| /* |
| * Copyright (C) 2006-2010 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> |
| |
| #define HASHIT(name) struct hash_it_t name = { \ |
| .index = 0, .walk = NULL, \ |
| .safe = NULL} |
| |
| /* 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 hash_it_t { |
| size_t index; |
| struct hlist_node *walk; |
| struct hlist_node *safe; |
| }; |
| |
| struct hashtable_t { |
| struct hlist_head *table; /* the hashtable itself, with the buckets */ |
| int elements; /* number of elements registered */ |
| int size; /* size of hashtable */ |
| }; |
| |
| /* allocates and clears the hash */ |
| struct hashtable_t *hash_new(int size); |
| |
| /* 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); |
| |
| /* 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 != NULL) |
| 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 == NULL) |
| return -1; |
| |
| bucket->data = data; |
| hlist_add_head(&bucket->hlist, head); |
| |
| hash->elements++; |
| 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) |
| { |
| struct hash_it_t hash_it_t; |
| struct element_t *bucket; |
| struct hlist_head *head; |
| |
| hash_it_t.index = choose(data, hash->size); |
| head = &hash->table[hash_it_t.index]; |
| |
| hlist_for_each(hash_it_t.walk, head) { |
| bucket = hlist_entry(hash_it_t.walk, struct element_t, hlist); |
| if (compare(bucket->data, data)) |
| return hash_remove_bucket(hash, &hash_it_t); |
| } |
| |
| 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; |
| } |
| |
| /* resize the hash, returns the pointer to the new hash or NULL on |
| * error. removes the old hash on success */ |
| static inline struct hashtable_t *hash_resize(struct hashtable_t *hash, |
| hashdata_choose_cb choose, |
| int size) |
| { |
| struct hashtable_t *new_hash; |
| struct hlist_head *head, *new_head; |
| struct hlist_node *walk, *safe; |
| struct element_t *bucket; |
| int i, new_index; |
| |
| /* initialize a new hash with the new size */ |
| new_hash = hash_new(size); |
| |
| if (new_hash == NULL) |
| return NULL; |
| |
| /* copy the elements */ |
| 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); |
| |
| new_index = choose(bucket->data, size); |
| new_head = &new_hash->table[new_index]; |
| |
| hlist_del(walk); |
| hlist_add_head(walk, new_head); |
| } |
| } |
| |
| hash_destroy(hash); |
| |
| return new_hash; |
| } |
| |
| /* iterate though the hash. First element is selected if an iterator |
| * initialized with HASHIT() is supplied as iter. Use the returned |
| * (or supplied) iterator to access the elements until hash_iterate returns |
| * NULL. */ |
| static inline struct hash_it_t *hash_iterate(struct hashtable_t *hash, |
| struct hash_it_t *iter) |
| { |
| if (!hash) |
| return NULL; |
| if (!iter) |
| return NULL; |
| |
| iter->walk = iter->safe; |
| |
| /* we search for the next head with list entries */ |
| if (!iter->walk) { |
| while (iter->index < hash->size) { |
| if (hlist_empty(&hash->table[iter->index])) |
| iter->index++; |
| else { |
| iter->walk = hash->table[iter->index].first; |
| |
| /* search next time */ |
| ++iter->index; |
| break; |
| } |
| } |
| } |
| |
| /* return iter when we found bucket otherwise null */ |
| if (!iter->walk) |
| return NULL; |
| |
| iter->safe = iter->walk->next; |
| return iter; |
| } |
| |
| #endif /* _NET_BATMAN_ADV_HASH_H_ */ |