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 struct hash_table;
  35
  36 typedef unsigned (*hash_func_t)(const void *key);
  37 typedef int (*hash_compare_func_t)(const void *key1, const void *key2);
  38
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 /**
  44  * Hash table constructor
  45  *
  46  * Creates a hash table with the specified number of buckets.  The supplied
  47  * \c hash and \c compare routines are used when adding elements to the table
  48  * and when searching for elements in the table.
  49  *
  50  * \param num_buckets  Number of buckets (bins) in the hash table.
  51  * \param hash         Function used to compute hash value of input keys.
  52  * \param compare      Function used to compare keys.
  53  */
  54 extern struct hash_table *hash_table_ctor(unsigned num_buckets,
  55     hash_func_t hash, hash_compare_func_t compare);
  56
  57
  58 /**
  59  * Release all memory associated with a hash table
  60  *
  61  * \warning
  62  * This function cannot release memory occupied either by keys or data.
  63  */
  64 extern void hash_table_dtor(struct hash_table *ht);
  65
  66
  67 /**
  68  * Flush all entries from a hash table
  69  *
  70  * \param ht  Table to be cleared of its entries.
  71  */
  72 extern void hash_table_clear(struct hash_table *ht);
  73
  74
  75 /**
  76  * Search a hash table for a specific element
  77  *
  78  * \param ht   Table to be searched
  79  * \param key  Key of the desired element
  80  *
  81  * \return
  82  * The \c data value supplied to \c hash_table_insert when the element with
  83  * the matching key was added.  If no matching key exists in the table,
  84  * \c NULL is returned.
  85  */
  86 extern void *hash_table_find(struct hash_table *ht, const void *key);
  87
  88
  89 /**
  90  * Add an element to a hash table
  91  *
  92  * \warning
  93  * If \c key is already in the hash table, it will be added again.  Future
  94  * calls to \c hash_table_find and \c hash_table_remove will return or remove,
  95  * repsectively, the most recently added instance of \c key.
  96  *
  97  * \sa hash_table_replace
  98  */
  99 extern void hash_table_insert(struct hash_table *ht, void *data,
 100     const void *key);
 101
 102 /**
 103  * Add an element to a hash table with replacement
 104  *
 105  * \warning
 106  * If \c key is already in the hash table, \c data will \b replace the most
 107  * recently inserted \c data (see the warning in \c hash_table_insert) for
 108  * that key.
 109  *
 110  * \sa hash_table_insert
 111  */
 112 extern void hash_table_replace(struct hash_table *ht, void *data,
 113     const void *key);
 114
 115 /**
 116  * Remove a specific element from a hash table.
 117  */
 118 extern void hash_table_remove(struct hash_table *ht, const void *key);
 119
 120 /**
 121  * Compute hash value of a string
 122  *
 123  * Computes the hash value of a string using the DJB2 algorithm developed by
 124  * Professor Daniel J. Bernstein.  It was published on comp.lang.c once upon
 125  * a time.  I was unable to find the original posting in the archives.
 126  *
 127  * \param key  Pointer to a NUL terminated string to be hashed.
 128  *
 129  * \sa hash_table_string_compare
 130  */
 131 extern unsigned hash_table_string_hash(const void *key);
 132
 133
 134 /**
 135  * Compare two strings used as keys
 136  *
 137  * This is just a macro wrapper around \c strcmp.
 138  *
 139  * \sa hash_table_string_hash
 140  */
 141 #define hash_table_string_compare ((hash_compare_func_t) strcmp)
 142
 143
 144 /**
 145  * Compute hash value of a pointer
 146  *
 147  * \param key  Pointer to be used as a hash key
 148  *
 149  * \note
 150  * The memory pointed to by \c key is \b never accessed.  The value of \c key
 151  * itself is used as the hash key
 152  *
 153  * \sa hash_table_pointer_compare
 154  */
 155 unsigned
 156 hash_table_pointer_hash(const void *key);
 157
 158
 159 /**
 160  * Compare two pointers used as keys
 161  *
 162  * \sa hash_table_pointer_hash
 163  */
 164 int
 165 hash_table_pointer_compare(const void *key1, const void *key2);
 166
 167 void
 168 hash_table_call_foreach(struct hash_table *ht,
 169                         void (*callback)(const void *key,
 170                                          void *data,
 171                                          void *closure),
 172                         void *closure);
 173
 174 #ifdef __cplusplus
 175 }
 176 #endif
 177 #endif /* HASH_TABLE_H */