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 "glheader.h"
  38 #include "hash.h"
  39 #include "util/hash_table.h"
  40
  41
  42 /**
  43  * Create a new hash table.
  44  *
  45  * \return pointer to a new, empty hash table.
  46  */
  47 struct _mesa_HashTable *
  48 _mesa_NewHashTable(void)
  49 {
  50    struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable);
  51
  52    if (table) {
  53       table->ht = _mesa_hash_table_create(NULL, uint_key_hash,
  54                                           uint_key_compare);
  55       if (table->ht == NULL) {
  56          free(table);
  57          _mesa_error_no_memory(__func__);
  58          return NULL;
  59       }
  60
  61       _mesa_hash_table_set_deleted_key(table->ht, uint_key(DELETED_KEY_VALUE));
  62       /*
  63        * Needs to be recursive, since the callback in _mesa_HashWalk()
  64        * is allowed to call _mesa_HashRemove().
  65        */
  66       mtx_init(&table->Mutex, mtx_recursive);
  67    }
  68    else {
  69       _mesa_error_no_memory(__func__);
  70    }
  71
  72    return table;
  73 }
  74
  75
  76
  77 /**
  78  * Delete a hash table.
  79  * Frees each entry on the hash table and then the hash table structure itself.
  80  * Note that the caller should have already traversed the table and deleted
  81  * the objects in the table (i.e. We don't free the entries' data pointer).
  82  *
  83  * \param table the hash table to delete.
  84  */
  85 void
  86 _mesa_DeleteHashTable(struct _mesa_HashTable *table)
  87 {
  88    assert(table);
  89
  90    if (_mesa_hash_table_next_entry(table->ht, NULL) != NULL) {
  91       _mesa_problem(NULL, "In _mesa_DeleteHashTable, found non-freed data");
  92    }
  93
  94    _mesa_hash_table_destroy(table->ht, NULL);
  95
  96    mtx_destroy(&table->Mutex);
  97    free(table);
  98 }
  99
 100
 101
 102 /**
 103  * Lookup an entry in the hash table, without locking.
 104  * \sa _mesa_HashLookup
 105  */
 106 static inline void *
 107 _mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key)
 108 {
 109    const struct hash_entry *entry;
 110
 111    assert(table);
 112    assert(key);
 113
 114    if (key == DELETED_KEY_VALUE)
 115       return table->deleted_key_data;
 116
 117    entry = _mesa_hash_table_search_pre_hashed(table->ht,
 118                                               uint_hash(key),
 119                                               uint_key(key));
 120    if (!entry)
 121       return NULL;
 122
 123    return entry->data;
 124 }
 125
 126
 127 /**
 128  * Lookup an entry in the hash table.
 129  *
 130  * \param table the hash table.
 131  * \param key the key.
 132  *
 133  * \return pointer to user's data or NULL if key not in table
 134  */
 135 void *
 136 _mesa_HashLookup(struct _mesa_HashTable *table, GLuint key)
 137 {
 138    void *res;
 139    _mesa_HashLockMutex(table);
 140    res = _mesa_HashLookup_unlocked(table, key);
 141    _mesa_HashUnlockMutex(table);
 142    return res;
 143 }
 144
 145
 146 /**
 147  * Lookup an entry in the hash table without locking the mutex.
 148  *
 149  * The hash table mutex must be locked manually by calling
 150  * _mesa_HashLockMutex() before calling this function.
 151  *
 152  * \param table the hash table.
 153  * \param key the key.
 154  *
 155  * \return pointer to user's data or NULL if key not in table
 156  */
 157 void *
 158 _mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key)
 159 {
 160    return _mesa_HashLookup_unlocked(table, key);
 161 }
 162
 163
 164 static inline void
 165 _mesa_HashInsert_unlocked(struct _mesa_HashTable *table, GLuint key, void *data)
 166 {
 167    uint32_t hash = uint_hash(key);
 168    struct hash_entry *entry;
 169
 170    assert(table);
 171    assert(key);
 172
 173    if (key > table->MaxKey)
 174       table->MaxKey = key;
 175
 176    if (key == DELETED_KEY_VALUE) {
 177       table->deleted_key_data = data;
 178    } else {
 179       entry = _mesa_hash_table_search_pre_hashed(table->ht, hash, uint_key(key));
 180       if (entry) {
 181          entry->data = data;
 182       } else {
 183          _mesa_hash_table_insert_pre_hashed(table->ht, hash, uint_key(key), data);
 184       }
 185    }
 186 }
 187
 188
 189 /**
 190  * Insert a key/pointer pair into the hash table without locking the mutex.
 191  * If an entry with this key already exists we'll replace the existing entry.
 192  *
 193  * The hash table mutex must be locked manually by calling
 194  * _mesa_HashLockMutex() before calling this function.
 195  *
 196  * \param table the hash table.
 197  * \param key the key (not zero).
 198  * \param data pointer to user data.
 199  */
 200 void
 201 _mesa_HashInsertLocked(struct _mesa_HashTable *table, GLuint key, void *data)
 202 {
 203    _mesa_HashInsert_unlocked(table, key, data);
 204 }
 205
 206
 207 /**
 208  * Insert a key/pointer pair into the hash table.
 209  * If an entry with this key already exists we'll replace the existing entry.
 210  *
 211  * \param table the hash table.
 212  * \param key the key (not zero).
 213  * \param data pointer to user data.
 214  */
 215 void
 216 _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data)
 217 {
 218    _mesa_HashLockMutex(table);
 219    _mesa_HashInsert_unlocked(table, key, data);
 220    _mesa_HashUnlockMutex(table);
 221 }
 222
 223
 224 /**
 225  * Remove an entry from the hash table.
 226  *
 227  * \param table the hash table.
 228  * \param key key of entry to remove.
 229  *
 230  * While holding the hash table's lock, searches the entry with the matching
 231  * key and unlinks it.
 232  */
 233 static inline void
 234 _mesa_HashRemove_unlocked(struct _mesa_HashTable *table, GLuint key)
 235 {
 236    struct hash_entry *entry;
 237
 238    assert(table);
 239    assert(key);
 240
 241    /* assert if _mesa_HashRemove illegally called from _mesa_HashDeleteAll
 242     * callback function. Have to check this outside of mutex lock.
 243     */
 244    assert(!table->InDeleteAll);
 245
 246    if (key == DELETED_KEY_VALUE) {
 247       table->deleted_key_data = NULL;
 248    } else {
 249       entry = _mesa_hash_table_search_pre_hashed(table->ht,
 250                                                  uint_hash(key),
 251                                                  uint_key(key));
 252       _mesa_hash_table_remove(table->ht, entry);
 253    }
 254 }
 255
 256
 257 void
 258 _mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key)
 259 {
 260    _mesa_HashRemove_unlocked(table, key);
 261 }
 262
 263 void
 264 _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key)
 265 {
 266    _mesa_HashLockMutex(table);
 267    _mesa_HashRemove_unlocked(table, key);
 268    _mesa_HashUnlockMutex(table);
 269 }
 270
 271 /**
 272  * Delete all entries in a hash table, but don't delete the table itself.
 273  * Invoke the given callback function for each table entry.
 274  *
 275  * \param table  the hash table to delete
 276  * \param callback  the callback function
 277  * \param userData  arbitrary pointer to pass along to the callback
 278  *                  (this is typically a struct gl_context pointer)
 279  */
 280 void
 281 _mesa_HashDeleteAll(struct _mesa_HashTable *table,
 282                     void (*callback)(GLuint key, void *data, void *userData),
 283                     void *userData)
 284 {
 285    struct hash_entry *entry;
 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    struct hash_entry *entry;
 319    hash_table_foreach(table->ht, entry) {
 320       callback((uintptr_t)entry->key, entry->data, userData);
 321    }
 322    if (table->deleted_key_data)
 323       callback(DELETED_KEY_VALUE, table->deleted_key_data, userData);
 324 }
 325
 326
 327 void
 328 _mesa_HashWalk(const struct _mesa_HashTable *table,
 329                void (*callback)(GLuint key, void *data, void *userData),
 330                void *userData)
 331 {
 332    /* cast-away const */
 333    struct _mesa_HashTable *table2 = (struct _mesa_HashTable *) table;
 334
 335    _mesa_HashLockMutex(table2);
 336    hash_walk_unlocked(table, callback, userData);
 337    _mesa_HashUnlockMutex(table2);
 338 }
 339
 340 void
 341 _mesa_HashWalkLocked(const struct _mesa_HashTable *table,
 342                void (*callback)(GLuint key, void *data, void *userData),
 343                void *userData)
 344 {
 345    hash_walk_unlocked(table, callback, userData);
 346 }
 347
 348 static void
 349 debug_print_entry(GLuint key, void *data, void *userData)
 350 {
 351    _mesa_debug(NULL, "%u %p\n", key, data);
 352 }
 353
 354 /**
 355  * Dump contents of hash table for debugging.
 356  *
 357  * \param table the hash table.
 358  */
 359 void
 360 _mesa_HashPrint(const struct _mesa_HashTable *table)
 361 {
 362    if (table->deleted_key_data)
 363       debug_print_entry(DELETED_KEY_VALUE, table->deleted_key_data, NULL);
 364    _mesa_HashWalk(table, debug_print_entry, NULL);
 365 }
 366
 367
 368 /**
 369  * Find a block of adjacent unused hash keys.
 370  *
 371  * \param table the hash table.
 372  * \param numKeys number of keys needed.
 373  *
 374  * \return Starting key of free block or 0 if failure.
 375  *
 376  * If there are enough free keys between the maximum key existing in the table
 377  * (_mesa_HashTable::MaxKey) and the maximum key possible, then simply return
 378  * the adjacent key. Otherwise do a full search for a free key block in the
 379  * allowable key range.
 380  */
 381 GLuint
 382 _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys)
 383 {
 384    const GLuint maxKey = ~((GLuint) 0) - 1;
 385    if (maxKey - numKeys > table->MaxKey) {
 386       /* the quick solution */
 387       return table->MaxKey + 1;
 388    }
 389    else {
 390       /* the slow solution */
 391       GLuint freeCount = 0;
 392       GLuint freeStart = 1;
 393       GLuint key;
 394       for (key = 1; key != maxKey; key++) {
 395          if (_mesa_HashLookup_unlocked(table, key)) {
 396             /* darn, this key is already in use */
 397             freeCount = 0;
 398             freeStart = key+1;
 399          }
 400          else {
 401             /* this key not in use, check if we've found enough */
 402             freeCount++;
 403             if (freeCount == numKeys) {
 404                return freeStart;
 405             }
 406          }
 407       }
 408       /* cannot allocate a block of numKeys consecutive keys */
 409       return 0;
 410    }
 411 }
 412
 413
 414 /**
 415  * Return the number of entries in the hash table.
 416  */
 417 GLuint
 418 _mesa_HashNumEntries(const struct _mesa_HashTable *table)
 419 {
 420    GLuint count = 0;
 421
 422    if (table->deleted_key_data)
 423       count++;
 424
 425    count += _mesa_hash_table_num_entries(table->ht);
 426
 427    return count;
 428 }