| 0,0 → 1,170 |
|---|
| /* |
| * Copyright (C) 2006 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /* |
| * This is an implementation of generic chained hash table. |
| */ |
| |
| #include <libadt/hash_table.h> |
| #include <libadt/list.h> |
| #include <unistd.h> |
| #include <malloc.h> |
| #include <assert.h> |
| #include <stdio.h> |
| #include <string.h> |
| |
| /** Create chained hash table. |
| * |
| * @param h Hash table structure. Will be initialized by this call. |
| * @param m Number of slots in the hash table. |
| * @param max_keys Maximal number of keys needed to identify an item. |
| * @param op Hash table operations structure. |
| * @return true on success |
| */ |
| int hash_table_create(hash_table_t *h, hash_count_t m, hash_count_t max_keys, hash_table_operations_t *op) |
| { |
| hash_count_t i; |
| |
| assert(h); |
| assert(op && op->hash && op->compare); |
| assert(max_keys > 0); |
| |
| h->entry = malloc(m * sizeof(link_t)); |
| if (!h->entry) { |
| printf("cannot allocate memory for hash table\n"); |
| return false; |
| } |
| memset((void *) h->entry, 0, m * sizeof(link_t)); |
| |
| for (i = 0; i < m; i++) |
| list_initialize(&h->entry[i]); |
| |
| h->entries = m; |
| h->max_keys = max_keys; |
| h->op = op; |
| return true; |
| } |
| |
| /** Insert item into hash table. |
| * |
| * @param h Hash table. |
| * @param hey Array of all keys necessary to compute hash index. |
| * @param item Item to be inserted into the hash table. |
| */ |
| void hash_table_insert(hash_table_t *h, unsigned long key[], link_t *item) |
| { |
| hash_index_t chain; |
| |
| assert(item); |
| assert(h && h->op && h->op->hash && h->op->compare); |
| |
| chain = h->op->hash(key); |
| assert(chain < h->entries); |
| |
| list_append(item, &h->entry[chain]); |
| } |
| |
| /** Search hash table for an item matching keys. |
| * |
| * @param h Hash table. |
| * @param key Array of all keys needed to compute hash index. |
| * |
| * @return Matching item on success, NULL if there is no such item. |
| */ |
| link_t *hash_table_find(hash_table_t *h, unsigned long key[]) |
| { |
| link_t *cur; |
| hash_index_t chain; |
| |
| assert(h && h->op && h->op->hash && h->op->compare); |
| |
| chain = h->op->hash(key); |
| assert(chain < h->entries); |
| |
| for (cur = h->entry[chain].next; cur != &h->entry[chain]; cur = cur->next) { |
| if (h->op->compare(key, h->max_keys, cur)) { |
| /* |
| * The entry is there. |
| */ |
| return cur; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /** Remove all matching items from hash table. |
| * |
| * For each removed item, h->remove_callback() is called. |
| * |
| * @param h Hash table. |
| * @param key Array of keys that will be compared against items of the hash table. |
| * @param keys Number of keys in the 'key' array. |
| */ |
| void hash_table_remove(hash_table_t *h, unsigned long key[], hash_count_t keys) |
| { |
| hash_index_t chain; |
| link_t *cur; |
| |
| assert(h && h->op && h->op->hash && h->op->compare && h->op->remove_callback); |
| assert(keys <= h->max_keys); |
| |
| if (keys == h->max_keys) { |
| |
| /* |
| * All keys are known, hash_table_find() can be used to find the entry. |
| */ |
| |
| cur = hash_table_find(h, key); |
| if (cur) { |
| list_remove(cur); |
| h->op->remove_callback(cur); |
| } |
| return; |
| } |
| |
| /* |
| * Fewer keys were passed. |
| * Any partially matching entries are to be removed. |
| */ |
| for (chain = 0; chain < h->entries; chain++) { |
| for (cur = h->entry[chain].next; cur != &h->entry[chain]; cur = cur->next) { |
| if (h->op->compare(key, keys, cur)) { |
| link_t *hlp; |
| |
| hlp = cur; |
| cur = cur->prev; |
| |
| list_remove(hlp); |
| h->op->remove_callback(hlp); |
| |
| continue; |
| } |
| } |
| } |
| } |