+++ /dev/null
-/*
- * 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
- *
- */
-
-#include "main.h"
-#include "hash.h"
-
-/* clears the hash */
-static void hash_init(struct hashtable_t *hash)
-{
- int i;
-
- hash->elements = 0;
-
- for (i = 0 ; i < hash->size; i++)
- hash->table[i] = NULL;
-}
-
-/* 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, void *arg)
-{
- struct element_t *bucket, *last_bucket;
- int i;
-
- for (i = 0; i < hash->size; i++) {
- bucket = hash->table[i];
-
- while (bucket != NULL) {
- if (free_cb != NULL)
- free_cb(bucket->data, arg);
-
- last_bucket = bucket;
- bucket = bucket->next;
- kfree(last_bucket);
- }
- }
-
- hash_destroy(hash);
-}
-
-/* free only the hashtable and the hash itself. */
-void hash_destroy(struct hashtable_t *hash)
-{
- kfree(hash->table);
- kfree(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. */
-
-struct hash_it_t *hash_iterate(struct hashtable_t *hash,
- struct hash_it_t *iter)
-{
- if (!hash)
- return NULL;
- if (!iter)
- return NULL;
-
- /* sanity checks first (if our bucket got deleted in the last
- * iteration): */
- if (iter->bucket != NULL) {
- if (iter->first_bucket != NULL) {
- /* we're on the first element and it got removed after
- * the last iteration. */
- if ((*iter->first_bucket) != iter->bucket) {
- /* there are still other elements in the list */
- if ((*iter->first_bucket) != NULL) {
- iter->prev_bucket = NULL;
- iter->bucket = (*iter->first_bucket);
- iter->first_bucket =
- &hash->table[iter->index];
- return iter;
- } else {
- iter->bucket = NULL;
- }
- }
- } else if (iter->prev_bucket != NULL) {
- /*
- * we're not on the first element, and the bucket got
- * removed after the last iteration. the last bucket's
- * next pointer is not pointing to our actual bucket
- * anymore. select the next.
- */
- if (iter->prev_bucket->next != iter->bucket)
- iter->bucket = iter->prev_bucket;
- }
- }
-
- /* now as we are sane, select the next one if there is some */
- if (iter->bucket != NULL) {
- if (iter->bucket->next != NULL) {
- iter->prev_bucket = iter->bucket;
- iter->bucket = iter->bucket->next;
- iter->first_bucket = NULL;
- return iter;
- }
- }
-
- /* if not returned yet, we've reached the last one on the index and have
- * to search forward */
- iter->index++;
- /* go through the entries of the hash table */
- while (iter->index < hash->size) {
- if ((hash->table[iter->index]) != NULL) {
- iter->prev_bucket = NULL;
- iter->bucket = hash->table[iter->index];
- iter->first_bucket = &hash->table[iter->index];
- return iter;
- } else {
- iter->index++;
- }
- }
-
- /* nothing to iterate over anymore */
- return NULL;
-}
-
-/* allocates and clears the hash */
-struct hashtable_t *hash_new(int size, hashdata_compare_cb compare,
- hashdata_choose_cb choose)
-{
- struct hashtable_t *hash;
-
- hash = kmalloc(sizeof(struct hashtable_t) , GFP_ATOMIC);
-
- if (hash == NULL)
- return NULL;
-
- hash->size = size;
- hash->table = kmalloc(sizeof(struct element_t *) * size, GFP_ATOMIC);
-
- if (hash->table == NULL) {
- kfree(hash);
- return NULL;
- }
-
- hash_init(hash);
-
- hash->compare = compare;
- hash->choose = choose;
-
- return hash;
-}
-
-/* adds data to the hashtable. returns 0 on success, -1 on error */
-int hash_add(struct hashtable_t *hash, void *data)
-{
- int index;
- struct element_t *bucket, *prev_bucket = NULL;
-
- if (!hash)
- return -1;
-
- index = hash->choose(data, hash->size);
- bucket = hash->table[index];
-
- while (bucket != NULL) {
- if (hash->compare(bucket->data, data))
- return -1;
-
- prev_bucket = bucket;
- bucket = bucket->next;
- }
-
- /* found the tail of the list, add new element */
- bucket = kmalloc(sizeof(struct element_t), GFP_ATOMIC);
-
- if (bucket == NULL)
- return -1;
-
- bucket->data = data;
- bucket->next = NULL;
-
- /* and link it */
- if (prev_bucket == NULL)
- hash->table[index] = bucket;
- else
- prev_bucket->next = bucket;
-
- hash->elements++;
- return 0;
-}
-
-/* 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)
-{
- int index;
- struct element_t *bucket;
-
- if (!hash)
- return NULL;
-
- index = hash->choose(keydata , hash->size);
- bucket = hash->table[index];
-
- while (bucket != NULL) {
- if (hash->compare(bucket->data, keydata))
- return bucket->data;
-
- bucket = bucket->next;
- }
-
- return NULL;
-}
-
-/* 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)
-{
- void *data_save;
-
- data_save = hash_it_t->bucket->data;
-
- if (hash_it_t->prev_bucket != NULL)
- hash_it_t->prev_bucket->next = hash_it_t->bucket->next;
- else if (hash_it_t->first_bucket != NULL)
- (*hash_it_t->first_bucket) = hash_it_t->bucket->next;
-
- kfree(hash_it_t->bucket);
- hash->elements--;
-
- return data_save;
-}
-
-/* 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)
-{
- struct hash_it_t hash_it_t;
-
- hash_it_t.index = hash->choose(data, hash->size);
- hash_it_t.bucket = hash->table[hash_it_t.index];
- hash_it_t.prev_bucket = NULL;
-
- while (hash_it_t.bucket != NULL) {
- if (hash->compare(hash_it_t.bucket->data, data)) {
- hash_it_t.first_bucket =
- (hash_it_t.bucket ==
- hash->table[hash_it_t.index] ?
- &hash->table[hash_it_t.index] : NULL);
- return hash_remove_bucket(hash, &hash_it_t);
- }
-
- hash_it_t.prev_bucket = hash_it_t.bucket;
- hash_it_t.bucket = hash_it_t.bucket->next;
- }
-
- return NULL;
-}
-
-/* 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)
-{
- struct hashtable_t *new_hash;
- struct element_t *bucket;
- int i;
-
- /* initialize a new hash with the new size */
- new_hash = hash_new(size, hash->compare, hash->choose);
-
- if (new_hash == NULL)
- return NULL;
-
- /* copy the elements */
- for (i = 0; i < hash->size; i++) {
- bucket = hash->table[i];
-
- while (bucket != NULL) {
- hash_add(new_hash, bucket->data);
- bucket = bucket->next;
- }
- }
-
- /* remove hash and eventual overflow buckets but not the content
- * itself. */
- hash_delete(hash, NULL, NULL);
-
- return new_hash;
-}
projects / mv-sheeva.git / blobdiff