queue.h

这是国外的resip协议栈

/*
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)queue.h	8.5 (Berkeley) 8/20/94
 * $FreeBSD: src/sys/sys/queue.h,v 1.54 2002/08/05 05:18:43 alfred Exp $
 */

#ifndef	_DB_QUEUE_H_
#define	_DB_QUEUE_H_

#if defined(__cplusplus)
extern "C" {
#endif

/*
 * 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_REVERSE	-	-	-	+
 * _INSERT_HEAD		+	+	+	+
 * _INSERT_BEFORE	-	+	-	+
 * _INSERT_AFTER	+	+	+	+
 * _INSERT_TAIL		-	-	+	+
 * _CONCAT		-	-	+	+
 * _REMOVE_HEAD		+	-	+	-
 * _REMOVE		+	+	+	+
 *
 */

/*
 * XXX
 * We #undef all of the macros because there are incompatible versions of this
 * file and these macros on various systems.  What makes the problem worse is
 * they are included and/or defined by system include files which we may have
 * already loaded into Berkeley DB before getting here.  For example, FreeBSD's
 * <rpc/rpc.h> includes its system <sys/queue.h>, and VxWorks UnixLib.h defines
 * several of the LIST_XXX macros.  Visual C.NET 7.0 also defines some of these
 * same macros in Vc7\PlatformSDK\Include\WinNT.h.  Make sure we use ours.
 */
#undef LIST_EMPTY
#undef LIST_ENTRY
#undef LIST_FIRST
#undef LIST_FOREACH
#undef LIST_HEAD
#undef LIST_HEAD_INITIALIZER
#undef LIST_INIT
#undef LIST_INSERT_AFTER
#undef LIST_INSERT_BEFORE
#undef LIST_INSERT_HEAD
#undef LIST_NEXT
#undef LIST_REMOVE
#undef QMD_TRACE_ELEM
#undef QMD_TRACE_HEAD
#undef QUEUE_MACRO_DEBUG
#undef SLIST_EMPTY
#undef SLIST_ENTRY
#undef SLIST_FIRST
#undef SLIST_FOREACH
#undef SLIST_FOREACH_PREVPTR
#undef SLIST_HEAD
#undef SLIST_HEAD_INITIALIZER
#undef SLIST_INIT
#undef SLIST_INSERT_AFTER
#undef SLIST_INSERT_HEAD
#undef SLIST_NEXT
#undef SLIST_REMOVE
#undef SLIST_REMOVE_HEAD
#undef STAILQ_CONCAT
#undef STAILQ_EMPTY
#undef STAILQ_ENTRY
#undef STAILQ_FIRST
#undef STAILQ_FOREACH
#undef STAILQ_HEAD
#undef STAILQ_HEAD_INITIALIZER
#undef STAILQ_INIT
#undef STAILQ_INSERT_AFTER
#undef STAILQ_INSERT_HEAD
#undef STAILQ_INSERT_TAIL
#undef STAILQ_LAST
#undef STAILQ_NEXT
#undef STAILQ_REMOVE
#undef STAILQ_REMOVE_HEAD
#undef STAILQ_REMOVE_HEAD_UNTIL
#undef TAILQ_CONCAT
#undef TAILQ_EMPTY
#undef TAILQ_ENTRY
#undef TAILQ_FIRST
#undef TAILQ_FOREACH
#undef TAILQ_FOREACH_REVERSE
#undef TAILQ_HEAD
#undef TAILQ_HEAD_INITIALIZER
#undef TAILQ_INIT
#undef TAILQ_INSERT_AFTER
#undef TAILQ_INSERT_BEFORE
#undef TAILQ_INSERT_HEAD
#undef TAILQ_INSERT_TAIL
#undef TAILQ_LAST
#undef TAILQ_NEXT
#undef TAILQ_PREV
#undef TAILQ_REMOVE
#undef TRACEBUF
#undef TRASHIT

#define	QUEUE_MACRO_DEBUG 0
#if 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_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);	\
	}								\
} while (0)

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

/*