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 #include "util/u_memory.h"
  42
  43
  44 /**
  45  * Create a new hash table.
  46  *
  47  * \return pointer to a new, empty hash table.
  48  */
  49 struct _mesa_HashTable *
  50 _mesa_NewHashTable(void)
  51 {
  52    struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable);
  53
  54    if (table) {
  55       table->ht = _mesa_hash_table_create(NULL, uint_key_hash,
  56                                           uint_key_compare);
  57       if (table->ht == NULL) {
  58          free(table);
  59          _mesa_error_no_memory(__func__);
  60          return NULL;
  61       }
  62
  63       _mesa_hash_table_set_deleted_key(table->ht, uint_key(DELETED_KEY_VALUE));
  64       /*
  65        * Needs to be recursive, since the callback in _mesa_HashWalk()
  66        * is allowed to call _mesa_HashRemove().
  67        */
  68       mtx_init(&table->Mutex, mtx_recursive);
  69    }
  70    else {
  71       _mesa_error_no_memory(__func__);
  72    }
  73
  74    return table;
  75 }
  76
  77
  78
  79 /**
  80  * Delete a hash table.
  81  * Frees each entry on the hash table and then the hash table structure itself.
  82  * Note that the caller should have already traversed the table and deleted
  83  * the objects in the table (i.e. We don't free the entries' data pointer).
  84  *
  85  * \param table the hash table to delete.
  86  */
  87 void
  88 _mesa_DeleteHashTable(struct _mesa_HashTable *table)
  89 {
  90    assert(table);
  91
  92    if (_mesa_hash_table_next_entry(table->ht, NULL) != NULL) {
  93       _mesa_problem(NULL, "In _mesa_DeleteHashTable, found non-freed data");
  94    }
  95
  96    _mesa_hash_table_destroy(table->ht, NULL);
  97
  98    mtx_destroy(&table->Mutex);
  99    free(table);
 100 }
 101
 102
 103
 104 /**
 105  * Lookup an entry in the hash table, without locking.
 106  * \sa _mesa_HashLookup
 107  */
 108 static inline void *
 109 _mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key)
 110 {
 111    const struct hash_entry *entry;
 112
 113    assert(table);
 114    assert(key);
 115
 116    if (key == DELETED_KEY_VALUE)
 117       return table->deleted_key_data;
 118
 119    entry = _mesa_hash_table_search_pre_hashed(table->ht,
 120                                               uint_hash(key),
 121                                               uint_key(key));
 122    if (!entry)
 123       return NULL;
 124
 125    return entry->data;
 126 }
 127
 128
 129 /**
 130  * Lookup an entry in the hash table.
 131  *
 132  * \param table the hash table.
 133  * \param key the key.
 134  *
 135  * \return pointer to user's data or NULL if key not in table
 136  */
 137 void *
 138 _mesa_HashLookup(struct _mesa_HashTable *table, GLuint key)
 139 {
 140    void *res;
 141    _mesa_HashLockMutex(table);
 142    res = _mesa_HashLookup_unlocked(table, key);
 143    _mesa_HashUnlockMutex(table);
 144    return res;
 145 }
 146
 147
 148 /**
 149  * Lookup an entry in the hash table without locking the mutex.
 150  *
 151  * The hash table mutex must be locked manually by calling
 152  * _mesa_HashLockMutex() before calling this function.
 153  *
 154  * \param table the hash table.
 155  * \param key the key.
 156  *
 157  * \return pointer to user's data or NULL if key not in table
 158  */
 159 void *
 160 _mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key)
 161 {
 162    return _mesa_HashLookup_unlocked(table, key);
 163 }
 164
 165
 166 static inline void
 167 _mesa_HashInsert_unlocked(struct _mesa_HashTable *table, GLuint key, void *data)
 168 {
 169    uint32_t hash = uint_hash(key);
 170    struct hash_entry *entry;
 171
 172    assert(table);
 173    assert(key);
 174
 175    if (key > table->MaxKey)
 176       table->MaxKey = key;
 177
 178    if (key == DELETED_KEY_VALUE) {
 179       table->deleted_key_data = data;
 180    } else {
 181       entry = _mesa_hash_table_search_pre_hashed(table->ht, hash, uint_key(key));
 182       if (entry) {
 183          entry->data = data;
 184       } else {
 185          _mesa_hash_table_insert_pre_hashed(table->ht, hash, uint_key(key), data);
 186       }
 187    }
 188 }
 189
 190
 191 /**
 192  * Insert a key/pointer pair into the hash table without locking the mutex.
 193  * If an entry with this key already exists we'll replace the existing entry.
 194  *
 195  * The hash table mutex must be locked manually by calling
 196  * _mesa_HashLockMutex() before calling this function.
 197  *
 198  * \param table the hash table.
 199  * \param key the key (not zero).
 200  * \param data pointer to user data.
 201  */
 202 void
 203 _mesa_HashInsertLocked(struct _mesa_HashTable *table, GLuint key, void *data)
 204 {
 205    _mesa_HashInsert_unlocked(table, key, data);
 206 }
 207
 208
 209 /**
 210  * Insert a key/pointer pair into the hash table.
 211  * If an entry with this key already exists we'll replace the existing entry.
 212  *
 213  * \param table the hash table.
 214  * \param key the key (not zero).
 215  * \param data pointer to user data.
 216  */
 217 void
 218 _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
 219 {
 220    _mesa_HashLockMutex(table);
 221    _mesa_HashInsert_unlocked(table, key, data);
 222    _mesa_HashUnlockMutex(table);
 223 }
 224
 225
 226 /**
 227  * Remove an entry from the hash table.
 228  *
 229  * \param table the hash table.
 230  * \param key key of entry to remove.
 231  *
 232  * While holding the hash table's lock, searches the entry with the matching
 233  * key and unlinks it.
 234  */
 235 static inline void
 236 _mesa_HashRemove_unlocked(struct _mesa_HashTable *table, GLuint key)
 237 {
 238    struct hash_entry *entry;
 239
 240    assert(table);
 241    assert(key);
 242
 243    /* assert if _mesa_HashRemove illegally called from _mesa_HashDeleteAll
 244     * callback function. Have to check this outside of mutex lock.
 245     */
 246    assert(!table->InDeleteAll);
 247
 248    if (key == DELETED_KEY_VALUE) {
 249       table->deleted_key_data = NULL;
 250    } else {
 251       entry = _mesa_hash_table_search_pre_hashed(table->ht,
 252                                                  uint_hash(key),
 253                                                  uint_key(key));
 254       _mesa_hash_table_remove(table->ht, entry);
 255    }
 256 }
 257
 258
 259 void
 260 _mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key)
 261 {
 262    _mesa_HashRemove_unlocked(table, key);
 263 }
 264
 265 void
 266 _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
 267 {
 268    _mesa_HashLockMutex(table);
 269    _mesa_HashRemove_unlocked(table, key);
 270    _mesa_HashUnlockMutex(table);
 271 }
 272
 273 /**
 274  * Delete all entries in a hash table, but don't delete the table itself.
 275  * Invoke the given callback function for each table entry.
 276  *
 277  * \param table  the hash table to delete
 278  * \param callback  the callback function
 279  * \param userData  arbitrary pointer to pass along to the callback
 280  *                  (this is typically a struct gl_context pointer)
 281  */
 282 void
 283 _mesa_HashDeleteAll(struct _mesa_HashTable *table,
 284                     void (*callback)(GLuint key, void *data, void *userData),
 285                     void *userData)
 286 {
 287    assert(callback);
 288    _mesa_HashLockMutex(table);
 289    table->InDeleteAll = GL_TRUE;
 290    hash_table_foreach(table->ht, entry) {
 291       callback((uintptr_t)entry->key, entry->data, userData);
 292       _mesa_hash_table_remove(table->ht, entry);
 293    }
 294    if (table->deleted_key_data) {
 295       callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
 296       table->deleted_key_data = NULL;
 297    }
 298    table->InDeleteAll = GL_FALSE;
 299    _mesa_HashUnlockMutex(table);
 300 }
 301
 302
 303 /**
 304  * Walk over all entries in a hash table, calling callback function for each.
 305  * \param table  the hash table to walk
 306  * \param callback  the callback function
 307  * \param userData  arbitrary pointer to pass along to the callback
 308  *                  (this is typically a struct gl_context pointer)
 309  */
 310 static void
 311 hash_walk_unlocked(const struct _mesa_HashTable *table,
 312                    void (*callback)(GLuint key, void *data, void *userData),
 313                    void *userData)
 314 {
 315    assert(table);
 316    assert(callback);
 317
 318    hash_table_foreach(table->ht, entry) {
 319       callback((uintptr_t)entry->key, entry->data, userData);
 320    }
 321    if (table->deleted_key_data)
 322       callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
 323 }
 324
 325
 326 void
 327 _mesa_HashWalk(const struct _mesa_HashTable *table,
 328                void (*callback)(GLuint key, void *data, void *userData),
 329                void *userData)
 330 {
 331    /* cast-away const */
 332    struct _mesa_HashTable *table2 = (struct _mesa_HashTable *) table;
 333
 334    _mesa_HashLockMutex(table2);
 335    hash_walk_unlocked(table, callback, userData);
 336    _mesa_HashUnlockMutex(table2);
 337 }
 338
 339 void
 340 _mesa_HashWalkLocked(const struct _mesa_HashTable *table,
 341                void (*callback)(GLuint key, void *data, void *userData),
 342                void *userData)
 343 {
 344    hash_walk_unlocked(table, callback, userData);
 345 }
 346
 347 static void
 348 debug_print_entry(GLuint key, void *data, void *userData)
 349 {
 350    _mesa_debug(NULL, "%u %p\n", key, data);
 351 }
 352
 353 /**
 354  * Dump contents of hash table for debugging.
 355  *
 356  * \param table the hash table.
 357  */
 358 void
 359 _mesa_HashPrint(const struct _mesa_HashTable *table)
 360 {
 361    if (table->deleted_key_data)
 362       debug_print_entry(DELETED_KEY_VALUE, table->deleted_key_data, NULL);
 363    _mesa_HashWalk(table, debug_print_entry, NULL);
 364 }
 365
 366
 367 /**
 368  * Find a block of adjacent unused hash keys.
 369  *
 370  * \param table the hash table.
 371  * \param numKeys number of keys needed.
 372  *
 373  * \return Starting key of free block or 0 if failure.
 374  *
 375  * If there are enough free keys between the maximum key existing in the table
 376  * (_mesa_HashTable::MaxKey) and the maximum key possible, then simply return
 377  * the adjacent key. Otherwise do a full search for a free key block in the
 378  * allowable key range.
 379  */
 380 GLuint
 381 _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
 382 {
 383    const GLuint maxKey = ~((GLuint) 0) - 1;
 384    if (maxKey - numKeys > table->MaxKey) {
 385       /* the quick solution */
 386       return table->MaxKey + 1;
 387    }
 388    else {
 389       /* the slow solution */
 390       GLuint freeCount = 0;
 391       GLuint freeStart = 1;
 392       GLuint key;
 393       for (key = 1; key != maxKey; key++) {
 394          if (_mesa_HashLookup_unlocked(table, key)) {
 395             /* darn, this key is already in use */
 396             freeCount = 0;
 397             freeStart = key+1;
 398          }
 399          else {
 400             /* this key not in use, check if we've found enough */
 401             freeCount++;
 402             if (freeCount == numKeys) {
 403                return freeStart;
 404             }
 405          }
 406       }
 407       /* cannot allocate a block of numKeys consecutive keys */
 408       return 0;
 409    }
 410 }
 411
 412
 413 /**
 414  * Return the number of entries in the hash table.
 415  */
 416 GLuint
 417 _mesa_HashNumEntries(const struct _mesa_HashTable *table)
 418 {
 419    GLuint count = 0;
 420
 421    if (table->deleted_key_data)
 422       count++;
 423
 424    count += _mesa_hash_table_num_entries(table->ht);
 425
 426    return count;
 427 }