1 /** 2 * \file hash.h 3 * Generic hash table. 4 */ 5 6 /* 7 * Mesa 3-D graphics library 8 * 9 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved. 10 * 11 * Permission is hereby granted, free of charge, to any person obtaining a 12 * copy of this software and associated documentation files (the "Software"), 13 * to deal in the Software without restriction, including without limitation 14 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 15 * and/or sell copies of the Software, and to permit persons to whom the 16 * Software is furnished to do so, subject to the following conditions: 17 * 18 * The above copyright notice and this permission notice shall be included 19 * in all copies or substantial portions of the Software. 20 * 21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 22 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 24 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 25 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 26 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 27 * OTHER DEALINGS IN THE SOFTWARE. 28 */ 29 30 31 #ifndef HASH_H 32 #define HASH_H 33 34 35 #include "glheader.h" 36 #include "imports.h" 37 38 /** 39 * Magic GLuint object name that gets stored outside of the struct hash_table. 40 * 41 * The hash table needs a particular pointer to be the marker for a key that 42 * was deleted from the table, along with NULL for the "never allocated in the 43 * table" marker. Legacy GL allows any GLuint to be used as a GL object name, 44 * and we use a 1:1 mapping from GLuints to key pointers, so we need to be 45 * able to track a GLuint that happens to match the deleted key outside of 46 * struct hash_table. We tell the hash table to use "1" as the deleted key 47 * value, so that we test the deleted-key-in-the-table path as best we can. 48 */ 49 #define DELETED_KEY_VALUE 1 50 51 /** @{ 52 * Mapping from our use of GLuint as both the key and the hash value to the 53 * hash_table.h API 54 * 55 * There exist many integer hash functions, designed to avoid collisions when 56 * the integers are spread across key space with some patterns. In GL, the 57 * pattern (in the case of glGen*()ed object IDs) is that the keys are unique 58 * contiguous integers starting from 1. Because of that, we just use the key 59 * as the hash value, to minimize the cost of the hash function. If objects 60 * are never deleted, we will never see a collision in the table, because the 61 * table resizes itself when it approaches full, and thus key % table_size == 62 * key. 63 * 64 * The case where we could have collisions for genned objects would be 65 * something like: glGenBuffers(&a, 100); glDeleteBuffers(&a + 50, 50); 66 * glGenBuffers(&b, 100), because objects 1-50 and 101-200 are allocated at 67 * the end of that sequence, instead of 1-150. So far it doesn't appear to be 68 * a problem. 69 */ 70 static inline bool 71 uint_key_compare(const void *a, const void *b) 72 { 73 return a == b; 74 } 75 76 static inline uint32_t 77 uint_hash(GLuint id) 78 { 79 return id; 80 } 81 82 static inline uint32_t 83 uint_key_hash(const void *key) 84 { 85 return uint_hash((uintptr_t)key); 86 } 87 88 static inline void * 89 uint_key(GLuint id) 90 { 91 return (void *)(uintptr_t) id; 92 } 93 /** @} */ 94 95 /** 96 * The hash table data structure. 97 */ 98 struct _mesa_HashTable { 99 struct hash_table *ht; 100 GLuint MaxKey; /**< highest key inserted so far */ 101 mtx_t Mutex; /**< mutual exclusion lock */ 102 GLboolean InDeleteAll; /**< Debug check */ 103 /** Value that would be in the table for DELETED_KEY_VALUE. */ 104 void *deleted_key_data; 105 }; 106 107 extern struct _mesa_HashTable *_mesa_NewHashTable(void); 108 109 extern void _mesa_DeleteHashTable(struct _mesa_HashTable *table); 110 111 extern void *_mesa_HashLookup(struct _mesa_HashTable *table, GLuint key); 112 113 extern void _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data); 114 115 extern void _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key); 116 117 /** 118 * Lock the hash table mutex. 119 * 120 * This function should be used when multiple objects need 121 * to be looked up in the hash table, to avoid having to lock 122 * and unlock the mutex each time. 123 * 124 * \param table the hash table. 125 */ 126 static inline void 127 _mesa_HashLockMutex(struct _mesa_HashTable *table) 128 { 129 assert(table); 130 mtx_lock(&table->Mutex); 131 } 132 133 134 /** 135 * Unlock the hash table mutex. 136 * 137 * \param table the hash table. 138 */ 139 static inline void 140 _mesa_HashUnlockMutex(struct _mesa_HashTable *table) 141 { 142 assert(table); 143 mtx_unlock(&table->Mutex); 144 } 145 146 extern void *_mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key); 147 148 extern void _mesa_HashInsertLocked(struct _mesa_HashTable *table, 149 GLuint key, void *data); 150 151 extern void _mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key); 152 153 extern void 154 _mesa_HashDeleteAll(struct _mesa_HashTable *table, 155 void (*callback)(GLuint key, void *data, void *userData), 156 void *userData); 157 158 extern void 159 _mesa_HashWalk(const struct _mesa_HashTable *table, 160 void (*callback)(GLuint key, void *data, void *userData), 161 void *userData); 162 163 extern void 164 _mesa_HashWalkLocked(const struct _mesa_HashTable *table, 165 void (*callback)(GLuint key, void *data, void *userData), 166 void *userData); 167 168 extern void _mesa_HashPrint(const struct _mesa_HashTable *table); 169 170 extern GLuint _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys); 171 172 extern GLuint 173 _mesa_HashNumEntries(const struct _mesa_HashTable *table); 174 175 extern void _mesa_test_hash_functions(void); 176 177 178 #endif 179
