/**

 * @file hash.h

 * @brief Implements a simple hash table.

 * @note Copyright (C) 2015 Richard Cochran <richardcochran@gmail.com>

 *

 * This program 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; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#ifndef HAVE_HASH_H

#define HAVE_HASH_H

struct hash;

/**

 * Create a new hash table.

 * @return  A pointer to a new hash table on success, NULL otherwise.

 */

struct hash *hash_create(void);

/**

 * Destroy an instance of a hash table.

 * @param ht   Pointer to a hash table obtained via @ref hash_create().

 * @param func Callback function, possibly NULL, to apply to the

 *             data of each element in the table.

 */

void hash_destroy(struct hash *ht, void (*func)(void *));

/**

 * Inserts an element into a hash table.

 * @param ht   Hash table into which the element is to be stored.

 * @param key  Key that identifies the element.

 * @param data Pointer to the user data to be stored.

 * @return Zero on success and non-zero on error.  Attempting to

 *         insert a duplicate key will fail with an error.

 */

int hash_insert(struct hash *ht, const char* key, void *data);

/**

 * Looks up an element from the hash table.

 * @param ht   Hash table to consult.

 * @param key  Key identifying the element of interest.

 * @return  Pointer to the element's data, or NULL if the key is not found.

 */

void *hash_lookup(struct hash *ht, const char* key);

#endif