7 * Mesa 3-D graphics library
9 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
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39 * Magic GLuint object name that gets stored outside of the struct hash_table.
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.
49 #define DELETED_KEY_VALUE 1
52 * Mapping from our use of GLuint as both the key and the hash value to the
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 ==
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
71 uint_key_compare(const void *a
, const void *b
)
76 static inline uint32_t
82 static inline uint32_t
83 uint_key_hash(const void *key
)
85 return uint_hash((uintptr_t)key
);
91 return (void *)(uintptr_t) id
;
96 * The hash table data structure.
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
;
107 extern struct _mesa_HashTable
*_mesa_NewHashTable(void);
109 extern void _mesa_DeleteHashTable(struct _mesa_HashTable
*table
);
111 extern void *_mesa_HashLookup(struct _mesa_HashTable
*table
, GLuint key
);
113 extern void _mesa_HashInsert(struct _mesa_HashTable
*table
, GLuint key
, void *data
);
115 extern void _mesa_HashRemove(struct _mesa_HashTable
*table
, GLuint key
);
118 * Lock the hash table mutex.
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.
124 * \param table the hash table.
127 _mesa_HashLockMutex(struct _mesa_HashTable
*table
)
130 mtx_lock(&table
->Mutex
);
135 * Unlock the hash table mutex.
137 * \param table the hash table.
140 _mesa_HashUnlockMutex(struct _mesa_HashTable
*table
)
143 mtx_unlock(&table
->Mutex
);
146 extern void *_mesa_HashLookupLocked(struct _mesa_HashTable
*table
, GLuint key
);
148 extern void _mesa_HashInsertLocked(struct _mesa_HashTable
*table
,
149 GLuint key
, void *data
);
151 extern void _mesa_HashRemoveLocked(struct _mesa_HashTable
*table
, GLuint key
);
154 _mesa_HashDeleteAll(struct _mesa_HashTable
*table
,
155 void (*callback
)(GLuint key
, void *data
, void *userData
),
159 _mesa_HashWalk(const struct _mesa_HashTable
*table
,
160 void (*callback
)(GLuint key
, void *data
, void *userData
),
164 _mesa_HashWalkLocked(const struct _mesa_HashTable
*table
,
165 void (*callback
)(GLuint key
, void *data
, void *userData
),
168 extern void _mesa_HashPrint(const struct _mesa_HashTable
*table
);
170 extern GLuint
_mesa_HashFindFreeKeyBlock(struct _mesa_HashTable
*table
, GLuint numKeys
);
173 _mesa_HashNumEntries(const struct _mesa_HashTable
*table
);
175 extern void _mesa_test_hash_functions(void);