2 * Copyright © 2009,2012 Intel Corporation
3 * Copyright © 1988-2004 Keith Packard and Bart Massey.
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Except as contained in this notice, the names of the authors
25 * or their institutions shall not be used in advertising or
26 * otherwise to promote the sale, use or other dealings in this
27 * Software without prior written authorization from the
31 * Eric Anholt <eric@anholt.net>
32 * Keith Packard <keithp@keithp.com>
36 * Implements an open-addressing, linear-reprobing hash table.
38 * For more information, see:
40 * http://cgit.freedesktop.org/~anholt/hash_table/tree/README
47 #include "hash_table.h"
50 #include "main/hash.h"
52 static const uint32_t deleted_key_value
;
55 * From Knuth -- a good choice for hash/rehash values is p, p-2 where
56 * p and p-2 are both prime. These tables are sized to have an extra 10%
57 * free to avoid exponential performance degradation as the hash table fills
60 uint32_t max_entries
, size
, rehash
;
75 { 16384, 18043, 18041 },
76 { 32768, 36109, 36107 },
77 { 65536, 72091, 72089 },
78 { 131072, 144409, 144407 },
79 { 262144, 288361, 288359 },
80 { 524288, 576883, 576881 },
81 { 1048576, 1153459, 1153457 },
82 { 2097152, 2307163, 2307161 },
83 { 4194304, 4613893, 4613891 },
84 { 8388608, 9227641, 9227639 },
85 { 16777216, 18455029, 18455027 },
86 { 33554432, 36911011, 36911009 },
87 { 67108864, 73819861, 73819859 },
88 { 134217728, 147639589, 147639587 },
89 { 268435456, 295279081, 295279079 },
90 { 536870912, 590559793, 590559791 },
91 { 1073741824, 1181116273, 1181116271},
92 { 2147483648ul, 2362232233ul, 2362232231ul}
96 entry_is_free(const struct hash_entry
*entry
)
98 return entry
->key
== NULL
;
102 entry_is_deleted(const struct hash_table
*ht
, struct hash_entry
*entry
)
104 return entry
->key
== ht
->deleted_key
;
108 entry_is_present(const struct hash_table
*ht
, struct hash_entry
*entry
)
110 return entry
->key
!= NULL
&& entry
->key
!= ht
->deleted_key
;
114 _mesa_hash_table_create(void *mem_ctx
,
115 uint32_t (*key_hash_function
)(const void *key
),
116 bool (*key_equals_function
)(const void *a
,
119 struct hash_table
*ht
;
121 ht
= ralloc(mem_ctx
, struct hash_table
);
126 ht
->size
= hash_sizes
[ht
->size_index
].size
;
127 ht
->rehash
= hash_sizes
[ht
->size_index
].rehash
;
128 ht
->max_entries
= hash_sizes
[ht
->size_index
].max_entries
;
129 ht
->key_hash_function
= key_hash_function
;
130 ht
->key_equals_function
= key_equals_function
;
131 ht
->table
= rzalloc_array(ht
, struct hash_entry
, ht
->size
);
133 ht
->deleted_entries
= 0;
134 ht
->deleted_key
= &deleted_key_value
;
136 if (ht
->table
== NULL
) {
145 * Frees the given hash table.
147 * If delete_function is passed, it gets called on each entry present before
151 _mesa_hash_table_destroy(struct hash_table
*ht
,
152 void (*delete_function
)(struct hash_entry
*entry
))
157 if (delete_function
) {
158 struct hash_entry
*entry
;
160 hash_table_foreach(ht
, entry
) {
161 delete_function(entry
);
168 * Deletes all entries of the given hash table without deleting the table
169 * itself or changing its structure.
171 * If delete_function is passed, it gets called on each entry present.
174 _mesa_hash_table_clear(struct hash_table
*ht
,
175 void (*delete_function
)(struct hash_entry
*entry
))
177 struct hash_entry
*entry
;
179 for (entry
= ht
->table
; entry
!= ht
->table
+ ht
->size
; entry
++) {
180 if (entry
->key
== NULL
)
183 if (delete_function
!= NULL
&& entry
->key
!= ht
->deleted_key
)
184 delete_function(entry
);
190 ht
->deleted_entries
= 0;
193 /** Sets the value of the key pointer used for deleted entries in the table.
195 * The assumption is that usually keys are actual pointers, so we use a
196 * default value of a pointer to an arbitrary piece of storage in the library.
197 * But in some cases a consumer wants to store some other sort of value in the
198 * table, like a uint32_t, in which case that pointer may conflict with one of
199 * their valid keys. This lets that user select a safe value.
201 * This must be called before any keys are actually deleted from the table.
204 _mesa_hash_table_set_deleted_key(struct hash_table
*ht
, const void *deleted_key
)
206 ht
->deleted_key
= deleted_key
;
209 static struct hash_entry
*
210 hash_table_search(struct hash_table
*ht
, uint32_t hash
, const void *key
)
212 uint32_t start_hash_address
= hash
% ht
->size
;
213 uint32_t hash_address
= start_hash_address
;
216 uint32_t double_hash
;
218 struct hash_entry
*entry
= ht
->table
+ hash_address
;
220 if (entry_is_free(entry
)) {
222 } else if (entry_is_present(ht
, entry
) && entry
->hash
== hash
) {
223 if (ht
->key_equals_function(key
, entry
->key
)) {
228 double_hash
= 1 + hash
% ht
->rehash
;
230 hash_address
= (hash_address
+ double_hash
) % ht
->size
;
231 } while (hash_address
!= start_hash_address
);
237 * Finds a hash table entry with the given key and hash of that key.
239 * Returns NULL if no entry is found. Note that the data pointer may be
240 * modified by the user.
243 _mesa_hash_table_search(struct hash_table
*ht
, const void *key
)
245 assert(ht
->key_hash_function
);
246 return hash_table_search(ht
, ht
->key_hash_function(key
), key
);
250 _mesa_hash_table_search_pre_hashed(struct hash_table
*ht
, uint32_t hash
,
253 assert(ht
->key_hash_function
== NULL
|| hash
== ht
->key_hash_function(key
));
254 return hash_table_search(ht
, hash
, key
);
257 static struct hash_entry
*
258 hash_table_insert(struct hash_table
*ht
, uint32_t hash
,
259 const void *key
, void *data
);
262 _mesa_hash_table_rehash(struct hash_table
*ht
, unsigned new_size_index
)
264 struct hash_table old_ht
;
265 struct hash_entry
*table
, *entry
;
267 if (new_size_index
>= ARRAY_SIZE(hash_sizes
))
270 table
= rzalloc_array(ht
, struct hash_entry
,
271 hash_sizes
[new_size_index
].size
);
278 ht
->size_index
= new_size_index
;
279 ht
->size
= hash_sizes
[ht
->size_index
].size
;
280 ht
->rehash
= hash_sizes
[ht
->size_index
].rehash
;
281 ht
->max_entries
= hash_sizes
[ht
->size_index
].max_entries
;
283 ht
->deleted_entries
= 0;
285 hash_table_foreach(&old_ht
, entry
) {
286 hash_table_insert(ht
, entry
->hash
, entry
->key
, entry
->data
);
289 ralloc_free(old_ht
.table
);
292 static struct hash_entry
*
293 hash_table_insert(struct hash_table
*ht
, uint32_t hash
,
294 const void *key
, void *data
)
296 uint32_t start_hash_address
, hash_address
;
297 struct hash_entry
*available_entry
= NULL
;
301 if (ht
->entries
>= ht
->max_entries
) {
302 _mesa_hash_table_rehash(ht
, ht
->size_index
+ 1);
303 } else if (ht
->deleted_entries
+ ht
->entries
>= ht
->max_entries
) {
304 _mesa_hash_table_rehash(ht
, ht
->size_index
);
307 start_hash_address
= hash
% ht
->size
;
308 hash_address
= start_hash_address
;
310 struct hash_entry
*entry
= ht
->table
+ hash_address
;
311 uint32_t double_hash
;
313 if (!entry_is_present(ht
, entry
)) {
314 /* Stash the first available entry we find */
315 if (available_entry
== NULL
)
316 available_entry
= entry
;
317 if (entry_is_free(entry
))
321 /* Implement replacement when another insert happens
322 * with a matching key. This is a relatively common
323 * feature of hash tables, with the alternative
324 * generally being "insert the new value as well, and
325 * return it first when the key is searched for".
327 * Note that the hash table doesn't have a delete
328 * callback. If freeing of old data pointers is
329 * required to avoid memory leaks, perform a search
332 if (!entry_is_deleted(ht
, entry
) &&
333 entry
->hash
== hash
&&
334 ht
->key_equals_function(key
, entry
->key
)) {
341 double_hash
= 1 + hash
% ht
->rehash
;
343 hash_address
= (hash_address
+ double_hash
) % ht
->size
;
344 } while (hash_address
!= start_hash_address
);
346 if (available_entry
) {
347 if (entry_is_deleted(ht
, available_entry
))
348 ht
->deleted_entries
--;
349 available_entry
->hash
= hash
;
350 available_entry
->key
= key
;
351 available_entry
->data
= data
;
353 return available_entry
;
356 /* We could hit here if a required resize failed. An unchecked-malloc
357 * application could ignore this result.
363 * Inserts the key with the given hash into the table.
365 * Note that insertion may rearrange the table on a resize or rehash,
366 * so previously found hash_entries are no longer valid after this function.
369 _mesa_hash_table_insert(struct hash_table
*ht
, const void *key
, void *data
)
371 assert(ht
->key_hash_function
);
372 return hash_table_insert(ht
, ht
->key_hash_function(key
), key
, data
);
376 _mesa_hash_table_insert_pre_hashed(struct hash_table
*ht
, uint32_t hash
,
377 const void *key
, void *data
)
379 assert(ht
->key_hash_function
== NULL
|| hash
== ht
->key_hash_function(key
));
380 return hash_table_insert(ht
, hash
, key
, data
);
384 * This function deletes the given hash table entry.
386 * Note that deletion doesn't otherwise modify the table, so an iteration over
387 * the table deleting entries is safe.
390 _mesa_hash_table_remove(struct hash_table
*ht
,
391 struct hash_entry
*entry
)
396 entry
->key
= ht
->deleted_key
;
398 ht
->deleted_entries
++;
402 * This function is an iterator over the hash table.
404 * Pass in NULL for the first entry, as in the start of a for loop. Note that
405 * an iteration over the table is O(table_size) not O(entries).
408 _mesa_hash_table_next_entry(struct hash_table
*ht
,
409 struct hash_entry
*entry
)
416 for (; entry
!= ht
->table
+ ht
->size
; entry
++) {
417 if (entry_is_present(ht
, entry
)) {
426 * Returns a random entry from the hash table.
428 * This may be useful in implementing random replacement (as opposed
429 * to just removing everything) in caches based on this hash table
430 * implementation. @predicate may be used to filter entries, or may
431 * be set to NULL for no filtering.
434 _mesa_hash_table_random_entry(struct hash_table
*ht
,
435 bool (*predicate
)(struct hash_entry
*entry
))
437 struct hash_entry
*entry
;
438 uint32_t i
= rand() % ht
->size
;
440 if (ht
->entries
== 0)
443 for (entry
= ht
->table
+ i
; entry
!= ht
->table
+ ht
->size
; entry
++) {
444 if (entry_is_present(ht
, entry
) &&
445 (!predicate
|| predicate(entry
))) {
450 for (entry
= ht
->table
; entry
!= ht
->table
+ i
; entry
++) {
451 if (entry_is_present(ht
, entry
) &&
452 (!predicate
|| predicate(entry
))) {
462 * Quick FNV-1a hash implementation based on:
463 * http://www.isthe.com/chongo/tech/comp/fnv/
465 * FNV-1a is not be the best hash out there -- Jenkins's lookup3 is supposed
466 * to be quite good, and it probably beats FNV. But FNV has the advantage
467 * that it involves almost no code. For an improvement on both, see Paul
468 * Hsieh's http://www.azillionmonkeys.com/qed/hash.html
471 _mesa_hash_data(const void *data
, size_t size
)
473 return _mesa_fnv32_1a_accumulate_block(_mesa_fnv32_1a_offset_bias
,
477 /** FNV-1a string hash implementation */
479 _mesa_hash_string(const char *key
)
481 uint32_t hash
= _mesa_fnv32_1a_offset_bias
;
484 hash
= _mesa_fnv32_1a_accumulate(hash
, *key
);
492 * String compare function for use as the comparison callback in
493 * _mesa_hash_table_create().
496 _mesa_key_string_equal(const void *a
, const void *b
)
498 return strcmp(a
, b
) == 0;
502 _mesa_key_pointer_equal(const void *a
, const void *b
)
508 * Hash table wrapper which supports 64-bit keys.
510 * TODO: unify all hash table implementations.
513 struct hash_key_u64
{
518 key_u64_hash(const void *key
)
520 return _mesa_hash_data(key
, sizeof(struct hash_key_u64
));
524 key_u64_equals(const void *a
, const void *b
)
526 const struct hash_key_u64
*aa
= a
;
527 const struct hash_key_u64
*bb
= b
;
529 return aa
->value
== bb
->value
;
532 struct hash_table_u64
*
533 _mesa_hash_table_u64_create(void *mem_ctx
)
535 struct hash_table_u64
*ht
;
537 ht
= CALLOC_STRUCT(hash_table_u64
);
541 if (sizeof(void *) == 8) {
542 ht
->table
= _mesa_hash_table_create(mem_ctx
, _mesa_hash_pointer
,
543 _mesa_key_pointer_equal
);
545 ht
->table
= _mesa_hash_table_create(mem_ctx
, key_u64_hash
,
550 _mesa_hash_table_set_deleted_key(ht
->table
, uint_key(DELETED_KEY_VALUE
));
556 _mesa_hash_table_u64_destroy(struct hash_table_u64
*ht
,
557 void (*delete_function
)(struct hash_entry
*entry
))
562 if (ht
->deleted_key_data
) {
563 if (delete_function
) {
564 struct hash_table
*table
= ht
->table
;
565 struct hash_entry deleted_entry
;
567 /* Create a fake entry for the delete function. */
568 deleted_entry
.hash
= table
->key_hash_function(table
->deleted_key
);
569 deleted_entry
.key
= table
->deleted_key
;
570 deleted_entry
.data
= ht
->deleted_key_data
;
572 delete_function(&deleted_entry
);
574 ht
->deleted_key_data
= NULL
;
577 _mesa_hash_table_destroy(ht
->table
, delete_function
);
582 _mesa_hash_table_u64_insert(struct hash_table_u64
*ht
, uint64_t key
,
585 if (key
== DELETED_KEY_VALUE
) {
586 ht
->deleted_key_data
= data
;
590 if (sizeof(void *) == 8) {
591 _mesa_hash_table_insert(ht
->table
, (void *)(uintptr_t)key
, data
);
593 struct hash_key_u64
*_key
= CALLOC_STRUCT(hash_key_u64
);
599 _mesa_hash_table_insert(ht
->table
, _key
, data
);
603 static struct hash_entry
*
604 hash_table_u64_search(struct hash_table_u64
*ht
, uint64_t key
)
606 if (sizeof(void *) == 8) {
607 return _mesa_hash_table_search(ht
->table
, (void *)(uintptr_t)key
);
609 struct hash_key_u64 _key
= { .value
= key
};
610 return _mesa_hash_table_search(ht
->table
, &_key
);
615 _mesa_hash_table_u64_search(struct hash_table_u64
*ht
, uint64_t key
)
617 struct hash_entry
*entry
;
619 if (key
== DELETED_KEY_VALUE
)
620 return ht
->deleted_key_data
;
622 entry
= hash_table_u64_search(ht
, key
);
630 _mesa_hash_table_u64_remove(struct hash_table_u64
*ht
, uint64_t key
)
632 struct hash_entry
*entry
;
634 if (key
== DELETED_KEY_VALUE
) {
635 ht
->deleted_key_data
= NULL
;
639 entry
= hash_table_u64_search(ht
, key
);
643 if (sizeof(void *) == 8) {
644 _mesa_hash_table_remove(ht
->table
, entry
);
646 struct hash_key
*_key
= (struct hash_key
*)entry
->key
;
648 _mesa_hash_table_remove(ht
->table
, entry
);