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 <stdbool.h>
36 #include <stdint.h>
37 #include "glheader.h"
38
39 #include "c11/threads.h"
40 #include "util/simple_mtx.h"
41
42 struct util_idalloc;
43
44 /**
45 * Magic GLuint object name that gets stored outside of the struct hash_table.
46 *
47 * The hash table needs a particular pointer to be the marker for a key that
48 * was deleted from the table, along with NULL for the "never allocated in the
49 * table" marker. Legacy GL allows any GLuint to be used as a GL object name,
50 * and we use a 1:1 mapping from GLuints to key pointers, so we need to be
51 * able to track a GLuint that happens to match the deleted key outside of
52 * struct hash_table. We tell the hash table to use "1" as the deleted key
53 * value, so that we test the deleted-key-in-the-table path as best we can.
54 */
55 #define DELETED_KEY_VALUE 1
56
57 /** @{
58 * Mapping from our use of GLuint as both the key and the hash value to the
59 * hash_table.h API
60 *
61 * There exist many integer hash functions, designed to avoid collisions when
62 * the integers are spread across key space with some patterns. In GL, the
63 * pattern (in the case of glGen*()ed object IDs) is that the keys are unique
64 * contiguous integers starting from 1. Because of that, we just use the key
65 * as the hash value, to minimize the cost of the hash function. If objects
66 * are never deleted, we will never see a collision in the table, because the
67 * table resizes itself when it approaches full, and thus key % table_size ==
68 * key.
69 *
70 * The case where we could have collisions for genned objects would be
71 * something like: glGenBuffers(&a, 100); glDeleteBuffers(&a + 50, 50);
72 * glGenBuffers(&b, 100), because objects 1-50 and 101-200 are allocated at
73 * the end of that sequence, instead of 1-150. So far it doesn't appear to be
74 * a problem.
75 */
76 static inline bool
uint_key_compare(const void * a,const void * b)77 uint_key_compare(const void *a, const void *b)
78 {
79 return a == b;
80 }
81
82 static inline uint32_t
uint_hash(GLuint id)83 uint_hash(GLuint id)
84 {
85 return id;
86 }
87
88 static inline uint32_t
uint_key_hash(const void * key)89 uint_key_hash(const void *key)
90 {
91 return uint_hash((uintptr_t)key);
92 }
93
94 static inline void *
uint_key(GLuint id)95 uint_key(GLuint id)
96 {
97 return (void *)(uintptr_t) id;
98 }
99 /** @} */
100
101 /**
102 * The hash table data structure.
103 */
104 struct _mesa_HashTable {
105 struct hash_table *ht;
106 GLuint MaxKey; /**< highest key inserted so far */
107 simple_mtx_t Mutex; /**< mutual exclusion lock */
108 /* Used when name reuse is enabled */
109 struct util_idalloc* id_alloc;
110
111 /** Value that would be in the table for DELETED_KEY_VALUE. */
112 void *deleted_key_data;
113 #ifndef NDEBUG
114 GLboolean InDeleteAll; /**< Debug check */
115 #endif
116 };
117
118 extern struct _mesa_HashTable *_mesa_NewHashTable(void);
119
120 extern void _mesa_DeleteHashTable(struct _mesa_HashTable *table);
121
122 extern void *_mesa_HashLookup(struct _mesa_HashTable *table, GLuint key);
123
124 extern void _mesa_HashInsert(struct _mesa_HashTable *table, GLuint key, void *data,
125 GLboolean isGenName);
126
127 extern void _mesa_HashRemove(struct _mesa_HashTable *table, GLuint key);
128
129 /**
130 * Lock the hash table mutex.
131 *
132 * This function should be used when multiple objects need
133 * to be looked up in the hash table, to avoid having to lock
134 * and unlock the mutex each time.
135 *
136 * \param table the hash table.
137 */
138 static inline void
_mesa_HashLockMutex(struct _mesa_HashTable * table)139 _mesa_HashLockMutex(struct _mesa_HashTable *table)
140 {
141 assert(table);
142 simple_mtx_lock(&table->Mutex);
143 }
144
145
146 /**
147 * Unlock the hash table mutex.
148 *
149 * \param table the hash table.
150 */
151 static inline void
_mesa_HashUnlockMutex(struct _mesa_HashTable * table)152 _mesa_HashUnlockMutex(struct _mesa_HashTable *table)
153 {
154 assert(table);
155 simple_mtx_unlock(&table->Mutex);
156 }
157
158 extern void *_mesa_HashLookupLocked(struct _mesa_HashTable *table, GLuint key);
159
160 extern void _mesa_HashInsertLocked(struct _mesa_HashTable *table,
161 GLuint key, void *data, GLboolean isGenName);
162
163 extern void _mesa_HashRemoveLocked(struct _mesa_HashTable *table, GLuint key);
164
165 extern void
166 _mesa_HashDeleteAll(struct _mesa_HashTable *table,
167 void (*callback)(void *data, void *userData),
168 void *userData);
169
170 extern void
171 _mesa_HashWalk(const struct _mesa_HashTable *table,
172 void (*callback)(void *data, void *userData),
173 void *userData);
174
175 extern void
176 _mesa_HashWalkLocked(const struct _mesa_HashTable *table,
177 void (*callback)(void *data, void *userData),
178 void *userData);
179
180 extern void _mesa_HashPrint(const struct _mesa_HashTable *table);
181
182 extern GLuint _mesa_HashFindFreeKeyBlock(struct _mesa_HashTable *table, GLuint numKeys);
183
184 extern bool
185 _mesa_HashFindFreeKeys(struct _mesa_HashTable *table, GLuint* keys, GLuint numKeys);
186
187 extern GLuint
188 _mesa_HashNumEntries(const struct _mesa_HashTable *table);
189
190 extern void _mesa_test_hash_functions(void);
191
192 extern void _mesa_HashEnableNameReuse(struct _mesa_HashTable *table);
193
194 static inline void
_mesa_HashWalkMaybeLocked(const struct _mesa_HashTable * table,void (* callback)(void * data,void * userData),void * userData,bool locked)195 _mesa_HashWalkMaybeLocked(const struct _mesa_HashTable *table,
196 void (*callback)(void *data, void *userData),
197 void *userData, bool locked)
198 {
199 if (locked)
200 _mesa_HashWalkLocked(table, callback, userData);
201 else
202 _mesa_HashWalk(table, callback, userData);
203 }
204
205 static inline struct gl_buffer_object *
_mesa_HashLookupMaybeLocked(struct _mesa_HashTable * table,GLuint key,bool locked)206 _mesa_HashLookupMaybeLocked(struct _mesa_HashTable *table, GLuint key,
207 bool locked)
208 {
209 if (locked)
210 return _mesa_HashLookupLocked(table, key);
211 else
212 return _mesa_HashLookup(table, key);
213 }
214
215 static inline void
_mesa_HashInsertMaybeLocked(struct _mesa_HashTable * table,GLuint key,void * data,GLboolean isGenName,bool locked)216 _mesa_HashInsertMaybeLocked(struct _mesa_HashTable *table,
217 GLuint key, void *data, GLboolean isGenName,
218 bool locked)
219 {
220 if (locked)
221 _mesa_HashInsertLocked(table, key, data, isGenName);
222 else
223 _mesa_HashInsert(table, key, data, isGenName);
224 }
225
226 static inline void
_mesa_HashLockMaybeLocked(struct _mesa_HashTable * table,bool locked)227 _mesa_HashLockMaybeLocked(struct _mesa_HashTable *table, bool locked)
228 {
229 if (!locked)
230 _mesa_HashLockMutex(table);
231 }
232
233 static inline void
_mesa_HashUnlockMaybeLocked(struct _mesa_HashTable * table,bool locked)234 _mesa_HashUnlockMaybeLocked(struct _mesa_HashTable *table, bool locked)
235 {
236 if (!locked)
237 _mesa_HashUnlockMutex(table);
238 }
239
240 #endif
241