/* apk_hash.h - 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.
 */

#ifndef APK_HASH_H
#define APK_HASH_H

#include <malloc.h>
#include "apk_defines.h"
#include "apk_blob.h"

typedef void *apk_hash_item;

typedef unsigned long (*apk_hash_f)(apk_blob_t);
typedef int (*apk_hash_compare_f)(apk_blob_t, apk_blob_t);
typedef int (*apk_hash_compare_item_f)(apk_hash_item, apk_blob_t);
typedef void (*apk_hash_delete_f)(apk_hash_item);
typedef int (*apk_hash_enumerator_f)(apk_hash_item, void *ctx);

struct apk_hash_ops {
	ptrdiff_t	node_offset;
	apk_blob_t	(*get_key)(apk_hash_item item);
	unsigned long	(*hash_key)(apk_blob_t key);
	unsigned long	(*hash_item)(apk_hash_item item);
	int		(*compare)(apk_blob_t itemkey, apk_blob_t key);
	int		(*compare_item)(apk_hash_item item, apk_blob_t key);
	void		(*delete_item)(apk_hash_item item);
};

typedef struct hlist_node apk_hash_node;
APK_ARRAY(apk_hash_array, struct hlist_head);

struct apk_hash {
	const struct apk_hash_ops *ops;
	struct apk_hash_array *buckets;
	int num_items;
};

void apk_hash_init(struct apk_hash *h, const struct apk_hash_ops *ops,
		   int num_buckets);
void apk_hash_free(struct apk_hash *h);

int apk_hash_foreach(struct apk_hash *h, apk_hash_enumerator_f e, void *ctx);
apk_hash_item apk_hash_get_hashed(struct apk_hash *h, apk_blob_t key, unsigned long hash);
void apk_hash_insert_hashed(struct apk_hash *h, apk_hash_item item, unsigned long hash);
void apk_hash_delete_hashed(struct apk_hash *h, apk_blob_t key, unsigned long hash);

static inline unsigned long apk_hash_from_key(struct apk_hash *h, apk_blob_t key)
{
	return h->ops->hash_key(key);
}

static inline unsigned long apk_hash_from_item(struct apk_hash *h, apk_hash_item item)
{
	if (h->ops->hash_item != NULL)
		return h->ops->hash_item(item);
	return apk_hash_from_key(h, h->ops->get_key(item));
}

static inline apk_hash_item apk_hash_get(struct apk_hash *h, apk_blob_t key)
{
	return apk_hash_get_hashed(h, key, apk_hash_from_key(h, key));
}


static inline void apk_hash_insert(struct apk_hash *h, apk_hash_item item)
{
	return apk_hash_insert_hashed(h, item, apk_hash_from_item(h, item));
}

static inline void apk_hash_delete(struct apk_hash *h, apk_blob_t key)
{
	return apk_hash_delete_hashed(h, key, apk_hash_from_key(h, key));
}

#endif