williamr@2: /*-
williamr@2:  * Copyright (c) 1991, 1993
williamr@2:  *	The Regents of the University of California.  All rights reserved.
williamr@2:  *
williamr@2:  * Redistribution and use in source and binary forms, with or without
williamr@2:  * modification, are permitted provided that the following conditions
williamr@2:  * are met:
williamr@2:  * 1. Redistributions of source code must retain the above copyright
williamr@2:  *    notice, this list of conditions and the following disclaimer.
williamr@2:  * 2. Redistributions in binary form must reproduce the above copyright
williamr@2:  *    notice, this list of conditions and the following disclaimer in the
williamr@2:  *    documentation and/or other materials provided with the distribution.
williamr@2:  * 4. Neither the name of the University nor the names of its contributors
williamr@2:  *    may be used to endorse or promote products derived from this software
williamr@2:  *    without specific prior written permission.
williamr@2:  *
williamr@2:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
williamr@2:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
williamr@2:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
williamr@2:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
williamr@2:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
williamr@2:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
williamr@2:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
williamr@2:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
williamr@2:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
williamr@2:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
williamr@2:  * SUCH DAMAGE.
williamr@2:  * © Portions copyright (c) 2007 Symbian Software Ltd. All rights reserved.
williamr@2:  *	@(#)queue.h	8.5 (Berkeley) 8/20/94
williamr@2:  * $FreeBSD: src/sys/sys/queue.h,v 1.60.2.1 2005/08/16 22:41:39 phk Exp $
williamr@2:  */
williamr@2: 
williamr@2: #ifndef _SYS_QUEUE_H_
williamr@2: #define	_SYS_QUEUE_H_
williamr@2: 
williamr@2: #include <sys/cdefs.h>
williamr@2: 
williamr@2: /*
williamr@2:  * This file defines four types of data structures: singly-linked lists,
williamr@2:  * singly-linked tail queues, lists and tail queues.
williamr@2:  *
williamr@2:  * A singly-linked list is headed by a single forward pointer. The elements
williamr@2:  * are singly linked for minimum space and pointer manipulation overhead at
williamr@2:  * the expense of O(n) removal for arbitrary elements. New elements can be
williamr@2:  * added to the list after an existing element or at the head of the list.
williamr@2:  * Elements being removed from the head of the list should use the explicit
williamr@2:  * macro for this purpose for optimum efficiency. A singly-linked list may
williamr@2:  * only be traversed in the forward direction.  Singly-linked lists are ideal
williamr@2:  * for applications with large datasets and few or no removals or for
williamr@2:  * implementing a LIFO queue.
williamr@2:  *
williamr@2:  * A singly-linked tail queue is headed by a pair of pointers, one to the
williamr@2:  * head of the list and the other to the tail of the list. The elements are
williamr@2:  * singly linked for minimum space and pointer manipulation overhead at the
williamr@2:  * expense of O(n) removal for arbitrary elements. New elements can be added
williamr@2:  * to the list after an existing element, at the head of the list, or at the
williamr@2:  * end of the list. Elements being removed from the head of the tail queue
williamr@2:  * should use the explicit macro for this purpose for optimum efficiency.
williamr@2:  * A singly-linked tail queue may only be traversed in the forward direction.
williamr@2:  * Singly-linked tail queues are ideal for applications with large datasets
williamr@2:  * and few or no removals or for implementing a FIFO queue.
williamr@2:  *
williamr@2:  * A list is headed by a single forward pointer (or an array of forward
williamr@2:  * pointers for a hash table header). The elements are doubly linked
williamr@2:  * so that an arbitrary element can be removed without a need to
williamr@2:  * traverse the list. New elements can be added to the list before
williamr@2:  * or after an existing element or at the head of the list. A list
williamr@2:  * may only be traversed in the forward direction.
williamr@2:  *
williamr@2:  * A tail queue is headed by a pair of pointers, one to the head of the
williamr@2:  * list and the other to the tail of the list. The elements are doubly
williamr@2:  * linked so that an arbitrary element can be removed without a need to
williamr@2:  * traverse the list. New elements can be added to the list before or
williamr@2:  * after an existing element, at the head of the list, or at the end of
williamr@2:  * the list. A tail queue may be traversed in either direction.
williamr@2:  *
williamr@2:  * For details on the use of these macros, see the queue(3) manual page.
williamr@2:  *
williamr@2:  *
williamr@2:  *				SLIST	LIST	STAILQ	TAILQ
williamr@2:  * _HEAD			+	+	+	+
williamr@2:  * _HEAD_INITIALIZER		+	+	+	+
williamr@2:  * _ENTRY			+	+	+	+
williamr@2:  * _INIT			+	+	+	+
williamr@2:  * _EMPTY			+	+	+	+
williamr@2:  * _FIRST			+	+	+	+
williamr@2:  * _NEXT			+	+	+	+
williamr@2:  * _PREV			-	-	-	+
williamr@2:  * _LAST			-	-	+	+
williamr@2:  * _FOREACH			+	+	+	+
williamr@2:  * _FOREACH_SAFE		+	+	+	+
williamr@2:  * _FOREACH_REVERSE		-	-	-	+
williamr@2:  * _FOREACH_REVERSE_SAFE	-	-	-	+
williamr@2:  * _INSERT_HEAD			+	+	+	+
williamr@2:  * _INSERT_BEFORE		-	+	-	+
williamr@2:  * _INSERT_AFTER		+	+	+	+
williamr@2:  * _INSERT_TAIL			-	-	+	+
williamr@2:  * _CONCAT			-	-	+	+
williamr@2:  * _REMOVE_HEAD			+	-	+	-
williamr@2:  * _REMOVE			+	+	+	+
williamr@2:  *
williamr@2:  */
williamr@2: #define	QUEUE_MACRO_DEBUG 0
williamr@2: #if QUEUE_MACRO_DEBUG
williamr@2: /* Store the last 2 places the queue element or head was altered */
williamr@2: struct qm_trace {
williamr@2: 	char * lastfile;
williamr@2: 	int lastline;
williamr@2: 	char * prevfile;
williamr@2: 	int prevline;
williamr@2: };
williamr@2: 
williamr@2: #define	TRACEBUF	struct qm_trace trace;
williamr@2: #define	TRASHIT(x)	do {(x) = (void *)-1;} while (0)
williamr@2: 
williamr@2: #define	QMD_TRACE_HEAD(head) do {					\
williamr@2: 	(head)->trace.prevline = (head)->trace.lastline;		\
williamr@2: 	(head)->trace.prevfile = (head)->trace.lastfile;		\
williamr@2: 	(head)->trace.lastline = __LINE__;				\
williamr@2: 	(head)->trace.lastfile = __FILE__;				\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	QMD_TRACE_ELEM(elem) do {					\
williamr@2: 	(elem)->trace.prevline = (elem)->trace.lastline;		\
williamr@2: 	(elem)->trace.prevfile = (elem)->trace.lastfile;		\
williamr@2: 	(elem)->trace.lastline = __LINE__;				\
williamr@2: 	(elem)->trace.lastfile = __FILE__;				\
williamr@2: } while (0)
williamr@2: 
williamr@2: #else
williamr@2: #define	QMD_TRACE_ELEM(elem)
williamr@2: #define	QMD_TRACE_HEAD(head)
williamr@2: #define	TRACEBUF
williamr@2: #define	TRASHIT(x)
williamr@2: #endif	/* QUEUE_MACRO_DEBUG */
williamr@2: 
williamr@2: /*
williamr@2:  * Singly-linked List declarations.
williamr@2:  */
williamr@2: #define	SLIST_HEAD(name, type)						\
williamr@2: struct name {								\
williamr@2: 	struct type *slh_first;	/* first element */			\
williamr@2: }
williamr@2: 
williamr@2: #define	SLIST_HEAD_INITIALIZER(head)					\
williamr@2: 	{ NULL }
williamr@2: 
williamr@2: #define	SLIST_ENTRY(type)						\
williamr@2: struct {								\
williamr@2: 	struct type *sle_next;	/* next element */			\
williamr@2: }
williamr@2: 
williamr@2: /*
williamr@2:  * Singly-linked List functions.
williamr@2:  */
williamr@2: #define	SLIST_EMPTY(head)	((head)->slh_first == NULL)
williamr@2: 
williamr@2: #define	SLIST_FIRST(head)	((head)->slh_first)
williamr@2: 
williamr@2: #define	SLIST_FOREACH(var, head, field)					\
williamr@2: 	for ((var) = SLIST_FIRST((head));				\
williamr@2: 	    (var);							\
williamr@2: 	    (var) = SLIST_NEXT((var), field))
williamr@2: 
williamr@2: #define	SLIST_FOREACH_SAFE(var, head, field, tvar)			\
williamr@2: 	for ((var) = SLIST_FIRST((head));				\
williamr@2: 	    (var) && ((tvar) = SLIST_NEXT((var), field), 1);		\
williamr@2: 	    (var) = (tvar))
williamr@2: 
williamr@2: #define	SLIST_FOREACH_PREVPTR(var, varp, head, field)			\
williamr@2: 	for ((varp) = &SLIST_FIRST((head));				\
williamr@2: 	    ((var) = *(varp)) != NULL;					\
williamr@2: 	    (varp) = &SLIST_NEXT((var), field))
williamr@2: 
williamr@2: #define	SLIST_INIT(head) do {						\
williamr@2: 	SLIST_FIRST((head)) = NULL;					\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
williamr@2: 	SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);	\
williamr@2: 	SLIST_NEXT((slistelm), field) = (elm);				\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	SLIST_INSERT_HEAD(head, elm, field) do {			\
williamr@2: 	SLIST_NEXT((elm), field) = SLIST_FIRST((head));			\
williamr@2: 	SLIST_FIRST((head)) = (elm);					\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)
williamr@2: 
williamr@2: #define	SLIST_REMOVE(head, elm, type, field) do {			\
williamr@2: 	if (SLIST_FIRST((head)) == (elm)) {				\
williamr@2: 		SLIST_REMOVE_HEAD((head), field);			\
williamr@2: 	}								\
williamr@2: 	else {								\
williamr@2: 		struct type *curelm = SLIST_FIRST((head));		\
williamr@2: 		while (SLIST_NEXT(curelm, field) != (elm))		\
williamr@2: 			curelm = SLIST_NEXT(curelm, field);		\
williamr@2: 		SLIST_NEXT(curelm, field) =				\
williamr@2: 		    SLIST_NEXT(SLIST_NEXT(curelm, field), field);	\
williamr@2: 	}								\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	SLIST_REMOVE_HEAD(head, field) do {				\
williamr@2: 	SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);	\
williamr@2: } while (0)
williamr@2: 
williamr@2: /*
williamr@2:  * Singly-linked Tail queue declarations.
williamr@2:  */
williamr@2: #define	STAILQ_HEAD(name, type)						\
williamr@2: struct name {								\
williamr@2: 	struct type *stqh_first;/* first element */			\
williamr@2: 	struct type **stqh_last;/* addr of last next element */		\
williamr@2: }
williamr@2: 
williamr@2: #define	STAILQ_HEAD_INITIALIZER(head)					\
williamr@2: 	{ NULL, &(head).stqh_first }
williamr@2: 
williamr@2: #define	STAILQ_ENTRY(type)						\
williamr@2: struct {								\
williamr@2: 	struct type *stqe_next;	/* next element */			\
williamr@2: }
williamr@2: 
williamr@2: /*
williamr@2:  * Singly-linked Tail queue functions.
williamr@2:  */
williamr@2: #define	STAILQ_CONCAT(head1, head2) do {				\
williamr@2: 	if (!STAILQ_EMPTY((head2))) {					\
williamr@2: 		*(head1)->stqh_last = (head2)->stqh_first;		\
williamr@2: 		(head1)->stqh_last = (head2)->stqh_last;		\
williamr@2: 		STAILQ_INIT((head2));					\
williamr@2: 	}								\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_EMPTY(head)	((head)->stqh_first == NULL)
williamr@2: 
williamr@2: #define	STAILQ_FIRST(head)	((head)->stqh_first)
williamr@2: 
williamr@2: #define	STAILQ_FOREACH(var, head, field)				\
williamr@2: 	for((var) = STAILQ_FIRST((head));				\
williamr@2: 	   (var);							\
williamr@2: 	   (var) = STAILQ_NEXT((var), field))
williamr@2: 
williamr@2: 
williamr@2: #define	STAILQ_FOREACH_SAFE(var, head, field, tvar)			\
williamr@2: 	for ((var) = STAILQ_FIRST((head));				\
williamr@2: 	    (var) && ((tvar) = STAILQ_NEXT((var), field), 1);		\
williamr@2: 	    (var) = (tvar))
williamr@2: 
williamr@2: #define	STAILQ_INIT(head) do {						\
williamr@2: 	STAILQ_FIRST((head)) = NULL;					\
williamr@2: 	(head)->stqh_last = &STAILQ_FIRST((head));			\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {		\
williamr@2: 	if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
williamr@2: 		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
williamr@2: 	STAILQ_NEXT((tqelm), field) = (elm);				\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_INSERT_HEAD(head, elm, field) do {			\
williamr@2: 	if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL)	\
williamr@2: 		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
williamr@2: 	STAILQ_FIRST((head)) = (elm);					\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_INSERT_TAIL(head, elm, field) do {			\
williamr@2: 	STAILQ_NEXT((elm), field) = NULL;				\
williamr@2: 	*(head)->stqh_last = (elm);					\
williamr@2: 	(head)->stqh_last = &STAILQ_NEXT((elm), field);			\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_LAST(head, type, field)					\
williamr@2: 	(STAILQ_EMPTY((head)) ?						\
williamr@2: 		NULL :							\
williamr@2: 	        ((struct type *)					\
williamr@2: 		((char *)((head)->stqh_last) - __offsetof(struct type, field))))
williamr@2: 
williamr@2: #define	STAILQ_NEXT(elm, field)	((elm)->field.stqe_next)
williamr@2: 
williamr@2: #define	STAILQ_REMOVE(head, elm, type, field) do {			\
williamr@2: 	if (STAILQ_FIRST((head)) == (elm)) {				\
williamr@2: 		STAILQ_REMOVE_HEAD((head), field);			\
williamr@2: 	}								\
williamr@2: 	else {								\
williamr@2: 		struct type *curelm = STAILQ_FIRST((head));		\
williamr@2: 		while (STAILQ_NEXT(curelm, field) != (elm))		\
williamr@2: 			curelm = STAILQ_NEXT(curelm, field);		\
williamr@2: 		if ((STAILQ_NEXT(curelm, field) =			\
williamr@2: 		     STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
williamr@2: 			(head)->stqh_last = &STAILQ_NEXT((curelm), field);\
williamr@2: 	}								\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_REMOVE_HEAD(head, field) do {				\
williamr@2: 	if ((STAILQ_FIRST((head)) =					\
williamr@2: 	     STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)		\
williamr@2: 		(head)->stqh_last = &STAILQ_FIRST((head));		\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {			\
williamr@2: 	if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL)	\
williamr@2: 		(head)->stqh_last = &STAILQ_FIRST((head));		\
williamr@2: } while (0)
williamr@2: 
williamr@2: /*
williamr@2:  * List declarations.
williamr@2:  */
williamr@2: #define	LIST_HEAD(name, type)						\
williamr@2: struct name {								\
williamr@2: 	struct type *lh_first;	/* first element */			\
williamr@2: }
williamr@2: 
williamr@2: #define	LIST_HEAD_INITIALIZER(head)					\
williamr@2: 	{ NULL }
williamr@2: 
williamr@2: #define	LIST_ENTRY(type)						\
williamr@2: struct {								\
williamr@2: 	struct type *le_next;	/* next element */			\
williamr@2: 	struct type **le_prev;	/* address of previous next element */	\
williamr@2: }
williamr@2: 
williamr@2: /*
williamr@2:  * List functions.
williamr@2:  */
williamr@2: 
williamr@2: #define	LIST_EMPTY(head)	((head)->lh_first == NULL)
williamr@2: 
williamr@2: #define	LIST_FIRST(head)	((head)->lh_first)
williamr@2: 
williamr@2: #define	LIST_FOREACH(var, head, field)					\
williamr@2: 	for ((var) = LIST_FIRST((head));				\
williamr@2: 	    (var);							\
williamr@2: 	    (var) = LIST_NEXT((var), field))
williamr@2: 
williamr@2: #define	LIST_FOREACH_SAFE(var, head, field, tvar)			\
williamr@2: 	for ((var) = LIST_FIRST((head));				\
williamr@2: 	    (var) && ((tvar) = LIST_NEXT((var), field), 1);		\
williamr@2: 	    (var) = (tvar))
williamr@2: 
williamr@2: #define	LIST_INIT(head) do {						\
williamr@2: 	LIST_FIRST((head)) = NULL;					\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	LIST_INSERT_AFTER(listelm, elm, field) do {			\
williamr@2: 	if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
williamr@2: 		LIST_NEXT((listelm), field)->field.le_prev =		\
williamr@2: 		    &LIST_NEXT((elm), field);				\
williamr@2: 	LIST_NEXT((listelm), field) = (elm);				\
williamr@2: 	(elm)->field.le_prev = &LIST_NEXT((listelm), field);		\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
williamr@2: 	(elm)->field.le_prev = (listelm)->field.le_prev;		\
williamr@2: 	LIST_NEXT((elm), field) = (listelm);				\
williamr@2: 	*(listelm)->field.le_prev = (elm);				\
williamr@2: 	(listelm)->field.le_prev = &LIST_NEXT((elm), field);		\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	LIST_INSERT_HEAD(head, elm, field) do {				\
williamr@2: 	if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)	\
williamr@2: 		LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
williamr@2: 	LIST_FIRST((head)) = (elm);					\
williamr@2: 	(elm)->field.le_prev = &LIST_FIRST((head));			\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	LIST_NEXT(elm, field)	((elm)->field.le_next)
williamr@2: 
williamr@2: #define	LIST_REMOVE(elm, field) do {					\
williamr@2: 	if (LIST_NEXT((elm), field) != NULL)				\
williamr@2: 		LIST_NEXT((elm), field)->field.le_prev = 		\
williamr@2: 		    (elm)->field.le_prev;				\
williamr@2: 	*(elm)->field.le_prev = LIST_NEXT((elm), field);		\
williamr@2: } while (0)
williamr@2: 
williamr@2: /*
williamr@2:  * Tail queue declarations.
williamr@2:  */
williamr@2: #define	TAILQ_HEAD(name, type)						\
williamr@2: struct name {								\
williamr@2: 	struct type *tqh_first;	/* first element */			\
williamr@2: 	struct type **tqh_last;	/* addr of last next element */		\
williamr@2: 	TRACEBUF							\
williamr@2: }
williamr@2: 
williamr@2: #define	TAILQ_HEAD_INITIALIZER(head)					\
williamr@2: 	{ NULL, &(head).tqh_first }
williamr@2: 
williamr@2: #define	TAILQ_ENTRY(type)						\
williamr@2: struct {								\
williamr@2: 	struct type *tqe_next;	/* next element */			\
williamr@2: 	struct type **tqe_prev;	/* address of previous next element */	\
williamr@2: 	TRACEBUF							\
williamr@2: }
williamr@2: 
williamr@2: /*
williamr@2:  * Tail queue functions.
williamr@2:  */
williamr@2: #define	TAILQ_CONCAT(head1, head2, field) do {				\
williamr@2: 	if (!TAILQ_EMPTY(head2)) {					\
williamr@2: 		*(head1)->tqh_last = (head2)->tqh_first;		\
williamr@2: 		(head2)->tqh_first->field.tqe_prev = (head1)->tqh_last;	\
williamr@2: 		(head1)->tqh_last = (head2)->tqh_last;			\
williamr@2: 		TAILQ_INIT((head2));					\
williamr@2: 		QMD_TRACE_HEAD(head1);					\
williamr@2: 		QMD_TRACE_HEAD(head2);					\
williamr@2: 	}								\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	TAILQ_EMPTY(head)	((head)->tqh_first == NULL)
williamr@2: 
williamr@2: #define	TAILQ_FIRST(head)	((head)->tqh_first)
williamr@2: 
williamr@2: #define	TAILQ_FOREACH(var, head, field)					\
williamr@2: 	for ((var) = TAILQ_FIRST((head));				\
williamr@2: 	    (var);							\
williamr@2: 	    (var) = TAILQ_NEXT((var), field))
williamr@2: 
williamr@2: #define	TAILQ_FOREACH_SAFE(var, head, field, tvar)			\
williamr@2: 	for ((var) = TAILQ_FIRST((head));				\
williamr@2: 	    (var) && ((tvar) = TAILQ_NEXT((var), field), 1);		\
williamr@2: 	    (var) = (tvar))
williamr@2: 
williamr@2: #define	TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
williamr@2: 	for ((var) = TAILQ_LAST((head), headname);			\
williamr@2: 	    (var);							\
williamr@2: 	    (var) = TAILQ_PREV((var), headname, field))
williamr@2: 
williamr@2: #define	TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)	\
williamr@2: 	for ((var) = TAILQ_LAST((head), headname);			\
williamr@2: 	    (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);	\
williamr@2: 	    (var) = (tvar))
williamr@2: 
williamr@2: #define	TAILQ_INIT(head) do {						\
williamr@2: 	TAILQ_FIRST((head)) = NULL;					\
williamr@2: 	(head)->tqh_last = &TAILQ_FIRST((head));			\
williamr@2: 	QMD_TRACE_HEAD(head);						\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
williamr@2: 	if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
williamr@2: 		TAILQ_NEXT((elm), field)->field.tqe_prev = 		\
williamr@2: 		    &TAILQ_NEXT((elm), field);				\
williamr@2: 	else {								\
williamr@2: 		(head)->tqh_last = &TAILQ_NEXT((elm), field);		\
williamr@2: 		QMD_TRACE_HEAD(head);					\
williamr@2: 	}								\
williamr@2: 	TAILQ_NEXT((listelm), field) = (elm);				\
williamr@2: 	(elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);		\
williamr@2: 	QMD_TRACE_ELEM(&(elm)->field);					\
williamr@2: 	QMD_TRACE_ELEM(&listelm->field);				\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
williamr@2: 	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
williamr@2: 	TAILQ_NEXT((elm), field) = (listelm);				\
williamr@2: 	*(listelm)->field.tqe_prev = (elm);				\
williamr@2: 	(listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);		\
williamr@2: 	QMD_TRACE_ELEM(&(elm)->field);					\
williamr@2: 	QMD_TRACE_ELEM(&listelm->field);				\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	TAILQ_INSERT_HEAD(head, elm, field) do {			\
williamr@2: 	if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)	\
williamr@2: 		TAILQ_FIRST((head))->field.tqe_prev =			\
williamr@2: 		    &TAILQ_NEXT((elm), field);				\
williamr@2: 	else								\
williamr@2: 		(head)->tqh_last = &TAILQ_NEXT((elm), field);		\
williamr@2: 	TAILQ_FIRST((head)) = (elm);					\
williamr@2: 	(elm)->field.tqe_prev = &TAILQ_FIRST((head));			\
williamr@2: 	QMD_TRACE_HEAD(head);						\
williamr@2: 	QMD_TRACE_ELEM(&(elm)->field);					\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	TAILQ_INSERT_TAIL(head, elm, field) do {			\
williamr@2: 	TAILQ_NEXT((elm), field) = NULL;				\
williamr@2: 	(elm)->field.tqe_prev = (head)->tqh_last;			\
williamr@2: 	*(head)->tqh_last = (elm);					\
williamr@2: 	(head)->tqh_last = &TAILQ_NEXT((elm), field);			\
williamr@2: 	QMD_TRACE_HEAD(head);						\
williamr@2: 	QMD_TRACE_ELEM(&(elm)->field);					\
williamr@2: } while (0)
williamr@2: 
williamr@2: #define	TAILQ_LAST(head, headname)					\
williamr@2: 	(*(((struct headname *)((head)->tqh_last))->tqh_last))
williamr@2: 
williamr@2: #define	TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
williamr@2: 
williamr@2: #define	TAILQ_PREV(elm, headname, field)				\
williamr@2: 	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
williamr@2: 
williamr@2: #define	TAILQ_REMOVE(head, elm, field) do {				\
williamr@2: 	if ((TAILQ_NEXT((elm), field)) != NULL)				\
williamr@2: 		TAILQ_NEXT((elm), field)->field.tqe_prev = 		\
williamr@2: 		    (elm)->field.tqe_prev;				\
williamr@2: 	else {								\
williamr@2: 		(head)->tqh_last = (elm)->field.tqe_prev;		\
williamr@2: 		QMD_TRACE_HEAD(head);					\
williamr@2: 	}								\
williamr@2: 	*(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);		\
williamr@2: 	TRASHIT((elm)->field.tqe_next);					\
williamr@2: 	TRASHIT((elm)->field.tqe_prev);					\
williamr@2: 	QMD_TRACE_ELEM(&(elm)->field);					\
williamr@2: } while (0)
williamr@2: 
williamr@2: 
williamr@2: #ifdef _KERNEL
williamr@2: 
williamr@2: /*
williamr@2:  * XXX insque() and remque() are an old way of handling certain queues.
williamr@2:  * They bogusly assumes that all queue heads look alike.
williamr@2:  */
williamr@2: 
williamr@2: struct quehead {
williamr@2: 	struct quehead *qh_link;
williamr@2: 	struct quehead *qh_rlink;
williamr@2: };
williamr@2: 
williamr@2: #ifdef __CC_SUPPORTS___INLINE
williamr@2: 
williamr@2: static __inline void
williamr@2: insque(void *a, void *b)
williamr@2: {
williamr@2: 	struct quehead *element = (struct quehead *)a,
williamr@2: 		 *head = (struct quehead *)b;
williamr@2: 
williamr@2: 	element->qh_link = head->qh_link;
williamr@2: 	element->qh_rlink = head;
williamr@2: 	head->qh_link = element;
williamr@2: 	element->qh_link->qh_rlink = element;
williamr@2: }
williamr@2: 
williamr@2: static __inline void
williamr@2: remque(void *a)
williamr@2: {
williamr@2: 	struct quehead *element = (struct quehead *)a;
williamr@2: 
williamr@2: 	element->qh_link->qh_rlink = element->qh_rlink;
williamr@2: 	element->qh_rlink->qh_link = element->qh_link;
williamr@2: 	element->qh_rlink = 0;
williamr@2: }
williamr@2: 
williamr@2: #endif /* __CC_SUPPORTS___INLINE */
williamr@2: 
williamr@2: #endif /* _KERNEL */
williamr@2: 
williamr@2: #endif /* !_SYS_QUEUE_H_ */