[openssh.git] / openbsd-compat / fake-queue.h

/*	$OpenBSD: queue.h,v 1.22 2001/06/23 04:39:35 angelos Exp $	*/
/*	$NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $	*/

/*
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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
 */

#ifndef	_SYS_QUEUE_H_
#define	_SYS_QUEUE_H_

/*
 * This file defines five types of data structures: singly-linked lists, 
 * lists, simple queues, tail queues, and circular queues.
 *
 *
 * A singly-linked list is headed by a single forward pointer. The elements
 * are singly linked for minimum space and pointer manipulation overhead at
 * the expense of O(n) removal for arbitrary elements. New elements can be
 * added to the list after an existing element or at the head of the list.
 * Elements being removed from the head of the list should use the explicit
 * macro for this purpose for optimum efficiency. A singly-linked list may
 * only be traversed in the forward direction.  Singly-linked lists are ideal
 * for applications with large datasets and few or no removals or for
 * implementing a LIFO queue.
 *
 * A list is headed by a single forward pointer (or an array of forward
 * pointers for a hash table header). The elements are doubly linked
 * so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before
 * or after an existing element or at the head of the list. A list
 * may only be traversed in the forward direction.
 *
 * A simple queue is headed by a pair of pointers, one the head of the
 * list and the other to the tail of the list. The elements are singly
 * linked to save space, so elements can only be removed from the
 * head of the list. New elements can be added to the list before or after
 * an existing element, at the head of the list, or at the end of the
 * list. A simple queue may only be traversed in the forward direction.
 *
 * A tail queue is headed by a pair of pointers, one to the head of the
 * list and the other to the tail of the list. The elements are doubly
 * linked so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before or
 * after an existing element, at the head of the list, or at the end of
 * the list. A tail queue may be traversed in either direction.
 *
 * A circle queue is headed by a pair of pointers, one to the head of the
 * list and the other to the tail of the list. The elements are doubly
 * linked so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before or after
 * an existing element, at the head of the list, or at the end of the list.
 * A circle queue may be traversed in either direction, but has a more
 * complex end of list detection.
 *
 * For details on the use of these macros, see the queue(3) manual page.
 */

/*
 * Singly-linked List definitions.
 */
#define SLIST_HEAD(name, type)						\
struct name {								\
	struct type *slh_first;	/* first element */			\
}
 
#define	SLIST_HEAD_INITIALIZER(head)					\
	{ NULL }
 
#define SLIST_ENTRY(type)						\
struct {								\
	struct type *sle_next;	/* next element */			\
}
 
/*
 * Singly-linked List access methods.
 */
#define	SLIST_FIRST(head)	((head)->slh_first)
#define	SLIST_END(head)		NULL
#define	SLIST_EMPTY(head)	(SLIST_FIRST(head) == SLIST_END(head))
#define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)

#define	SLIST_FOREACH(var, head, field)					\
	for((var) = SLIST_FIRST(head);					\
	    (var) != SLIST_END(head);					\
	    (var) = SLIST_NEXT(var, field))

/*
 * Singly-linked List functions.
 */
#define	SLIST_INIT(head) {						\
	SLIST_FIRST(head) = SLIST_END(head);				\
}

#define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
	(elm)->field.sle_next = (slistelm)->field.sle_next;		\
	(slistelm)->field.sle_next = (elm);				\
} while (0)

#define	SLIST_INSERT_HEAD(head, elm, field) do {			\
	(elm)->field.sle_next = (head)->slh_first;			\
	(head)->slh_first = (elm);					\
} while (0)

#define	SLIST_REMOVE_HEAD(head, field) do {				\
	(head)->slh_first = (head)->slh_first->field.sle_next;		\
} while (0)

#define SLIST_REMOVE(head, elm, type, field) do {			\
	if ((head)->slh_first == (elm)) {				\
		SLIST_REMOVE_HEAD((head), field);			\
	}								\
	else {								\
		struct type *curelm = (head)->slh_first;		\
		while( curelm->field.sle_next != (elm) )		\
			curelm = curelm->field.sle_next;		\
		curelm->field.sle_next =				\
		    curelm->field.sle_next->field.sle_next;		\
	}								\
} while (0)

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

#define LIST_HEAD_INITIALIZER(head)					\
	{ NULL }

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

/*
 * List access methods
 */
#define	LIST_FIRST(head)		((head)->lh_first)
#define	LIST_END(head)			NULL
#define	LIST_EMPTY(head)		(LIST_FIRST(head) == LIST_END(head))
#define	LIST_NEXT(elm, field)		((elm)->field.le_next)

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

/*
 * List functions.
 */
#define	LIST_INIT(head) do {						\
	LIST_FIRST(head) = LIST_END(head);				\
} while (0)

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

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

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

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

#define LIST_REPLACE(elm, elm2, field) do {				\
	if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)	\
		(elm2)->field.le_next->field.le_prev =			\
		    &(elm2)->field.le_next;				\
	(elm2)->field.le_prev = (elm)->field.le_prev;			\
	*(elm2)->field.le_prev = (elm2);				\
} while (0)

/*
 * Simple queue definitions.
 */
#define SIMPLEQ_HEAD(name, type)					\
struct name {								\
	struct type *sqh_first;	/* first element */			\
	struct type **sqh_last;	/* addr of last next element */		\
}

#define SIMPLEQ_HEAD_INITIALIZER(head)					\
	{ NULL, &(head).sqh_first }

#define SIMPLEQ_ENTRY(type)						\
struct {								\
	struct type *sqe_next;	/* next element */			\
}

/*
 * Simple queue access methods.
 */
#define	SIMPLEQ_FIRST(head)	    ((head)->sqh_first)
#define	SIMPLEQ_END(head)	    NULL
#define	SIMPLEQ_EMPTY(head)	    (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
#define	SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)

#define SIMPLEQ_FOREACH(var, head, field)				\
	for((var) = SIMPLEQ_FIRST(head);				\
	    (var) != SIMPLEQ_END(head);					\
	    (var) = SIMPLEQ_NEXT(var, field))

/*
 * Simple queue functions.
 */
#define	SIMPLEQ_INIT(head) do {						\
	(head)->sqh_first = NULL;					\
	(head)->sqh_last = &(head)->sqh_first;				\
} while (0)

#define SIMPLEQ_INSERT_HEAD(head, elm, field) do {			\
	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)	\
		(head)->sqh_last = &(elm)->field.sqe_next;		\
	(head)->sqh_first = (elm);					\
} while (0)

#define SIMPLEQ_INSERT_TAIL(head, elm, field) do {			\
	(elm)->field.sqe_next = NULL;					\
	*(head)->sqh_last = (elm);					\
	(head)->sqh_last = &(elm)->field.sqe_next;			\
} while (0)

#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
		(head)->sqh_last = &(elm)->field.sqe_next;		\
	(listelm)->field.sqe_next = (elm);				\
} while (0)

#define SIMPLEQ_REMOVE_HEAD(head, elm, field) do {			\
	if (((head)->sqh_first = (elm)->field.sqe_next) == NULL)	\
		(head)->sqh_last = &(head)->sqh_first;			\
} while (0)

/*
 * Tail queue definitions.
 */
#define TAILQ_HEAD(name, type)						\
struct name {								\
	struct type *tqh_first;	/* first element */			\
	struct type **tqh_last;	/* addr of last next element */		\
}

#define TAILQ_HEAD_INITIALIZER(head)					\
	{ NULL, &(head).tqh_first }

#define TAILQ_ENTRY(type)						\
struct {								\
	struct type *tqe_next;	/* next element */			\
	struct type **tqe_prev;	/* address of previous next element */	\
}

/* 
 * tail queue access methods 
 */
#define	TAILQ_FIRST(head)		((head)->tqh_first)
#define	TAILQ_END(head)			NULL
#define	TAILQ_NEXT(elm, field)		((elm)->field.tqe_next)
#define TAILQ_LAST(head, headname)					\
	(*(((struct headname *)((head)->tqh_last))->tqh_last))
/* XXX */
#define TAILQ_PREV(elm, headname, field)				\
	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
#define	TAILQ_EMPTY(head)						\
	(TAILQ_FIRST(head) == TAILQ_END(head))

#define TAILQ_FOREACH(var, head, field)					\
	for((var) = TAILQ_FIRST(head);					\
	    (var) != TAILQ_END(head);					\
	    (var) = TAILQ_NEXT(var, field))

#define TAILQ_FOREACH_REVERSE(var, head, field, headname)		\
	for((var) = TAILQ_LAST(head, headname);				\
	    (var) != TAILQ_END(head);					\
	    (var) = TAILQ_PREV(var, headname, field))

/*
 * Tail queue functions.
 */
#define	TAILQ_INIT(head) do {						\
	(head)->tqh_first = NULL;					\
	(head)->tqh_last = &(head)->tqh_first;				\
} while (0)

#define TAILQ_INSERT_HEAD(head, elm, field) do {			\
	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)	\
		(head)->tqh_first->field.tqe_prev =			\
		    &(elm)->field.tqe_next;				\
	else								\
		(head)->tqh_last = &(elm)->field.tqe_next;		\
	(head)->tqh_first = (elm);					\
	(elm)->field.tqe_prev = &(head)->tqh_first;			\
} while (0)

#define TAILQ_INSERT_TAIL(head, elm, field) do {			\
	(elm)->field.tqe_next = NULL;					\
	(elm)->field.tqe_prev = (head)->tqh_last;			\
	*(head)->tqh_last = (elm);					\
	(head)->tqh_last = &(elm)->field.tqe_next;			\
} while (0)

#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
		(elm)->field.tqe_next->field.tqe_prev =			\
		    &(elm)->field.tqe_next;				\
	else								\
		(head)->tqh_last = &(elm)->field.tqe_next;		\
	(listelm)->field.tqe_next = (elm);				\
	(elm)->field.tqe_prev = &(listelm)->field.tqe_next;		\
} while (0)

#define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
	(elm)->field.tqe_next = (listelm);				\
	*(listelm)->field.tqe_prev = (elm);				\
	(listelm)->field.tqe_prev = &(elm)->field.tqe_next;		\
} while (0)

#define TAILQ_REMOVE(head, elm, field) do {				\
	if (((elm)->field.tqe_next) != NULL)				\
		(elm)->field.tqe_next->field.tqe_prev =			\
		    (elm)->field.tqe_prev;				\
	else								\
		(head)->tqh_last = (elm)->field.tqe_prev;		\
	*(elm)->field.tqe_prev = (elm)->field.tqe_next;			\
} while (0)

#define TAILQ_REPLACE(head, elm, elm2, field) do {			\
	if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)	\
		(elm2)->field.tqe_next->field.tqe_prev =		\
		    &(elm2)->field.tqe_next;				\
	else								\
		(head)->tqh_last = &(elm2)->field.tqe_next;		\
	(elm2)->field.tqe_prev = (elm)->field.tqe_prev;			\
	*(elm2)->field.tqe_prev = (elm2);				\
} while (0)

/*
 * Circular queue definitions.
 */
#define CIRCLEQ_HEAD(name, type)					\
struct name {								\
	struct type *cqh_first;		/* first element */		\
	struct type *cqh_last;		/* last element */		\
}

#define CIRCLEQ_HEAD_INITIALIZER(head)					\
	{ CIRCLEQ_END(&head), CIRCLEQ_END(&head) }

#define CIRCLEQ_ENTRY(type)						\
struct {								\
	struct type *cqe_next;		/* next element */		\
	struct type *cqe_prev;		/* previous element */		\
}

/*
 * Circular queue access methods 
 */
#define	CIRCLEQ_FIRST(head)		((head)->cqh_first)
#define	CIRCLEQ_LAST(head)		((head)->cqh_last)
#define	CIRCLEQ_END(head)		((void *)(head))
#define	CIRCLEQ_NEXT(elm, field)	((elm)->field.cqe_next)
#define	CIRCLEQ_PREV(elm, field)	((elm)->field.cqe_prev)
#define	CIRCLEQ_EMPTY(head)						\
	(CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))

#define CIRCLEQ_FOREACH(var, head, field)				\
	for((var) = CIRCLEQ_FIRST(head);				\
	    (var) != CIRCLEQ_END(head);					\
	    (var) = CIRCLEQ_NEXT(var, field))

#define CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
	for((var) = CIRCLEQ_LAST(head);					\
	    (var) != CIRCLEQ_END(head);					\
	    (var) = CIRCLEQ_PREV(var, field))

/*
 * Circular queue functions.
 */
#define	CIRCLEQ_INIT(head) do {						\
	(head)->cqh_first = CIRCLEQ_END(head);				\
	(head)->cqh_last = CIRCLEQ_END(head);				\
} while (0)

#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
	(elm)->field.cqe_next = (listelm)->field.cqe_next;		\
	(elm)->field.cqe_prev = (listelm);				\
	if ((listelm)->field.cqe_next == CIRCLEQ_END(head))		\
		(head)->cqh_last = (elm);				\
	else								\
		(listelm)->field.cqe_next->field.cqe_prev = (elm);	\
	(listelm)->field.cqe_next = (elm);				\
} while (0)

#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {		\
	(elm)->field.cqe_next = (listelm);				\
	(elm)->field.cqe_prev = (listelm)->field.cqe_prev;		\
	if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))		\
		(head)->cqh_first = (elm);				\
	else								\
		(listelm)->field.cqe_prev->field.cqe_next = (elm);	\
	(listelm)->field.cqe_prev = (elm);				\
} while (0)

#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
	(elm)->field.cqe_next = (head)->cqh_first;			\
	(elm)->field.cqe_prev = CIRCLEQ_END(head);			\
	if ((head)->cqh_last == CIRCLEQ_END(head))			\
		(head)->cqh_last = (elm);				\
	else								\
		(head)->cqh_first->field.cqe_prev = (elm);		\
	(head)->cqh_first = (elm);					\
} while (0)

#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
	(elm)->field.cqe_next = CIRCLEQ_END(head);			\
	(elm)->field.cqe_prev = (head)->cqh_last;			\
	if ((head)->cqh_first == CIRCLEQ_END(head))			\
		(head)->cqh_first = (elm);				\
	else								\
		(head)->cqh_last->field.cqe_next = (elm);		\
	(head)->cqh_last = (elm);					\
} while (0)

#define	CIRCLEQ_REMOVE(head, elm, field) do {				\
	if ((elm)->field.cqe_next == CIRCLEQ_END(head))			\
		(head)->cqh_last = (elm)->field.cqe_prev;		\
	else								\
		(elm)->field.cqe_next->field.cqe_prev =			\
		    (elm)->field.cqe_prev;				\
	if ((elm)->field.cqe_prev == CIRCLEQ_END(head))			\
		(head)->cqh_first = (elm)->field.cqe_next;		\
	else								\
		(elm)->field.cqe_prev->field.cqe_next =			\
		    (elm)->field.cqe_next;				\
} while (0)

#define CIRCLEQ_REPLACE(head, elm, elm2, field) do {			\
	if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==		\
	    CIRCLEQ_END(head))						\
		(head).cqh_last = (elm2);				\
	else								\
		(elm2)->field.cqe_next->field.cqe_prev = (elm2);	\
	if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==		\
	    CIRCLEQ_END(head))						\
		(head).cqh_first = (elm2);				\
	else								\
		(elm2)->field.cqe_prev->field.cqe_next = (elm2);	\
} while (0)

#endif	/* !_SYS_QUEUE_H_ */
Commit	Line	Data
1656cbed	1	/* $OpenBSD: queue.h,v 1.22 2001/06/23 04:39:35 angelos Exp $ */
bf5f69f7	2	/* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */
	3
	4	/*
	5	* Copyright (c) 1991, 1993
	6	* The Regents of the University of California. All rights reserved.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*
	36	* @(#)queue.h 8.5 (Berkeley) 8/20/94
	37	*/
	38
	39	#ifndef _SYS_QUEUE_H_
	40	#define _SYS_QUEUE_H_
	41
	42	/*
	43	* This file defines five types of data structures: singly-linked lists,
	44	* lists, simple queues, tail queues, and circular queues.
	45	*
	46	*
	47	* A singly-linked list is headed by a single forward pointer. The elements
	48	* are singly linked for minimum space and pointer manipulation overhead at
	49	* the expense of O(n) removal for arbitrary elements. New elements can be
	50	* added to the list after an existing element or at the head of the list.
	51	* Elements being removed from the head of the list should use the explicit
	52	* macro for this purpose for optimum efficiency. A singly-linked list may
	53	* only be traversed in the forward direction. Singly-linked lists are ideal
	54	* for applications with large datasets and few or no removals or for
	55	* implementing a LIFO queue.
	56	*
	57	* A list is headed by a single forward pointer (or an array of forward
	58	* pointers for a hash table header). The elements are doubly linked
	59	* so that an arbitrary element can be removed without a need to
	60	* traverse the list. New elements can be added to the list before
	61	* or after an existing element or at the head of the list. A list
	62	* may only be traversed in the forward direction.
	63	*
	64	* A simple queue is headed by a pair of pointers, one the head of the
	65	* list and the other to the tail of the list. The elements are singly
66	* linked to save space, so elements can only be removed from the
67	* head of the list. New elements can be added to the list before or after
68	* an existing element, at the head of the list, or at the end of the
69	* list. A simple queue may only be traversed in the forward direction.
70	*
71	* A tail queue is headed by a pair of pointers, one to the head of the
72	* list and the other to the tail of the list. The elements are doubly
73	* linked so that an arbitrary element can be removed without a need to
74	* traverse the list. New elements can be added to the list before or
75	* after an existing element, at the head of the list, or at the end of
76	* the list. A tail queue may be traversed in either direction.
77	*
78	* A circle queue is headed by a pair of pointers, one to the head of the
79	* list and the other to the tail of the list. The elements are doubly
80	* linked so that an arbitrary element can be removed without a need to
81	* traverse the list. New elements can be added to the list before or after
82	* an existing element, at the head of the list, or at the end of the list.
83	* A circle queue may be traversed in either direction, but has a more
84	* complex end of list detection.
85	*
86	* For details on the use of these macros, see the queue(3) manual page.
87	*/
88
89	/*
90	* Singly-linked List definitions.
91	*/
92	#define SLIST_HEAD(name, type) \
93	struct name { \
94	struct type slh_first; / first element */ \
95	}
96
97	#define SLIST_HEAD_INITIALIZER(head) \
98	{ NULL }
99
100	#define SLIST_ENTRY(type) \
101	struct { \
102	struct type sle_next; / next element */ \
103	}
104
105	/*
106	* Singly-linked List access methods.
107	*/
108	#define SLIST_FIRST(head) ((head)->slh_first)
109	#define SLIST_END(head) NULL
110	#define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head))
111	#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
112
113	#define SLIST_FOREACH(var, head, field) \
114	for((var) = SLIST_FIRST(head); \
115	(var) != SLIST_END(head); \
116	(var) = SLIST_NEXT(var, field))
117
118	/*
119	* Singly-linked List functions.
120	*/
121	#define SLIST_INIT(head) { \
122	SLIST_FIRST(head) = SLIST_END(head); \
123	}
124
125	#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
126	(elm)->field.sle_next = (slistelm)->field.sle_next; \
127	(slistelm)->field.sle_next = (elm); \
128	} while (0)
129
130	#define SLIST_INSERT_HEAD(head, elm, field) do { \
131	(elm)->field.sle_next = (head)->slh_first; \
132	(head)->slh_first = (elm); \
133	} while (0)
134
135	#define SLIST_REMOVE_HEAD(head, field) do { \
136	(head)->slh_first = (head)->slh_first->field.sle_next; \
137	} while (0)
138
1656cbed	139	#define SLIST_REMOVE(head, elm, type, field) do { \
	140	if ((head)->slh_first == (elm)) { \
	141	SLIST_REMOVE_HEAD((head), field); \
	142	} \
	143	else { \
	144	struct type *curelm = (head)->slh_first; \
	145	while( curelm->field.sle_next != (elm) ) \
	146	curelm = curelm->field.sle_next; \
	147	curelm->field.sle_next = \
	148	curelm->field.sle_next->field.sle_next; \
	149	} \
	150	} while (0)
	151
bf5f69f7	152	/*
	153	* List definitions.
	154	*/
	155	#define LIST_HEAD(name, type) \
	156	struct name { \
	157	struct type lh_first; / first element */ \
	158	}
	159
	160	#define LIST_HEAD_INITIALIZER(head) \
	161	{ NULL }
	162
	163	#define LIST_ENTRY(type) \
	164	struct { \
	165	struct type le_next; / next element */ \
	166	struct type *le_prev; / address of previous next element */ \
	167	}
	168
	169	/*
	170	* List access methods
	171	*/
	172	#define LIST_FIRST(head) ((head)->lh_first)
	173	#define LIST_END(head) NULL
	174	#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
	175	#define LIST_NEXT(elm, field) ((elm)->field.le_next)
	176
	177	#define LIST_FOREACH(var, head, field) \
	178	for((var) = LIST_FIRST(head); \
	179	(var)!= LIST_END(head); \
	180	(var) = LIST_NEXT(var, field))
	181
	182	/*
	183	* List functions.
	184	*/
	185	#define LIST_INIT(head) do { \
	186	LIST_FIRST(head) = LIST_END(head); \
	187	} while (0)
	188
	189	#define LIST_INSERT_AFTER(listelm, elm, field) do { \
	190	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
	191	(listelm)->field.le_next->field.le_prev = \
	192	&(elm)->field.le_next; \
	193	(listelm)->field.le_next = (elm); \
	194	(elm)->field.le_prev = &(listelm)->field.le_next; \
	195	} while (0)
	196
	197	#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
	198	(elm)->field.le_prev = (listelm)->field.le_prev; \
	199	(elm)->field.le_next = (listelm); \
	200	*(listelm)->field.le_prev = (elm); \
	201	(listelm)->field.le_prev = &(elm)->field.le_next; \
	202	} while (0)
	203
	204	#define LIST_INSERT_HEAD(head, elm, field) do { \
	205	if (((elm)->field.le_next = (head)->lh_first) != NULL) \
	206	(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
	207	(head)->lh_first = (elm); \
	208	(elm)->field.le_prev = &(head)->lh_first; \
	209	} while (0)
	210
	211	#define LIST_REMOVE(elm, field) do { \
	212	if ((elm)->field.le_next != NULL) \
	213	(elm)->field.le_next->field.le_prev = \
	214	(elm)->field.le_prev; \
	215	*(elm)->field.le_prev = (elm)->field.le_next; \
216	} while (0)
217
218	#define LIST_REPLACE(elm, elm2, field) do { \
219	if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
220	(elm2)->field.le_next->field.le_prev = \
221	&(elm2)->field.le_next; \
222	(elm2)->field.le_prev = (elm)->field.le_prev; \
223	*(elm2)->field.le_prev = (elm2); \
224	} while (0)
225
226	/*
227	* Simple queue definitions.
228	*/
229	#define SIMPLEQ_HEAD(name, type) \
230	struct name { \
231	struct type sqh_first; / first element */ \
232	struct type *sqh_last; / addr of last next element */ \
233	}
234
235	#define SIMPLEQ_HEAD_INITIALIZER(head) \
236	{ NULL, &(head).sqh_first }
237
238	#define SIMPLEQ_ENTRY(type) \
239	struct { \
240	struct type sqe_next; / next element */ \
241	}
242
243	/*
244	* Simple queue access methods.
245	*/
246	#define SIMPLEQ_FIRST(head) ((head)->sqh_first)
247	#define SIMPLEQ_END(head) NULL
248	#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
249	#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
250
251	#define SIMPLEQ_FOREACH(var, head, field) \
252	for((var) = SIMPLEQ_FIRST(head); \
253	(var) != SIMPLEQ_END(head); \
254	(var) = SIMPLEQ_NEXT(var, field))
255
256	/*
257	* Simple queue functions.
258	*/
259	#define SIMPLEQ_INIT(head) do { \
260	(head)->sqh_first = NULL; \
261	(head)->sqh_last = &(head)->sqh_first; \
262	} while (0)
263
264	#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
265	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
266	(head)->sqh_last = &(elm)->field.sqe_next; \
267	(head)->sqh_first = (elm); \
268	} while (0)
269
270	#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
271	(elm)->field.sqe_next = NULL; \
272	*(head)->sqh_last = (elm); \
273	(head)->sqh_last = &(elm)->field.sqe_next; \
274	} while (0)
275
276	#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
277	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
278	(head)->sqh_last = &(elm)->field.sqe_next; \
279	(listelm)->field.sqe_next = (elm); \
280	} while (0)
281
282	#define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \
283	if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \
284	(head)->sqh_last = &(head)->sqh_first; \
285	} while (0)
286
287	/*
288	* Tail queue definitions.
289	*/
290	#define TAILQ_HEAD(name, type) \
291	struct name { \
292	struct type tqh_first; / first element */ \
293	struct type *tqh_last; / addr of last next element */ \
294	}
295
296	#define TAILQ_HEAD_INITIALIZER(head) \
297	{ NULL, &(head).tqh_first }
298
299	#define TAILQ_ENTRY(type) \
300	struct { \
301	struct type tqe_next; / next element */ \
302	struct type *tqe_prev; / address of previous next element */ \
303	}
304
305	/*
306	* tail queue access methods
307	*/
308	#define TAILQ_FIRST(head) ((head)->tqh_first)
309	#define TAILQ_END(head) NULL
310	#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
311	#define TAILQ_LAST(head, headname) \
312	((((struct headname )((head)->tqh_last))->tqh_last))
313	/* XXX */
314	#define TAILQ_PREV(elm, headname, field) \
315	((((struct headname )((elm)->field.tqe_prev))->tqh_last))
316	#define TAILQ_EMPTY(head) \
317	(TAILQ_FIRST(head) == TAILQ_END(head))
318
319	#define TAILQ_FOREACH(var, head, field) \
320	for((var) = TAILQ_FIRST(head); \
321	(var) != TAILQ_END(head); \
322	(var) = TAILQ_NEXT(var, field))
323
324	#define TAILQ_FOREACH_REVERSE(var, head, field, headname) \
325	for((var) = TAILQ_LAST(head, headname); \
326	(var) != TAILQ_END(head); \
327	(var) = TAILQ_PREV(var, headname, field))
328
329	/*
330	* Tail queue functions.
331	*/
332	#define TAILQ_INIT(head) do { \
333	(head)->tqh_first = NULL; \
334	(head)->tqh_last = &(head)->tqh_first; \
335	} while (0)
336
337	#define TAILQ_INSERT_HEAD(head, elm, field) do { \
338	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
339	(head)->tqh_first->field.tqe_prev = \
340	&(elm)->field.tqe_next; \
341	else \
342	(head)->tqh_last = &(elm)->field.tqe_next; \
343	(head)->tqh_first = (elm); \
344	(elm)->field.tqe_prev = &(head)->tqh_first; \
345	} while (0)
346
347	#define TAILQ_INSERT_TAIL(head, elm, field) do { \
348	(elm)->field.tqe_next = NULL; \
349	(elm)->field.tqe_prev = (head)->tqh_last; \
350	*(head)->tqh_last = (elm); \
351	(head)->tqh_last = &(elm)->field.tqe_next; \
352	} while (0)
353
354	#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
355	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
356	(elm)->field.tqe_next->field.tqe_prev = \
357	&(elm)->field.tqe_next; \
358	else \
359	(head)->tqh_last = &(elm)->field.tqe_next; \
360	(listelm)->field.tqe_next = (elm); \
361	(elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
362	} while (0)
363
364	#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
365	(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
366	(elm)->field.tqe_next = (listelm); \
367	*(listelm)->field.tqe_prev = (elm); \
368	(listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
369	} while (0)
370
371	#define TAILQ_REMOVE(head, elm, field) do { \
372	if (((elm)->field.tqe_next) != NULL) \
373	(elm)->field.tqe_next->field.tqe_prev = \
374	(elm)->field.tqe_prev; \
375	else \
376	(head)->tqh_last = (elm)->field.tqe_prev; \
377	*(elm)->field.tqe_prev = (elm)->field.tqe_next; \
378	} while (0)
379
380	#define TAILQ_REPLACE(head, elm, elm2, field) do { \
381	if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
382	(elm2)->field.tqe_next->field.tqe_prev = \
383	&(elm2)->field.tqe_next; \
384	else \
385	(head)->tqh_last = &(elm2)->field.tqe_next; \
386	(elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
387	*(elm2)->field.tqe_prev = (elm2); \
388	} while (0)
389
390	/*
391	* Circular queue definitions.
392	*/
393	#define CIRCLEQ_HEAD(name, type) \
394	struct name { \
395	struct type cqh_first; / first element */ \
396	struct type cqh_last; / last element */ \
397	}
398
399	#define CIRCLEQ_HEAD_INITIALIZER(head) \
400	{ CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
401
402	#define CIRCLEQ_ENTRY(type) \
403	struct { \
404	struct type cqe_next; / next element */ \
405	struct type cqe_prev; / previous element */ \
406	}
407
408	/*
409	* Circular queue access methods
410	*/
411	#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
412	#define CIRCLEQ_LAST(head) ((head)->cqh_last)
413	#define CIRCLEQ_END(head) ((void *)(head))
414	#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
415	#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
416	#define CIRCLEQ_EMPTY(head) \
417	(CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
418
419	#define CIRCLEQ_FOREACH(var, head, field) \
420	for((var) = CIRCLEQ_FIRST(head); \
421	(var) != CIRCLEQ_END(head); \
422	(var) = CIRCLEQ_NEXT(var, field))
423
424	#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
425	for((var) = CIRCLEQ_LAST(head); \
426	(var) != CIRCLEQ_END(head); \
427	(var) = CIRCLEQ_PREV(var, field))
428
429	/*
430	* Circular queue functions.
431	*/
432	#define CIRCLEQ_INIT(head) do { \
433	(head)->cqh_first = CIRCLEQ_END(head); \
434	(head)->cqh_last = CIRCLEQ_END(head); \
435	} while (0)
436
437	#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
438	(elm)->field.cqe_next = (listelm)->field.cqe_next; \
439	(elm)->field.cqe_prev = (listelm); \
440	if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \
441	(head)->cqh_last = (elm); \
442	else \
443	(listelm)->field.cqe_next->field.cqe_prev = (elm); \
444	(listelm)->field.cqe_next = (elm); \
445	} while (0)
446
447	#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
448	(elm)->field.cqe_next = (listelm); \
449	(elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
450	if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \
451	(head)->cqh_first = (elm); \
452	else \
453	(listelm)->field.cqe_prev->field.cqe_next = (elm); \
454	(listelm)->field.cqe_prev = (elm); \
455	} while (0)
456
457	#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
458	(elm)->field.cqe_next = (head)->cqh_first; \
459	(elm)->field.cqe_prev = CIRCLEQ_END(head); \
460	if ((head)->cqh_last == CIRCLEQ_END(head)) \
461	(head)->cqh_last = (elm); \
462	else \
463	(head)->cqh_first->field.cqe_prev = (elm); \
464	(head)->cqh_first = (elm); \
465	} while (0)
466
467	#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
468	(elm)->field.cqe_next = CIRCLEQ_END(head); \
469	(elm)->field.cqe_prev = (head)->cqh_last; \
470	if ((head)->cqh_first == CIRCLEQ_END(head)) \
471	(head)->cqh_first = (elm); \
472	else \
473	(head)->cqh_last->field.cqe_next = (elm); \
474	(head)->cqh_last = (elm); \
475	} while (0)
476
477	#define CIRCLEQ_REMOVE(head, elm, field) do { \
478	if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \
479	(head)->cqh_last = (elm)->field.cqe_prev; \
480	else \
481	(elm)->field.cqe_next->field.cqe_prev = \
482	(elm)->field.cqe_prev; \
483	if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \
484	(head)->cqh_first = (elm)->field.cqe_next; \
485	else \
486	(elm)->field.cqe_prev->field.cqe_next = \
487	(elm)->field.cqe_next; \
488	} while (0)
489
490	#define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \
491	if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \
492	CIRCLEQ_END(head)) \
493	(head).cqh_last = (elm2); \
494	else \
495	(elm2)->field.cqe_next->field.cqe_prev = (elm2); \
496	if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \
497	CIRCLEQ_END(head)) \
498	(head).cqh_first = (elm2); \
499	else \
500	(elm2)->field.cqe_prev->field.cqe_next = (elm2); \
501	} while (0)
502
503	#endif /* !_SYS_QUEUE_H_ */