/*-
 * Copyright (c) 2015--2019 Taylor R. Campbell
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef	CRITBIT_H
#define	CRITBIT_H

#ifdef _KERNEL
#include <sys/types.h>
#else  /* !_KERNEL */
#include <stdbool.h>
#include <stdint.h>
#endif	/* _KERNEL */

struct critbit;
struct critbit_node;

struct critbit_ops {
	const void	*(*cbo_key)(const struct critbit *,
			    const struct critbit_node *, size_t *);
	void		(*cbo_membar_producer)(void);
	void		(*cbo_membar_datadep_consumer)(void);
	struct critbit_branch *
			(*cbo_branch_alloc)(struct critbit *);
	void		(*cbo_branch_free)(struct critbit *,
			    struct critbit_branch *);
};

struct critbit {
	uintptr_t			cb_root;
	const struct critbit_ops	*cb_ops;
};

struct critbit_branch {
	uintptr_t		cbb_child[2];
	uint16_t		cbb_idx;
	uint16_t		cbb_bits;
};

/* Needed only for alignment.  */
struct critbit_node {
} __aligned(2);

#define	CRITBIT_MAX_KEYLEN	65535

void	critbit_init(struct critbit *, const struct critbit_ops *);
void	critbit_destroy(struct critbit *);

void	critbit_node_init(struct critbit_node *, const void *, size_t);
void	critbit_node_destroy(struct critbit_node *);

struct critbit_branch *
	critbit_branch_alloc(struct critbit *);
void	critbit_branch_free(struct critbit *, struct critbit_branch *);

bool	critbit_empty(const struct critbit *);
struct critbit_node *
	critbit_lookup(const struct critbit *, const void *, size_t);
struct critbit_node *
	critbit_min(const struct critbit *);
struct critbit_node *
	critbit_max(const struct critbit *);
struct critbit_node *
	critbit_min_prefix(const struct critbit *, const void *, size_t);
struct critbit_node *
	critbit_max_prefix(const struct critbit *, const void *, size_t);
struct critbit_node *
	critbit_insert(struct critbit *, struct critbit_node *);
struct critbit_node *
	critbit_insert_explicit(struct critbit *, struct critbit_node *,
	    struct critbit_branch **);
void	critbit_delete(struct critbit *, struct critbit_node *);
void	critbit_delete_explicit(struct critbit *, struct critbit_node *,
	    struct critbit_branch **);
struct critbit_node *
	critbit_delete_key(struct critbit *, const void *, size_t);
struct critbit_node *
	critbit_delete_key_explicit(struct critbit *, const void *, size_t,
	    struct critbit_branch **);

struct critbit_iter {
	struct critbit	*cbi_critbit;
	uintptr_t	cbi_root;
	unsigned char	*cbi_stack;	/* dir_{8i+j} is 1 & (stack[i] >> j) */
	unsigned	cbi_stacklen;
	unsigned	cbi_depth;	/* number of bits down the stack */
};

void	critbit_iter_init(struct critbit *, struct critbit_iter *, void *,
	    size_t);
void	critbit_iter_destroy(struct critbit *, struct critbit_iter *);
struct critbit_node *
	critbit_iter_min(struct critbit *, struct critbit_iter *);
struct critbit_node *
	critbit_iter_max(struct critbit *, struct critbit_iter *);
struct critbit_node *
	critbit_iter_min_prefix(struct critbit *, struct critbit_iter *,
	    const void *, size_t);
struct critbit_node *
	critbit_iter_max_prefix(struct critbit *, struct critbit_iter *,
	    const void *, size_t);
struct critbit_node *
	critbit_iter_next(struct critbit *, struct critbit_iter *);
struct critbit_node *
	critbit_iter_prev(struct critbit *, struct critbit_iter *);

void	critbit_check(struct critbit *);
void	critbit_print(struct critbit *);

#endif	/* CRITBIT_H */