| /* |
| * Copyright © 2009-2012 Intel Corporation |
| * Copyright © 1988-2004 Keith Packard and Bart Massey. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| * |
| * Except as contained in this notice, the names of the authors |
| * or their institutions shall not be used in advertising or |
| * otherwise to promote the sale, use or other dealings in this |
| * Software without prior written authorization from the |
| * authors. |
| * |
| * Authors: |
| * Eric Anholt <eric@anholt.net> |
| * Keith Packard <keithp@keithp.com> |
| */ |
| |
| #include <stdlib.h> |
| #include <assert.h> |
| |
| #include "macros.h" |
| #include "ralloc.h" |
| #include "set.h" |
| |
| /* |
| * From Knuth -- a good choice for hash/rehash values is p, p-2 where |
| * p and p-2 are both prime. These tables are sized to have an extra 10% |
| * free to avoid exponential performance degradation as the hash table fills |
| */ |
| |
| static const uint32_t deleted_key_value; |
| static const void *deleted_key = &deleted_key_value; |
| |
| static const struct { |
| uint32_t max_entries, size, rehash; |
| } hash_sizes[] = { |
| { 2, 5, 3 }, |
| { 4, 7, 5 }, |
| { 8, 13, 11 }, |
| { 16, 19, 17 }, |
| { 32, 43, 41 }, |
| { 64, 73, 71 }, |
| { 128, 151, 149 }, |
| { 256, 283, 281 }, |
| { 512, 571, 569 }, |
| { 1024, 1153, 1151 }, |
| { 2048, 2269, 2267 }, |
| { 4096, 4519, 4517 }, |
| { 8192, 9013, 9011 }, |
| { 16384, 18043, 18041 }, |
| { 32768, 36109, 36107 }, |
| { 65536, 72091, 72089 }, |
| { 131072, 144409, 144407 }, |
| { 262144, 288361, 288359 }, |
| { 524288, 576883, 576881 }, |
| { 1048576, 1153459, 1153457 }, |
| { 2097152, 2307163, 2307161 }, |
| { 4194304, 4613893, 4613891 }, |
| { 8388608, 9227641, 9227639 }, |
| { 16777216, 18455029, 18455027 }, |
| { 33554432, 36911011, 36911009 }, |
| { 67108864, 73819861, 73819859 }, |
| { 134217728, 147639589, 147639587 }, |
| { 268435456, 295279081, 295279079 }, |
| { 536870912, 590559793, 590559791 }, |
| { 1073741824, 1181116273, 1181116271 }, |
| { 2147483648ul, 2362232233ul, 2362232231ul } |
| }; |
| |
| static int |
| entry_is_free(struct set_entry *entry) |
| { |
| return entry->key == NULL; |
| } |
| |
| static int |
| entry_is_deleted(struct set_entry *entry) |
| { |
| return entry->key == deleted_key; |
| } |
| |
| static int |
| entry_is_present(struct set_entry *entry) |
| { |
| return entry->key != NULL && entry->key != deleted_key; |
| } |
| |
| struct set * |
| _mesa_set_create(void *mem_ctx, |
| uint32_t (*key_hash_function)(const void *key), |
| bool (*key_equals_function)(const void *a, |
| const void *b)) |
| { |
| struct set *ht; |
| |
| ht = ralloc(mem_ctx, struct set); |
| if (ht == NULL) |
| return NULL; |
| |
| ht->size_index = 0; |
| ht->size = hash_sizes[ht->size_index].size; |
| ht->rehash = hash_sizes[ht->size_index].rehash; |
| ht->max_entries = hash_sizes[ht->size_index].max_entries; |
| ht->key_hash_function = key_hash_function; |
| ht->key_equals_function = key_equals_function; |
| ht->table = rzalloc_array(ht, struct set_entry, ht->size); |
| ht->entries = 0; |
| ht->deleted_entries = 0; |
| |
| if (ht->table == NULL) { |
| ralloc_free(ht); |
| return NULL; |
| } |
| |
| return ht; |
| } |
| |
| /** |
| * Frees the given set. |
| * |
| * If delete_function is passed, it gets called on each entry present before |
| * freeing. |
| */ |
| void |
| _mesa_set_destroy(struct set *ht, void (*delete_function)(struct set_entry *entry)) |
| { |
| if (!ht) |
| return; |
| |
| if (delete_function) { |
| struct set_entry *entry; |
| |
| set_foreach (ht, entry) { |
| delete_function(entry); |
| } |
| } |
| ralloc_free(ht->table); |
| ralloc_free(ht); |
| } |
| |
| /** |
| * Finds a set entry with the given key and hash of that key. |
| * |
| * Returns NULL if no entry is found. |
| */ |
| static struct set_entry * |
| set_search(const struct set *ht, uint32_t hash, const void *key) |
| { |
| uint32_t hash_address; |
| |
| hash_address = hash % ht->size; |
| do { |
| uint32_t double_hash; |
| |
| struct set_entry *entry = ht->table + hash_address; |
| |
| if (entry_is_free(entry)) { |
| return NULL; |
| } else if (entry_is_present(entry) && entry->hash == hash) { |
| if (ht->key_equals_function(key, entry->key)) { |
| return entry; |
| } |
| } |
| |
| double_hash = 1 + hash % ht->rehash; |
| |
| hash_address = (hash_address + double_hash) % ht->size; |
| } while (hash_address != hash % ht->size); |
| |
| return NULL; |
| } |
| |
| struct set_entry * |
| _mesa_set_search(const struct set *set, const void *key) |
| { |
| assert(set->key_hash_function); |
| return set_search(set, set->key_hash_function(key), key); |
| } |
| |
| struct set_entry * |
| _mesa_set_search_pre_hashed(const struct set *set, uint32_t hash, |
| const void *key) |
| { |
| assert(set->key_hash_function == NULL || |
| hash == set->key_hash_function(key)); |
| return set_search(set, hash, key); |
| } |
| |
| static struct set_entry * |
| set_add(struct set *ht, uint32_t hash, const void *key); |
| |
| static void |
| set_rehash(struct set *ht, unsigned new_size_index) |
| { |
| struct set old_ht; |
| struct set_entry *table, *entry; |
| |
| if (new_size_index >= ARRAY_SIZE(hash_sizes)) |
| return; |
| |
| table = rzalloc_array(ht, struct set_entry, |
| hash_sizes[new_size_index].size); |
| if (table == NULL) |
| return; |
| |
| old_ht = *ht; |
| |
| ht->table = table; |
| ht->size_index = new_size_index; |
| ht->size = hash_sizes[ht->size_index].size; |
| ht->rehash = hash_sizes[ht->size_index].rehash; |
| ht->max_entries = hash_sizes[ht->size_index].max_entries; |
| ht->entries = 0; |
| ht->deleted_entries = 0; |
| |
| for (entry = old_ht.table; |
| entry != old_ht.table + old_ht.size; |
| entry++) { |
| if (entry_is_present(entry)) { |
| set_add(ht, entry->hash, entry->key); |
| } |
| } |
| |
| ralloc_free(old_ht.table); |
| } |
| |
| /** |
| * Inserts the key with the given hash into the table. |
| * |
| * Note that insertion may rearrange the table on a resize or rehash, |
| * so previously found hash_entries are no longer valid after this function. |
| */ |
| static struct set_entry * |
| set_add(struct set *ht, uint32_t hash, const void *key) |
| { |
| uint32_t hash_address; |
| struct set_entry *available_entry = NULL; |
| |
| if (ht->entries >= ht->max_entries) { |
| set_rehash(ht, ht->size_index + 1); |
| } else if (ht->deleted_entries + ht->entries >= ht->max_entries) { |
| set_rehash(ht, ht->size_index); |
| } |
| |
| hash_address = hash % ht->size; |
| do { |
| struct set_entry *entry = ht->table + hash_address; |
| uint32_t double_hash; |
| |
| if (!entry_is_present(entry)) { |
| /* Stash the first available entry we find */ |
| if (available_entry == NULL) |
| available_entry = entry; |
| if (entry_is_free(entry)) |
| break; |
| } |
| |
| /* Implement replacement when another insert happens |
| * with a matching key. This is a relatively common |
| * feature of hash tables, with the alternative |
| * generally being "insert the new value as well, and |
| * return it first when the key is searched for". |
| * |
| * Note that the hash table doesn't have a delete callback. |
| * If freeing of old keys is required to avoid memory leaks, |
| * perform a search before inserting. |
| */ |
| if (!entry_is_deleted(entry) && |
| entry->hash == hash && |
| ht->key_equals_function(key, entry->key)) { |
| entry->key = key; |
| return entry; |
| } |
| |
| double_hash = 1 + hash % ht->rehash; |
| |
| hash_address = (hash_address + double_hash) % ht->size; |
| } while (hash_address != hash % ht->size); |
| |
| if (available_entry) { |
| if (entry_is_deleted(available_entry)) |
| ht->deleted_entries--; |
| available_entry->hash = hash; |
| available_entry->key = key; |
| ht->entries++; |
| return available_entry; |
| } |
| |
| /* We could hit here if a required resize failed. An unchecked-malloc |
| * application could ignore this result. |
| */ |
| return NULL; |
| } |
| |
| struct set_entry * |
| _mesa_set_add(struct set *set, const void *key) |
| { |
| assert(set->key_hash_function); |
| return set_add(set, set->key_hash_function(key), key); |
| } |
| |
| struct set_entry * |
| _mesa_set_add_pre_hashed(struct set *set, uint32_t hash, const void *key) |
| { |
| assert(set->key_hash_function == NULL || |
| hash == set->key_hash_function(key)); |
| return set_add(set, hash, key); |
| } |
| |
| /** |
| * This function deletes the given hash table entry. |
| * |
| * Note that deletion doesn't otherwise modify the table, so an iteration over |
| * the table deleting entries is safe. |
| */ |
| void |
| _mesa_set_remove(struct set *ht, struct set_entry *entry) |
| { |
| if (!entry) |
| return; |
| |
| entry->key = deleted_key; |
| ht->entries--; |
| ht->deleted_entries++; |
| } |
| |
| /** |
| * This function is an iterator over the hash table. |
| * |
| * Pass in NULL for the first entry, as in the start of a for loop. Note that |
| * an iteration over the table is O(table_size) not O(entries). |
| */ |
| struct set_entry * |
| _mesa_set_next_entry(const struct set *ht, struct set_entry *entry) |
| { |
| if (entry == NULL) |
| entry = ht->table; |
| else |
| entry = entry + 1; |
| |
| for (; entry != ht->table + ht->size; entry++) { |
| if (entry_is_present(entry)) { |
| return entry; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| struct set_entry * |
| _mesa_set_random_entry(struct set *ht, |
| int (*predicate)(struct set_entry *entry)) |
| { |
| struct set_entry *entry; |
| uint32_t i = rand() % ht->size; |
| |
| if (ht->entries == 0) |
| return NULL; |
| |
| for (entry = ht->table + i; entry != ht->table + ht->size; entry++) { |
| if (entry_is_present(entry) && |
| (!predicate || predicate(entry))) { |
| return entry; |
| } |
| } |
| |
| for (entry = ht->table; entry != ht->table + i; entry++) { |
| if (entry_is_present(entry) && |
| (!predicate || predicate(entry))) { |
| return entry; |
| } |
| } |
| |
| return NULL; |
| } |