1/*	$OpenBSD: queue.h,v 1.32 2007/04/30 18:42:34 pedro Exp $	*/
2/*	$NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $	*/
3
4/*
5 * Copyright (c) 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 *	@(#)queue.h	8.5 (Berkeley) 8/20/94
33 */
34
35/* OPENBSD ORIGINAL: sys/sys/queue.h */
36
37#ifndef	_FAKE_QUEUE_H_
38#define	_FAKE_QUEUE_H_
39
40/*
41 * Require for OS/X and other platforms that have old/broken/incomplete
42 * <sys/queue.h>.
43 */
44#undef SLIST_HEAD
45#undef SLIST_HEAD_INITIALIZER
46#undef SLIST_ENTRY
47#undef SLIST_FOREACH_PREVPTR
48#undef SLIST_FIRST
49#undef SLIST_END
50#undef SLIST_EMPTY
51#undef SLIST_NEXT
52#undef SLIST_FOREACH
53#undef SLIST_INIT
54#undef SLIST_INSERT_AFTER
55#undef SLIST_INSERT_HEAD
56#undef SLIST_REMOVE_HEAD
57#undef SLIST_REMOVE
58#undef SLIST_REMOVE_NEXT
59#undef LIST_HEAD
60#undef LIST_HEAD_INITIALIZER
61#undef LIST_ENTRY
62#undef LIST_FIRST
63#undef LIST_END
64#undef LIST_EMPTY
65#undef LIST_NEXT
66#undef LIST_FOREACH
67#undef LIST_INIT
68#undef LIST_INSERT_AFTER
69#undef LIST_INSERT_BEFORE
70#undef LIST_INSERT_HEAD
71#undef LIST_REMOVE
72#undef LIST_REPLACE
73#undef SIMPLEQ_HEAD
74#undef SIMPLEQ_HEAD_INITIALIZER
75#undef SIMPLEQ_ENTRY
76#undef SIMPLEQ_FIRST
77#undef SIMPLEQ_END
78#undef SIMPLEQ_EMPTY
79#undef SIMPLEQ_NEXT
80#undef SIMPLEQ_FOREACH
81#undef SIMPLEQ_INIT
82#undef SIMPLEQ_INSERT_HEAD
83#undef SIMPLEQ_INSERT_TAIL
84#undef SIMPLEQ_INSERT_AFTER
85#undef SIMPLEQ_REMOVE_HEAD
86#undef TAILQ_HEAD
87#undef TAILQ_HEAD_INITIALIZER
88#undef TAILQ_ENTRY
89#undef TAILQ_FIRST
90#undef TAILQ_END
91#undef TAILQ_NEXT
92#undef TAILQ_LAST
93#undef TAILQ_PREV
94#undef TAILQ_EMPTY
95#undef TAILQ_FOREACH
96#undef TAILQ_FOREACH_REVERSE
97#undef TAILQ_INIT
98#undef TAILQ_INSERT_HEAD
99#undef TAILQ_INSERT_TAIL
100#undef TAILQ_INSERT_AFTER
101#undef TAILQ_INSERT_BEFORE
102#undef TAILQ_REMOVE
103#undef TAILQ_REPLACE
104#undef CIRCLEQ_HEAD
105#undef CIRCLEQ_HEAD_INITIALIZER
106#undef CIRCLEQ_ENTRY
107#undef CIRCLEQ_FIRST
108#undef CIRCLEQ_LAST
109#undef CIRCLEQ_END
110#undef CIRCLEQ_NEXT
111#undef CIRCLEQ_PREV
112#undef CIRCLEQ_EMPTY
113#undef CIRCLEQ_FOREACH
114#undef CIRCLEQ_FOREACH_REVERSE
115#undef CIRCLEQ_INIT
116#undef CIRCLEQ_INSERT_AFTER
117#undef CIRCLEQ_INSERT_BEFORE
118#undef CIRCLEQ_INSERT_HEAD
119#undef CIRCLEQ_INSERT_TAIL
120#undef CIRCLEQ_REMOVE
121#undef CIRCLEQ_REPLACE
122
123/*
124 * This file defines five types of data structures: singly-linked lists,
125 * lists, simple queues, tail queues, and circular queues.
126 *
127 *
128 * A singly-linked list is headed by a single forward pointer. The elements
129 * are singly linked for minimum space and pointer manipulation overhead at
130 * the expense of O(n) removal for arbitrary elements. New elements can be
131 * added to the list after an existing element or at the head of the list.
132 * Elements being removed from the head of the list should use the explicit
133 * macro for this purpose for optimum efficiency. A singly-linked list may
134 * only be traversed in the forward direction.  Singly-linked lists are ideal
135 * for applications with large datasets and few or no removals or for
136 * implementing a LIFO queue.
137 *
138 * A list is headed by a single forward pointer (or an array of forward
139 * pointers for a hash table header). The elements are doubly linked
140 * so that an arbitrary element can be removed without a need to
141 * traverse the list. New elements can be added to the list before
142 * or after an existing element or at the head of the list. A list
143 * may only be traversed in the forward direction.
144 *
145 * A simple queue is headed by a pair of pointers, one the head of the
146 * list and the other to the tail of the list. The elements are singly
147 * linked to save space, so elements can only be removed from the
148 * head of the list. New elements can be added to the list before or after
149 * an existing element, at the head of the list, or at the end of the
150 * list. A simple queue may only be traversed in the forward direction.
151 *
152 * A tail queue is headed by a pair of pointers, one to the head of the
153 * list and the other to the tail of the list. The elements are doubly
154 * linked so that an arbitrary element can be removed without a need to
155 * traverse the list. New elements can be added to the list before or
156 * after an existing element, at the head of the list, or at the end of
157 * the list. A tail queue may be traversed in either direction.
158 *
159 * A circle queue is headed by a pair of pointers, one to the head of the
160 * list and the other to the tail of the list. The elements are doubly
161 * linked so that an arbitrary element can be removed without a need to
162 * traverse the list. New elements can be added to the list before or after
163 * an existing element, at the head of the list, or at the end of the list.
164 * A circle queue may be traversed in either direction, but has a more
165 * complex end of list detection.
166 *
167 * For details on the use of these macros, see the queue(3) manual page.
168 */
169
170#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
171#define _Q_INVALIDATE(a) (a) = ((void *)-1)
172#else
173#define _Q_INVALIDATE(a)
174#endif
175
176/*
177 * Singly-linked List definitions.
178 */
179#define SLIST_HEAD(name, type)						\
180struct name {								\
181	struct type *slh_first;	/* first element */			\
182}
183
184#define	SLIST_HEAD_INITIALIZER(head)					\
185	{ NULL }
186
187#define SLIST_ENTRY(type)						\
188struct {								\
189	struct type *sle_next;	/* next element */			\
190}
191
192/*
193 * Singly-linked List access methods.
194 */
195#define	SLIST_FIRST(head)	((head)->slh_first)
196#define	SLIST_END(head)		NULL
197#define	SLIST_EMPTY(head)	(SLIST_FIRST(head) == SLIST_END(head))
198#define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)
199
200#define	SLIST_FOREACH(var, head, field)					\
201	for((var) = SLIST_FIRST(head);					\
202	    (var) != SLIST_END(head);					\
203	    (var) = SLIST_NEXT(var, field))
204
205#define	SLIST_FOREACH_PREVPTR(var, varp, head, field)			\
206	for ((varp) = &SLIST_FIRST((head));				\
207	    ((var) = *(varp)) != SLIST_END(head);			\
208	    (varp) = &SLIST_NEXT((var), field))
209
210/*
211 * Singly-linked List functions.
212 */
213#define	SLIST_INIT(head) {						\
214	SLIST_FIRST(head) = SLIST_END(head);				\
215}
216
217#define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
218	(elm)->field.sle_next = (slistelm)->field.sle_next;		\
219	(slistelm)->field.sle_next = (elm);				\
220} while (0)
221
222#define	SLIST_INSERT_HEAD(head, elm, field) do {			\
223	(elm)->field.sle_next = (head)->slh_first;			\
224	(head)->slh_first = (elm);					\
225} while (0)
226
227#define	SLIST_REMOVE_NEXT(head, elm, field) do {			\
228	(elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;	\
229} while (0)
230
231#define	SLIST_REMOVE_HEAD(head, field) do {				\
232	(head)->slh_first = (head)->slh_first->field.sle_next;		\
233} while (0)
234
235#define SLIST_REMOVE(head, elm, type, field) do {			\
236	if ((head)->slh_first == (elm)) {				\
237		SLIST_REMOVE_HEAD((head), field);			\
238	} else {							\
239		struct type *curelm = (head)->slh_first;		\
240									\
241		while (curelm->field.sle_next != (elm))			\
242			curelm = curelm->field.sle_next;		\
243		curelm->field.sle_next =				\
244		    curelm->field.sle_next->field.sle_next;		\
245		_Q_INVALIDATE((elm)->field.sle_next);			\
246	}								\
247} while (0)
248
249/*
250 * List definitions.
251 */
252#define LIST_HEAD(name, type)						\
253struct name {								\
254	struct type *lh_first;	/* first element */			\
255}
256
257#define LIST_HEAD_INITIALIZER(head)					\
258	{ NULL }
259
260#define LIST_ENTRY(type)						\
261struct {								\
262	struct type *le_next;	/* next element */			\
263	struct type **le_prev;	/* address of previous next element */	\
264}
265
266/*
267 * List access methods
268 */
269#define	LIST_FIRST(head)		((head)->lh_first)
270#define	LIST_END(head)			NULL
271#define	LIST_EMPTY(head)		(LIST_FIRST(head) == LIST_END(head))
272#define	LIST_NEXT(elm, field)		((elm)->field.le_next)
273
274#define LIST_FOREACH(var, head, field)					\
275	for((var) = LIST_FIRST(head);					\
276	    (var)!= LIST_END(head);					\
277	    (var) = LIST_NEXT(var, field))
278
279/*
280 * List functions.
281 */
282#define	LIST_INIT(head) do {						\
283	LIST_FIRST(head) = LIST_END(head);				\
284} while (0)
285
286#define LIST_INSERT_AFTER(listelm, elm, field) do {			\
287	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)	\
288		(listelm)->field.le_next->field.le_prev =		\
289		    &(elm)->field.le_next;				\
290	(listelm)->field.le_next = (elm);				\
291	(elm)->field.le_prev = &(listelm)->field.le_next;		\
292} while (0)
293
294#define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
295	(elm)->field.le_prev = (listelm)->field.le_prev;		\
296	(elm)->field.le_next = (listelm);				\
297	*(listelm)->field.le_prev = (elm);				\
298	(listelm)->field.le_prev = &(elm)->field.le_next;		\
299} while (0)
300
301#define LIST_INSERT_HEAD(head, elm, field) do {				\
302	if (((elm)->field.le_next = (head)->lh_first) != NULL)		\
303		(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
304	(head)->lh_first = (elm);					\
305	(elm)->field.le_prev = &(head)->lh_first;			\
306} while (0)
307
308#define LIST_REMOVE(elm, field) do {					\
309	if ((elm)->field.le_next != NULL)				\
310		(elm)->field.le_next->field.le_prev =			\
311		    (elm)->field.le_prev;				\
312	*(elm)->field.le_prev = (elm)->field.le_next;			\
313	_Q_INVALIDATE((elm)->field.le_prev);				\
314	_Q_INVALIDATE((elm)->field.le_next);				\
315} while (0)
316
317#define LIST_REPLACE(elm, elm2, field) do {				\
318	if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)	\
319		(elm2)->field.le_next->field.le_prev =			\
320		    &(elm2)->field.le_next;				\
321	(elm2)->field.le_prev = (elm)->field.le_prev;			\
322	*(elm2)->field.le_prev = (elm2);				\
323	_Q_INVALIDATE((elm)->field.le_prev);				\
324	_Q_INVALIDATE((elm)->field.le_next);				\
325} while (0)
326
327/*
328 * Simple queue definitions.
329 */
330#define SIMPLEQ_HEAD(name, type)					\
331struct name {								\
332	struct type *sqh_first;	/* first element */			\
333	struct type **sqh_last;	/* addr of last next element */		\
334}
335
336#define SIMPLEQ_HEAD_INITIALIZER(head)					\
337	{ NULL, &(head).sqh_first }
338
339#define SIMPLEQ_ENTRY(type)						\
340struct {								\
341	struct type *sqe_next;	/* next element */			\
342}
343
344/*
345 * Simple queue access methods.
346 */
347#define	SIMPLEQ_FIRST(head)	    ((head)->sqh_first)
348#define	SIMPLEQ_END(head)	    NULL
349#define	SIMPLEQ_EMPTY(head)	    (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
350#define	SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
351
352#define SIMPLEQ_FOREACH(var, head, field)				\
353	for((var) = SIMPLEQ_FIRST(head);				\
354	    (var) != SIMPLEQ_END(head);					\
355	    (var) = SIMPLEQ_NEXT(var, field))
356
357/*
358 * Simple queue functions.
359 */
360#define	SIMPLEQ_INIT(head) do {						\
361	(head)->sqh_first = NULL;					\
362	(head)->sqh_last = &(head)->sqh_first;				\
363} while (0)
364
365#define SIMPLEQ_INSERT_HEAD(head, elm, field) do {			\
366	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)	\
367		(head)->sqh_last = &(elm)->field.sqe_next;		\
368	(head)->sqh_first = (elm);					\
369} while (0)
370
371#define SIMPLEQ_INSERT_TAIL(head, elm, field) do {			\
372	(elm)->field.sqe_next = NULL;					\
373	*(head)->sqh_last = (elm);					\
374	(head)->sqh_last = &(elm)->field.sqe_next;			\
375} while (0)
376
377#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
378	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
379		(head)->sqh_last = &(elm)->field.sqe_next;		\
380	(listelm)->field.sqe_next = (elm);				\
381} while (0)
382
383#define SIMPLEQ_REMOVE_HEAD(head, field) do {			\
384	if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
385		(head)->sqh_last = &(head)->sqh_first;			\
386} while (0)
387
388/*
389 * Tail queue definitions.
390 */
391#define TAILQ_HEAD(name, type)						\
392struct name {								\
393	struct type *tqh_first;	/* first element */			\
394	struct type **tqh_last;	/* addr of last next element */		\
395}
396
397#define TAILQ_HEAD_INITIALIZER(head)					\
398	{ NULL, &(head).tqh_first }
399
400#define TAILQ_ENTRY(type)						\
401struct {								\
402	struct type *tqe_next;	/* next element */			\
403	struct type **tqe_prev;	/* address of previous next element */	\
404}
405
406/*
407 * tail queue access methods
408 */
409#define	TAILQ_FIRST(head)		((head)->tqh_first)
410#define	TAILQ_END(head)			NULL
411#define	TAILQ_NEXT(elm, field)		((elm)->field.tqe_next)
412#define TAILQ_LAST(head, headname)					\
413	(*(((struct headname *)((head)->tqh_last))->tqh_last))
414/* XXX */
415#define TAILQ_PREV(elm, headname, field)				\
416	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
417#define	TAILQ_EMPTY(head)						\
418	(TAILQ_FIRST(head) == TAILQ_END(head))
419
420#define TAILQ_FOREACH(var, head, field)					\
421	for((var) = TAILQ_FIRST(head);					\
422	    (var) != TAILQ_END(head);					\
423	    (var) = TAILQ_NEXT(var, field))
424
425#define TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
426	for((var) = TAILQ_LAST(head, headname);				\
427	    (var) != TAILQ_END(head);					\
428	    (var) = TAILQ_PREV(var, headname, field))
429
430/*
431 * Tail queue functions.
432 */
433#define	TAILQ_INIT(head) do {						\
434	(head)->tqh_first = NULL;					\
435	(head)->tqh_last = &(head)->tqh_first;				\
436} while (0)
437
438#define TAILQ_INSERT_HEAD(head, elm, field) do {			\
439	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)	\
440		(head)->tqh_first->field.tqe_prev =			\
441		    &(elm)->field.tqe_next;				\
442	else								\
443		(head)->tqh_last = &(elm)->field.tqe_next;		\
444	(head)->tqh_first = (elm);					\
445	(elm)->field.tqe_prev = &(head)->tqh_first;			\
446} while (0)
447
448#define TAILQ_INSERT_TAIL(head, elm, field) do {			\
449	(elm)->field.tqe_next = NULL;					\
450	(elm)->field.tqe_prev = (head)->tqh_last;			\
451	*(head)->tqh_last = (elm);					\
452	(head)->tqh_last = &(elm)->field.tqe_next;			\
453} while (0)
454
455#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
456	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
457		(elm)->field.tqe_next->field.tqe_prev =			\
458		    &(elm)->field.tqe_next;				\
459	else								\
460		(head)->tqh_last = &(elm)->field.tqe_next;		\
461	(listelm)->field.tqe_next = (elm);				\
462	(elm)->field.tqe_prev = &(listelm)->field.tqe_next;		\
463} while (0)
464
465#define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
466	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
467	(elm)->field.tqe_next = (listelm);				\
468	*(listelm)->field.tqe_prev = (elm);				\
469	(listelm)->field.tqe_prev = &(elm)->field.tqe_next;		\
470} while (0)
471
472#define TAILQ_REMOVE(head, elm, field) do {				\
473	if (((elm)->field.tqe_next) != NULL)				\
474		(elm)->field.tqe_next->field.tqe_prev =			\
475		    (elm)->field.tqe_prev;				\
476	else								\
477		(head)->tqh_last = (elm)->field.tqe_prev;		\
478	*(elm)->field.tqe_prev = (elm)->field.tqe_next;			\
479	_Q_INVALIDATE((elm)->field.tqe_prev);				\
480	_Q_INVALIDATE((elm)->field.tqe_next);				\
481} while (0)
482
483#define TAILQ_REPLACE(head, elm, elm2, field) do {			\
484	if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)	\
485		(elm2)->field.tqe_next->field.tqe_prev =		\
486		    &(elm2)->field.tqe_next;				\
487	else								\
488		(head)->tqh_last = &(elm2)->field.tqe_next;		\
489	(elm2)->field.tqe_prev = (elm)->field.tqe_prev;			\
490	*(elm2)->field.tqe_prev = (elm2);				\
491	_Q_INVALIDATE((elm)->field.tqe_prev);				\
492	_Q_INVALIDATE((elm)->field.tqe_next);				\
493} while (0)
494
495/*
496 * Circular queue definitions.
497 */
498#define CIRCLEQ_HEAD(name, type)					\
499struct name {								\
500	struct type *cqh_first;		/* first element */		\
501	struct type *cqh_last;		/* last element */		\
502}
503
504#define CIRCLEQ_HEAD_INITIALIZER(head)					\
505	{ CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
506
507#define CIRCLEQ_ENTRY(type)						\
508struct {								\
509	struct type *cqe_next;		/* next element */		\
510	struct type *cqe_prev;		/* previous element */		\
511}
512
513/*
514 * Circular queue access methods
515 */
516#define	CIRCLEQ_FIRST(head)		((head)->cqh_first)
517#define	CIRCLEQ_LAST(head)		((head)->cqh_last)
518#define	CIRCLEQ_END(head)		((void *)(head))
519#define	CIRCLEQ_NEXT(elm, field)	((elm)->field.cqe_next)
520#define	CIRCLEQ_PREV(elm, field)	((elm)->field.cqe_prev)
521#define	CIRCLEQ_EMPTY(head)						\
522	(CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
523
524#define CIRCLEQ_FOREACH(var, head, field)				\
525	for((var) = CIRCLEQ_FIRST(head);				\
526	    (var) != CIRCLEQ_END(head);					\
527	    (var) = CIRCLEQ_NEXT(var, field))
528
529#define CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
530	for((var) = CIRCLEQ_LAST(head);					\
531	    (var) != CIRCLEQ_END(head);					\
532	    (var) = CIRCLEQ_PREV(var, field))
533
534/*
535 * Circular queue functions.
536 */
537#define	CIRCLEQ_INIT(head) do {						\
538	(head)->cqh_first = CIRCLEQ_END(head);				\
539	(head)->cqh_last = CIRCLEQ_END(head);				\
540} while (0)
541
542#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
543	(elm)->field.cqe_next = (listelm)->field.cqe_next;		\
544	(elm)->field.cqe_prev = (listelm);				\
545	if ((listelm)->field.cqe_next == CIRCLEQ_END(head))		\
546		(head)->cqh_last = (elm);				\
547	else								\
548		(listelm)->field.cqe_next->field.cqe_prev = (elm);	\
549	(listelm)->field.cqe_next = (elm);				\
550} while (0)
551
552#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {		\
553	(elm)->field.cqe_next = (listelm);				\
554	(elm)->field.cqe_prev = (listelm)->field.cqe_prev;		\
555	if ((listelm)->field.cqe_prev == CIRCLEQ_END(head))		\
556		(head)->cqh_first = (elm);				\
557	else								\
558		(listelm)->field.cqe_prev->field.cqe_next = (elm);	\
559	(listelm)->field.cqe_prev = (elm);				\
560} while (0)
561
562#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
563	(elm)->field.cqe_next = (head)->cqh_first;			\
564	(elm)->field.cqe_prev = CIRCLEQ_END(head);			\
565	if ((head)->cqh_last == CIRCLEQ_END(head))			\
566		(head)->cqh_last = (elm);				\
567	else								\
568		(head)->cqh_first->field.cqe_prev = (elm);		\
569	(head)->cqh_first = (elm);					\
570} while (0)
571
572#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
573	(elm)->field.cqe_next = CIRCLEQ_END(head);			\
574	(elm)->field.cqe_prev = (head)->cqh_last;			\
575	if ((head)->cqh_first == CIRCLEQ_END(head))			\
576		(head)->cqh_first = (elm);				\
577	else								\
578		(head)->cqh_last->field.cqe_next = (elm);		\
579	(head)->cqh_last = (elm);					\
580} while (0)
581
582#define	CIRCLEQ_REMOVE(head, elm, field) do {				\
583	if ((elm)->field.cqe_next == CIRCLEQ_END(head))			\
584		(head)->cqh_last = (elm)->field.cqe_prev;		\
585	else								\
586		(elm)->field.cqe_next->field.cqe_prev =			\
587		    (elm)->field.cqe_prev;				\
588	if ((elm)->field.cqe_prev == CIRCLEQ_END(head))			\
589		(head)->cqh_first = (elm)->field.cqe_next;		\
590	else								\
591		(elm)->field.cqe_prev->field.cqe_next =			\
592		    (elm)->field.cqe_next;				\
593	_Q_INVALIDATE((elm)->field.cqe_prev);				\
594	_Q_INVALIDATE((elm)->field.cqe_next);				\
595} while (0)
596
597#define CIRCLEQ_REPLACE(head, elm, elm2, field) do {			\
598	if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==		\
599	    CIRCLEQ_END(head))						\
600		(head).cqh_last = (elm2);				\
601	else								\
602		(elm2)->field.cqe_next->field.cqe_prev = (elm2);	\
603	if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==		\
604	    CIRCLEQ_END(head))						\
605		(head).cqh_first = (elm2);				\
606	else								\
607		(elm2)->field.cqe_prev->field.cqe_next = (elm2);	\
608	_Q_INVALIDATE((elm)->field.cqe_prev);				\
609	_Q_INVALIDATE((elm)->field.cqe_next);				\
610} while (0)
611
612#endif	/* !_FAKE_QUEUE_H_ */
613