/* * Copyright 2006 Rob Kendrick <rjek@rjek.com> * * This file is part of NetSurf, http://www.netsurf-browser.org/ * * NetSurf is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * * NetSurf is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ /** * \file * Interface to Write-Once hash table for string to string mapping */ #ifndef _NETSURF_UTILS_HASHTABLE_H_ #define _NETSURF_UTILS_HASHTABLE_H_ #include <stdbool.h> struct hash_table; /** * Create a new hash table, and return a context for it. The memory consumption * of a hash table is approximately 8 + (nchains * 12) bytes if it is empty. * * \param chains Number of chains/buckets this hash table will have. This * should be a prime number, and ideally a prime number just * over a power of two, for best performance and distribution. * \return struct hash_table containing the context of this hash table or NULL * if there is insufficent memory to create it and its chains. */ struct hash_table *hash_create(unsigned int chains); /** * Destroys a hash table, freeing all memory associated with it. * * \param ht Hash table to destroy. After the function returns, this * will nolonger be valid. */ void hash_destroy(struct hash_table *ht); /** * Adds a key/value pair to a hash table. If the key you're adding is already * in the hash table, it does not replace it, but it does take precedent over * it. The old key/value pair will be inaccessable but still in memory until * hash_destroy() is called on the hash table. * * \param ht The hash table context to add the key/value pair to. * \param key The key to associate the value with. A copy is made. * \param value The value to associate the key with. A copy is made. * \return true if the add succeeded, false otherwise. (Failure most likely * indicates insufficent memory to make copies of the key and value. */ bool hash_add(struct hash_table *ht, const char *key, const char *value); /** * Looks up a the value associated with with a key from a specific hash table. * * \param ht The hash table context to look up the key in. * \param key The key to search for. * \return The value associated with the key, or NULL if it was not found. */ const char *hash_get(struct hash_table *ht, const char *key); #endif