| /** |
| * \file hash.c |
| * Generic hash table. |
| * |
| * Used for display lists, texture objects, vertex/fragment programs, |
| * buffer objects, etc. The hash functions are thread-safe. |
| * |
| * \note key=0 is illegal. |
| * |
| * \author Brian Paul |
| */ |
| |
| /* |
| * Mesa 3-D graphics library |
| * |
| * Copyright (C) 1999-2006 Brian Paul All Rights Reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included |
| * in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR |
| * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
| * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| * OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| |
| #include "glheader.h" |
| #include "imports.h" |
| #include "hash.h" |
| #include "util/hash_table.h" |
| |
| /** |
| * Magic GLuint object name that gets stored outside of the struct hash_table. |
| * |
| * The hash table needs a particular pointer to be the marker for a key that |
| * was deleted from the table, along with NULL for the "never allocated in the |
| * table" marker. Legacy GL allows any GLuint to be used as a GL object name, |
| * and we use a 1:1 mapping from GLuints to key pointers, so we need to be |
| * able to track a GLuint that happens to match the deleted key outside of |
| * struct hash_table. We tell the hash table to use "1" as the deleted key |
| * value, so that we test the deleted-key-in-the-table path as best we can. |
| */ |
| #define DELETED_KEY_VALUE 1 |
| |
| /** |
| * The hash table data structure. |
| */ |
| struct _mesa_HashTable { |
| struct hash_table *ht; |
| GLuint MaxKey; /**< highest key inserted so far */ |
| mtx_t Mutex; /**< mutual exclusion lock */ |
| GLboolean InDeleteAll; /**< Debug check */ |
| /** Value that would be in the table for DELETED_KEY_VALUE. */ |
| void *deleted_key_data; |
| }; |
| |
| /** @{ |
| * Mapping from our use of GLuint as both the key and the hash value to the |
| * hash_table.h API |
| * |
| * There exist many integer hash functions, designed to avoid collisions when |
| * the integers are spread across key space with some patterns. In GL, the |
| * pattern (in the case of glGen*()ed object IDs) is that the keys are unique |
| * contiguous integers starting from 1. Because of that, we just use the key |
| * as the hash value, to minimize the cost of the hash function. If objects |
| * are never deleted, we will never see a collision in the table, because the |
| * table resizes itself when it approaches full, and thus key % table_size == |
| * key. |
| * |
| * The case where we could have collisions for genned objects would be |
| * something like: glGenBuffers(&a, 100); glDeleteBuffers(&a + 50, 50); |
| * glGenBuffers(&b, 100), because objects 1-50 and 101-200 are allocated at |
| * the end of that sequence, instead of 1-150. So far it doesn't appear to be |
| * a problem. |
| */ |
| static bool |
| uint_key_compare(const void *a, const void *b) |
| { |
| return a == b; |
| } |
| |
| static uint32_t |
| uint_hash(GLuint id) |
| { |
| return id; |
| } |
| |
| static uint32_t |
| uint_key_hash(const void *key) |
| { |
| return uint_hash((uintptr_t)key); |
| } |
| |
| static void * |
| uint_key(GLuint id) |
| { |
| return (void *)(uintptr_t) id; |
| } |
| /** @} */ |
| |
| /** |
| * Create a new hash table. |
| * |
| * \return pointer to a new, empty hash table. |
| */ |
| struct _mesa_HashTable * |
| _mesa_NewHashTable(void) |
| { |
| struct _mesa_HashTable *table = CALLOC_STRUCT(_mesa_HashTable); |
| |
| if (table) { |
| table->ht = _mesa_hash_table_create(NULL, uint_key_hash, |
| uint_key_compare); |
| if (table->ht == NULL) { |
| free(table); |
| _mesa_error_no_memory(__func__); |
| return NULL; |
| } |
| |
| _mesa_hash_table_set_deleted_key(table->ht, uint_key(DELETED_KEY_VALUE)); |
| /* |
| * Needs to be recursive, since the callback in _mesa_HashWalk() |
| * is allowed to call _mesa_HashRemove(). |
| */ |
| mtx_init(&table->Mutex, mtx_recursive); |
| } |
| else { |
| _mesa_error_no_memory(__func__); |
| } |
| |
| return table; |
| } |
| |
| |
| |
| /** |
| * Delete a hash table. |
| * Frees each entry on the hash table and then the hash table structure itself. |
| * Note that the caller should have already traversed the table and deleted |
| * the objects in the table (i.e. We don't free the entries' data pointer). |
| * |
| * \param table the hash table to delete. |
| */ |
| void |
| _mesa_DeleteHashTable(struct _mesa_HashTable *table) |
| { |
| assert(table); |
| |
| if (_mesa_hash_table_next_entry(table->ht, NULL) != NULL) { |
| _mesa_problem(NULL, "In _mesa_DeleteHashTable, found non-freed data"); |
| } |
| |
| _mesa_hash_table_destroy(table->ht, NULL); |
| |
| mtx_destroy(&table->Mutex); |
| free(table); |
| } |
| |
| |
| |
| /** |
| * Lookup an entry in the hash table, without locking. |
| * \sa _mesa_HashLookup |
| */ |
| static inline void * |
| _mesa_HashLookup_unlocked(struct _mesa_HashTable *table, GLuint key) |
| { |
| const struct hash_entry *entry; |
| |
| assert(table); |
| assert(key); |
| |
| if (key == DELETED_KEY_VALUE) |
| return table->deleted_key_data; |
| |
| entry = _mesa_hash_table_search(table->ht, uint_key(key)); |
| if (!entry) |
| return NULL; |
| |
| return entry->data; |
| } |
| |
| |
| /** |
| * Lookup an entry in the hash table. |
| * |
| * \param table the hash table. |
| * \param key the key. |
| * |
| * \return pointer to user's data or NULL if key not in table |
| */ |
| void * |
| _mesa_HashLookup(struct _mesa_HashTable *table, GLuint key) |
| { |
| void *res; |
| assert(table); |
| mtx_lock(&table->Mutex); |
| res = _mesa_HashLookup_unlocked(table, key); |
| mtx_unlock(&table->Mutex); |
| return res; |
| } |
| |
| |
| /** |
| * Lookup an entry in the hash table without locking the mutex. |
| * |
| * The hash table mutex must be locked manually by calling |
| * _mesa_HashLockMutex() before calling this function. |
| * |
| * \param table the hash table. |
| * \param key the key. |
| * |
| * \return pointer to user's data or NULL if key not in table |
| */ |
| void * |
| _mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key) |
| { |
| return _mesa_HashLookup_unlocked(table, key); |
| } |
| |
| |
| /** |
| * Lock the hash table mutex. |
| * |
| * This function should be used when multiple objects need |
| * to be looked up in the hash table, to avoid having to lock |
| * and unlock the mutex each time. |
| * |
| * \param table the hash table. |
| */ |
| void |
| _mesa_HashLockMutex(struct _mesa_HashTable *table) |
| { |
| assert(table); |
| mtx_lock(&table->Mutex); |
| } |
| |
| |
| /** |
| * Unlock the hash table mutex. |
| * |
| * \param table the hash table. |
| */ |
| void |
| _mesa_HashUnlockMutex(struct _mesa_HashTable *table) |
| { |
| assert(table); |
| mtx_unlock(&table->Mutex); |
| } |
| |
| |
| static inline void |
| _mesa_HashInsert_unlocked(struct _mesa_HashTable *table, GLuint key, void *data) |
| { |
| uint32_t hash = uint_hash(key); |
| struct hash_entry *entry; |
| |
| assert(table); |
| assert(key); |
| |
| if (key > table->MaxKey) |
| table->MaxKey = key; |
| |
| if (key == DELETED_KEY_VALUE) { |
| table->deleted_key_data = data; |
| } else { |
| entry = _mesa_hash_table_search_pre_hashed(table->ht, hash, uint_key(key)); |
| if (entry) { |
| entry->data = data; |
| } else { |
| _mesa_hash_table_insert_pre_hashed(table->ht, hash, uint_key(key), data); |
| } |
| } |
| } |
| |
| |
| /** |
| * Insert a key/pointer pair into the hash table without locking the mutex. |
| * If an entry with this key already exists we'll replace the existing entry. |
| * |
| * The hash table mutex must be locked manually by calling |
| * _mesa_HashLockMutex() before calling this function. |
| * |
| * \param table the hash table. |
| * \param key the key (not zero). |
| * \param data pointer to user data. |
| */ |
| void |
| _mesa_HashInsertLocked(struct _mesa_HashTable *table, GLuint key, void *data) |
| { |
| _mesa_HashInsert_unlocked(table, key, data); |
| } |
| |
| |
| /** |
| * Insert a key/pointer pair into the hash table. |
| * If an entry with this key already exists we'll replace the existing entry. |
| * |
| * \param table the hash table. |
| * \param key the key (not zero). |
| * \param data pointer to user data. |
| */ |
| void |
| _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data) |
| { |
| assert(table); |
| mtx_lock(&table->Mutex); |
| _mesa_HashInsert_unlocked(table, key, data); |
| mtx_unlock(&table->Mutex); |
| } |
| |
| |
| /** |
| * Remove an entry from the hash table. |
| * |
| * \param table the hash table. |
| * \param key key of entry to remove. |
| * |
| * While holding the hash table's lock, searches the entry with the matching |
| * key and unlinks it. |
| */ |
| static inline void |
| _mesa_HashRemove_unlocked(struct _mesa_HashTable *table, GLuint key) |
| { |
| struct hash_entry *entry; |
| |
| assert(table); |
| assert(key); |
| |
| /* have to check this outside of mutex lock */ |
| if (table->InDeleteAll) { |
| _mesa_problem(NULL, "_mesa_HashRemove illegally called from " |
| "_mesa_HashDeleteAll callback function"); |
| return; |
| } |
| |
| if (key == DELETED_KEY_VALUE) { |
| table->deleted_key_data = NULL; |
| } else { |
| entry = _mesa_hash_table_search(table->ht, uint_key(key)); |
| _mesa_hash_table_remove(table->ht, entry); |
| } |
| } |
| |
| |
| void |
| _mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key) |
| { |
| _mesa_HashRemove_unlocked(table, key); |
| } |
| |
| void |
| _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key) |
| { |
| mtx_lock(&table->Mutex); |
| _mesa_HashRemove_unlocked(table, key); |
| mtx_unlock(&table->Mutex); |
| } |
| |
| /** |
| * Delete all entries in a hash table, but don't delete the table itself. |
| * Invoke the given callback function for each table entry. |
| * |
| * \param table the hash table to delete |
| * \param callback the callback function |
| * \param userData arbitrary pointer to pass along to the callback |
| * (this is typically a struct gl_context pointer) |
| */ |
| void |
| _mesa_HashDeleteAll(struct _mesa_HashTable *table, |
| void (*callback)(GLuint key, void *data, void *userData), |
| void *userData) |
| { |
| struct hash_entry *entry; |
| |
| assert(table); |
| assert(callback); |
| mtx_lock(&table->Mutex); |
| table->InDeleteAll = GL_TRUE; |
| hash_table_foreach(table->ht, entry) { |
| callback((uintptr_t)entry->key, entry->data, userData); |
| _mesa_hash_table_remove(table->ht, entry); |
| } |
| if (table->deleted_key_data) { |
| callback(DELETED_KEY_VALUE, table->deleted_key_data, userData); |
| table->deleted_key_data = NULL; |
| } |
| table->InDeleteAll = GL_FALSE; |
| mtx_unlock(&table->Mutex); |
| } |
| |
| |
| /** |
| * Walk over all entries in a hash table, calling callback function for each. |
| * \param table the hash table to walk |
| * \param callback the callback function |
| * \param userData arbitrary pointer to pass along to the callback |
| * (this is typically a struct gl_context pointer) |
| */ |
| void |
| _mesa_HashWalk(const struct _mesa_HashTable *table, |
| void (*callback)(GLuint key, void *data, void *userData), |
| void *userData) |
| { |
| /* cast-away const */ |
| struct _mesa_HashTable *table2 = (struct _mesa_HashTable *) table; |
| struct hash_entry *entry; |
| |
| assert(table); |
| assert(callback); |
| mtx_lock(&table2->Mutex); |
| hash_table_foreach(table->ht, entry) { |
| callback((uintptr_t)entry->key, entry->data, userData); |
| } |
| if (table->deleted_key_data) |
| callback(DELETED_KEY_VALUE, table->deleted_key_data, userData); |
| mtx_unlock(&table2->Mutex); |
| } |
| |
| static void |
| debug_print_entry(GLuint key, void *data, void *userData) |
| { |
| _mesa_debug(NULL, "%u %p\n", key, data); |
| } |
| |
| /** |
| * Dump contents of hash table for debugging. |
| * |
| * \param table the hash table. |
| */ |
| void |
| _mesa_HashPrint(const struct _mesa_HashTable *table) |
| { |
| if (table->deleted_key_data) |
| debug_print_entry(DELETED_KEY_VALUE, table->deleted_key_data, NULL); |
| _mesa_HashWalk(table, debug_print_entry, NULL); |
| } |
| |
| |
| /** |
| * Find a block of adjacent unused hash keys. |
| * |
| * \param table the hash table. |
| * \param numKeys number of keys needed. |
| * |
| * \return Starting key of free block or 0 if failure. |
| * |
| * If there are enough free keys between the maximum key existing in the table |
| * (_mesa_HashTable::MaxKey) and the maximum key possible, then simply return |
| * the adjacent key. Otherwise do a full search for a free key block in the |
| * allowable key range. |
| */ |
| GLuint |
| _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys) |
| { |
| const GLuint maxKey = ~((GLuint) 0) - 1; |
| if (maxKey - numKeys > table->MaxKey) { |
| /* the quick solution */ |
| return table->MaxKey + 1; |
| } |
| else { |
| /* the slow solution */ |
| GLuint freeCount = 0; |
| GLuint freeStart = 1; |
| GLuint key; |
| for (key = 1; key != maxKey; key++) { |
| if (_mesa_HashLookup_unlocked(table, key)) { |
| /* darn, this key is already in use */ |
| freeCount = 0; |
| freeStart = key+1; |
| } |
| else { |
| /* this key not in use, check if we've found enough */ |
| freeCount++; |
| if (freeCount == numKeys) { |
| return freeStart; |
| } |
| } |
| } |
| /* cannot allocate a block of numKeys consecutive keys */ |
| return 0; |
| } |
| } |
| |
| |
| /** |
| * Return the number of entries in the hash table. |
| */ |
| GLuint |
| _mesa_HashNumEntries(const struct _mesa_HashTable *table) |
| { |
| GLuint count = 0; |
| |
| if (table->deleted_key_data) |
| count++; |
| |
| count += _mesa_hash_table_num_entries(table->ht); |
| |
| return count; |
| } |