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>
43 * From Knuth -- a good choice for hash/rehash values is p, p-2 where
44 * p and p-2 are both prime. These tables are sized to have an extra 10%
45 * free to avoid exponential performance degradation as the hash table fills
48 uint32_t deleted_key_value;
49 const void *deleted_key = &deleted_key_value;
52 uint32_t max_entries, size, rehash;
67 { 16384, 18043, 18041 },
68 { 32768, 36109, 36107 },
69 { 65536, 72091, 72089 },
70 { 131072, 144409, 144407 },
71 { 262144, 288361, 288359 },
72 { 524288, 576883, 576881 },
73 { 1048576, 1153459, 1153457 },
74 { 2097152, 2307163, 2307161 },
75 { 4194304, 4613893, 4613891 },
76 { 8388608, 9227641, 9227639 },
77 { 16777216, 18455029, 18455027 },
78 { 33554432, 36911011, 36911009 },
79 { 67108864, 73819861, 73819859 },
80 { 134217728, 147639589, 147639587 },
81 { 268435456, 295279081, 295279079 },
82 { 536870912, 590559793, 590559791 },
83 { 1073741824, 1181116273, 1181116271 },
84 { 2147483648ul, 2362232233ul, 2362232231ul }
88 entry_is_free(struct set_entry *entry)
90 return entry->key == NULL;
94 entry_is_deleted(struct set_entry *entry)
96 return entry->key == deleted_key;
100 entry_is_present(struct set_entry *entry)
102 return entry->key != NULL && entry->key != deleted_key;
106 _mesa_set_create(void *mem_ctx,
107 uint32_t (*key_hash_function)(const void *key),
108 bool (*key_equals_function)(const void *a,
113 ht = ralloc(mem_ctx, struct set);
118 ht->size = hash_sizes[ht->size_index].size;
119 ht->rehash = hash_sizes[ht->size_index].rehash;
120 ht->max_entries = hash_sizes[ht->size_index].max_entries;
121 ht->key_hash_function = key_hash_function;
122 ht->key_equals_function = key_equals_function;
123 ht->table = rzalloc_array(ht, struct set_entry, ht->size);
125 ht->deleted_entries = 0;
127 if (ht->table == NULL) {
136 * Frees the given set.
138 * If delete_function is passed, it gets called on each entry present before
142 _mesa_set_destroy(struct set *ht, void (*delete_function)(struct set_entry *entry))
147 if (delete_function) {
148 struct set_entry *entry;
150 set_foreach (ht, entry) {
151 delete_function(entry);
154 ralloc_free(ht->table);
159 * Finds a set entry with the given key and hash of that key.
161 * Returns NULL if no entry is found.
163 static struct set_entry *
164 set_search(const struct set *ht, uint32_t hash, const void *key)
166 uint32_t hash_address;
168 hash_address = hash % ht->size;
170 uint32_t double_hash;
172 struct set_entry *entry = ht->table + hash_address;
174 if (entry_is_free(entry)) {
176 } else if (entry_is_present(entry) && entry->hash == hash) {
177 if (ht->key_equals_function(key, entry->key)) {
182 double_hash = 1 + hash % ht->rehash;
184 hash_address = (hash_address + double_hash) % ht->size;
185 } while (hash_address != hash % ht->size);
191 _mesa_set_search(const struct set *set, const void *key)
193 assert(set->key_hash_function);
194 return set_search(set, set->key_hash_function(key), key);
198 _mesa_set_search_pre_hashed(const struct set *set, uint32_t hash,
201 assert(set->key_hash_function == NULL ||
202 hash == set->key_hash_function(key));
203 return set_search(set, hash, key);
206 static struct set_entry *
207 set_add(struct set *ht, uint32_t hash, const void *key);
210 set_rehash(struct set *ht, unsigned new_size_index)
213 struct set_entry *table, *entry;
215 if (new_size_index >= ARRAY_SIZE(hash_sizes))
218 table = rzalloc_array(ht, struct set_entry,
219 hash_sizes[new_size_index].size);
226 ht->size_index = new_size_index;
227 ht->size = hash_sizes[ht->size_index].size;
228 ht->rehash = hash_sizes[ht->size_index].rehash;
229 ht->max_entries = hash_sizes[ht->size_index].max_entries;
231 ht->deleted_entries = 0;
233 for (entry = old_ht.table;
234 entry != old_ht.table + old_ht.size;
236 if (entry_is_present(entry)) {
237 set_add(ht, entry->hash, entry->key);
241 ralloc_free(old_ht.table);
245 * Inserts the key with the given hash into the table.
247 * Note that insertion may rearrange the table on a resize or rehash,
248 * so previously found hash_entries are no longer valid after this function.
250 static struct set_entry *
251 set_add(struct set *ht, uint32_t hash, const void *key)
253 uint32_t hash_address;
254 struct set_entry *available_entry = NULL;
256 if (ht->entries >= ht->max_entries) {
257 set_rehash(ht, ht->size_index + 1);
258 } else if (ht->deleted_entries + ht->entries >= ht->max_entries) {
259 set_rehash(ht, ht->size_index);
262 hash_address = hash % ht->size;
264 struct set_entry *entry = ht->table + hash_address;
265 uint32_t double_hash;
267 if (!entry_is_present(entry)) {
268 /* Stash the first available entry we find */
269 if (available_entry == NULL)
270 available_entry = entry;
271 if (entry_is_free(entry))
275 /* Implement replacement when another insert happens
276 * with a matching key. This is a relatively common
277 * feature of hash tables, with the alternative
278 * generally being "insert the new value as well, and
279 * return it first when the key is searched for".
281 * Note that the hash table doesn't have a delete callback.
282 * If freeing of old keys is required to avoid memory leaks,
283 * perform a search before inserting.
285 if (!entry_is_deleted(entry) &&
286 entry->hash == hash &&
287 ht->key_equals_function(key, entry->key)) {
292 double_hash = 1 + hash % ht->rehash;
294 hash_address = (hash_address + double_hash) % ht->size;
295 } while (hash_address != hash % ht->size);
297 if (available_entry) {
298 if (entry_is_deleted(available_entry))
299 ht->deleted_entries--;
300 available_entry->hash = hash;
301 available_entry->key = key;
303 return available_entry;
306 /* We could hit here if a required resize failed. An unchecked-malloc
307 * application could ignore this result.
313 _mesa_set_add(struct set *set, const void *key)
315 assert(set->key_hash_function);
316 return set_add(set, set->key_hash_function(key), key);
320 _mesa_set_add_pre_hashed(struct set *set, uint32_t hash, const void *key)
322 assert(set->key_hash_function == NULL ||
323 hash == set->key_hash_function(key));
324 return set_add(set, hash, key);
328 * This function deletes the given hash table entry.
330 * Note that deletion doesn't otherwise modify the table, so an iteration over
331 * the table deleting entries is safe.
334 _mesa_set_remove(struct set *ht, struct set_entry *entry)
339 entry->key = deleted_key;
341 ht->deleted_entries++;
345 * This function is an iterator over the hash table.
347 * Pass in NULL for the first entry, as in the start of a for loop. Note that
348 * an iteration over the table is O(table_size) not O(entries).
351 _mesa_set_next_entry(const struct set *ht, struct set_entry *entry)
358 for (; entry != ht->table + ht->size; entry++) {
359 if (entry_is_present(entry)) {
368 _mesa_set_random_entry(struct set *ht,
369 int (*predicate)(struct set_entry *entry))
371 struct set_entry *entry;
372 uint32_t i = rand() % ht->size;
374 if (ht->entries == 0)
377 for (entry = ht->table + i; entry != ht->table + ht->size; entry++) {
378 if (entry_is_present(entry) &&
379 (!predicate || predicate(entry))) {
384 for (entry = ht->table; entry != ht->table + i; entry++) {
385 if (entry_is_present(entry) &&
386 (!predicate || predicate(entry))) {