1 /************************************************************************** 2 * 3 * Copyright 2008 VMware, Inc. 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. 21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR 22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 **************************************************************************/ 27 28 /** 29 * @file 30 * Generic handle table implementation. 31 * 32 * @author Jos Fonseca <jfonseca (at) vmware.com> 33 */ 34 35 36 #include "pipe/p_compiler.h" 37 #include "util/u_debug.h" 38 39 #include "util/u_memory.h" 40 #include "util/u_handle_table.h" 41 42 43 #define HANDLE_TABLE_INITIAL_SIZE 16 44 45 46 struct handle_table 47 { 48 /** Object array. Empty handles have a null object */ 49 void **objects; 50 51 /** Number of objects the handle can currently hold */ 52 unsigned size; 53 /** Number of consecutive objects allocated at the start of the table */ 54 unsigned filled; 55 56 /** Optional object destructor */ 57 void (*destroy)(void *object); 58 }; 59 60 61 struct handle_table * 62 handle_table_create(void) 63 { 64 struct handle_table *ht; 65 66 ht = MALLOC_STRUCT(handle_table); 67 if (!ht) 68 return NULL; 69 70 ht->objects = (void **)CALLOC(HANDLE_TABLE_INITIAL_SIZE, sizeof(void *)); 71 if(!ht->objects) { 72 FREE(ht); 73 return NULL; 74 } 75 76 ht->size = HANDLE_TABLE_INITIAL_SIZE; 77 ht->filled = 0; 78 79 ht->destroy = NULL; 80 81 return ht; 82 } 83 84 85 void 86 handle_table_set_destroy(struct handle_table *ht, 87 void (*destroy)(void *object)) 88 { 89 assert(ht); 90 if (!ht) 91 return; 92 ht->destroy = destroy; 93 } 94 95 96 /** 97 * Resize the table if necessary 98 */ 99 static inline int 100 handle_table_resize(struct handle_table *ht, 101 unsigned minimum_size) 102 { 103 unsigned new_size; 104 void **new_objects; 105 106 if(ht->size > minimum_size) 107 return ht->size; 108 109 new_size = ht->size; 110 while(!(new_size > minimum_size)) 111 new_size *= 2; 112 assert(new_size); 113 114 new_objects = (void **)REALLOC((void *)ht->objects, 115 ht->size*sizeof(void *), 116 new_size*sizeof(void *)); 117 if (!new_objects) 118 return 0; 119 120 memset(new_objects + ht->size, 0, (new_size - ht->size)*sizeof(void *)); 121 122 ht->size = new_size; 123 ht->objects = new_objects; 124 125 return ht->size; 126 } 127 128 129 static inline void 130 handle_table_clear(struct handle_table *ht, 131 unsigned index) 132 { 133 void *object; 134 135 /* The order here is important so that the object being destroyed is not 136 * present in the table when seen by the destroy callback, because the 137 * destroy callback may directly or indirectly call the other functions in 138 * this module. 139 */ 140 141 object = ht->objects[index]; 142 if (object) { 143 ht->objects[index] = NULL; 144 145 if(ht->destroy) 146 ht->destroy(object); 147 } 148 } 149 150 151 unsigned 152 handle_table_add(struct handle_table *ht, 153 void *object) 154 { 155 unsigned index; 156 unsigned handle; 157 158 assert(ht); 159 assert(object); 160 if(!object || !ht) 161 return 0; 162 163 /* linear search for an empty handle */ 164 while(ht->filled < ht->size) { 165 if(!ht->objects[ht->filled]) 166 break; 167 ++ht->filled; 168 } 169 170 index = ht->filled; 171 handle = index + 1; 172 173 /* check integer overflow */ 174 if(!handle) 175 return 0; 176 177 /* grow the table if necessary */ 178 if(!handle_table_resize(ht, index)) 179 return 0; 180 181 assert(!ht->objects[index]); 182 ht->objects[index] = object; 183 ++ht->filled; 184 185 return handle; 186 } 187 188 189 unsigned 190 handle_table_set(struct handle_table *ht, 191 unsigned handle, 192 void *object) 193 { 194 unsigned index; 195 196 assert(ht); 197 assert(handle); 198 if(!handle || !ht) 199 return 0; 200 201 assert(object); 202 if (!object) 203 return 0; 204 205 index = handle - 1; 206 207 /* grow the table if necessary */ 208 if(!handle_table_resize(ht, index)) 209 return 0; 210 211 handle_table_clear(ht, index); 212 213 ht->objects[index] = object; 214 215 return handle; 216 } 217 218 219 void * 220 handle_table_get(struct handle_table *ht, 221 unsigned handle) 222 { 223 void *object; 224 225 assert(ht); 226 assert(handle); 227 if(!handle || !ht || handle > ht->size) 228 return NULL; 229 230 object = ht->objects[handle - 1]; 231 232 return object; 233 } 234 235 236 void 237 handle_table_remove(struct handle_table *ht, 238 unsigned handle) 239 { 240 void *object; 241 unsigned index; 242 243 assert(ht); 244 assert(handle); 245 if(!handle || !ht || handle > ht->size) 246 return; 247 248 index = handle - 1; 249 object = ht->objects[index]; 250 if (!object) 251 return; 252 253 handle_table_clear(ht, index); 254 255 if(index < ht->filled) 256 ht->filled = index; 257 } 258 259 260 unsigned 261 handle_table_get_next_handle(struct handle_table *ht, 262 unsigned handle) 263 { 264 unsigned index; 265 266 for(index = handle; index < ht->size; ++index) { 267 if(ht->objects[index]) 268 return index + 1; 269 } 270 271 return 0; 272 } 273 274 275 unsigned 276 handle_table_get_first_handle(struct handle_table *ht) 277 { 278 return handle_table_get_next_handle(ht, 0); 279 } 280 281 282 void 283 handle_table_destroy(struct handle_table *ht) 284 { 285 unsigned index; 286 assert(ht); 287 288 if (!ht) 289 return; 290 291 if(ht->destroy) 292 for(index = 0; index < ht->size; ++index) 293 handle_table_clear(ht, index); 294 295 FREE(ht->objects); 296 FREE(ht); 297 } 298 299
