/* * 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> */ /** * Implements an open-addressing, linear-reprobing hash table. * * For more information, see: * * http://cgit.freedesktop.org/~anholt/hash_table/tree/README */ #include <stdlib.h> #include <string.h> #include <assert.h> #include "hash_table.h" #include "ralloc.h" #include "macros.h" #include "main/hash.h" static const uint32_t deleted_key_value; /** * 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 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(const struct hash_entry *entry) { return entry->key == NULL; } static int entry_is_deleted(const struct hash_table *ht, struct hash_entry *entry) { return entry->key == ht->deleted_key; } static int entry_is_present(const struct hash_table *ht, struct hash_entry *entry) { return entry->key != NULL && entry->key != ht->deleted_key; } struct hash_table * _mesa_hash_table_create(void *mem_ctx, uint32_t (*key_hash_function)(const void *key), bool (*key_equals_function)(const void *a, const void *b)) { struct hash_table *ht; ht = ralloc(mem_ctx, struct hash_table); 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 hash_entry, ht->size); ht->entries = 0; ht->deleted_entries = 0; ht->deleted_key = &deleted_key_value; if (ht->table == NULL) { ralloc_free(ht); return NULL; } return ht; } /** * Frees the given hash table. * * If delete_function is passed, it gets called on each entry present before * freeing. */ void _mesa_hash_table_destroy(struct hash_table *ht, void (*delete_function)(struct hash_entry *entry)) { if (!ht) return; if (delete_function) { struct hash_entry *entry; hash_table_foreach(ht, entry) { delete_function(entry); } } ralloc_free(ht); } /** * Deletes all entries of the given hash table without deleting the table * itself or changing its structure. * * If delete_function is passed, it gets called on each entry present. */ void _mesa_hash_table_clear(struct hash_table *ht, void (*delete_function)(struct hash_entry *entry)) { struct hash_entry *entry; for (entry = ht->table; entry != ht->table + ht->size; entry++) { if (entry->key == NULL) continue; if (delete_function != NULL && entry->key != ht->deleted_key) delete_function(entry); entry->key = NULL; } ht->entries = 0; ht->deleted_entries = 0; } /** Sets the value of the key pointer used for deleted entries in the table. * * The assumption is that usually keys are actual pointers, so we use a * default value of a pointer to an arbitrary piece of storage in the library. * But in some cases a consumer wants to store some other sort of value in the * table, like a uint32_t, in which case that pointer may conflict with one of * their valid keys. This lets that user select a safe value. * * This must be called before any keys are actually deleted from the table. */ void _mesa_hash_table_set_deleted_key(struct hash_table *ht, const void *deleted_key) { ht->deleted_key = deleted_key; } static struct hash_entry * hash_table_search(struct hash_table *ht, uint32_t hash, const void *key) { uint32_t start_hash_address = hash % ht->size; uint32_t hash_address = start_hash_address; do { uint32_t double_hash; struct hash_entry *entry = ht->table + hash_address; if (entry_is_free(entry)) { return NULL; } else if (entry_is_present(ht, 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 != start_hash_address); return NULL; } /** * Finds a hash table entry with the given key and hash of that key. * * Returns NULL if no entry is found. Note that the data pointer may be * modified by the user. */ struct hash_entry * _mesa_hash_table_search(struct hash_table *ht, const void *key) { assert(ht->key_hash_function); return hash_table_search(ht, ht->key_hash_function(key), key); } struct hash_entry * _mesa_hash_table_search_pre_hashed(struct hash_table *ht, uint32_t hash, const void *key) { assert(ht->key_hash_function == NULL || hash == ht->key_hash_function(key)); return hash_table_search(ht, hash, key); } static struct hash_entry * hash_table_insert(struct hash_table *ht, uint32_t hash, const void *key, void *data); static void _mesa_hash_table_rehash(struct hash_table *ht, unsigned new_size_index) { struct hash_table old_ht; struct hash_entry *table, *entry; if (new_size_index >= ARRAY_SIZE(hash_sizes)) return; table = rzalloc_array(ht, struct hash_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; hash_table_foreach(&old_ht, entry) { hash_table_insert(ht, entry->hash, entry->key, entry->data); } ralloc_free(old_ht.table); } static struct hash_entry * hash_table_insert(struct hash_table *ht, uint32_t hash, const void *key, void *data) { uint32_t start_hash_address, hash_address; struct hash_entry *available_entry = NULL; assert(key != NULL); if (ht->entries >= ht->max_entries) { _mesa_hash_table_rehash(ht, ht->size_index + 1); } else if (ht->deleted_entries + ht->entries >= ht->max_entries) { _mesa_hash_table_rehash(ht, ht->size_index); } start_hash_address = hash % ht->size; hash_address = start_hash_address; do { struct hash_entry *entry = ht->table + hash_address; uint32_t double_hash; if (!entry_is_present(ht, 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 data pointers is * required to avoid memory leaks, perform a search * before inserting. */ if (!entry_is_deleted(ht, entry) && entry->hash == hash && ht->key_equals_function(key, entry->key)) { entry->key = key; entry->data = data; return entry; } double_hash = 1 + hash % ht->rehash; hash_address = (hash_address + double_hash) % ht->size; } while (hash_address != start_hash_address); if (available_entry) { if (entry_is_deleted(ht, available_entry)) ht->deleted_entries--; available_entry->hash = hash; available_entry->key = key; available_entry->data = data; ht->entries++; return available_entry; } /* We could hit here if a required resize failed. An unchecked-malloc * application could ignore this result. */ return NULL; } /** * 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. */ struct hash_entry * _mesa_hash_table_insert(struct hash_table *ht, const void *key, void *data) { assert(ht->key_hash_function); return hash_table_insert(ht, ht->key_hash_function(key), key, data); } struct hash_entry * _mesa_hash_table_insert_pre_hashed(struct hash_table *ht, uint32_t hash, const void *key, void *data) { assert(ht->key_hash_function == NULL || hash == ht->key_hash_function(key)); return hash_table_insert(ht, hash, key, data); } /** * 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_hash_table_remove(struct hash_table *ht, struct hash_entry *entry) { if (!entry) return; entry->key = ht->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 hash_entry * _mesa_hash_table_next_entry(struct hash_table *ht, struct hash_entry *entry) { if (entry == NULL) entry = ht->table; else entry = entry + 1; for (; entry != ht->table + ht->size; entry++) { if (entry_is_present(ht, entry)) { return entry; } } return NULL; } /** * Returns a random entry from the hash table. * * This may be useful in implementing random replacement (as opposed * to just removing everything) in caches based on this hash table * implementation. @predicate may be used to filter entries, or may * be set to NULL for no filtering. */ struct hash_entry * _mesa_hash_table_random_entry(struct hash_table *ht, bool (*predicate)(struct hash_entry *entry)) { struct hash_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(ht, entry) && (!predicate || predicate(entry))) { return entry; } } for (entry = ht->table; entry != ht->table + i; entry++) { if (entry_is_present(ht, entry) && (!predicate || predicate(entry))) { return entry; } } return NULL; } /** * Quick FNV-1a hash implementation based on: * http://www.isthe.com/chongo/tech/comp/fnv/ * * FNV-1a is not be the best hash out there -- Jenkins's lookup3 is supposed * to be quite good, and it probably beats FNV. But FNV has the advantage * that it involves almost no code. For an improvement on both, see Paul * Hsieh's http://www.azillionmonkeys.com/qed/hash.html */ uint32_t _mesa_hash_data(const void *data, size_t size) { return _mesa_fnv32_1a_accumulate_block(_mesa_fnv32_1a_offset_bias, data, size); } /** FNV-1a string hash implementation */ uint32_t _mesa_hash_string(const char *key) { uint32_t hash = _mesa_fnv32_1a_offset_bias; while (*key != 0) { hash = _mesa_fnv32_1a_accumulate(hash, *key); key++; } return hash; } /** * String compare function for use as the comparison callback in * _mesa_hash_table_create(). */ bool _mesa_key_string_equal(const void *a, const void *b) { return strcmp(a, b) == 0; } bool _mesa_key_pointer_equal(const void *a, const void *b) { return a == b; } /** * Hash table wrapper which supports 64-bit keys. * * TODO: unify all hash table implementations. */ struct hash_key_u64 { uint64_t value; }; static uint32_t key_u64_hash(const void *key) { return _mesa_hash_data(key, sizeof(struct hash_key_u64)); } static bool key_u64_equals(const void *a, const void *b) { const struct hash_key_u64 *aa = a; const struct hash_key_u64 *bb = b; return aa->value == bb->value; } struct hash_table_u64 * _mesa_hash_table_u64_create(void *mem_ctx) { struct hash_table_u64 *ht; ht = CALLOC_STRUCT(hash_table_u64); if (!ht) return NULL; if (sizeof(void *) == 8) { ht->table = _mesa_hash_table_create(mem_ctx, _mesa_hash_pointer, _mesa_key_pointer_equal); } else { ht->table = _mesa_hash_table_create(mem_ctx, key_u64_hash, key_u64_equals); } if (ht->table) _mesa_hash_table_set_deleted_key(ht->table, uint_key(DELETED_KEY_VALUE)); return ht; } void _mesa_hash_table_u64_destroy(struct hash_table_u64 *ht, void (*delete_function)(struct hash_entry *entry)) { if (!ht) return; if (ht->deleted_key_data) { if (delete_function) { struct hash_table *table = ht->table; struct hash_entry deleted_entry; /* Create a fake entry for the delete function. */ deleted_entry.hash = table->key_hash_function(table->deleted_key); deleted_entry.key = table->deleted_key; deleted_entry.data = ht->deleted_key_data; delete_function(&deleted_entry); } ht->deleted_key_data = NULL; } _mesa_hash_table_destroy(ht->table, delete_function); free(ht); } void _mesa_hash_table_u64_insert(struct hash_table_u64 *ht, uint64_t key, void *data) { if (key == DELETED_KEY_VALUE) { ht->deleted_key_data = data; return; } if (sizeof(void *) == 8) { _mesa_hash_table_insert(ht->table, (void *)(uintptr_t)key, data); } else { struct hash_key_u64 *_key = CALLOC_STRUCT(hash_key_u64); if (!_key) return; _key->value = key; _mesa_hash_table_insert(ht->table, _key, data); } } static struct hash_entry * hash_table_u64_search(struct hash_table_u64 *ht, uint64_t key) { if (sizeof(void *) == 8) { return _mesa_hash_table_search(ht->table, (void *)(uintptr_t)key); } else { struct hash_key_u64 _key = { .value = key }; return _mesa_hash_table_search(ht->table, &_key); } } void * _mesa_hash_table_u64_search(struct hash_table_u64 *ht, uint64_t key) { struct hash_entry *entry; if (key == DELETED_KEY_VALUE) return ht->deleted_key_data; entry = hash_table_u64_search(ht, key); if (!entry) return NULL; return entry->data; } void _mesa_hash_table_u64_remove(struct hash_table_u64 *ht, uint64_t key) { struct hash_entry *entry; if (key == DELETED_KEY_VALUE) { ht->deleted_key_data = NULL; return; } entry = hash_table_u64_search(ht, key); if (!entry) return; if (sizeof(void *) == 8) { _mesa_hash_table_remove(ht->table, entry); } else { struct hash_key *_key = (struct hash_key *)entry->key; _mesa_hash_table_remove(ht->table, entry); free(_key); } }