1 /* $Id: hash.c,v 1.11 2001/11/02 00:57:04 brianp Exp $ */
4 * Mesa 3-D graphics library
7 * Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
16 * The above copyright notice and this permission notice shall be included
17 * in all copies or substantial portions of the Software.
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
23 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
41 * This is used to implement display list and texture object lookup.
42 * NOTE: key=0 is illegal.
46 #define TABLE_SIZE 1024
51 struct HashEntry
*Next
;
54 struct _mesa_HashTable
{
55 struct HashEntry
*Table
[TABLE_SIZE
];
57 _glthread_Mutex Mutex
;
63 * Return pointer to a new, empty hash table.
65 struct _mesa_HashTable
*_mesa_NewHashTable(void)
67 struct _mesa_HashTable
*table
= CALLOC_STRUCT(_mesa_HashTable
);
69 _glthread_INIT_MUTEX(table
->Mutex
);
77 * Delete a hash table.
79 void _mesa_DeleteHashTable(struct _mesa_HashTable
*table
)
83 for (i
=0;i
<TABLE_SIZE
;i
++) {
84 struct HashEntry
*entry
= table
->Table
[i
];
86 struct HashEntry
*next
= entry
->Next
;
97 * Lookup an entry in the hash table.
98 * Input: table - the hash table
100 * Return: user data pointer or NULL if key not in table
102 void *_mesa_HashLookup(const struct _mesa_HashTable
*table
, GLuint key
)
105 const struct HashEntry
*entry
;
110 pos
= key
& (TABLE_SIZE
-1);
111 entry
= table
->Table
[pos
];
113 if (entry
->Key
== key
) {
124 * Insert into the hash table. If an entry with this key already exists
125 * we'll replace the existing entry.
126 * Input: table - the hash table
127 * key - the key (not zero)
128 * data - pointer to user data
130 void _mesa_HashInsert(struct _mesa_HashTable
*table
, GLuint key
, void *data
)
132 /* search for existing entry with this key */
134 struct HashEntry
*entry
;
139 _glthread_LOCK_MUTEX(table
->Mutex
);
141 if (key
> table
->MaxKey
)
144 pos
= key
& (TABLE_SIZE
-1);
145 entry
= table
->Table
[pos
];
147 if (entry
->Key
== key
) {
148 /* replace entry's data */
150 _glthread_UNLOCK_MUTEX(table
->Mutex
);
156 /* alloc and insert new table entry */
157 entry
= MALLOC_STRUCT(HashEntry
);
160 entry
->Next
= table
->Table
[pos
];
161 table
->Table
[pos
] = entry
;
163 _glthread_UNLOCK_MUTEX(table
->Mutex
);
169 * Remove an entry from the hash table.
170 * Input: table - the hash table
171 * key - key of entry to remove
173 void _mesa_HashRemove(struct _mesa_HashTable
*table
, GLuint key
)
176 struct HashEntry
*entry
, *prev
;
181 _glthread_LOCK_MUTEX(table
->Mutex
);
183 pos
= key
& (TABLE_SIZE
-1);
185 entry
= table
->Table
[pos
];
187 if (entry
->Key
== key
) {
190 prev
->Next
= entry
->Next
;
193 table
->Table
[pos
] = entry
->Next
;
196 _glthread_UNLOCK_MUTEX(table
->Mutex
);
203 _glthread_UNLOCK_MUTEX(table
->Mutex
);
209 * Return the key of the "first" entry in the hash table.
210 * This is used in the course of deleting all display lists when
211 * a context is destroyed.
213 GLuint
_mesa_HashFirstEntry(struct _mesa_HashTable
*table
)
217 _glthread_LOCK_MUTEX(table
->Mutex
);
218 for (pos
=0; pos
< TABLE_SIZE
; pos
++) {
219 if (table
->Table
[pos
]) {
220 _glthread_UNLOCK_MUTEX(table
->Mutex
);
221 return table
->Table
[pos
]->Key
;
224 _glthread_UNLOCK_MUTEX(table
->Mutex
);
231 * Dump contents of hash table for debugging.
233 void _mesa_HashPrint(const struct _mesa_HashTable
*table
)
237 for (i
=0;i
<TABLE_SIZE
;i
++) {
238 const struct HashEntry
*entry
= table
->Table
[i
];
240 printf("%u %p\n", entry
->Key
, entry
->Data
);
249 * Find a block of 'numKeys' adjacent unused hash keys.
250 * Input: table - the hash table
251 * numKeys - number of keys needed
252 * Return: starting key of free block or 0 if failure
254 GLuint
_mesa_HashFindFreeKeyBlock(struct _mesa_HashTable
*table
, GLuint numKeys
)
256 GLuint maxKey
= ~((GLuint
) 0);
257 _glthread_LOCK_MUTEX(table
->Mutex
);
258 if (maxKey
- numKeys
> table
->MaxKey
) {
259 /* the quick solution */
260 _glthread_UNLOCK_MUTEX(table
->Mutex
);
261 return table
->MaxKey
+ 1;
264 /* the slow solution */
265 GLuint freeCount
= 0;
266 GLuint freeStart
= 1;
268 for (key
=1; key
!=maxKey
; key
++) {
269 if (_mesa_HashLookup(table
, key
)) {
270 /* darn, this key is already in use */
275 /* this key not in use, check if we've found enough */
277 if (freeCount
== numKeys
) {
278 _glthread_UNLOCK_MUTEX(table
->Mutex
);
283 /* cannot allocate a block of numKeys consecutive keys */
284 _glthread_UNLOCK_MUTEX(table
->Mutex
);
291 #ifdef HASH_TEST_HARNESS
292 int main(int argc
, char *argv
[])
297 printf("&a = %p\n", &a
);
298 printf("&b = %p\n", &b
);
300 t
= _mesa_NewHashTable();
301 _mesa_HashInsert(t
, 501, &a
);
302 _mesa_HashInsert(t
, 10, &c
);
303 _mesa_HashInsert(t
, 0xfffffff8, &b
);
305 printf("Find 501: %p\n", _mesa_HashLookup(t
,501));
306 printf("Find 1313: %p\n", _mesa_HashLookup(t
,1313));
307 printf("Find block of 100: %d\n", _mesa_HashFindFreeKeyBlock(t
, 100));
308 _mesa_DeleteHashTable(t
);