src/mesa/program/hash_table.h

   1 /*
   2  * Copyright © 2008 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
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file hash_table.h
  26  * \brief Implementation of a generic, opaque hash table data type.
  27  *
  28  * \author Ian Romanick <ian.d.romanick@intel.com>
  29  */
  30
  31 #ifndef HASH_TABLE_H
  32 #define HASH_TABLE_H
  33
  34 #include <string.h>
  35
  36 struct hash_table;
  37
  38 typedef unsigned (*hash_func_t)(const void *key);
  39 typedef int (*hash_compare_func_t)(const void *key1, const void *key2);
  40
  41 #ifdef __cplusplus
  42 extern "C" {
  43 #endif
  44
  45 /**
  46  * Hash table constructor
  47  *
  48  * Creates a hash table with the specified number of buckets.  The supplied
  49  * \c hash and \c compare routines are used when adding elements to the table
  50  * and when searching for elements in the table.
  51  *
  52  * \param num_buckets  Number of buckets (bins) in the hash table.
  53  * \param hash         Function used to compute hash value of input keys.
  54  * \param compare      Function used to compare keys.
  55  */
  56 extern struct hash_table *hash_table_ctor(unsigned num_buckets,
  57     hash_func_t hash, hash_compare_func_t compare);
  58
  59
  60 /**
  61  * Release all memory associated with a hash table
  62  *
  63  * \warning
  64  * This function cannot release memory occupied either by keys or data.
  65  */
  66 extern void hash_table_dtor(struct hash_table *ht);
  67
  68
  69 /**
  70  * Flush all entries from a hash table
  71  *
  72  * \param ht  Table to be cleared of its entries.
  73  */
  74 extern void hash_table_clear(struct hash_table *ht);
  75
  76
  77 /**
  78  * Search a hash table for a specific element
  79  *
  80  * \param ht   Table to be searched
  81  * \param key  Key of the desired element
  82  *
  83  * \return
  84  * The \c data value supplied to \c hash_table_insert when the element with
  85  * the matching key was added.  If no matching key exists in the table,
  86  * \c NULL is returned.
  87  */
  88 extern void *hash_table_find(struct hash_table *ht, const void *key);
  89
  90
  91 /**
  92  * Add an element to a hash table
  93  */
  94 extern void hash_table_insert(struct hash_table *ht, void *data,
  95     const void *key);
  96
  97 /**
  98  * Remove a specific element from a hash table.
  99  */
 100 extern void hash_table_remove(struct hash_table *ht, const void *key);
 101
 102 /**
 103  * Compute hash value of a string
 104  *
 105  * Computes the hash value of a string using the DJB2 algorithm developed by
 106  * Professor Daniel J. Bernstein.  It was published on comp.lang.c once upon
 107  * a time.  I was unable to find the original posting in the archives.
 108  *
 109  * \param key  Pointer to a NUL terminated string to be hashed.
 110  *
 111  * \sa hash_table_string_compare
 112  */
 113 extern unsigned hash_table_string_hash(const void *key);
 114
 115
 116 /**
 117  * Compare two strings used as keys
 118  *
 119  * This is just a macro wrapper around \c strcmp.
 120  *
 121  * \sa hash_table_string_hash
 122  */
 123 #define hash_table_string_compare ((hash_compare_func_t) strcmp)
 124
 125
 126 /**
 127  * Compute hash value of a pointer
 128  *
 129  * \param key  Pointer to be used as a hash key
 130  *
 131  * \note
 132  * The memory pointed to by \c key is \b never accessed.  The value of \c key
 133  * itself is used as the hash key
 134  *
 135  * \sa hash_table_pointer_compare
 136  */
 137 unsigned
 138 hash_table_pointer_hash(const void *key);
 139
 140
 141 /**
 142  * Compare two pointers used as keys
 143  *
 144  * \sa hash_table_pointer_hash
 145  */
 146 int
 147 hash_table_pointer_compare(const void *key1, const void *key2);
 148
 149 #ifdef __cplusplus
 150 };
 151 #endif
 152 #endif /* HASH_TABLE_H */