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_init(struct hash_table
*ht
,
116 uint32_t (*key_hash_function
)(const void *key
),
117 bool (*key_equals_function
)(const void *a
,
121 ht
->size
= hash_sizes
[ht
->size_index
].size
;
122 ht
->rehash
= hash_sizes
[ht
->size_index
].rehash
;
123 ht
->max_entries
= hash_sizes
[ht
->size_index
].max_entries
;
124 ht
->key_hash_function
= key_hash_function
;
125 ht
->key_equals_function
= key_equals_function
;
126 ht
->table
= rzalloc_array(mem_ctx
, struct hash_entry
, ht
->size
);
128 ht
->deleted_entries
= 0;
129 ht
->deleted_key
= &deleted_key_value
;
131 return ht
->table
!= NULL
;
135 _mesa_hash_table_create(void *mem_ctx
,
136 uint32_t (*key_hash_function
)(const void *key
),
137 bool (*key_equals_function
)(const void *a
,
140 struct hash_table
*ht
;
142 /* mem_ctx is used to allocate the hash table, but the hash table is used
143 * to allocate all of the suballocations.
145 ht
= ralloc(mem_ctx
, struct hash_table
);
149 if (!_mesa_hash_table_init(ht
, ht
, key_hash_function
, key_equals_function
)) {
158 _mesa_hash_table_clone(struct hash_table
*src
, void *dst_mem_ctx
)
160 struct hash_table
*ht
;
162 ht
= ralloc(dst_mem_ctx
, struct hash_table
);
166 memcpy(ht
, src
, sizeof(struct hash_table
));
168 ht
->table
= ralloc_array(ht
, struct hash_entry
, ht
->size
);
169 if (ht
->table
== NULL
) {
174 memcpy(ht
->table
, src
->table
, ht
->size
* sizeof(struct hash_entry
));
180 * Frees the given hash table.
182 * If delete_function is passed, it gets called on each entry present before
186 _mesa_hash_table_destroy(struct hash_table
*ht
,
187 void (*delete_function
)(struct hash_entry
*entry
))
192 if (delete_function
) {
193 hash_table_foreach(ht
, entry
) {
194 delete_function(entry
);
201 * Deletes all entries of the given hash table without deleting the table
202 * itself or changing its structure.
204 * If delete_function is passed, it gets called on each entry present.
207 _mesa_hash_table_clear(struct hash_table
*ht
,
208 void (*delete_function
)(struct hash_entry
*entry
))
210 struct hash_entry
*entry
;
212 for (entry
= ht
->table
; entry
!= ht
->table
+ ht
->size
; entry
++) {
213 if (entry
->key
== NULL
)
216 if (delete_function
!= NULL
&& entry
->key
!= ht
->deleted_key
)
217 delete_function(entry
);
223 ht
->deleted_entries
= 0;
226 /** Sets the value of the key pointer used for deleted entries in the table.
228 * The assumption is that usually keys are actual pointers, so we use a
229 * default value of a pointer to an arbitrary piece of storage in the library.
230 * But in some cases a consumer wants to store some other sort of value in the
231 * table, like a uint32_t, in which case that pointer may conflict with one of
232 * their valid keys. This lets that user select a safe value.
234 * This must be called before any keys are actually deleted from the table.
237 _mesa_hash_table_set_deleted_key(struct hash_table
*ht
, const void *deleted_key
)
239 ht
->deleted_key
= deleted_key
;
242 static struct hash_entry
*
243 hash_table_search(struct hash_table
*ht
, uint32_t hash
, const void *key
)
245 uint32_t start_hash_address
= hash
% ht
->size
;
246 uint32_t hash_address
= start_hash_address
;
249 uint32_t double_hash
;
251 struct hash_entry
*entry
= ht
->table
+ hash_address
;
253 if (entry_is_free(entry
)) {
255 } else if (entry_is_present(ht
, entry
) && entry
->hash
== hash
) {
256 if (ht
->key_equals_function(key
, entry
->key
)) {
261 double_hash
= 1 + hash
% ht
->rehash
;
263 hash_address
= (hash_address
+ double_hash
) % ht
->size
;
264 } while (hash_address
!= start_hash_address
);
270 * Finds a hash table entry with the given key and hash of that key.
272 * Returns NULL if no entry is found. Note that the data pointer may be
273 * modified by the user.
276 _mesa_hash_table_search(struct hash_table
*ht
, const void *key
)
278 assert(ht
->key_hash_function
);
279 return hash_table_search(ht
, ht
->key_hash_function(key
), key
);
283 _mesa_hash_table_search_pre_hashed(struct hash_table
*ht
, uint32_t hash
,
286 assert(ht
->key_hash_function
== NULL
|| hash
== ht
->key_hash_function(key
));
287 return hash_table_search(ht
, hash
, key
);
290 static struct hash_entry
*
291 hash_table_insert(struct hash_table
*ht
, uint32_t hash
,
292 const void *key
, void *data
);
295 _mesa_hash_table_rehash(struct hash_table
*ht
, unsigned new_size_index
)
297 struct hash_table old_ht
;
298 struct hash_entry
*table
;
300 if (new_size_index
>= ARRAY_SIZE(hash_sizes
))
303 table
= rzalloc_array(ralloc_parent(ht
->table
), struct hash_entry
,
304 hash_sizes
[new_size_index
].size
);
311 ht
->size_index
= new_size_index
;
312 ht
->size
= hash_sizes
[ht
->size_index
].size
;
313 ht
->rehash
= hash_sizes
[ht
->size_index
].rehash
;
314 ht
->max_entries
= hash_sizes
[ht
->size_index
].max_entries
;
316 ht
->deleted_entries
= 0;
318 hash_table_foreach(&old_ht
, entry
) {
319 hash_table_insert(ht
, entry
->hash
, entry
->key
, entry
->data
);
322 ralloc_free(old_ht
.table
);
325 static struct hash_entry
*
326 hash_table_insert(struct hash_table
*ht
, uint32_t hash
,
327 const void *key
, void *data
)
329 uint32_t start_hash_address
, hash_address
;
330 struct hash_entry
*available_entry
= NULL
;
334 if (ht
->entries
>= ht
->max_entries
) {
335 _mesa_hash_table_rehash(ht
, ht
->size_index
+ 1);
336 } else if (ht
->deleted_entries
+ ht
->entries
>= ht
->max_entries
) {
337 _mesa_hash_table_rehash(ht
, ht
->size_index
);
340 start_hash_address
= hash
% ht
->size
;
341 hash_address
= start_hash_address
;
343 struct hash_entry
*entry
= ht
->table
+ hash_address
;
344 uint32_t double_hash
;
346 if (!entry_is_present(ht
, entry
)) {
347 /* Stash the first available entry we find */
348 if (available_entry
== NULL
)
349 available_entry
= entry
;
350 if (entry_is_free(entry
))
354 /* Implement replacement when another insert happens
355 * with a matching key. This is a relatively common
356 * feature of hash tables, with the alternative
357 * generally being "insert the new value as well, and
358 * return it first when the key is searched for".
360 * Note that the hash table doesn't have a delete
361 * callback. If freeing of old data pointers is
362 * required to avoid memory leaks, perform a search
365 if (!entry_is_deleted(ht
, entry
) &&
366 entry
->hash
== hash
&&
367 ht
->key_equals_function(key
, entry
->key
)) {
374 double_hash
= 1 + hash
% ht
->rehash
;
376 hash_address
= (hash_address
+ double_hash
) % ht
->size
;
377 } while (hash_address
!= start_hash_address
);
379 if (available_entry
) {
380 if (entry_is_deleted(ht
, available_entry
))
381 ht
->deleted_entries
--;
382 available_entry
->hash
= hash
;
383 available_entry
->key
= key
;
384 available_entry
->data
= data
;
386 return available_entry
;
389 /* We could hit here if a required resize failed. An unchecked-malloc
390 * application could ignore this result.
396 * Inserts the key with the given hash into the table.
398 * Note that insertion may rearrange the table on a resize or rehash,
399 * so previously found hash_entries are no longer valid after this function.
402 _mesa_hash_table_insert(struct hash_table
*ht
, const void *key
, void *data
)
404 assert(ht
->key_hash_function
);
405 return hash_table_insert(ht
, ht
->key_hash_function(key
), key
, data
);
409 _mesa_hash_table_insert_pre_hashed(struct hash_table
*ht
, uint32_t hash
,
410 const void *key
, void *data
)
412 assert(ht
->key_hash_function
== NULL
|| hash
== ht
->key_hash_function(key
));
413 return hash_table_insert(ht
, hash
, key
, data
);
417 * This function deletes the given hash table entry.
419 * Note that deletion doesn't otherwise modify the table, so an iteration over
420 * the table deleting entries is safe.
423 _mesa_hash_table_remove(struct hash_table
*ht
,
424 struct hash_entry
*entry
)
429 entry
->key
= ht
->deleted_key
;
431 ht
->deleted_entries
++;
435 * Removes the entry with the corresponding key, if exists.
437 void _mesa_hash_table_remove_key(struct hash_table
*ht
,
440 _mesa_hash_table_remove(ht
, _mesa_hash_table_search(ht
, key
));
444 * This function is an iterator over the hash table.
446 * Pass in NULL for the first entry, as in the start of a for loop. Note that
447 * an iteration over the table is O(table_size) not O(entries).
450 _mesa_hash_table_next_entry(struct hash_table
*ht
,
451 struct hash_entry
*entry
)
458 for (; entry
!= ht
->table
+ ht
->size
; entry
++) {
459 if (entry_is_present(ht
, entry
)) {
468 * Returns a random entry from the hash table.
470 * This may be useful in implementing random replacement (as opposed
471 * to just removing everything) in caches based on this hash table
472 * implementation. @predicate may be used to filter entries, or may
473 * be set to NULL for no filtering.
476 _mesa_hash_table_random_entry(struct hash_table
*ht
,
477 bool (*predicate
)(struct hash_entry
*entry
))
479 struct hash_entry
*entry
;
480 uint32_t i
= rand() % ht
->size
;
482 if (ht
->entries
== 0)
485 for (entry
= ht
->table
+ i
; entry
!= ht
->table
+ ht
->size
; entry
++) {
486 if (entry_is_present(ht
, entry
) &&
487 (!predicate
|| predicate(entry
))) {
492 for (entry
= ht
->table
; entry
!= ht
->table
+ i
; entry
++) {
493 if (entry_is_present(ht
, entry
) &&
494 (!predicate
|| predicate(entry
))) {
504 * Quick FNV-1a hash implementation based on:
505 * http://www.isthe.com/chongo/tech/comp/fnv/
507 * FNV-1a is not be the best hash out there -- Jenkins's lookup3 is supposed
508 * to be quite good, and it probably beats FNV. But FNV has the advantage
509 * that it involves almost no code. For an improvement on both, see Paul
510 * Hsieh's http://www.azillionmonkeys.com/qed/hash.html
513 _mesa_hash_data(const void *data
, size_t size
)
515 return _mesa_fnv32_1a_accumulate_block(_mesa_fnv32_1a_offset_bias
,
519 /** FNV-1a string hash implementation */
521 _mesa_hash_string(const void *_key
)
523 uint32_t hash
= _mesa_fnv32_1a_offset_bias
;
524 const char *key
= _key
;
527 hash
= _mesa_fnv32_1a_accumulate(hash
, *key
);
535 * String compare function for use as the comparison callback in
536 * _mesa_hash_table_create().
539 _mesa_key_string_equal(const void *a
, const void *b
)
541 return strcmp(a
, b
) == 0;
545 _mesa_key_pointer_equal(const void *a
, const void *b
)
551 * Helper to create a hash table with pointer keys.
554 _mesa_pointer_hash_table_create(void *mem_ctx
)
556 return _mesa_hash_table_create(mem_ctx
, _mesa_hash_pointer
,
557 _mesa_key_pointer_equal
);
561 * Hash table wrapper which supports 64-bit keys.
563 * TODO: unify all hash table implementations.
566 struct hash_key_u64
{
571 key_u64_hash(const void *key
)
573 return _mesa_hash_data(key
, sizeof(struct hash_key_u64
));
577 key_u64_equals(const void *a
, const void *b
)
579 const struct hash_key_u64
*aa
= a
;
580 const struct hash_key_u64
*bb
= b
;
582 return aa
->value
== bb
->value
;
585 struct hash_table_u64
*
586 _mesa_hash_table_u64_create(void *mem_ctx
)
588 struct hash_table_u64
*ht
;
590 ht
= CALLOC_STRUCT(hash_table_u64
);
594 if (sizeof(void *) == 8) {
595 ht
->table
= _mesa_hash_table_create(mem_ctx
, _mesa_hash_pointer
,
596 _mesa_key_pointer_equal
);
598 ht
->table
= _mesa_hash_table_create(mem_ctx
, key_u64_hash
,
603 _mesa_hash_table_set_deleted_key(ht
->table
, uint_key(DELETED_KEY_VALUE
));
609 _mesa_hash_table_u64_destroy(struct hash_table_u64
*ht
,
610 void (*delete_function
)(struct hash_entry
*entry
))
615 if (ht
->deleted_key_data
) {
616 if (delete_function
) {
617 struct hash_table
*table
= ht
->table
;
618 struct hash_entry deleted_entry
;
620 /* Create a fake entry for the delete function. */
621 deleted_entry
.hash
= table
->key_hash_function(table
->deleted_key
);
622 deleted_entry
.key
= table
->deleted_key
;
623 deleted_entry
.data
= ht
->deleted_key_data
;
625 delete_function(&deleted_entry
);
627 ht
->deleted_key_data
= NULL
;
630 _mesa_hash_table_destroy(ht
->table
, delete_function
);
635 _mesa_hash_table_u64_insert(struct hash_table_u64
*ht
, uint64_t key
,
638 if (key
== DELETED_KEY_VALUE
) {
639 ht
->deleted_key_data
= data
;
643 if (sizeof(void *) == 8) {
644 _mesa_hash_table_insert(ht
->table
, (void *)(uintptr_t)key
, data
);
646 struct hash_key_u64
*_key
= CALLOC_STRUCT(hash_key_u64
);
652 _mesa_hash_table_insert(ht
->table
, _key
, data
);
656 static struct hash_entry
*
657 hash_table_u64_search(struct hash_table_u64
*ht
, uint64_t key
)
659 if (sizeof(void *) == 8) {
660 return _mesa_hash_table_search(ht
->table
, (void *)(uintptr_t)key
);
662 struct hash_key_u64 _key
= { .value
= key
};
663 return _mesa_hash_table_search(ht
->table
, &_key
);
668 _mesa_hash_table_u64_search(struct hash_table_u64
*ht
, uint64_t key
)
670 struct hash_entry
*entry
;
672 if (key
== DELETED_KEY_VALUE
)
673 return ht
->deleted_key_data
;
675 entry
= hash_table_u64_search(ht
, key
);
683 _mesa_hash_table_u64_remove(struct hash_table_u64
*ht
, uint64_t key
)
685 struct hash_entry
*entry
;
687 if (key
== DELETED_KEY_VALUE
) {
688 ht
->deleted_key_data
= NULL
;
692 entry
= hash_table_u64_search(ht
, key
);
696 if (sizeof(void *) == 8) {
697 _mesa_hash_table_remove(ht
->table
, entry
);
699 struct hash_key
*_key
= (struct hash_key
*)entry
->key
;
701 _mesa_hash_table_remove(ht
->table
, entry
);