Use queue.h in grep(1)

Makefile

@@ -8,6 +8,7 @@ HDR = \
 	crypt.h  \
 	fs.h     \
 	md5.h    \
+	queue.h  \
 	sha1.h   \
 	sha256.h \
 	sha512.h \

grep.c

@@ -5,6 +5,7 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "queue.h"
 #include "text.h"
 #include "util.h"
 
@@ -19,11 +20,13 @@ static int Hflag = 0;
 static int many;
 static char mode = 0;
 
-static struct plist {
+struct pattern {
 	char *pattern;
 	regex_t preg;
-	struct plist *next;
+	TAILQ_ENTRY(pattern) entry;
-} *phead;
+};
+
+static TAILQ_HEAD(phead, pattern) phead;
 
 static void
 usage(void)
@@ -34,11 +37,13 @@ usage(void)
 int
 main(int argc, char *argv[])
 {
-	struct plist *pnode, *tmp;
+	struct pattern *pnode, *tmp;
 	int i, n, m, flags = REG_NOSUB, match = NoMatch;
 	char buf[BUFSIZ];
 	FILE *fp;
 
+	TAILQ_INIT(&phead);
+
 	ARGBEGIN {
 	case 'E':
 		flags |= REG_EXTENDED;
@@ -77,7 +82,7 @@ main(int argc, char *argv[])
 	}
 
 	/* Compile regex for all search patterns */
-	for (pnode = phead; pnode; pnode = pnode->next) {
+	TAILQ_FOREACH(pnode, &phead, entry) {
 		if ((n = regcomp(&pnode->preg, pnode->pattern, flags)) != 0) {
 			regerror(n, &pnode->preg, buf, sizeof buf);
 			enprintf(Error, "invalid pattern: %s\n", buf);
@@ -99,13 +104,11 @@ main(int argc, char *argv[])
 			fclose(fp);
 		}
 	}
-	pnode = phead;
+	TAILQ_FOREACH_SAFE(pnode, &phead, entry, tmp) {
-	while (pnode) {
+		TAILQ_REMOVE(&phead, pnode, entry);
-		tmp = pnode->next;
 		regfree(&pnode->preg);
 		free(pnode->pattern);
 		free(pnode);
-		pnode = tmp;
 	}
 	return match;
 }
@@ -113,12 +116,11 @@ main(int argc, char *argv[])
 static void
 addpattern(const char *pattern)
 {
-	struct plist *pnode;
+	struct pattern *pnode;
 
 	pnode = emalloc(sizeof(*pnode));
 	pnode->pattern = estrdup(pattern);
-	pnode->next = phead;
+	TAILQ_INSERT_TAIL(&phead, pnode, entry);
-	phead = pnode;
 }
 
 static int
@@ -127,14 +129,14 @@ grep(FILE *fp, const char *str)
 	char *buf = NULL;
 	size_t len = 0, size = 0;
 	long c = 0, n;
-	struct plist *pnode;
+	struct pattern *pnode;
 	int match = NoMatch;
 
 	for (n = 1; (len = agetline(&buf, &size, fp)) != -1; n++) {
 		/* Remove the trailing newline if one is present. */
 		if (len && buf[len - 1] == '\n')
 			buf[len - 1] = '\0';
-		for (pnode = phead; pnode; pnode = pnode->next) {
+		TAILQ_FOREACH(pnode, &phead, entry) {
 			if (regexec(&pnode->preg, buf, 0, NULL, 0) ^ vflag)
 				continue;
 			switch (mode) {

queue.h

@@ -0,0 +1,648 @@
+/*	$OpenBSD: queue.h,v 1.38 2013/07/03 15:05:21 fgsch Exp $	*/
+/*	$NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $	*/
+
+/*
+ * 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
+ */
+
+#ifndef	_SYS_QUEUE_H_
+#define	_SYS_QUEUE_H_
+
+/*
+ * This file defines five types of data structures: singly-linked lists, 
+ * lists, simple queues, 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 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 simple queue is headed by a pair of pointers, one the head of the
+ * list and the other to the tail of the list. The elements are singly
+ * linked to save space, so elements can only be removed from the
+ * head of 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 simple queue 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.
+ */
+
+#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
+#define _Q_INVALIDATE(a) (a) = ((void *)-1)
+#else
+#define _Q_INVALIDATE(a)
+#endif
+
+/*
+ * Singly-linked List definitions.
+ */
+#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 access methods.
+ */
+#define	SLIST_FIRST(head)	((head)->slh_first)
+#define	SLIST_END(head)		NULL
+#define	SLIST_EMPTY(head)	(SLIST_FIRST(head) == SLIST_END(head))
+#define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)
+
+#define	SLIST_FOREACH(var, head, field)					\
+	for((var) = SLIST_FIRST(head);					\
+	    (var) != SLIST_END(head);					\
+	    (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))
+
+/*
+ * Singly-linked List functions.
+ */
+#define	SLIST_INIT(head) {						\
+	SLIST_FIRST(head) = SLIST_END(head);				\
+}
+
+#define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
+	(elm)->field.sle_next = (slistelm)->field.sle_next;		\
+	(slistelm)->field.sle_next = (elm);				\
+} while (0)
+
+#define	SLIST_INSERT_HEAD(head, elm, field) do {			\
+	(elm)->field.sle_next = (head)->slh_first;			\
+	(head)->slh_first = (elm);					\
+} while (0)
+
+#define	SLIST_REMOVE_AFTER(elm, field) do {				\
+	(elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;	\
+} while (0)
+
+#define	SLIST_REMOVE_HEAD(head, field) do {				\
+	(head)->slh_first = (head)->slh_first->field.sle_next;		\
+} while (0)
+
+#define SLIST_REMOVE(head, elm, type, field) do {			\
+	if ((head)->slh_first == (elm)) {				\
+		SLIST_REMOVE_HEAD((head), field);			\
+	} else {							\
+		struct type *curelm = (head)->slh_first;		\
+									\
+		while (curelm->field.sle_next != (elm))			\
+			curelm = curelm->field.sle_next;		\
+		curelm->field.sle_next =				\
+		    curelm->field.sle_next->field.sle_next;		\
+		_Q_INVALIDATE((elm)->field.sle_next);			\
+	}								\
+} while (0)
+
+/*
+ * List definitions.
+ */
+#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 access methods
+ */
+#define	LIST_FIRST(head)		((head)->lh_first)
+#define	LIST_END(head)			NULL
+#define	LIST_EMPTY(head)		(LIST_FIRST(head) == LIST_END(head))
+#define	LIST_NEXT(elm, field)		((elm)->field.le_next)
+
+#define LIST_FOREACH(var, head, field)					\
+	for((var) = LIST_FIRST(head);					\
+	    (var)!= LIST_END(head);					\
+	    (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))
+
+/*
+ * List functions.
+ */
+#define	LIST_INIT(head) do {						\
+	LIST_FIRST(head) = LIST_END(head);				\
+} while (0)
+
+#define LIST_INSERT_AFTER(listelm, elm, field) do {			\
+	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)	\
+		(listelm)->field.le_next->field.le_prev =		\
+		    &(elm)->field.le_next;				\
+	(listelm)->field.le_next = (elm);				\
+	(elm)->field.le_prev = &(listelm)->field.le_next;		\
+} while (0)
+
+#define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
+	(elm)->field.le_prev = (listelm)->field.le_prev;		\
+	(elm)->field.le_next = (listelm);				\
+	*(listelm)->field.le_prev = (elm);				\
+	(listelm)->field.le_prev = &(elm)->field.le_next;		\
+} while (0)
+
+#define LIST_INSERT_HEAD(head, elm, field) do {				\
+	if (((elm)->field.le_next = (head)->lh_first) != NULL)		\
+		(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
+	(head)->lh_first = (elm);					\
+	(elm)->field.le_prev = &(head)->lh_first;			\
+} while (0)
+
+#define LIST_REMOVE(elm, field) do {					\
+	if ((elm)->field.le_next != NULL)				\
+		(elm)->field.le_next->field.le_prev =			\
+		    (elm)->field.le_prev;				\
+	*(elm)->field.le_prev = (elm)->field.le_next;			\
+	_Q_INVALIDATE((elm)->field.le_prev);				\
+	_Q_INVALIDATE((elm)->field.le_next);				\
+} while (0)
+
+#define LIST_REPLACE(elm, elm2, field) do {				\
+	if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)	\
+		(elm2)->field.le_next->field.le_prev =			\
+		    &(elm2)->field.le_next;				\
+	(elm2)->field.le_prev = (elm)->field.le_prev;			\
+	*(elm2)->field.le_prev = (elm2);				\
+	_Q_INVALIDATE((elm)->field.le_prev);				\
+	_Q_INVALIDATE((elm)->field.le_next);				\
+} while (0)
+
+/*
+ * Simple queue definitions.
+ */
+#define SIMPLEQ_HEAD(name, type)					\
+struct name {								\
+	struct type *sqh_first;	/* first element */			\
+	struct type **sqh_last;	/* addr of last next element */		\
+}
+
+#define SIMPLEQ_HEAD_INITIALIZER(head)					\
+	{ NULL, &(head).sqh_first }
+
+#define SIMPLEQ_ENTRY(type)						\
+struct {								\
+	struct type *sqe_next;	/* next element */			\
+}
+
+/*
+ * Simple queue access methods.
+ */
+#define	SIMPLEQ_FIRST(head)	    ((head)->sqh_first)
+#define	SIMPLEQ_END(head)	    NULL
+#define	SIMPLEQ_EMPTY(head)	    (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
+#define	SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
+
+#define SIMPLEQ_FOREACH(var, head, field)				\
+	for((var) = SIMPLEQ_FIRST(head);				\
+	    (var) != SIMPLEQ_END(head);					\
+	    (var) = SIMPLEQ_NEXT(var, field))
+
+#define	SIMPLEQ_FOREACH_SAFE(var, head, field, tvar)			\
+	for ((var) = SIMPLEQ_FIRST(head);				\
+	    (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1);		\
+	    (var) = (tvar))
+
+/*
+ * Simple queue functions.
+ */
+#define	SIMPLEQ_INIT(head) do {						\
+	(head)->sqh_first = NULL;					\
+	(head)->sqh_last = &(head)->sqh_first;				\
+} while (0)
+
+#define SIMPLEQ_INSERT_HEAD(head, elm, field) do {			\
+	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)	\
+		(head)->sqh_last = &(elm)->field.sqe_next;		\
+	(head)->sqh_first = (elm);					\
+} while (0)
+
+#define SIMPLEQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.sqe_next = NULL;					\
+	*(head)->sqh_last = (elm);					\
+	(head)->sqh_last = &(elm)->field.sqe_next;			\
+} while (0)
+
+#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
+		(head)->sqh_last = &(elm)->field.sqe_next;		\
+	(listelm)->field.sqe_next = (elm);				\
+} while (0)
+
+#define SIMPLEQ_REMOVE_HEAD(head, field) do {			\
+	if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
+		(head)->sqh_last = &(head)->sqh_first;			\
+} while (0)
+
+#define SIMPLEQ_REMOVE_AFTER(head, elm, field) do {			\
+	if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
+	    == NULL)							\
+		(head)->sqh_last = &(elm)->field.sqe_next;		\
+} while (0)
+
+/*
+ * XOR Simple queue definitions.
+ */
+#define XSIMPLEQ_HEAD(name, type)					\
+struct name {								\
+	struct type *sqx_first;	/* first element */			\
+	struct type **sqx_last;	/* addr of last next element */		\
+	unsigned long sqx_cookie;					\
+}
+
+#define XSIMPLEQ_ENTRY(type)						\
+struct {								\
+	struct type *sqx_next;	/* next element */			\
+}
+
+/*
+ * XOR Simple queue access methods.
+ */
+#define XSIMPLEQ_XOR(head, ptr)	    ((__typeof(ptr))((head)->sqx_cookie ^ \
+					(unsigned long)(ptr)))
+#define	XSIMPLEQ_FIRST(head)	    XSIMPLEQ_XOR(head, ((head)->sqx_first))
+#define	XSIMPLEQ_END(head)	    NULL
+#define	XSIMPLEQ_EMPTY(head)	    (XSIMPLEQ_FIRST(head) == XSIMPLEQ_END(head))
+#define	XSIMPLEQ_NEXT(head, elm, field)    XSIMPLEQ_XOR(head, ((elm)->field.sqx_next))
+
+
+#define XSIMPLEQ_FOREACH(var, head, field)				\
+	for ((var) = XSIMPLEQ_FIRST(head);				\
+	    (var) != XSIMPLEQ_END(head);				\
+	    (var) = XSIMPLEQ_NEXT(head, var, field))
+
+#define	XSIMPLEQ_FOREACH_SAFE(var, head, field, tvar)			\
+	for ((var) = XSIMPLEQ_FIRST(head);				\
+	    (var) && ((tvar) = XSIMPLEQ_NEXT(head, var, field), 1);	\
+	    (var) = (tvar))
+
+/*
+ * XOR Simple queue functions.
+ */
+#define	XSIMPLEQ_INIT(head) do {					\
+	arc4random_buf(&(head)->sqx_cookie, sizeof((head)->sqx_cookie)); \
+	(head)->sqx_first = XSIMPLEQ_XOR(head, NULL);			\
+	(head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first);	\
+} while (0)
+
+#define XSIMPLEQ_INSERT_HEAD(head, elm, field) do {			\
+	if (((elm)->field.sqx_next = (head)->sqx_first) ==		\
+	    XSIMPLEQ_XOR(head, NULL))					\
+		(head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
+	(head)->sqx_first = XSIMPLEQ_XOR(head, (elm));			\
+} while (0)
+
+#define XSIMPLEQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL);		\
+	*(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \
+	(head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next);	\
+} while (0)
+
+#define XSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	if (((elm)->field.sqx_next = (listelm)->field.sqx_next) ==	\
+	    XSIMPLEQ_XOR(head, NULL))					\
+		(head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
+	(listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm));		\
+} while (0)
+
+#define XSIMPLEQ_REMOVE_HEAD(head, field) do {				\
+	if (((head)->sqx_first = XSIMPLEQ_XOR(head,			\
+	    (head)->sqx_first)->field.sqx_next) == XSIMPLEQ_XOR(head, NULL)) \
+		(head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
+} while (0)
+
+#define XSIMPLEQ_REMOVE_AFTER(head, elm, field) do {			\
+	if (((elm)->field.sqx_next = XSIMPLEQ_XOR(head,			\
+	    (elm)->field.sqx_next)->field.sqx_next)			\
+	    == XSIMPLEQ_XOR(head, NULL))				\
+		(head)->sqx_last = 					\
+		    XSIMPLEQ_XOR(head, &(elm)->field.sqx_next);		\
+} while (0)
+
+		    
+/*
+ * Tail queue definitions.
+ */
+#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 access methods 
+ */
+#define	TAILQ_FIRST(head)		((head)->tqh_first)
+#define	TAILQ_END(head)			NULL
+#define	TAILQ_NEXT(elm, field)		((elm)->field.tqe_next)
+#define TAILQ_LAST(head, headname)					\
+	(*(((struct headname *)((head)->tqh_last))->tqh_last))
+/* XXX */
+#define TAILQ_PREV(elm, headname, field)				\
+	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+#define	TAILQ_EMPTY(head)						\
+	(TAILQ_FIRST(head) == TAILQ_END(head))
+
+#define TAILQ_FOREACH(var, head, field)					\
+	for((var) = TAILQ_FIRST(head);					\
+	    (var) != TAILQ_END(head);					\
+	    (var) = TAILQ_NEXT(var, field))
+
+#define	TAILQ_FOREACH_SAFE(var, head, field, tvar)			\
+	for ((var) = TAILQ_FIRST(head);					\
+	    (var) != TAILQ_END(head) &&					\
+	    ((tvar) = TAILQ_NEXT(var, field), 1);			\
+	    (var) = (tvar))
+
+
+#define TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
+	for((var) = TAILQ_LAST(head, headname);				\
+	    (var) != TAILQ_END(head);					\
+	    (var) = TAILQ_PREV(var, headname, field))
+
+#define	TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)	\
+	for ((var) = TAILQ_LAST(head, headname);			\
+	    (var) != TAILQ_END(head) &&					\
+	    ((tvar) = TAILQ_PREV(var, headname, field), 1);		\
+	    (var) = (tvar))
+
+/*
+ * Tail queue functions.
+ */
+#define	TAILQ_INIT(head) do {						\
+	(head)->tqh_first = NULL;					\
+	(head)->tqh_last = &(head)->tqh_first;				\
+} while (0)
+
+#define TAILQ_INSERT_HEAD(head, elm, field) do {			\
+	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)	\
+		(head)->tqh_first->field.tqe_prev =			\
+		    &(elm)->field.tqe_next;				\
+	else								\
+		(head)->tqh_last = &(elm)->field.tqe_next;		\
+	(head)->tqh_first = (elm);					\
+	(elm)->field.tqe_prev = &(head)->tqh_first;			\
+} while (0)
+
+#define TAILQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.tqe_next = NULL;					\
+	(elm)->field.tqe_prev = (head)->tqh_last;			\
+	*(head)->tqh_last = (elm);					\
+	(head)->tqh_last = &(elm)->field.tqe_next;			\
+} while (0)
+
+#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
+		(elm)->field.tqe_next->field.tqe_prev =			\
+		    &(elm)->field.tqe_next;				\
+	else								\
+		(head)->tqh_last = &(elm)->field.tqe_next;		\
+	(listelm)->field.tqe_next = (elm);				\
+	(elm)->field.tqe_prev = &(listelm)->field.tqe_next;		\
+} while (0)
+
+#define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
+	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
+	(elm)->field.tqe_next = (listelm);				\
+	*(listelm)->field.tqe_prev = (elm);				\
+	(listelm)->field.tqe_prev = &(elm)->field.tqe_next;		\
+} while (0)
+
+#define TAILQ_REMOVE(head, elm, field) do {				\
+	if (((elm)->field.tqe_next) != NULL)				\
+		(elm)->field.tqe_next->field.tqe_prev =			\
+		    (elm)->field.tqe_prev;				\
+	else								\
+		(head)->tqh_last = (elm)->field.tqe_prev;		\
+	*(elm)->field.tqe_prev = (elm)->field.tqe_next;			\
+	_Q_INVALIDATE((elm)->field.tqe_prev);				\
+	_Q_INVALIDATE((elm)->field.tqe_next);				\
+} while (0)
+
+#define TAILQ_REPLACE(head, elm, elm2, field) do {			\
+	if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)	\
+		(elm2)->field.tqe_next->field.tqe_prev =		\
+		    &(elm2)->field.tqe_next;				\
+	else								\
+		(head)->tqh_last = &(elm2)->field.tqe_next;		\
+	(elm2)->field.tqe_prev = (elm)->field.tqe_prev;			\
+	*(elm2)->field.tqe_prev = (elm2);				\
+	_Q_INVALIDATE((elm)->field.tqe_prev);				\
+	_Q_INVALIDATE((elm)->field.tqe_next);				\
+} while (0)
+
+/*
+ * Circular queue definitions.
+ */
+#define CIRCLEQ_HEAD(name, type)					\
+struct name {								\
+	struct type *cqh_first;		/* first element */		\
+	struct type *cqh_last;		/* last element */		\
+}
+
+#define CIRCLEQ_HEAD_INITIALIZER(head)					\
+	{ CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
+
+#define CIRCLEQ_ENTRY(type)						\
+struct {								\
+	struct type *cqe_next;		/* next element */		\
+	struct type *cqe_prev;		/* previous element */		\
+}
+
+/*
+ * Circular queue access methods 
+ */
+#define	CIRCLEQ_FIRST(head)		((head)->cqh_first)
+#define	CIRCLEQ_LAST(head)		((head)->cqh_last)
+#define	CIRCLEQ_END(head)		((void *)(head))
+#define	CIRCLEQ_NEXT(elm, field)	((elm)->field.cqe_next)
+#define	CIRCLEQ_PREV(elm, field)	((elm)->field.cqe_prev)
+#define	CIRCLEQ_EMPTY(head)						\
+	(CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
+
+#define CIRCLEQ_FOREACH(var, head, field)				\
+	for((var) = CIRCLEQ_FIRST(head);				\
+	    (var) != CIRCLEQ_END(head);					\
+	    (var) = CIRCLEQ_NEXT(var, field))
+
+#define	CIRCLEQ_FOREACH_SAFE(var, head, field, tvar)			\
+	for ((var) = CIRCLEQ_FIRST(head);				\
+	    (var) != CIRCLEQ_END(head) &&				\
+	    ((tvar) = CIRCLEQ_NEXT(var, field), 1);			\
+	    (var) = (tvar))
+
+#define CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
+	for((var) = CIRCLEQ_LAST(head);					\
+	    (var) != CIRCLEQ_END(head);					\
+	    (var) = CIRCLEQ_PREV(var, field))
+
+#define	CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)	\
+	for ((var) = CIRCLEQ_LAST(head, headname);			\
+	    (var) != CIRCLEQ_END(head) && 				\
+	    ((tvar) = CIRCLEQ_PREV(var, headname, field), 1);		\
+	    (var) = (tvar))
+
+/*
+ * Circular queue functions.
+ */
+#define	CIRCLEQ_INIT(head) do {						\
+	(head)->cqh_first = CIRCLEQ_END(head);				\
+	(head)->cqh_last = CIRCLEQ_END(head);				\
+} while (0)
+
+#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
+	(elm)->field.cqe_next = (listelm)->field.cqe_next;		\
+	(elm)->field.cqe_prev = (listelm);				\
+	if ((listelm)->field.cqe_next == CIRCLEQ_END(head))		\
+		(head)->cqh_last = (elm);				\
+	else								\
+		(listelm)->field.cqe_next->field.cqe_prev = (elm);	\
+	(listelm)->field.cqe_next = (elm);				\
+} while (0)
+
+#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {		\
+	(elm)->field.cqe_next = (listelm);				\
+	(elm)->field.cqe_prev = (listelm)->field.cqe_prev;		\
+	if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))		\
+		(head)->cqh_first = (elm);				\
+	else								\
+		(listelm)->field.cqe_prev->field.cqe_next = (elm);	\
+	(listelm)->field.cqe_prev = (elm);				\
+} while (0)
+
+#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
+	(elm)->field.cqe_next = (head)->cqh_first;			\
+	(elm)->field.cqe_prev = CIRCLEQ_END(head);			\
+	if ((head)->cqh_last == CIRCLEQ_END(head))			\
+		(head)->cqh_last = (elm);				\
+	else								\
+		(head)->cqh_first->field.cqe_prev = (elm);		\
+	(head)->cqh_first = (elm);					\
+} while (0)
+
+#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
+	(elm)->field.cqe_next = CIRCLEQ_END(head);			\
+	(elm)->field.cqe_prev = (head)->cqh_last;			\
+	if ((head)->cqh_first == CIRCLEQ_END(head))			\
+		(head)->cqh_first = (elm);				\
+	else								\
+		(head)->cqh_last->field.cqe_next = (elm);		\
+	(head)->cqh_last = (elm);					\
+} while (0)
+
+#define	CIRCLEQ_REMOVE(head, elm, field) do {				\
+	if ((elm)->field.cqe_next == CIRCLEQ_END(head))			\
+		(head)->cqh_last = (elm)->field.cqe_prev;		\
+	else								\
+		(elm)->field.cqe_next->field.cqe_prev =			\
+		    (elm)->field.cqe_prev;				\
+	if ((elm)->field.cqe_prev == CIRCLEQ_END(head))			\
+		(head)->cqh_first = (elm)->field.cqe_next;		\
+	else								\
+		(elm)->field.cqe_prev->field.cqe_next =			\
+		    (elm)->field.cqe_next;				\
+	_Q_INVALIDATE((elm)->field.cqe_prev);				\
+	_Q_INVALIDATE((elm)->field.cqe_next);				\
+} while (0)
+
+#define CIRCLEQ_REPLACE(head, elm, elm2, field) do {			\
+	if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==		\
+	    CIRCLEQ_END(head))						\
+		(head)->cqh_last = (elm2);				\
+	else								\
+		(elm2)->field.cqe_next->field.cqe_prev = (elm2);	\
+	if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==		\
+	    CIRCLEQ_END(head))						\
+		(head)->cqh_first = (elm2);				\
+	else								\
+		(elm2)->field.cqe_prev->field.cqe_next = (elm2);	\
+	_Q_INVALIDATE((elm)->field.cqe_prev);				\
+	_Q_INVALIDATE((elm)->field.cqe_next);				\
+} while (0)
+
+#endif	/* !_SYS_QUEUE_H_ */