 }
 167
 168 /**
 169  * Return an iterator pointing to the first entry in the collision list.
 170  */
 171 static inline struct cso_hash_iter
 172 cso_hash_find(struct cso_hash *hash, unsigned key)
 173 {
 174    struct cso_node **nextNode = cso_hash_find_node(hash, key);
 175    struct cso_hash_iter iter = {hash, *nextNode};
 176    return iter;
 177 }
 178
 179 static inline struct cso_hash_iter
 180 cso_hash_iter_next(struct cso_hash_iter iter)
 181 {
 182    struct cso_hash_iter next = {iter.hash, cso_hash_data_next(iter.node)};
 183    return next;
 184 }
 185
 186 #ifdef  __cplusplus
 187 }
 188 #endif
 189
 190 #endif