release/src/router/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 Library 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  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library 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 1997-1999.  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 "glib.h"
  32
  33
  34 typedef struct _GCacheNode  GCacheNode;
  35 typedef struct _GRealCache  GRealCache;
  36
  37 struct _GCacheNode
  38 {
  39   /* A reference counted node */
  40   gpointer value;
  41   gint ref_count;
  42 };
  43
  44 struct _GRealCache
  45 {
  46   /* Called to create a value from a key */
  47   GCacheNewFunc value_new_func;
  48
  49   /* Called to destroy a value */
  50   GCacheDestroyFunc value_destroy_func;
  51
  52   /* Called to duplicate a key */
  53   GCacheDupFunc key_dup_func;
  54
  55   /* Called to destroy a key */
  56   GCacheDestroyFunc key_destroy_func;
  57
  58   /* Associates keys with nodes */
  59   GHashTable *key_table;
  60
  61   /* Associates nodes with keys */
  62   GHashTable *value_table;
  63 };
  64
  65
  66 static GCacheNode* g_cache_node_new     (gpointer value);
  67 static void        g_cache_node_destroy (GCacheNode *node);
  68
  69
  70 static GMemChunk *node_mem_chunk = NULL;
  71 G_LOCK_DEFINE_STATIC (node_mem_chunk);
  72
  73 GCache*
  74 g_cache_new (GCacheNewFunc      value_new_func,
  75              GCacheDestroyFunc  value_destroy_func,
  76              GCacheDupFunc      key_dup_func,
  77              GCacheDestroyFunc  key_destroy_func,
  78              GHashFunc          hash_key_func,
  79              GHashFunc          hash_value_func,
  80              GCompareFunc       key_compare_func)
  81 {
  82   GRealCache *cache;
  83
  84   g_return_val_if_fail (value_new_func != NULL, NULL);
  85   g_return_val_if_fail (value_destroy_func != NULL, NULL);
  86   g_return_val_if_fail (key_dup_func != NULL, NULL);
  87   g_return_val_if_fail (key_destroy_func != NULL, NULL);
  88   g_return_val_if_fail (hash_key_func != NULL, NULL);
  89   g_return_val_if_fail (hash_value_func != NULL, NULL);
  90   g_return_val_if_fail (key_compare_func != NULL, NULL);
  91
  92   cache = g_new (GRealCache, 1);
  93   cache->value_new_func = value_new_func;
  94   cache->value_destroy_func = value_destroy_func;
  95   cache->key_dup_func = key_dup_func;
  96   cache->key_destroy_func = key_destroy_func;
  97   cache->key_table = g_hash_table_new (hash_key_func, key_compare_func);
  98   cache->value_table = g_hash_table_new (hash_value_func, NULL);
  99
 100   return (GCache*) cache;
 101 }
 102
 103 void
 104 g_cache_destroy (GCache *cache)
 105 {
 106   GRealCache *rcache;
 107
 108   g_return_if_fail (cache != NULL);
 109
 110   rcache = (GRealCache*) cache;
 111   g_hash_table_destroy (rcache->key_table);
 112   g_hash_table_destroy (rcache->value_table);
 113   g_free (rcache);
 114 }
 115
 116 gpointer
 117 g_cache_insert (GCache   *cache,
 118                 gpointer  key)
 119 {
 120   GRealCache *rcache;
 121   GCacheNode *node;
 122   gpointer value;
 123
 124   g_return_val_if_fail (cache != NULL, NULL);
 125
 126   rcache = (GRealCache*) cache;
 127
 128   node = g_hash_table_lookup (rcache->key_table, key);
 129   if (node)
 130     {
 131       node->ref_count += 1;
 132       return node->value;
 133     }
 134
 135   key = (* rcache->key_dup_func) (key);
 136   value = (* rcache->value_new_func) (key);
 137   node = g_cache_node_new (value);
 138
 139   g_hash_table_insert (rcache->key_table, key, node);
 140   g_hash_table_insert (rcache->value_table, value, key);
 141
 142   return node->value;
 143 }
 144
 145 void
 146 g_cache_remove (GCache   *cache,
 147                 gpointer  value)
 148 {
 149   GRealCache *rcache;
 150   GCacheNode *node;
 151   gpointer key;
 152
 153   g_return_if_fail (cache != NULL);
 154
 155   rcache = (GRealCache*) cache;
 156
 157   key = g_hash_table_lookup (rcache->value_table, value);
 158   node = g_hash_table_lookup (rcache->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 (rcache->value_table, value);
 166       g_hash_table_remove (rcache->key_table, key);
 167
 168       (* rcache->key_destroy_func) (key);
 169       (* rcache->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   GRealCache *rcache;
 180
 181   g_return_if_fail (cache != NULL);
 182   g_return_if_fail (func != NULL);
 183
 184   rcache = (GRealCache*) cache;
 185
 186   g_hash_table_foreach (rcache->value_table, func, user_data);
 187 }
 188
 189 void
 190 g_cache_value_foreach (GCache   *cache,
 191                        GHFunc    func,
 192                        gpointer  user_data)
 193 {
 194   GRealCache *rcache;
 195
 196   g_return_if_fail (cache != NULL);
 197   g_return_if_fail (func != NULL);
 198
 199   rcache = (GRealCache*) cache;
 200
 201   g_hash_table_foreach (rcache->key_table, func, user_data);
 202 }
 203
 204
 205 static GCacheNode*
 206 g_cache_node_new (gpointer value)
 207 {
 208   GCacheNode *node;
 209
 210   G_LOCK (node_mem_chunk);
 211   if (!node_mem_chunk)
 212     node_mem_chunk = g_mem_chunk_new ("cache node mem chunk", sizeof (GCacheNode),
 213                                       1024, G_ALLOC_AND_FREE);
 214
 215   node = g_chunk_new (GCacheNode, node_mem_chunk);
 216   G_UNLOCK (node_mem_chunk);
 217
 218   node->value = value;
 219   node->ref_count = 1;
 220
 221   return node;
 222 }
 223
 224 static void
 225 g_cache_node_destroy (GCacheNode *node)
 226 {
 227   G_LOCK (node_mem_chunk);
 228   g_mem_chunk_free (node_mem_chunk, node);
 229   G_UNLOCK (node_mem_chunk);
 230 }