src/mesa/main/hash.c

   1 /**
   2  * \file hash.c
   3  * Generic hash table.
   4  *
   5  * Used for display lists, texture objects, vertex/fragment programs,
   6  * buffer objects, etc.  The hash functions are thread-safe.
   7  *
   8  * \note key=0 is illegal.
   9  *
  10  * \author Brian Paul
  11  */
  12
  13 /*
  14  * Mesa 3-D graphics library
  15  *
  16  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
  17  *
  18  * Permission is hereby granted, free of charge, to any person obtaining a
  19  * copy of this software and associated documentation files (the "Software"),
  20  * to deal in the Software without restriction, including without limitation
  21  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  22  * and/or sell copies of the Software, and to permit persons to whom the
  23  * Software is furnished to do so, subject to the following conditions:
  24  *
  25  * The above copyright notice and this permission notice shall be included
  26  * in all copies or substantial portions of the Software.
  27  *
  28  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  29  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  30  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  31  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  32  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  33  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  34  * OTHER DEALINGS IN THE SOFTWARE.
  35  */
  36
  37 #include "errors.h"
  38 #include "glheader.h"
  39 #include "hash.h"
  40 #include "util/hash_table.h"
  41
  42
  43 /**
  44  * Create a new hash table.
  45  *
  46  * \return pointer to a new, empty hash table.
  47  */
  48 struct _mesa_HashTable *
  49 _mesa_NewHashTable(void)
  50 {
  51    struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable);
  52
  53    if (table) {
  54       table->ht = _mesa_hash_table_create(NULL, uint_key_hash,
  55                                           uint_key_compare);
  56       if (table->ht == NULL) {
  57          free(table);
  58          _mesa_error_no_memory(__func__);
  59          return NULL;
  60       }
  61
  62       _mesa_hash_table_set_deleted_key(table->ht, uint_key(DELETED_KEY_VALUE));
  63       /*
  64        * Needs to be recursive, since the callback in _mesa_HashWalk()
  65        * is allowed to call _mesa_HashRemove().
  66        */
  67       mtx_init(&table->Mutex, mtx_recursive);
  68    }
  69    else {
  70       _mesa_error_no_memory(__func__);
  71    }
  72
  73    return table;
  74 }
  75
  76
  77
  78 /**
  79  * Delete a hash table.
  80  * Frees each entry on the hash table and then the hash table structure itself.
  81  * Note that the caller should have already traversed the table and deleted
  82  * the objects in the table (i.e. We don't free the entries' data pointer).
  83  *
  84  * \param table the hash table to delete.
  85  */
  86 void
  87 _mesa_DeleteHashTable(struct _mesa_HashTable *table)
  88 {
  89    assert(table);
  90
  91    if (_mesa_hash_table_next_entry(table->ht, NULL) != NULL) {
  92       _mesa_problem(NULL, "In _mesa_DeleteHashTable, found non-freed data");
  93    }
  94
  95    _mesa_hash_table_destroy(table->ht, NULL);
  96
  97    mtx_destroy(&table->Mutex);
  98    free(table);
  99 }
 100
 101
 102
 103 /**
 104  * Lookup an entry in the hash table, without locking.
 105  * \sa _mesa_HashLookup
 106  */
 107 static inline void *
 108 _mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key)
 109 {
 110    const struct hash_entry *entry;
 111
 112    assert(table);
 113    assert(key);
 114
 115    if (key == DELETED_KEY_VALUE)
 116       return table->deleted_key_data;
 117
 118    entry = _mesa_hash_table_search_pre_hashed(table->ht,
 119                                               uint_hash(key),
 120                                               uint_key(key));
 121    if (!entry)
 122       return NULL;
 123
 124    return entry->data;
 125 }
 126
 127
 128 /**
 129  * Lookup an entry in the hash table.
 130  *
 131  * \param table the hash table.
 132  * \param key the key.
 133  *
 134  * \return pointer to user's data or NULL if key not in table
 135  */
 136 void *
 137 _mesa_HashLookup(struct _mesa_HashTable *table, GLuint key)
 138 {
 139    void *res;
 140    _mesa_HashLockMutex(table);
 141    res = _mesa_HashLookup_unlocked(table, key);
 142    _mesa_HashUnlockMutex(table);
 143    return res;
 144 }
 145
 146
 147 /**
 148  * Lookup an entry in the hash table without locking the mutex.
 149  *
 150  * The hash table mutex must be locked manually by calling
 151  * _mesa_HashLockMutex() before calling this function.
 152  *
 153  * \param table the hash table.
 154  * \param key the key.
 155  *
 156  * \return pointer to user's data or NULL if key not in table
 157  */
 158 void *
 159 _mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key)
 160 {
 161    return _mesa_HashLookup_unlocked(table, key);
 162 }
 163
 164
 165 static inline void
 166 _mesa_HashInsert_unlocked(struct _mesa_HashTable *table, GLuint key, void *data)
 167 {
 168    uint32_t hash = uint_hash(key);
 169    struct hash_entry *entry;
 170
 171    assert(table);
 172    assert(key);
 173
 174    if (key > table->MaxKey)
 175       table->MaxKey = key;
 176
 177    if (key == DELETED_KEY_VALUE) {
 178       table->deleted_key_data = data;
 179    } else {
 180       entry = _mesa_hash_table_search_pre_hashed(table->ht, hash, uint_key(key));
 181       if (entry) {
 182          entry->data = data;
 183       } else {
 184          _mesa_hash_table_insert_pre_hashed(table->ht, hash, uint_key(key), data);
 185       }
 186    }
 187 }
 188
 189
 190 /**
 191  * Insert a key/pointer pair into the hash table without locking the mutex.
 192  * If an entry with this key already exists we'll replace the existing entry.
 193  *
 194  * The hash table mutex must be locked manually by calling
 195  * _mesa_HashLockMutex() before calling this function.
 196  *
 197  * \param table the hash table.
 198  * \param key the key (not zero).
 199  * \param data pointer to user data.
 200  */
 201 void
 202 _mesa_HashInsertLocked(struct _mesa_HashTable *table, GLuint key, void *data)
 203 {
 204    _mesa_HashInsert_unlocked(table, key, data);
 205 }
 206
 207
 208 /**
 209  * Insert a key/pointer pair into the hash table.
 210  * If an entry with this key already exists we'll replace the existing entry.
 211  *
 212  * \param table the hash table.
 213  * \param key the key (not zero).
 214  * \param data pointer to user data.
 215  */
 216 void
 217 _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
 218 {
 219    _mesa_HashLockMutex(table);
 220    _mesa_HashInsert_unlocked(table, key, data);
 221    _mesa_HashUnlockMutex(table);
 222 }
 223
 224
 225 /**
 226  * Remove an entry from the hash table.
 227  *
 228  * \param table the hash table.
 229  * \param key key of entry to remove.
 230  *
 231  * While holding the hash table's lock, searches the entry with the matching
 232  * key and unlinks it.
 233  */
 234 static inline void
 235 _mesa_HashRemove_unlocked(struct _mesa_HashTable *table, GLuint key)
 236 {
 237    struct hash_entry *entry;
 238
 239    assert(table);
 240    assert(key);
 241
 242    /* assert if _mesa_HashRemove illegally called from _mesa_HashDeleteAll
 243     * callback function. Have to check this outside of mutex lock.
 244     */
 245    assert(!table->InDeleteAll);
 246
 247    if (key == DELETED_KEY_VALUE) {
 248       table->deleted_key_data = NULL;
 249    } else {
 250       entry = _mesa_hash_table_search_pre_hashed(table->ht,
 251                                                  uint_hash(key),
 252                                                  uint_key(key));
 253       _mesa_hash_table_remove(table->ht, entry);
 254    }
 255 }
 256
 257
 258 void
 259 _mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key)
 260 {
 261    _mesa_HashRemove_unlocked(table, key);
 262 }
 263
 264 void
 265 _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
 266 {
 267    _mesa_HashLockMutex(table);
 268    _mesa_HashRemove_unlocked(table, key);
 269    _mesa_HashUnlockMutex(table);
 270 }
 271
 272 /**
 273  * Delete all entries in a hash table, but don't delete the table itself.
 274  * Invoke the given callback function for each table entry.
 275  *
 276  * \param table  the hash table to delete
 277  * \param callback  the callback function
 278  * \param userData  arbitrary pointer to pass along to the callback
 279  *                  (this is typically a struct gl_context pointer)
 280  */
 281 void
 282 _mesa_HashDeleteAll(struct _mesa_HashTable *table,
 283                     void (*callback)(GLuint key, void *data, void *userData),
 284                     void *userData)
 285 {
 286    assert(callback);
 287    _mesa_HashLockMutex(table);
 288    table->InDeleteAll = GL_TRUE;
 289    hash_table_foreach(table->ht, entry) {
 290       callback((uintptr_t)entry->key, entry->data, userData);
 291       _mesa_hash_table_remove(table->ht, entry);
 292    }
 293    if (table->deleted_key_data) {
 294       callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
 295       table->deleted_key_data = NULL;
 296    }
 297    table->InDeleteAll = GL_FALSE;
 298    _mesa_HashUnlockMutex(table);
 299 }
 300
 301
 302 /**
 303  * Walk over all entries in a hash table, calling callback function for each.
 304  * \param table  the hash table to walk
 305  * \param callback  the callback function
 306  * \param userData  arbitrary pointer to pass along to the callback
 307  *                  (this is typically a struct gl_context pointer)
 308  */
 309 static void
 310 hash_walk_unlocked(const struct _mesa_HashTable *table,
 311                    void (*callback)(GLuint key, void *data, void *userData),
 312                    void *userData)
 313 {
 314    assert(table);
 315    assert(callback);
 316
 317    hash_table_foreach(table->ht, entry) {
 318       callback((uintptr_t)entry->key, entry->data, userData);
 319    }
 320    if (table->deleted_key_data)
 321       callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
 322 }
 323
 324
 325 void
 326 _mesa_HashWalk(const struct _mesa_HashTable *table,
 327                void (*callback)(GLuint key, void *data, void *userData),
 328                void *userData)
 329 {
 330    /* cast-away const */
 331    struct _mesa_HashTable *table2 = (struct _mesa_HashTable *) table;
 332
 333    _mesa_HashLockMutex(table2);
 334    hash_walk_unlocked(table, callback, userData);
 335    _mesa_HashUnlockMutex(table2);
 336 }
 337
 338 void
 339 _mesa_HashWalkLocked(const struct _mesa_HashTable *table,
 340                void (*callback)(GLuint key, void *data, void *userData),
 341                void *userData)
 342 {
 343    hash_walk_unlocked(table, callback, userData);
 344 }
 345
 346 static void
 347 debug_print_entry(GLuint key, void *data, void *userData)
 348 {
 349    _mesa_debug(NULL, "%u %p\n", key, data);
 350 }
 351
 352 /**
 353  * Dump contents of hash table for debugging.
 354  *
 355  * \param table the hash table.
 356  */
 357 void
 358 _mesa_HashPrint(const struct _mesa_HashTable *table)
 359 {
 360    if (table->deleted_key_data)
 361       debug_print_entry(DELETED_KEY_VALUE, table->deleted_key_data, NULL);
 362    _mesa_HashWalk(table, debug_print_entry, NULL);
 363 }
 364
 365
 366 /**
 367  * Find a block of adjacent unused hash keys.
 368  *
 369  * \param table the hash table.
 370  * \param numKeys number of keys needed.
 371  *
 372  * \return Starting key of free block or 0 if failure.
 373  *
 374  * If there are enough free keys between the maximum key existing in the table
 375  * (_mesa_HashTable::MaxKey) and the maximum key possible, then simply return
 376  * the adjacent key. Otherwise do a full search for a free key block in the
 377  * allowable key range.
 378  */
 379 GLuint
 380 _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
 381 {
 382    const GLuint maxKey = ~((GLuint) 0) - 1;
 383    if (maxKey - numKeys > table->MaxKey) {
 384       /* the quick solution */
 385       return table->MaxKey + 1;
 386    }
 387    else {
 388       /* the slow solution */
 389       GLuint freeCount = 0;
 390       GLuint freeStart = 1;
 391       GLuint key;
 392       for (key = 1; key != maxKey; key++) {
 393          if (_mesa_HashLookup_unlocked(table, key)) {
 394             /* darn, this key is already in use */
 395             freeCount = 0;
 396             freeStart = key+1;
 397          }
 398          else {
 399             /* this key not in use, check if we've found enough */
 400             freeCount++;
 401             if (freeCount == numKeys) {
 402                return freeStart;
 403             }
 404          }
 405       }
 406       /* cannot allocate a block of numKeys consecutive keys */
 407       return 0;
 408    }
 409 }
 410
 411
 412 /**
 413  * Return the number of entries in the hash table.
 414  */
 415 GLuint
 416 _mesa_HashNumEntries(const struct _mesa_HashTable *table)
 417 {
 418    GLuint count = 0;
 419
 420    if (table->deleted_key_data)
 421       count++;
 422
 423    count += _mesa_hash_table_num_entries(table->ht);
 424
 425    return count;
 426 }