list.h
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 /*-
  * Copyright (c) 1991, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 4. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  *	@(#)queue.h	8.5 (Berkeley) 8/20/94
  * $FreeBSD: /repoman/r/ncvs/src/sys/sys/queue.h,v 1.68 2006/10/24 11:20:29 ru Exp $
  */
 
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 #ifndef _SER_LIST_H
 #define	_SER_LIST_H
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 /* #include <sys/cdefs.h> - not needed and not present on all the systems */
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 /*
  * 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 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.
  *
  * For details on the use of these macros, see the queue(3) manual page.
  *
  *
  *				SLIST	LIST	STAILQ	TAILQ
  * _HEAD			+	+	+	+
  * _HEAD_INITIALIZER		+	+	+	+
  * _ENTRY			+	+	+	+
  * _INIT			+	+	+	+
  * _EMPTY			+	+	+	+
  * _FIRST			+	+	+	+
  * _NEXT			+	+	+	+
  * _PREV			-	-	-	+
  * _LAST			-	-	+	+
  * _FOREACH			+	+	+	+
  * _FOREACH_SAFE		+	+	+	+
  * _FOREACH_REVERSE		-	-	-	+
  * _FOREACH_REVERSE_SAFE	-	-	-	+
  * _INSERT_HEAD			+	+	+	+
  * _INSERT_BEFORE		-	+	-	+
  * _INSERT_AFTER		+	+	+	+
  * _INSERT_TAIL			-	-	+	+
  * _CONCAT			-	-	+	+
  * _REMOVE_HEAD			+	-	+	-
  * _REMOVE			+	+	+	+
  *
  */
 #ifdef QUEUE_MACRO_DEBUG
 /* Store the last 2 places the queue element or head was altered */
 struct qm_trace {
 	char * lastfile;
 	int lastline;
 	char * prevfile;
 	int prevline;
 };
 
 #define	TRACEBUF	struct qm_trace trace;
 #define	TRASHIT(x)	do {(x) = (void *)-1;} while (0)
 
 #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
 #define	QMD_TRACE_ELEM(elem)
 #define	QMD_TRACE_HEAD(head)
 #define	TRACEBUF
 #define	TRASHIT(x)
 #endif	/* QUEUE_MACRO_DEBUG */
 
 /*
  * 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_FOREACH_SAFE(var, head, field, tvar)			\
 	for ((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 {			\
 	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);	\
 	}								\
 	TRASHIT((elm)->field.sle_next);					\
 } 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_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_SAFE(var, head, field, tvar)			\
 	for ((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 :							\
 	        ((struct type *)(void *)				\
 		((char *)((head)->stqh_last) - __offsetof(struct type, field))))
 
 #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);\
 	}								\
 	TRASHIT((elm)->field.stqe_next);				\
 } 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)
 
 /*
  * 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_FOREACH_SAFE(var, head, field, tvar)			\
 	for ((var) = LIST_FIRST((head));				\
 	    (var) && ((tvar) = LIST_NEXT((var), field), 1);		\
 	    (var) = (tvar))
 
 #define	LIST_INIT(head) do {						\
 	LIST_FIRST((head)) = NULL;					\
 } while (0)
 
 #define	LIST_INSERT_AFTER(listelm, elm, field) do {			\
 	QMD_LIST_CHECK_NEXT(listelm, field);				\
 	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 {			\
 	QMD_LIST_CHECK_PREV(listelm, field);				\
 	(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 {				\
 	QMD_LIST_CHECK_HEAD((head), field);				\
 	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 {					\
 	QMD_LIST_CHECK_NEXT(elm, field);				\
 	QMD_LIST_CHECK_PREV(elm, field);				\
 	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);		\
 	TRASHIT((elm)->field.le_next);					\
 	TRASHIT((elm)->field.le_prev);					\
 } 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 */		\
 	TRACEBUF							\
 }
 
 #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 */	\
 	TRACEBUF							\
 }
 
 /*
  * Tail queue functions.
  */
 
 #define	TAILQ_CONCAT(head1, head2, field) do {				\
 	if (!TAILQ_EMPTY(head2)) {					\
 		*(head1)->tqh_last = (head2)->tqh_first;		\
 		(head2)->tqh_first->field.tqe_prev = (head1)->tqh_last;	\
 		(head1)->tqh_last = (head2)->tqh_last;			\
 		TAILQ_INIT((head2));					\
 		QMD_TRACE_HEAD(head1);					\
 		QMD_TRACE_HEAD(head2);					\
 	}								\
 } while (0)
 
 #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_SAFE(var, head, field, tvar)			\
 	for ((var) = TAILQ_FIRST((head));				\
 	    (var) && ((tvar) = TAILQ_NEXT((var), field), 1);		\
 	    (var) = (tvar))
 
 #define	TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
 	for ((var) = TAILQ_LAST((head), headname);			\
 	    (var);							\
 	    (var) = TAILQ_PREV((var), headname, field))
 
 #define	TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)	\
 	for ((var) = TAILQ_LAST((head), headname);			\
 	    (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);	\
 	    (var) = (tvar))
 
 #define	TAILQ_INIT(head) do {						\
 	TAILQ_FIRST((head)) = NULL;					\
 	(head)->tqh_last = &TAILQ_FIRST((head));			\
 	QMD_TRACE_HEAD(head);						\
 } while (0)
 
 #define	TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
 	QMD_TAILQ_CHECK_NEXT(listelm, field);				\
 	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);		\
 		QMD_TRACE_HEAD(head);					\
 	}								\
 	TAILQ_NEXT((listelm), field) = (elm);				\
 	(elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);		\
 	QMD_TRACE_ELEM(&(elm)->field);					\
 	QMD_TRACE_ELEM(&listelm->field);				\
 } while (0)
 
 #define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
 	QMD_TAILQ_CHECK_PREV(listelm, field);				\
 	(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);		\
 	QMD_TRACE_ELEM(&(elm)->field);					\
 	QMD_TRACE_ELEM(&listelm->field);				\
 } while (0)
 
 #define	TAILQ_INSERT_HEAD(head, elm, field) do {			\
 	QMD_TAILQ_CHECK_HEAD(head, field);				\
 	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));			\
 	QMD_TRACE_HEAD(head);						\
 	QMD_TRACE_ELEM(&(elm)->field);					\
 } while (0)
 
 #define	TAILQ_INSERT_TAIL(head, elm, field) do {			\
 	QMD_TAILQ_CHECK_TAIL(head, field);				\
 	TAILQ_NEXT((elm), field) = NULL;				\
 	(elm)->field.tqe_prev = (head)->tqh_last;			\
 	*(head)->tqh_last = (elm);					\
 	(head)->tqh_last = &TAILQ_NEXT((elm), field);			\
 	QMD_TRACE_HEAD(head);						\
 	QMD_TRACE_ELEM(&(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 {				\
 	QMD_TAILQ_CHECK_NEXT(elm, field);				\
 	QMD_TAILQ_CHECK_PREV(elm, field);				\
 	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;		\
 		QMD_TRACE_HEAD(head);					\
 	}								\
 	*(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);		\
 	TRASHIT((elm)->field.tqe_next);					\
 	TRASHIT((elm)->field.tqe_prev);					\
 	QMD_TRACE_ELEM(&(elm)->field);					\
 } while (0)
 
 #endif /* !_LIST_H */