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/*
* Ouroboros - Copyright (C) 2016
*
* Hash table with separate chaining on collisions
*
* Sander Vrijders <sander.vrijders@intec.ugent.be>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <ouroboros/config.h>
#include <ouroboros/hashtable.h>
#include <ouroboros/list.h>
#include <ouroboros/errno.h>
#include <assert.h>
struct htable_entry {
struct list_head next;
uint64_t key;
void * val;
};
struct htable {
struct list_head * buckets;
bool hash_key;
uint64_t buckets_size;
};
struct htable * htable_create(uint64_t buckets, bool hash_key)
{
struct htable * tmp;
unsigned int i;
if (buckets == 0)
return NULL;
buckets--;
buckets |= buckets >> 1;
buckets |= buckets >> 2;
buckets |= buckets >> 4;
buckets |= buckets >> 8;
buckets |= buckets >> 16;
buckets |= buckets >> 32;
buckets++;
tmp = malloc(sizeof(*tmp));
if (tmp == NULL)
return NULL;
tmp->hash_key = hash_key;
tmp->buckets_size = buckets;
tmp->buckets = malloc(buckets * sizeof(*tmp->buckets));
if (tmp->buckets == NULL) {
free(tmp);
return NULL;
}
for (i = 0; i < buckets; i++)
list_head_init(&(tmp->buckets[i]));
return tmp;
}
int htable_destroy(struct htable * table)
{
unsigned int i;
struct list_head * pos = NULL;
struct list_head * n = NULL;
struct htable_entry * entry;
assert(table);
for (i = 0; i < table->buckets_size; i++) {
list_for_each_safe(pos, n, &(table->buckets[i])) {
entry = list_entry(pos, struct htable_entry, next);
free(entry->val);
free(entry);
}
}
free(table->buckets);
free(table);
return 0;
}
static uint64_t hash(uint64_t x)
{
x = (x ^ (x >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
x = (x ^ (x >> 27)) * UINT64_C(0x94d049bb133111eb);
x = x ^ (x >> 31);
return x;
}
static uint64_t calc_key(struct htable * table, uint64_t key)
{
if (table->hash_key == true)
key = hash(key);
return (key & (table->buckets_size - 1));
}
int htable_insert(struct htable * table, uint64_t key, void * val)
{
struct htable_entry * entry;
uint64_t lookup_key;
struct list_head * pos = NULL;
assert(table);
lookup_key = calc_key(table, key);
list_for_each(pos, &(table->buckets[lookup_key])) {
entry = list_entry(pos, struct htable_entry, next);
if (entry->key == key)
return -1;
}
entry = malloc(sizeof(*entry));
if (entry == NULL)
return -ENOMEM;
entry->key = key;
entry->val = val;
list_head_init(&entry->next);
list_add(&entry->next, &(table->buckets[lookup_key]));
return 0;
}
void * htable_lookup(struct htable * table, uint64_t key)
{
struct htable_entry * entry;
struct list_head * pos = NULL;
uint64_t lookup_key;
assert(table);
lookup_key = calc_key(table, key);
list_for_each(pos, &(table->buckets[lookup_key])) {
entry = list_entry(pos, struct htable_entry, next);
if (entry->key == key)
return entry->val;
}
return NULL;
}
int htable_delete(struct htable * table, uint64_t key)
{
struct htable_entry * entry;
uint64_t lookup_key;
struct list_head * pos = NULL;
struct list_head * n = NULL;
assert(table);
lookup_key = calc_key(table, key);
list_for_each_safe(pos, n, &(table->buckets[lookup_key])) {
entry = list_entry(pos, struct htable_entry, next);
if (entry->key == key) {
list_del(&entry->next);
free(entry->val);
free(entry);
return 0;
}
}
return -1;
}
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