[deliverable/linux.git] / net / batman-adv / hash.h

/*
 * Copyright (C) 2006-2011 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 _NET_BATMAN_ADV_HASH_H_
#define _NET_BATMAN_ADV_HASH_H_

#include <linux/list.h>

/* callback to a compare function.  should
 * compare 2 element datas for their keys,
 * return 0 if same and not 0 if not
 * same */
typedef int (*hashdata_compare_cb)(void *, void *);

/* the hashfunction, should return an index
 * based on the key in the data of the first
 * argument and the size the second */
typedef int (*hashdata_choose_cb)(void *, int);
typedef void (*hashdata_free_cb)(void *, void *);

struct element_t {
	void *data;		/* pointer to the data */
	struct hlist_node hlist;	/* bucket list pointer */
};

struct hashtable_t {
	struct hlist_head *table;   /* the hashtable itself, with the buckets */
	int size;		    /* size of hashtable */
};

/* allocates and clears the hash */
struct hashtable_t *hash_new(int size);

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

/* 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. */
static inline void hash_delete(struct hashtable_t *hash,
			       hashdata_free_cb free_cb, void *arg)
{
	struct hlist_head *head;
	struct hlist_node *walk, *safe;
	struct element_t *bucket;
	int i;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		hlist_for_each_safe(walk, safe, head) {
			bucket = hlist_entry(walk, struct element_t, hlist);
			if (free_cb)
				free_cb(bucket->data, arg);

			hlist_del(walk);
			kfree(bucket);
		}
	}

	hash_destroy(hash);
}

/* adds data to the hashtable. returns 0 on success, -1 on error */
static inline int hash_add(struct hashtable_t *hash,
			   hashdata_compare_cb compare,
			   hashdata_choose_cb choose, void *data)
{
	int index;
	struct hlist_head *head;
	struct hlist_node *walk, *safe;
	struct element_t *bucket;

	if (!hash)
		return -1;

	index = choose(data, hash->size);
	head = &hash->table[index];

	hlist_for_each_safe(walk, safe, head) {
		bucket = hlist_entry(walk, struct element_t, hlist);
		if (compare(bucket->data, data))
			return -1;
	}

	/* no duplicate found in list, add new element */
	bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC);

	if (!bucket)
		return -1;

	bucket->data = data;
	hlist_add_head(&bucket->hlist, head);

	return 0;
}

/* 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. */
static inline void *hash_remove(struct hashtable_t *hash,
				hashdata_compare_cb compare,
				hashdata_choose_cb choose, void *data)
{
	size_t index;
	struct hlist_node *walk;
	struct element_t *bucket;
	struct hlist_head *head;
	void *data_save;

	index = choose(data, hash->size);
	head = &hash->table[index];

	hlist_for_each_entry(bucket, walk, head, hlist) {
		if (compare(bucket->data, data)) {
			data_save = bucket->data;
			hlist_del(walk);
			kfree(bucket);
			return data_save;
		}
	}

	return NULL;
}

/* finds data, based on the key in keydata. returns the found data on success,
 * or NULL on error */
static inline void *hash_find(struct hashtable_t *hash,
			      hashdata_compare_cb compare,
			      hashdata_choose_cb choose, void *keydata)
{
	int index;
	struct hlist_head *head;
	struct hlist_node *walk;
	struct element_t *bucket;

	if (!hash)
		return NULL;

	index = choose(keydata , hash->size);
	head = &hash->table[index];

	hlist_for_each(walk, head) {
		bucket = hlist_entry(walk, struct element_t, hlist);
		if (compare(bucket->data, keydata))
			return bucket->data;
	}

	return NULL;
}

#endif /* _NET_BATMAN_ADV_HASH_H_ */
Commit	Line	Data
c6c8fea2	1	/*
64afe353	2	* Copyright (C) 2006-2011 B.A.T.M.A.N. contributors:
c6c8fea2 SE	3	*
	4	* Simon Wunderlich, Marek Lindner
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of version 2 of the GNU General Public
	8	* License as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	18	* 02110-1301, USA
	19	*
	20	*/
	21
	22	#ifndef _NET_BATMAN_ADV_HASH_H_
	23	#define _NET_BATMAN_ADV_HASH_H_
	24
	25	#include <linux/list.h>
	26
	27	/* callback to a compare function. should
	28	* compare 2 element datas for their keys,
	29	* return 0 if same and not 0 if not
	30	* same */
	31	typedef int (hashdata_compare_cb)(void , void *);
	32
	33	/* the hashfunction, should return an index
	34	* based on the key in the data of the first
	35	* argument and the size the second */
	36	typedef int (hashdata_choose_cb)(void , int);
	37	typedef void (hashdata_free_cb)(void , void *);
	38
	39	struct element_t {
	40	void data; / pointer to the data */
	41	struct hlist_node hlist; /* bucket list pointer */
	42	};
	43
	44	struct hashtable_t {
	45	struct hlist_head table; / the hashtable itself, with the buckets */
	46	int size; /* size of hashtable */
	47	};
	48
	49	/* allocates and clears the hash */
	50	struct hashtable_t *hash_new(int size);
	51
c6c8fea2 SE	52	/* free only the hashtable and the hash itself. */
	53	void hash_destroy(struct hashtable_t *hash);
	54
	55	/* remove the hash structure. if hashdata_free_cb != NULL, this function will be
	56	* called to remove the elements inside of the hash. if you don't remove the
	57	* elements, memory might be leaked. */
	58	static inline void hash_delete(struct hashtable_t *hash,
	59	hashdata_free_cb free_cb, void *arg)
	60	{
	61	struct hlist_head *head;
	62	struct hlist_node walk, safe;
	63	struct element_t *bucket;
	64	int i;
	65
	66	for (i = 0; i < hash->size; i++) {
	67	head = &hash->table[i];
	68
	69	hlist_for_each_safe(walk, safe, head) {
	70	bucket = hlist_entry(walk, struct element_t, hlist);
	71	if (free_cb)
	72	free_cb(bucket->data, arg);
	73
	74	hlist_del(walk);
	75	kfree(bucket);
	76	}
	77	}
	78
	79	hash_destroy(hash);
	80	}
	81
	82	/* adds data to the hashtable. returns 0 on success, -1 on error */
	83	static inline int hash_add(struct hashtable_t *hash,
	84	hashdata_compare_cb compare,
	85	hashdata_choose_cb choose, void *data)
	86	{
	87	int index;
	88	struct hlist_head *head;
	89	struct hlist_node walk, safe;
	90	struct element_t *bucket;
	91
	92	if (!hash)
	93	return -1;
	94
	95	index = choose(data, hash->size);
	96	head = &hash->table[index];
	97
	98	hlist_for_each_safe(walk, safe, head) {
	99	bucket = hlist_entry(walk, struct element_t, hlist);
	100	if (compare(bucket->data, data))
	101	return -1;
	102	}
	103
	104	/* no duplicate found in list, add new element */
	105	bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC);
	106
	107	if (!bucket)
	108	return -1;
	109
	110	bucket->data = data;
	111	hlist_add_head(&bucket->hlist, head);
	112
	113	return 0;
	114	}
	115
116	/* removes data from hash, if found. returns pointer do data on success, so you
117	* can remove the used structure yourself, or NULL on error . data could be the
118	* structure you use with just the key filled, we just need the key for
119	* comparing. */
120	static inline void hash_remove(struct hashtable_t hash,
121	hashdata_compare_cb compare,
122	hashdata_choose_cb choose, void *data)
123	{
124	size_t index;
125	struct hlist_node *walk;
126	struct element_t *bucket;
127	struct hlist_head *head;
128	void *data_save;
129
130	index = choose(data, hash->size);
131	head = &hash->table[index];
132
133	hlist_for_each_entry(bucket, walk, head, hlist) {
134	if (compare(bucket->data, data)) {
135	data_save = bucket->data;
136	hlist_del(walk);
137	kfree(bucket);
138	return data_save;
139	}
140	}
141
142	return NULL;
143	}
144
145	/* finds data, based on the key in keydata. returns the found data on success,
146	* or NULL on error */
147	static inline void hash_find(struct hashtable_t hash,
148	hashdata_compare_cb compare,
149	hashdata_choose_cb choose, void *keydata)
150	{
151	int index;
152	struct hlist_head *head;
153	struct hlist_node *walk;
154	struct element_t *bucket;
155
156	if (!hash)
157	return NULL;
158
159	index = choose(keydata , hash->size);
160	head = &hash->table[index];
161
162	hlist_for_each(walk, head) {
163	bucket = hlist_entry(walk, struct element_t, hlist);
164	if (compare(bucket->data, keydata))
165	return bucket->data;
166	}
167
168	return NULL;
169	}
170
171	#endif /* _NET_BATMAN_ADV_HASH_H_ */