/* 
 * Copyright (C) 2006-2012 B.A.T.M.A.N. contributors:
 *
 * Simon Wunderlich, Marek Lindner
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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 _BATMAN_HASH_H
#define _BATMAN_HASH_H



typedef int (*hashdata_compare_cb)(void *, void *);
typedef int (*hashdata_choose_cb)(void *, int);
typedef void (*hashdata_free_cb)(void *);

struct element_t {
	void *data;						/* pointer to the data */
	struct element_t *next;			/* overflow bucket pointer */
};

struct hash_it_t {
	int index;
	struct element_t *bucket;
	struct element_t *prev_bucket;
	struct element_t **first_bucket;
};

struct hashtable_t {
	struct element_t **table;					/* the hashtable itself, with the buckets */
	int elements;								/* number of elements registered */
	int size;									/* size of hashtable */
	hashdata_compare_cb compare;			    /* callback to a compare function.
												 * should compare 2 element datas for their keys,
												 * return 0 if same and not 0 if not same */
	hashdata_choose_cb choose;					/* the hashfunction, should return an index based
												 * on the key in the data of the first argument
												 * and the size the second */
};

/* clears the hash */
void 				 hash_init(struct hashtable_t *hash);

/* allocates and clears the hash */
struct hashtable_t	*hash_new(int size, hashdata_compare_cb compare, hashdata_choose_cb choose);

/* remove bucket (this might be used in hash_iterate() if you already found the bucket
 * you want to delete and don't need the overhead to find it again with hash_remove().
 * But usually, you don't want to use this function, as it fiddles with hash-internals. */
void 				*hash_remove_bucket(struct hashtable_t *hash, struct hash_it_t *hash_it_t);

/* remove the hash structure. if hashdata_free_cb != NULL,
 * this function will be called to remove the elements inside of the hash.
 * if you don't remove the elements, memory might be leaked. */
void 				 hash_delete(struct hashtable_t *hash, hashdata_free_cb free_cb);

/* free only the hashtable and the hash itself. */
void 				 hash_destroy(struct hashtable_t *hash);

/* adds data to the hashtable. returns 0 on success, -1 on error */
int 				 hash_add(struct hashtable_t *hash, void *data);

/* removes data from hash, if found. returns pointer do data on success,
 * so you can remove the used structure yourself, or NULL on error .
 * data could be the structure you use with just the key filled,
 * we just need the key for comparing. */
void 				*hash_remove(struct hashtable_t *hash, void *data);

/* finds data, based on the key in keydata. returns the found data on success, or NULL on error */
void 				*hash_find(struct hashtable_t *hash, void *keydata);

/* resize the hash, returns the pointer to the new hash or NULL on error. removes the old hash on success */
struct hashtable_t	*hash_resize(struct hashtable_t *hash, int size);

/* print the hash table for debugging */
void 				 hash_debug( struct hashtable_t *hash);

/* iterate though the hash. first element is selected with iter_in NULL.
 * use the returned iterator to access the elements until hash_it_t returns NULL. */
struct hash_it_t 	*hash_iterate(struct hashtable_t *hash, struct hash_it_t *iter_in);

#endif
