/*- * 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. Neither the name of the University nor the names of its contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * *	@(#)queue.h	8.5 (Berkeley) 8/20/94 * $FreeBSD$ */ #ifndef _SYS_QUEUE_H_#define	_SYS_QUEUE_H_ #include <sys/cdefs.h> /* * This file defines four types of data structures: singly-linked lists, * singly-linked tail queues, lists and tail 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 be traversed in either 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. * * For details on the use of these macros, see the queue(3) manual page. * * Below is a summary of implemented functions where: *  +  means the macro is available *  -  means the macro is not available *  s  means the macro is available but is slow (runs in O(n) time) * *				SLIST	LIST	STAILQ	TAILQ * _HEAD			+	+	+	+ * _CLASS_HEAD			+	+	+	+ * _HEAD_INITIALIZER		+	+	+	+ * _ENTRY			+	+	+	+ * _CLASS_ENTRY			+	+	+	+ * _INIT			+	+	+	+ * _EMPTY			+	+	+	+ * _FIRST			+	+	+	+ * _NEXT			+	+	+	+ * _PREV			-	+	-	+ * _LAST			-	-	+	+ * _LAST_FAST			-	-	-	+ * _FOREACH			+	+	+	+ * _FOREACH_FROM		+	+	+	+ * _FOREACH_SAFE		+	+	+	+ * _FOREACH_FROM_SAFE		+	+	+	+ * _FOREACH_REVERSE		-	-	-	+ * _FOREACH_REVERSE_FROM	-	-	-	+ * _FOREACH_REVERSE_SAFE	-	-	-	+ * _FOREACH_REVERSE_FROM_SAFE	-	-	-	+ * _INSERT_HEAD			+	+	+	+ * _INSERT_BEFORE		-	+	-	+ * _INSERT_AFTER		+	+	+	+ * _INSERT_TAIL			-	-	+	+ * _CONCAT			s	s	+	+ * _REMOVE_AFTER		+	-	+	- * _REMOVE_HEAD			+	-	+	- * _REMOVE			s	+	s	+ * _SWAP			+	+	+	+ * */#ifdef QUEUE_MACRO_DEBUG#warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH#define	QUEUE_MACRO_DEBUG_TRACE#define	QUEUE_MACRO_DEBUG_TRASH#endif #ifdef QUEUE_MACRO_DEBUG_TRACE/* Store the last 2 places the queue element or head was altered */struct qm_trace {	unsigned long	 lastline;	unsigned long	 prevline;	const char	*lastfile;	const char	*prevfile;}; #define	TRACEBUF	struct qm_trace trace;#define	TRACEBUF_INITIALIZER	{ __LINE__, 0, __FILE__, NULL } , #define	QMD_TRACE_HEAD(head) do {					\	(head)->trace.prevline = (head)->trace.lastline;		\	(head)->trace.prevfile = (head)->trace.lastfile;		\	(head)->trace.lastline = __LINE__;				\	(head)->trace.lastfile = __FILE__;				\} while (0) #define	QMD_TRACE_ELEM(elem) do {					\	(elem)->trace.prevline = (elem)->trace.lastline;		\	(elem)->trace.prevfile = (elem)->trace.lastfile;		\	(elem)->trace.lastline = __LINE__;				\	(elem)->trace.lastfile = __FILE__;				\} while (0) #else	/* !QUEUE_MACRO_DEBUG_TRACE */#define	QMD_TRACE_ELEM(elem)#define	QMD_TRACE_HEAD(head)#define	TRACEBUF#define	TRACEBUF_INITIALIZER#endif	/* QUEUE_MACRO_DEBUG_TRACE */ #ifdef QUEUE_MACRO_DEBUG_TRASH#define	TRASHIT(x)		do {(x) = (void *)-1;} while (0)#define	QMD_IS_TRASHED(x)	((x) == (void *)(intptr_t)-1)#else	/* !QUEUE_MACRO_DEBUG_TRASH */#define	TRASHIT(x)#define	QMD_IS_TRASHED(x)	0#endif	/* QUEUE_MACRO_DEBUG_TRASH */ #if defined(QUEUE_MACRO_DEBUG_TRACE) || defined(QUEUE_MACRO_DEBUG_TRASH)#define	QMD_SAVELINK(name, link)	void **name = (void *)&(link)#else	/* !QUEUE_MACRO_DEBUG_TRACE && !QUEUE_MACRO_DEBUG_TRASH */#define	QMD_SAVELINK(name, link)#endif	/* QUEUE_MACRO_DEBUG_TRACE || QUEUE_MACRO_DEBUG_TRASH */ #ifdef __cplusplus/* * In C++ there can be structure lists and class lists: */#define	QUEUE_TYPEOF(type) type#else#define	QUEUE_TYPEOF(type) struct type#endif /* * Singly-linked List declarations. */#define	SLIST_HEAD(name, type)						\struct name {								\	struct type *slh_first;	/* first element */			\} #define	SLIST_CLASS_HEAD(name, type)					\struct name {								\	class type *slh_first;	/* first element */			\} #define	SLIST_HEAD_INITIALIZER(head)					\	{ NULL } #define	SLIST_ENTRY(type)						\struct {								\	struct type *sle_next;	/* next element */			\} #define	SLIST_CLASS_ENTRY(type)						\struct {								\	class type *sle_next;		/* next element */		\} /* * Singly-linked List functions. */#if (defined(_KERNEL) && defined(INVARIANTS))#define	QMD_SLIST_CHECK_PREVPTR(prevp, elm) do {			\	if (*(prevp) != (elm))						\		panic("Bad prevptr *(%p) == %p != %p",			\		    (prevp), *(prevp), (elm));				\} while (0)#else#define	QMD_SLIST_CHECK_PREVPTR(prevp, elm)#endif #define SLIST_CONCAT(head1, head2, type, field) do {			\	QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1);		\	if (curelm == NULL) {						\		if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL)	\			SLIST_INIT(head2);				\	} else if (SLIST_FIRST(head2) != NULL) {			\		while (SLIST_NEXT(curelm, field) != NULL)		\			curelm = SLIST_NEXT(curelm, field);		\		SLIST_NEXT(curelm, field) = SLIST_FIRST(head2);		\		SLIST_INIT(head2);					\	}								\} while (0) #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_FOREACH_FROM(var, head, field)				\	for ((var) = ((var) ? (var) : SLIST_FIRST((head)));		\	    (var);							\	    (var) = SLIST_NEXT((var), field)) #define	SLIST_FOREACH_SAFE(var, head, field, tvar)			\	for ((var) = SLIST_FIRST((head));				\	    (var) && ((tvar) = SLIST_NEXT((var), field), 1);		\	    (var) = (tvar)) #define	SLIST_FOREACH_FROM_SAFE(var, head, field, tvar)			\	for ((var) = ((var) ? (var) : SLIST_FIRST((head)));		\	    (var) && ((tvar) = SLIST_NEXT((var), field), 1);		\	    (var) = (tvar)) #define	SLIST_FOREACH_PREVPTR(var, varp, head, field)			\	for ((varp) = &SLIST_FIRST((head));				\	    ((var) = *(varp)) != NULL;					\	    (varp) = &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 {			\	QMD_SAVELINK(oldnext, (elm)->field.sle_next);			\	if (SLIST_FIRST((head)) == (elm)) {				\		SLIST_REMOVE_HEAD((head), field);			\	}								\	else {								\		QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head);		\		while (SLIST_NEXT(curelm, field) != (elm))		\			curelm = SLIST_NEXT(curelm, field);		\		SLIST_REMOVE_AFTER(curelm, field);			\	}								\	TRASHIT(*oldnext);						\} while (0) #define SLIST_REMOVE_AFTER(elm, field) do {				\	SLIST_NEXT(elm, field) =					\	    SLIST_NEXT(SLIST_NEXT(elm, field), field);			\} while (0) #define	SLIST_REMOVE_HEAD(head, field) do {				\	SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);	\} while (0) #define	SLIST_REMOVE_PREVPTR(prevp, elm, field) do {			\	QMD_SLIST_CHECK_PREVPTR(prevp, elm);				\	*(prevp) = SLIST_NEXT(elm, field);				\	TRASHIT((elm)->field.sle_next);					\} while (0) #define SLIST_SWAP(head1, head2, type) do {				\	QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1);		\	SLIST_FIRST(head1) = SLIST_FIRST(head2);			\	SLIST_FIRST(head2) = swap_first;				\} 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_CLASS_HEAD(name, type)					\struct name {								\	class type *stqh_first;	/* first element */			\	class 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 */			\} #define	STAILQ_CLASS_ENTRY(type)					\struct {								\	class type *stqe_next;	/* next element */			\} /* * Singly-linked Tail queue functions. */#define	STAILQ_CONCAT(head1, head2) do {				\	if (!STAILQ_EMPTY((head2))) {					\		*(head1)->stqh_last = (head2)->stqh_first;		\		(head1)->stqh_last = (head2)->stqh_last;		\		STAILQ_INIT((head2));					\	}								\} while (0) #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_FOREACH_FROM(var, head, field)				\	for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));		\	   (var);							\	   (var) = STAILQ_NEXT((var), field)) #define	STAILQ_FOREACH_SAFE(var, head, field, tvar)			\	for ((var) = STAILQ_FIRST((head));				\	    (var) && ((tvar) = STAILQ_NEXT((var), field), 1);		\	    (var) = (tvar)) #define	STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)		\	for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));		\	    (var) && ((tvar) = STAILQ_NEXT((var), field), 1);		\	    (var) = (tvar)) #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;				\	*(head)->stqh_last = (elm);					\	(head)->stqh_last = &STAILQ_NEXT((elm), field);			\} while (0) #define	STAILQ_LAST(head, type, field)				\	(STAILQ_EMPTY((head)) ? NULL :				\	    __containerof((head)->stqh_last,			\	    QUEUE_TYPEOF(type), field.stqe_next)) #define	STAILQ_NEXT(elm, field)	((elm)->field.stqe_next) #define	STAILQ_REMOVE(head, elm, type, field) do {			\	QMD_SAVELINK(oldnext, (elm)->field.stqe_next);			\	if (STAILQ_FIRST((head)) == (elm)) {				\		STAILQ_REMOVE_HEAD((head), field);			\	}								\	else {								\		QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head);	\		while (STAILQ_NEXT(curelm, field) != (elm))		\			curelm = STAILQ_NEXT(curelm, field);		\		STAILQ_REMOVE_AFTER(head, curelm, field);		\	}								\	TRASHIT(*oldnext);						\} while (0) #define STAILQ_REMOVE_AFTER(head, elm, field) do {			\	if ((STAILQ_NEXT(elm, field) =					\	     STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)	\		(head)->stqh_last = &STAILQ_NEXT((elm), 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) #define STAILQ_SWAP(head1, head2, type) do {				\	QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1);		\	QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last;		\	STAILQ_FIRST(head1) = STAILQ_FIRST(head2);			\	(head1)->stqh_last = (head2)->stqh_last;			\	STAILQ_FIRST(head2) = swap_first;				\	(head2)->stqh_last = swap_last;					\	if (STAILQ_EMPTY(head1))					\		(head1)->stqh_last = &STAILQ_FIRST(head1);		\	if (STAILQ_EMPTY(head2))					\		(head2)->stqh_last = &STAILQ_FIRST(head2);		\} while (0)  /* * List declarations. */#define	LIST_HEAD(name, type)						\struct name {								\	struct type *lh_first;	/* first element */			\} #define	LIST_CLASS_HEAD(name, type)					\struct name {								\	class 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 */	\} #define	LIST_CLASS_ENTRY(type)						\struct {								\	class type *le_next;	/* next element */			\	class type **le_prev;	/* address of previous next element */	\} /* * List functions. */ #if (defined(_KERNEL) && defined(INVARIANTS))/* * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME) * * If the list is non-empty, validates that the first element of the list * points back at 'head.' */#define	QMD_LIST_CHECK_HEAD(head, field) do {				\	if (LIST_FIRST((head)) != NULL &&				\	    LIST_FIRST((head))->field.le_prev !=			\	     &LIST_FIRST((head)))					\		panic("Bad list head %p first->prev != head", (head));	\} while (0) /* * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME) * * If an element follows 'elm' in the list, validates that the next element * points back at 'elm.' */#define	QMD_LIST_CHECK_NEXT(elm, field) do {				\

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