glib/gcache.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 /*
  28  * MT safe
  29  */
  30
  31 #include "config.h"
  32
  33 #include "glib.h"
  34 #include "galias.h"
  35
  36
  37 typedef struct _GCacheNode  GCacheNode;
  38
  39 struct _GCacheNode
  40 {
  41   /* A reference counted node */
  42   gpointer value;
  43   gint ref_count;
  44 };
  45
  46 struct _GCache
  47 {
  48   /* Called to create a value from a key */
  49   GCacheNewFunc value_new_func;
  50
  51   /* Called to destroy a value */
  52   GCacheDestroyFunc value_destroy_func;
  53
  54   /* Called to duplicate a key */
  55   GCacheDupFunc key_dup_func;
  56
  57   /* Called to destroy a key */
  58   GCacheDestroyFunc key_destroy_func;
  59
  60   /* Associates keys with nodes */
  61   GHashTable *key_table;
  62
  63   /* Associates nodes with keys */
  64   GHashTable *value_table;
  65 };
  66
  67 static inline GCacheNode*
  68 g_cache_node_new (gpointer value)
  69 {
  70   GCacheNode *node = g_slice_new (GCacheNode);
  71   node->value = value;
  72   node->ref_count = 1;
  73   return node;
  74 }
  75
  76 static inline void
  77 g_cache_node_destroy (GCacheNode *node)
  78 {
  79   g_slice_free (GCacheNode, node);
  80 }
  81
  82 GCache*
  83 g_cache_new (GCacheNewFunc      value_new_func,
  84              GCacheDestroyFunc  value_destroy_func,
  85              GCacheDupFunc      key_dup_func,
  86              GCacheDestroyFunc  key_destroy_func,
  87              GHashFunc          hash_key_func,
  88              GHashFunc          hash_value_func,
  89              GEqualFunc         key_equal_func)
  90 {
  91   GCache *cache;
  92
  93   g_return_val_if_fail (value_new_func != NULL, NULL);
  94   g_return_val_if_fail (value_destroy_func != NULL, NULL);
  95   g_return_val_if_fail (key_dup_func != NULL, NULL);
  96   g_return_val_if_fail (key_destroy_func != NULL, NULL);
  97   g_return_val_if_fail (hash_key_func != NULL, NULL);
  98   g_return_val_if_fail (hash_value_func != NULL, NULL);
  99   g_return_val_if_fail (key_equal_func != NULL, NULL);
 100
 101   cache = g_slice_new (GCache);
 102   cache->value_new_func = value_new_func;
 103   cache->value_destroy_func = value_destroy_func;
 104   cache->key_dup_func = key_dup_func;
 105   cache->key_destroy_func = key_destroy_func;
 106   cache->key_table = g_hash_table_new (hash_key_func, key_equal_func);
 107   cache->value_table = g_hash_table_new (hash_value_func, NULL);
 108
 109   return cache;
 110 }
 111
 112 void
 113 g_cache_destroy (GCache *cache)
 114 {
 115   g_return_if_fail (cache != NULL);
 116
 117   g_hash_table_destroy (cache->key_table);
 118   g_hash_table_destroy (cache->value_table);
 119   g_slice_free (GCache, cache);
 120 }
 121
 122 gpointer
 123 g_cache_insert (GCache   *cache,
 124                 gpointer  key)
 125 {
 126   GCacheNode *node;
 127   gpointer value;
 128
 129   g_return_val_if_fail (cache != NULL, NULL);
 130
 131   node = g_hash_table_lookup (cache->key_table, key);
 132   if (node)
 133     {
 134       node->ref_count += 1;
 135       return node->value;
 136     }
 137
 138   key = (* cache->key_dup_func) (key);
 139   value = (* cache->value_new_func) (key);
 140   node = g_cache_node_new (value);
 141
 142   g_hash_table_insert (cache->key_table, key, node);
 143   g_hash_table_insert (cache->value_table, value, key);
 144
 145   return node->value;
 146 }
 147
 148 void
 149 g_cache_remove (GCache        *cache,
 150                 gconstpointer  value)
 151 {
 152   GCacheNode *node;
 153   gpointer key;
 154
 155   g_return_if_fail (cache != NULL);
 156
 157   key = g_hash_table_lookup (cache->value_table, value);
 158   node = g_hash_table_lookup (cache->key_table, key);
 159
 160   g_return_if_fail (node != NULL);
 161
 162   node->ref_count -= 1;
 163   if (node->ref_count == 0)
 164     {
 165       g_hash_table_remove (cache->value_table, value);
 166       g_hash_table_remove (cache->key_table, key);
 167
 168       (* cache->key_destroy_func) (key);
 169       (* cache->value_destroy_func) (node->value);
 170       g_cache_node_destroy (node);
 171     }
 172 }
 173
 174 void
 175 g_cache_key_foreach (GCache   *cache,
 176                      GHFunc    func,
 177                      gpointer  user_data)
 178 {
 179   g_return_if_fail (cache != NULL);
 180   g_return_if_fail (func != NULL);
 181
 182   g_hash_table_foreach (cache->value_table, func, user_data);
 183 }
 184
 185 void
 186 g_cache_value_foreach (GCache   *cache,
 187                        GHFunc    func,
 188                        gpointer  user_data)
 189 {
 190   g_return_if_fail (cache != NULL);
 191   g_return_if_fail (func != NULL);
 192
 193   g_hash_table_foreach (cache->key_table, func, user_data);
 194 }
 195
 196 #define __G_CACHE_C__
 197 #include "galiasdef.c"