src/util/hash_table.h

   1 /*
   2  * Copyright © 2009,2012 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27
  28 #ifndef _HASH_TABLE_H
  29 #define _HASH_TABLE_H
  30
  31 #include <stdlib.h>
  32 #include <inttypes.h>
  33 #include <stdbool.h>
  34 #include "c99_compat.h"
  35 #include "macros.h"
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 struct hash_entry {
  42    uint32_t hash;
  43    const void *key;
  44    void *data;
  45 };
  46
  47 struct hash_table {
  48    struct hash_entry *table;
  49    uint32_t (*key_hash_function)(const void *key);
  50    bool (*key_equals_function)(const void *a, const void *b);
  51    const void *deleted_key;
  52    uint32_t size;
  53    uint32_t rehash;
  54    uint32_t max_entries;
  55    uint32_t size_index;
  56    uint32_t entries;
  57    uint32_t deleted_entries;
  58 };
  59
  60 struct hash_table *
  61 _mesa_hash_table_create(void *mem_ctx,
  62                         uint32_t (*key_hash_function)(const void *key),
  63                         bool (*key_equals_function)(const void *a,
  64                                                     const void *b));
  65 void _mesa_hash_table_destroy(struct hash_table *ht,
  66                               void (*delete_function)(struct hash_entry *entry));
  67 void _mesa_hash_table_set_deleted_key(struct hash_table *ht,
  68                                       const void *deleted_key);
  69
  70 struct hash_entry *
  71 _mesa_hash_table_insert(struct hash_table *ht, const void *key, void *data);
  72 struct hash_entry *
  73 _mesa_hash_table_insert_pre_hashed(struct hash_table *ht, uint32_t hash,
  74                                    const void *key, void *data);
  75 struct hash_entry *
  76 _mesa_hash_table_search(struct hash_table *ht, const void *key);
  77 struct hash_entry *
  78 _mesa_hash_table_search_pre_hashed(struct hash_table *ht, uint32_t hash,
  79                                   const void *key);
  80 void _mesa_hash_table_remove(struct hash_table *ht,
  81                              struct hash_entry *entry);
  82
  83 struct hash_entry *_mesa_hash_table_next_entry(struct hash_table *ht,
  84                                                struct hash_entry *entry);
  85 struct hash_entry *
  86 _mesa_hash_table_random_entry(struct hash_table *ht,
  87                               bool (*predicate)(struct hash_entry *entry));
  88
  89 uint32_t _mesa_hash_data(const void *data, size_t size);
  90 uint32_t _mesa_hash_string(const char *key);
  91 bool _mesa_key_string_equal(const void *a, const void *b);
  92 bool _mesa_key_pointer_equal(const void *a, const void *b);
  93
  94 static inline uint32_t _mesa_key_hash_string(const void *key)
  95 {
  96    return _mesa_hash_string((const char *)key);
  97 }
  98
  99 static inline uint32_t _mesa_hash_pointer(const void *pointer)
 100 {
 101    return _mesa_hash_data(&pointer, sizeof(pointer));
 102 }
 103
 104 static const uint32_t _mesa_fnv32_1a_offset_bias = 2166136261u;
 105
 106 static inline uint32_t
 107 _mesa_fnv32_1a_accumulate_block(uint32_t hash, const void *data, size_t size)
 108 {
 109    const uint8_t *bytes = (const uint8_t *)data;
 110
 111    while (size-- != 0) {
 112       hash ^= *bytes;
 113       hash = hash * 0x01000193;
 114       bytes++;
 115    }
 116
 117    return hash;
 118 }
 119
 120 #define _mesa_fnv32_1a_accumulate(hash, expr) \
 121    _mesa_fnv32_1a_accumulate_block(hash, &(expr), sizeof(expr))
 122
 123 /**
 124  * This foreach function is safe against deletion (which just replaces
 125  * an entry's data with the deleted marker), but not against insertion
 126  * (which may rehash the table, making entry a dangling pointer).
 127  */
 128 #define hash_table_foreach(ht, entry)                   \
 129    for (entry = _mesa_hash_table_next_entry(ht, NULL);  \
 130         entry != NULL;                                  \
 131         entry = _mesa_hash_table_next_entry(ht, entry))
 132
 133 #ifdef __cplusplus
 134 } /* extern C */
 135 #endif
 136
 137 #endif /* _HASH_TABLE_H */