drivers/scsi/aic7xxx/queue.h - linux/kernel/git/viro/vfs - Git at Google

 /*
  * 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.
  *
  * 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: src/sys/sys/queue.h,v 1.38 2000/05/26 02:06:56 jake Exp $
  */

 #ifndef _SYS_QUEUE_H_
 #define	_SYS_QUEUE_H_

 /*
  * This file defines five types of data structures: singly-linked lists,
  * singly-linked tail queues, lists, 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 singly-linked 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
  * 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, at the head of the list, or at the
  * end of the list. Elements being removed from the head of the tail queue
  * should use the explicit macro for this purpose for optimum efficiency.
  * A singly-linked tail queue may only be traversed in the forward direction.
  * Singly-linked tail queues are ideal for applications with large datasets
  * and few or no removals or for implementing a FIFO 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 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.
  *
  *
  *			SLIST	LIST	STAILQ	TAILQ	CIRCLEQ
  * _HEAD		+	+	+	+	+
  * _HEAD_INITIALIZER	+	+	+	+	+
  * _ENTRY		+	+	+	+	+
  * _INIT		+	+	+	+	+
  * _EMPTY		+	+	+	+	+
  * _FIRST		+	+	+	+	+
  * _NEXT		+	+	+	+	+
  * _PREV		-	-	-	+	+
  * _LAST		-	-	+	+	+
  * _FOREACH		+	+	+	+	+
  * _FOREACH_REVERSE	-	-	-	+	+
  * _INSERT_HEAD		+	+	+	+	+
  * _INSERT_BEFORE	-	+	-	+	+
  * _INSERT_AFTER	+	+	+	+	+
  * _INSERT_TAIL		-	-	+	+	+
  * _REMOVE_HEAD		+	-	+	-	-
  * _REMOVE		+	+	+	+	+
  *
  */

 /*
  * Singly-linked List declarations.
  */
 #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 functions.
  */
 #define	SLIST_EMPTY(head)	((head)->slh_first == NULL)

 #define	SLIST_FIRST(head)	((head)->slh_first)

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

 #define	SLIST_INIT(head) do {						\
 	SLIST_FIRST((head)) = NULL;					\
 } while (0)

 #define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
 	SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);	\
 	SLIST_NEXT((slistelm), field) = (elm);				\
 } while (0)

 #define	SLIST_INSERT_HEAD(head, elm, field) do {			\
 	SLIST_NEXT((elm), field) = SLIST_FIRST((head));			\
 	SLIST_FIRST((head)) = (elm);					\
 } while (0)

 #define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)

 #define	SLIST_REMOVE(head, elm, type, field) do {			\
 	if (SLIST_FIRST((head)) == (elm)) {				\
 		SLIST_REMOVE_HEAD((head), field);			\
 	}								\
 	else {								\
 		struct type *curelm = SLIST_FIRST((head));		\
 		while (SLIST_NEXT(curelm, field) != (elm))		\
 			curelm = SLIST_NEXT(curelm, field);		\
 		SLIST_NEXT(curelm, field) =				\
 		    SLIST_NEXT(SLIST_NEXT(curelm, field), field);	\
 	}								\
 } while (0)

 #define	SLIST_REMOVE_HEAD(head, field) do {				\
 	SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);	\
 } while (0)

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

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

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

 /*
  * Singly-linked Tail queue functions.
  */
 #define	STAILQ_EMPTY(head)	((head)->stqh_first == NULL)

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

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

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

 #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)

 #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)

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

 #define	STAILQ_LAST(head)	(*(head)->stqh_last)

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

 #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)

 #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)

 #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.
  */
 #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 functions.
  */

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

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

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

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

 #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)

 #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)

 #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)

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

 #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)

 /*
  * Tail queue declarations.
  */
 #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 functions.
  */
 #define	TAILQ_EMPTY(head)	((head)->tqh_first == NULL)

 #define	TAILQ_FIRST(head)	((head)->tqh_first)

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

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

 #define	TAILQ_INIT(head) do {						\
 	TAILQ_FIRST((head)) = NULL;					\
 	(head)->tqh_last = &TAILQ_FIRST((head));			\
 } while (0)

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

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

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

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

 #define	TAILQ_LAST(head, headname)					\
 	(*(((struct headname *)((head)->tqh_last))->tqh_last))

 #define	TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)

 #define	TAILQ_PREV(elm, headname, field)				\
 	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))

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

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

 #define	CIRCLEQ_HEAD_INITIALIZER(head)					\
 	{ (void *)&(head), (void *)&(head) }

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

 /*
  * Circular queue functions.
  */
 #define	CIRCLEQ_EMPTY(head)	((head)->cqh_first == (void *)(head))

 #define	CIRCLEQ_FIRST(head)	((head)->cqh_first)

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

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

 #define	CIRCLEQ_INIT(head) do {						\
 	CIRCLEQ_FIRST((head)) = (void *)(head);				\
 	CIRCLEQ_LAST((head)) = (void *)(head);				\
 } while (0)

 #define	CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
 	CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field);	\
 	CIRCLEQ_PREV((elm), field) = (listelm);				\
 	if (CIRCLEQ_NEXT((listelm), field) == (void *)(head))		\
 		CIRCLEQ_LAST((head)) = (elm);				\
 	else								\
 		CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\
 	CIRCLEQ_NEXT((listelm), field) = (elm);				\
 } while (0)

 #define	CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {		\
 	CIRCLEQ_NEXT((elm), field) = (listelm);				\
 	CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field);	\
 	if (CIRCLEQ_PREV((listelm), field) == (void *)(head))		\
 		CIRCLEQ_FIRST((head)) = (elm);				\
 	else								\
 		CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\
 	CIRCLEQ_PREV((listelm), field) = (elm);				\
 } while (0)

 #define	CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
 	CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head));		\
 	CIRCLEQ_PREV((elm), field) = (void *)(head);			\
 	if (CIRCLEQ_LAST((head)) == (void *)(head))			\
 		CIRCLEQ_LAST((head)) = (elm);				\
 	else								\
 		CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm);	\
 	CIRCLEQ_FIRST((head)) = (elm);					\
 } while (0)

 #define	CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
 	CIRCLEQ_NEXT((elm), field) = (void *)(head);			\
 	CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head));		\
 	if (CIRCLEQ_FIRST((head)) == (void *)(head))			\
 		CIRCLEQ_FIRST((head)) = (elm);				\
 	else								\
 		CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm);	\
 	CIRCLEQ_LAST((head)) = (elm);					\
 } while (0)

 #define	CIRCLEQ_LAST(head)	((head)->cqh_last)

 #define	CIRCLEQ_NEXT(elm,field)	((elm)->field.cqe_next)

 #define	CIRCLEQ_PREV(elm,field)	((elm)->field.cqe_prev)

 #define	CIRCLEQ_REMOVE(head, elm, field) do {				\
 	if (CIRCLEQ_NEXT((elm), field) == (void *)(head))		\
 		CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field);	\
 	else								\
 		CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) =	\
 		    CIRCLEQ_PREV((elm), field);				\
 	if (CIRCLEQ_PREV((elm), field) == (void *)(head))		\
 		CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field);	\
 	else								\
 		CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) =	\
 		    CIRCLEQ_NEXT((elm), field);				\
 } while (0)

 #endif /* !_SYS_QUEUE_H_ */
	/*
	* 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.
	*
	* 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: src/sys/sys/queue.h,v 1.38 2000/05/26 02:06:56 jake Exp $
	*/

	#ifndef _SYS_QUEUE_H_
	#define _SYS_QUEUE_H_

	/*
	* This file defines five types of data structures: singly-linked lists,
	* singly-linked tail queues, lists, 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 singly-linked 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
	* 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, at the head of the list, or at the
	* end of the list. Elements being removed from the head of the tail queue
	* should use the explicit macro for this purpose for optimum efficiency.
	* A singly-linked tail queue may only be traversed in the forward direction.
	* Singly-linked tail queues are ideal for applications with large datasets
	* and few or no removals or for implementing a FIFO 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 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.
	*
	*
	* SLIST LIST STAILQ TAILQ CIRCLEQ
	* _HEAD + + + + +
	* _HEAD_INITIALIZER + + + + +
	* _ENTRY + + + + +
	* _INIT + + + + +
	* _EMPTY + + + + +
	* _FIRST + + + + +
	* _NEXT + + + + +
	* _PREV - - - + +
	* _LAST - - + + +
	* _FOREACH + + + + +
	* _FOREACH_REVERSE - - - + +
	* _INSERT_HEAD + + + + +
	* _INSERT_BEFORE - + - + +
	* _INSERT_AFTER + + + + +
	* _INSERT_TAIL - - + + +
	* _REMOVE_HEAD + - + - -
	* _REMOVE + + + + +
	*
	*/

	/*
	* Singly-linked List declarations.
	*/
	#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 functions.
	*/
	#define SLIST_EMPTY(head) ((head)->slh_first == NULL)

	#define SLIST_FIRST(head) ((head)->slh_first)

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

	#define SLIST_INIT(head) do { \
	SLIST_FIRST((head)) = NULL; \
	} while (0)

	#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
	SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
	SLIST_NEXT((slistelm), field) = (elm); \
	} while (0)

	#define SLIST_INSERT_HEAD(head, elm, field) do { \
	SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
	SLIST_FIRST((head)) = (elm); \
	} while (0)

	#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)

	#define SLIST_REMOVE(head, elm, type, field) do { \
	if (SLIST_FIRST((head)) == (elm)) { \
	SLIST_REMOVE_HEAD((head), field); \
	} \
	else { \
	struct type *curelm = SLIST_FIRST((head)); \
	while (SLIST_NEXT(curelm, field) != (elm)) \
	curelm = SLIST_NEXT(curelm, field); \
	SLIST_NEXT(curelm, field) = \
	SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
	} \
	} while (0)

	#define SLIST_REMOVE_HEAD(head, field) do { \
	SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
	} while (0)

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

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

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

	/*
	* Singly-linked Tail queue functions.
	*/
	#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)

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

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

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

	#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)

	#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)

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

	#define STAILQ_LAST(head) (*(head)->stqh_last)

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

	#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)

	#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)

	#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.
	*/
	#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 functions.
	*/

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

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

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

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

	#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)

	#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)

	#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)

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

	#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)

	/*
	* Tail queue declarations.
	*/
	#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 functions.
	*/
	#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)

	#define TAILQ_FIRST(head) ((head)->tqh_first)

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

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

	#define TAILQ_INIT(head) do { \
	TAILQ_FIRST((head)) = NULL; \
	(head)->tqh_last = &TAILQ_FIRST((head)); \
	} while (0)

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

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

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

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

	#define TAILQ_LAST(head, headname) \
	((((struct headname )((head)->tqh_last))->tqh_last))

	#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)

	#define TAILQ_PREV(elm, headname, field) \
	((((struct headname )((elm)->field.tqe_prev))->tqh_last))

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

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

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

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

	/*
	* Circular queue functions.
	*/
	#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))

	#define CIRCLEQ_FIRST(head) ((head)->cqh_first)

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

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

	#define CIRCLEQ_INIT(head) do { \
	CIRCLEQ_FIRST((head)) = (void *)(head); \
	CIRCLEQ_LAST((head)) = (void *)(head); \
	} while (0)

	#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
	CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \
	CIRCLEQ_PREV((elm), field) = (listelm); \
	if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \
	CIRCLEQ_LAST((head)) = (elm); \
	else \
	CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\
	CIRCLEQ_NEXT((listelm), field) = (elm); \
	} while (0)

	#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
	CIRCLEQ_NEXT((elm), field) = (listelm); \
	CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \
	if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \
	CIRCLEQ_FIRST((head)) = (elm); \
	else \
	CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\
	CIRCLEQ_PREV((listelm), field) = (elm); \
	} while (0)

	#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
	CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \
	CIRCLEQ_PREV((elm), field) = (void *)(head); \
	if (CIRCLEQ_LAST((head)) == (void *)(head)) \
	CIRCLEQ_LAST((head)) = (elm); \
	else \
	CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \
	CIRCLEQ_FIRST((head)) = (elm); \
	} while (0)

	#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
	CIRCLEQ_NEXT((elm), field) = (void *)(head); \
	CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \
	if (CIRCLEQ_FIRST((head)) == (void *)(head)) \
	CIRCLEQ_FIRST((head)) = (elm); \
	else \
	CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \
	CIRCLEQ_LAST((head)) = (elm); \
	} while (0)

	#define CIRCLEQ_LAST(head) ((head)->cqh_last)

	#define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)

	#define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)

	#define CIRCLEQ_REMOVE(head, elm, field) do { \
	if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \
	CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \
	else \
	CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \
	CIRCLEQ_PREV((elm), field); \
	if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \
	CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \
	else \
	CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \
	CIRCLEQ_NEXT((elm), field); \
	} while (0)

	#endif /* !_SYS_QUEUE_H_ */