src/gallium/auxiliary/cso_cache/cso_hash.h

   1 /**************************************************************************
   2  *
   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
  73 struct cso_hash *cso_hash_create(void);
  74 void             cso_hash_delete(struct cso_hash *hash);
  75
  76
  77 int              cso_hash_size(struct cso_hash *hash);
  78
  79
  80 /**
  81  * Adds a data with the given key to the hash. If entry with the given
  82  * key is already in the hash, this current entry is instered before it
  83  * in the collision list.
  84  * Function returns iterator pointing to the inserted item in the hash.
  85  */
  86 struct cso_hash_iter cso_hash_insert(struct cso_hash *hash, unsigned key,
  87                                      void *data);
  88 /**
  89  * Removes the item pointed to by the current iterator from the hash.
  90  * Note that the data itself is not erased and if it was a malloc'ed pointer
  91  * it will have to be freed after calling this function by the callee.
  92  * Function returns iterator pointing to the item after the removed one in
  93  * the hash.
  94  */
  95 struct cso_hash_iter cso_hash_erase(struct cso_hash *hash, struct cso_hash_iter iter);
  96
  97 void  *cso_hash_take(struct cso_hash *hash, unsigned key);
  98
  99
 100
 101 struct cso_hash_iter cso_hash_first_node(struct cso_hash *hash);
 102
 103 /**
 104  * Return an iterator pointing to the first entry in the collision list.
 105  */
 106 struct cso_hash_iter cso_hash_find(struct cso_hash *hash, unsigned key);
 107
 108 /**
 109  * Returns true if a value with the given key exists in the hash
 110  */
 111 boolean   cso_hash_contains(struct cso_hash *hash, unsigned key);
 112
 113
 114 unsigned  cso_hash_iter_key(struct cso_hash_iter iter);
 115
 116
 117 struct cso_hash_iter cso_hash_iter_next(struct cso_hash_iter iter);
 118 struct cso_hash_iter cso_hash_iter_prev(struct cso_hash_iter iter);
 119
 120
 121 /**
 122  * Convenience routine to iterate over the collision list while doing a memory
 123  * comparison to see which entry in the list is a direct copy of our template
 124  * and returns that entry.
 125  */
 126 void *cso_hash_find_data_from_template( struct cso_hash *hash,
 127                                         unsigned hash_key,
 128                                         void *templ,
 129                                         int size );
 130
 131 static inline int
 132 cso_hash_iter_is_null(struct cso_hash_iter iter)
 133 {
 134    if (!iter.node || iter.node == iter.hash->data.e)
 135       return 1;
 136    return 0;
 137 }
 138
 139 static inline void *
 140 cso_hash_iter_data(struct cso_hash_iter iter)
 141 {
 142    if (!iter.node || iter.hash->data.e == iter.node)
 143       return 0;
 144    return iter.node->value;
 145 }
 146
 147 #ifdef  __cplusplus
 148 }
 149 #endif
 150
 151 #endif