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)						\
180 struct name {								\
181 	struct type *slh_first;	/* first element */			\
182 }
183 
184 #define	SLIST_HEAD_INITIALIZER(head)					\
185 	{ NULL }
186 
187 #define SLIST_ENTRY(type)						\
188 struct {								\
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)						\
253 struct name {								\
254 	struct type *lh_first;	/* first element */			\
255 }
256 
257 #define LIST_HEAD_INITIALIZER(head)					\
258 	{ NULL }
259 
260 #define LIST_ENTRY(type)						\
261 struct {								\
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)					\
331 struct 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)						\
340 struct {								\
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)						\
392 struct 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)						\
401 struct {								\
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)					\
499 struct 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)						\
508 struct {								\
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