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/*
* hashtable.c
* really simple hash table implementation
*
* Copyright (c) 2011 Nikias Bassen, All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "hashtable.h"
hashtable_t* hash_table_new(hash_func_t hash_func, compare_func_t compare_func)
{
hashtable_t* ht = (hashtable_t*)malloc(sizeof(hashtable_t));
int i;
for (i = 0; i < 256; i++) {
ht->entries[i] = NULL;
}
ht->count = 0;
ht->hash_func = hash_func;
ht->compare_func = compare_func;
return ht;
}
void hash_table_destroy(hashtable_t *ht)
{
if (!ht) return;
int i = 0;
for (i = 0; i < 256; i++) {
if (ht->entries[i]) {
hashentry_t* e = ht->entries[i];
while (e) {
free(e->value);
hashentry_t* old = e;
e = e->next;
free(old);
}
}
}
free(ht);
}
void hash_table_insert(hashtable_t* ht, void *key, void *value)
{
if (!ht || !key) return;
int i;
unsigned int hash = ht->hash_func(key);
int idx0 = hash & 0xFF;
// get the idx0 list
hashentry_t* e = ht->entries[idx0];
while (e) {
if (ht->compare_func(e->key, key)) {
// element already present. replace value.
e->value = value;
return;
}
e = e->next;
}
// if we get here, the element is not yet in the list.
// make a new entry.
hashentry_t* entry = (hashentry_t*)malloc(sizeof(hashentry_t));
entry->key = key;
entry->value = value;
if (!ht->entries[idx0]) {
// first entry
entry->next = NULL;
} else {
// add to list
entry->next = ht->entries[idx0];
}
ht->entries[idx0] = entry;
ht->count++;
}
void* hash_table_lookup(hashtable_t* ht, void *key)
{
if (!ht || !key) return NULL;
unsigned int hash = ht->hash_func(key);
int idx0 = hash & 0xFF;
hashentry_t* e = ht->entries[idx0];
while (e) {
if (ht->compare_func(e->key, key)) {
return e->value;
}
e = e->next;
}
return NULL;
}
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