/* Hash routine.
   Copyright (C) 1998 Kunihiro Ishiguro

This file is part of GNU Zebra.

GNU Zebra is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 2, or (at your
option) any later version.

GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#ifndef _ZEBRA_HASH_H
#define _ZEBRA_HASH_H

#include "memory.h"

DECLARE_MTYPE(HASH)
DECLARE_MTYPE(HASH_BACKET)

/* Default hash table size.  */
#define HASH_INITIAL_SIZE     256	/* initial number of backets. */
#define HASH_THRESHOLD	      10	/* expand when backet. */

#define HASHWALK_CONTINUE 0
#define HASHWALK_ABORT -1

struct hash_backet {
	/* Linked list.  */
	struct hash_backet *next;

	/* Hash key. */
	unsigned int key;

	/* Data.  */
	void *data;
};

struct hash {
	/* Hash backet. */
	struct hash_backet **index;

	/* Hash table size. Must be power of 2 */
	unsigned int size;

	/* If expansion failed. */
	int no_expand;

	/* Key make function. */
	unsigned int (*hash_key)(void *);

	/* Data compare function. */
	int (*hash_cmp)(const void *, const void *);

	/* Backet alloc. */
	unsigned long count;
};

extern struct hash *hash_create(unsigned int (*)(void *),
				int (*)(const void *, const void *));
extern struct hash *hash_create_size(unsigned int, unsigned int (*)(void *),
				     int (*)(const void *, const void *));

extern void *hash_get(struct hash *, void *, void *(*)(void *));
extern void *hash_alloc_intern(void *);
extern void *hash_lookup(struct hash *, void *);
extern void *hash_release(struct hash *, void *);

extern void hash_iterate(struct hash *, void (*)(struct hash_backet *, void *),
			 void *);

extern void hash_walk(struct hash *, int (*)(struct hash_backet *, void *),
		      void *);

extern void hash_clean(struct hash *, void (*)(void *));
extern void hash_free(struct hash *);

extern unsigned int string_hash_make(const char *);

#endif /* _ZEBRA_HASH_H */