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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2006-2020 B.A.T.M.A.N. contributors:
*
* Simon Wunderlich, Marek Lindner
*
* License-Filename: LICENSES/preferred/GPL-2.0
*/
#include "hash.h"
#include <stdlib.h>
#include <stdio.h>
#include "alfred.h"
/* clears the hash */
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)
{
struct element_t *bucket, *last_bucket;
int i;
for (i = 0; i < hash->size; i++) {
bucket = hash->table[i];
while (bucket) {
if (free_cb)
free_cb(bucket->data);
last_bucket = bucket;
bucket = bucket->next;
debugFree(last_bucket, 1301);
}
}
hash_destroy(hash);
}
/* adds data to the hashtable and reuse bucket.
* returns 0 on success, -1 on error */
static int hash_add_bucket(struct hashtable_t *hash, void *data,
struct element_t *bucket, int check_duplicate)
{
int index;
struct element_t *bucket_it, *prev_bucket = NULL;
index = hash->choose(data, hash->size);
bucket_it = hash->table[index];
while (bucket_it) {
if (check_duplicate &&
hash->compare(bucket_it->data, data))
return -1;
prev_bucket = bucket_it;
bucket_it = bucket_it->next;
}
/* init the new bucket */
bucket->data = data;
bucket->next = NULL;
/* and link it */
if (!prev_bucket)
hash->table[index] = bucket;
else
prev_bucket->next = bucket;
hash->elements++;
return 0;
}
/* free only the hashtable and the hash itself. */
void hash_destroy(struct hashtable_t *hash)
{
debugFree(hash->table, 1302);
debugFree(hash, 1303);
}
/* free hash_it_t pointer when stopping hash_iterate early */
void hash_iterate_free(struct hash_it_t *iter_in)
{
debugFree(iter_in, 1304);
}
/* 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)
{
struct hash_it_t *iter;
if (!iter_in) {
iter = debugMalloc(sizeof(struct hash_it_t), 301);
if (!iter)
return NULL;
iter->index = -1;
iter->bucket = NULL;
iter->prev_bucket = NULL;
} else {
iter = iter_in;
}
/* sanity checks first (if our bucket got deleted in the last
* iteration): */
if (iter->bucket) {
if (iter->first_bucket) {
/* 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) {
iter->prev_bucket = NULL;
iter->bucket = (*iter->first_bucket);
iter->first_bucket = &hash->table[iter->index];
return iter;
}
iter->bucket = NULL;
}
} else if (iter->prev_bucket) {
/* 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) {
if (iter->bucket->next) {
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]) {
iter->index++;
continue;
}
iter->prev_bucket = NULL;
iter->bucket = hash->table[iter->index];
iter->first_bucket = &hash->table[iter->index];
return iter; /* if this table entry is not null, return it */
}
/* nothing to iterate over anymore */
hash_iterate_free(iter);
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 = debugMalloc(sizeof(struct hashtable_t), 302);
if (!hash)
return NULL;
hash->size = size;
hash->table = debugMalloc(sizeof(struct element_t *) * size, 303);
if (!hash->table) {
debugFree(hash, 1305);
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 ret;
struct element_t *bucket;
/* found the tail of the list, add new element */
bucket = debugMalloc(sizeof(struct element_t), 304);
if (!bucket)
return -1;
ret = hash_add_bucket(hash, data, bucket, 1);
if (ret < 0)
debugFree(bucket, 1307);
return ret;
}
/* 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;
index = hash->choose(keydata, hash->size);
bucket = hash->table[index];
while (bucket) {
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;
/* save the pointer to the data */
data_save = hash_it_t->bucket->data;
if (hash_it_t->prev_bucket)
hash_it_t->prev_bucket->next = hash_it_t->bucket->next;
else if (hash_it_t->first_bucket)
(*hash_it_t->first_bucket) = hash_it_t->bucket->next;
debugFree(hash_it_t->bucket, 1306);
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) {
if (hash->compare(hash_it_t.bucket->data, data)) {
struct element_t **first_bucket = NULL;
if (hash_it_t.bucket == hash->table[hash_it_t.index])
first_bucket = &hash->table[hash_it_t.index];
hash_it_t.first_bucket = first_bucket;
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)
return NULL;
/* copy the elements */
for (i = 0; i < hash->size; i++) {
while (hash->table[i]) {
bucket = hash->table[i];
hash->table[i] = bucket->next;
hash_add_bucket(new_hash, bucket->data, bucket, 0);
}
}
/* remove hash and eventual overflow buckets but not the
* content itself. */
hash_delete(hash, NULL);
return new_hash;
}
/* print the hash table for debugging */
/* void hash_debug(struct hashtable_t *hash) {
int i;
struct element_t *bucket;
for (i = 0; i < hash->size; i++) {
printf("[%d] ", i);
bucket = hash->table[i];
while (bucket) {
printf("-> [%10p] ", (void *)bucket);
bucket = bucket->next;
}
printf("\n");
}
printf("\n");
}*/
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