path: root/src/hash.c

/* hash.c - Alpine Package Keeper (APK)
 *
 * Copyright (C) 2005-2008 Natanael Copa <n@tanael.org>
 * Copyright (C) 2008 Timo Teräs <timo.teras@iki.fi>
 * All rights reserved.
 *
 * 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. See http://www.gnu.org/ for details.
 */

#include "apk_defines.h"
#include "apk_hash.h"

unsigned long apk_hash_string(const char *str)
{
	unsigned long hash = 5381;
	int c;

	while ((c = *str++) != 0)
		hash = hash * 33 + c;

	return hash;
}

unsigned long apk_hash_csum(const void *ptr)
{
	return *(const unsigned long *) ptr;
}

void apk_hash_init(struct apk_hash *h, const struct apk_hash_ops *ops,
		   int num_buckets)
{
	h->ops = ops;
	h->buckets = apk_hash_array_resize(NULL, num_buckets);
	h->num_items = 0;
}

void apk_hash_free(struct apk_hash *h)
{
	apk_hash_foreach(h, (apk_hash_enumerator_f) h->ops->delete_item, NULL);
	free(h->buckets);
}

int apk_hash_foreach(struct apk_hash *h, apk_hash_enumerator_f e, void *ctx)
{
	apk_hash_node *pos, *n;
	ptrdiff_t offset = h->ops->node_offset;
	int i, r;

	for (i = 0; i < h->buckets->num; i++) {
		hlist_for_each_safe(pos, n, &h->buckets->item[i]) {
			r = e(((void *) pos) - offset, ctx);
			if (r != 0)
				return r;
		}
	}

	return 0;
}

apk_hash_item apk_hash_get(struct apk_hash *h, apk_hash_key key)
{
	ptrdiff_t offset = h->ops->node_offset;
	unsigned long hash;
	apk_hash_node *pos;
	apk_hash_item item;
	apk_hash_key itemkey;

	hash = h->ops->hash_key(key) % h->buckets->num;
	hlist_for_each(pos, &h->buckets->item[hash]) {
		item = ((void *) pos) - offset;
		itemkey = h->ops->get_key(item);
		if (h->ops->compare(key, itemkey) == 0)
			return item;
	}

	return NULL;
}

void apk_hash_insert(struct apk_hash *h, apk_hash_item item)
{
	apk_hash_key key;
	unsigned long hash;
	apk_hash_node *node;

	key = h->ops->get_key(item);
	hash = h->ops->hash_key(key) % h->buckets->num;
	node = (apk_hash_node *) (item + h->ops->node_offset);
	hlist_add_head(node, &h->buckets->item[hash]);
	h->num_items++;
}

void apk_hash_delete(struct apk_hash *h, apk_hash_key key)
{
}