/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  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.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)queue.h	8.5 (Berkeley) 8/20/94
 * $FreeBSD$
 *
 * $FreeBSD$
 */

#ifndef _QUEUE_H_
#define	_QUEUE_H_

#undef __offsetof
#define	__offsetof(type, field)	((size_t)(&((type *)0)->field))

/*
 * Singly-linked Tail queue declarations.
 */
#undef STAILQ_HEAD
#define	STAILQ_HEAD(name, type)						\
struct name {								\
	struct type *stqh_first;/* first element */			\
	struct type **stqh_last;/* addr of last next element */		\
}

#undef STAILQ_HEAD_INITIALIZER
#define	STAILQ_HEAD_INITIALIZER(head)					\
	{ NULL, &(head).stqh_first }

#undef STAILQ_ENTRY
#define	STAILQ_ENTRY(type)						\
struct {								\
	struct type *stqe_next;	/* next element */			\
}

#undef STAILQ_EMPTY
#define	STAILQ_EMPTY(head)	((head)->stqh_first == NULL)

#undef STAILQ_FIRST
#define	STAILQ_FIRST(head)	((head)->stqh_first)

#undef STAILQ_FOREACH
#define	STAILQ_FOREACH(var, head, field)				\
	for((var) = STAILQ_FIRST((head));				\
	   (var);							\
	   (var) = STAILQ_NEXT((var), field))

#undef STAILQ_FOREACH_SAFE
#define	STAILQ_FOREACH_SAFE(var, head, field, tvar)			\
	for ((var) = STAILQ_FIRST((head));				\
	    (var) && ((tvar) = STAILQ_NEXT((var), field), 1);		\
	    (var) = (tvar))

#undef STAILQ_INIT
#define	STAILQ_INIT(head) do {						\
	STAILQ_FIRST((head)) = NULL;					\
	(head)->stqh_last = &STAILQ_FIRST((head));			\
} while (0)

#undef STAILQ_INSERT_AFTER
#define	STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {		\
	if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
	STAILQ_NEXT((tqelm), field) = (elm);				\
} while (0)

#undef STAILQ_INSERT_HEAD
#define	STAILQ_INSERT_HEAD(head, elm, field) do {			\
	if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL)	\
		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
	STAILQ_FIRST((head)) = (elm);					\
} while (0)

#undef STAILQ_INSERT_TAIL
#define	STAILQ_INSERT_TAIL(head, elm, field) do {			\
	STAILQ_NEXT((elm), field) = NULL;				\
	*(head)->stqh_last = (elm);					\
	(head)->stqh_last = &STAILQ_NEXT((elm), field);			\
} while (0)

#undef STAILQ_LAST
#define	STAILQ_LAST(head, type, field)					\
	(STAILQ_EMPTY((head)) ?						\
		NULL :							\
	        ((struct type *)(void *)				\
		((char *)((head)->stqh_last) - __offsetof(struct type, field))))

#undef STAILQ_NEXT
#define	STAILQ_NEXT(elm, field)	((elm)->field.stqe_next)

#undef STAILQ_REMOVE
#define	STAILQ_REMOVE(head, elm, type, field) do {			\
	if (STAILQ_FIRST((head)) == (elm)) {				\
		STAILQ_REMOVE_HEAD((head), field);			\
	}								\
	else {								\
		struct type *curelm = STAILQ_FIRST((head));		\
		while (STAILQ_NEXT(curelm, field) != (elm))		\
			curelm = STAILQ_NEXT(curelm, field);		\
		if ((STAILQ_NEXT(curelm, field) =			\
		     STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
			(head)->stqh_last = &STAILQ_NEXT((curelm), field);\
	}								\
} while (0)

#undef STAILQ_REMOVE_HEAD
#define	STAILQ_REMOVE_HEAD(head, field) do {				\
	if ((STAILQ_FIRST((head)) =					\
	     STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)		\
		(head)->stqh_last = &STAILQ_FIRST((head));		\
} while (0)

#undef STAILQ_REMOVE_HEAD_UNTIL
#define	STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {			\
	if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL)	\
		(head)->stqh_last = &STAILQ_FIRST((head));		\
} while (0)

/*
 * List declarations.
 */
#undef LIST_HEAD
#define	LIST_HEAD(name, type)						\
struct name {								\
	struct type *lh_first;	/* first element */			\
}

#undef LIST_HEAD_INITIALIZER
#define	LIST_HEAD_INITIALIZER(head)					\
	{ NULL }

#undef LIST_ENTRY
#define	LIST_ENTRY(type)						\
struct {								\
	struct type *le_next;	/* next element */			\
	struct type **le_prev;	/* address of previous next element */	\
}

/*
 * List functions.
 */

#undef LIST_EMPTY
#define	LIST_EMPTY(head)	((head)->lh_first == NULL)

#undef LIST_FIRST
#define	LIST_FIRST(head)	((head)->lh_first)

#undef LIST_FOREACH
#define	LIST_FOREACH(var, head, field)					\
	for ((var) = LIST_FIRST((head));				\
	    (var);							\
	    (var) = LIST_NEXT((var), field))

#undef LIST_FOREACH_SAFE
#define	LIST_FOREACH_SAFE(var, head, field, tvar)			\
	for ((var) = LIST_FIRST((head));				\
	    (var) && ((tvar) = LIST_NEXT((var), field), 1);		\
	    (var) = (tvar))

#undef LIST_INIT
#define	LIST_INIT(head) do {						\
	LIST_FIRST((head)) = NULL;					\
} while (0)

#undef LIST_INSERT_AFTER
#define	LIST_INSERT_AFTER(listelm, elm, field) do {			\
	if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
		LIST_NEXT((listelm), field)->field.le_prev =		\
		    &LIST_NEXT((elm), field);				\
	LIST_NEXT((listelm), field) = (elm);				\
	(elm)->field.le_prev = &LIST_NEXT((listelm), field);		\
} while (0)

#undef LIST_INSERT_BEFORE
#define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
	(elm)->field.le_prev = (listelm)->field.le_prev;		\
	LIST_NEXT((elm), field) = (listelm);				\
	*(listelm)->field.le_prev = (elm);				\
	(listelm)->field.le_prev = &LIST_NEXT((elm), field);		\
} while (0)

#undef LIST_INSERT_HEAD
#define	LIST_INSERT_HEAD(head, elm, field) do {				\
	if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)	\
		LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
	LIST_FIRST((head)) = (elm);					\
	(elm)->field.le_prev = &LIST_FIRST((head));			\
} while (0)

#undef LIST_NEXT
#define	LIST_NEXT(elm, field)	((elm)->field.le_next)

#undef LIST_REMOVE
#define	LIST_REMOVE(elm, field) do {					\
	if (LIST_NEXT((elm), field) != NULL)				\
		LIST_NEXT((elm), field)->field.le_prev = 		\
		    (elm)->field.le_prev;				\
	*(elm)->field.le_prev = LIST_NEXT((elm), field);		\
} while (0)

#endif /* !_QUEUE_H_ */