1/* $OpenBSD: queue.h,v 1.38 2013/07/03 15:05:21 fgsch 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#ifndef _SYS_QUEUE_H_
36#define _SYS_QUEUE_H_
37
38/*
39 * This file defines five types of data structures: singly-linked lists,
40 * lists, simple queues, tail queues, and circular queues.
41 *
42 *
43 * A singly-linked list is headed by a single forward pointer. The elements
44 * are singly linked for minimum space and pointer manipulation overhead at
45 * the expense of O(n) removal for arbitrary elements. New elements can be
46 * added to the list after an existing element or at the head of the list.
47 * Elements being removed from the head of the list should use the explicit
48 * macro for this purpose for optimum efficiency. A singly-linked list may
49 * only be traversed in the forward direction. Singly-linked lists are ideal
50 * for applications with large datasets and few or no removals or for
51 * implementing a LIFO queue.
52 *
53 * A list is headed by a single forward pointer (or an array of forward
54 * pointers for a hash table header). The elements are doubly linked
55 * so that an arbitrary element can be removed without a need to
56 * traverse the list. New elements can be added to the list before
57 * or after an existing element or at the head of the list. A list
58 * may only be traversed in the forward direction.
59 *
60 * A simple queue is headed by a pair of pointers, one the head of the
61 * list and the other to the tail of the list. The elements are singly
62 * linked to save space, so elements can only be removed from the
63 * head of the list. New elements can be added to the list before or after
64 * an existing element, at the head of the list, or at the end of the
65 * list. A simple queue may only be traversed in the forward direction.
66 *
67 * A tail queue is headed by a pair of pointers, one to the head of the
68 * list and the other to the tail of the list. The elements are doubly
69 * linked so that an arbitrary element can be removed without a need to
70 * traverse the list. New elements can be added to the list before or
71 * after an existing element, at the head of the list, or at the end of
72 * the list. A tail queue may be traversed in either direction.
73 *
74 * A circle queue is headed by a pair of pointers, one to the head of the
75 * list and the other to the tail of the list. The elements are doubly
76 * linked so that an arbitrary element can be removed without a need to
77 * traverse the list. New elements can be added to the list before or after
78 * an existing element, at the head of the list, or at the end of the list.
79 * A circle queue may be traversed in either direction, but has a more
80 * complex end of list detection.
81 *
82 * For details on the use of these macros, see the queue(3) manual page.
83 */
84
85#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
86#define _Q_INVALIDATE(a) (a) = ((void *)-1)
87#else
88#define _Q_INVALIDATE(a)
89#endif
90
91/*
92 * Singly-linked List definitions.
93 */
94#define SLIST_HEAD(name, type) \
95 struct name { \
96 struct type *slh_first; /* first element */ \
97 }
98
99#define SLIST_HEAD_INITIALIZER(head) {NULL}
100
101#define SLIST_ENTRY(type) \
102 struct { \
103 struct type *sle_next; /* next element */ \
104 }
105
106/*
107 * Singly-linked List access methods.
108 */
109#define SLIST_FIRST(head) ((head)->slh_first)
110#define SLIST_END(head) NULL
111#define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head))
112#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
113
114#define SLIST_FOREACH(var, head, field) \
115 for ((var) = SLIST_FIRST(head); (var) != SLIST_END(head); (var) = SLIST_NEXT(var, field))
116
117#define SLIST_FOREACH_SAFE(var, head, field, tvar) \
118 for ((var) = SLIST_FIRST(head); (var) && ((tvar) = SLIST_NEXT(var, field), 1); (var) = (tvar))
119
120/*
121 * Singly-linked List functions.
122 */
123#define SLIST_INIT(head) \
124 { \
125 SLIST_FIRST(head) = SLIST_END(head); \
126 }
127
128#define SLIST_INSERT_AFTER(slistelm, elm, field) \
129 do { \
130 (elm)->field.sle_next = (slistelm)->field.sle_next; \
131 (slistelm)->field.sle_next = (elm); \
132 } while (0)
133
134#define SLIST_INSERT_HEAD(head, elm, field) \
135 do { \
136 (elm)->field.sle_next = (head)->slh_first; \
137 (head)->slh_first = (elm); \
138 } while (0)
139
140#define SLIST_REMOVE_AFTER(elm, field) \
141 do { \
142 (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \
143 } while (0)
144
145#define SLIST_REMOVE_HEAD(head, field) \
146 do { \
147 (head)->slh_first = (head)->slh_first->field.sle_next; \
148 } while (0)
149
150#define SLIST_REMOVE(head, elm, type, field) \
151 do { \
152 if ((head)->slh_first == (elm)) { \
153 SLIST_REMOVE_HEAD((head), field); \
154 } else { \
155 struct type *curelm = (head)->slh_first; \
156 \
157 while (curelm->field.sle_next != (elm)) \
158 curelm = curelm->field.sle_next; \
159 curelm->field.sle_next = curelm->field.sle_next->field.sle_next; \
160 _Q_INVALIDATE((elm)->field.sle_next); \
161 } \
162 } while (0)
163
164/*
165 * List definitions.
166 */
167#define LIST_HEAD(name, type) \
168 struct name { \
169 struct type *lh_first; /* first element */ \
170 }
171
172#define LIST_HEAD_INITIALIZER(head) {NULL}
173
174#define LIST_ENTRY(type) \
175 struct { \
176 struct type *le_next; /* next element */ \
177 struct type **le_prev; /* address of previous next element */ \
178 }
179
180/*
181 * List access methods
182 */
183#define LIST_FIRST(head) ((head)->lh_first)
184#define LIST_END(head) NULL
185#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
186#define LIST_NEXT(elm, field) ((elm)->field.le_next)
187
188#define LIST_FOREACH(var, head, field) \
189 for ((var) = LIST_FIRST(head); (var) != LIST_END(head); (var) = LIST_NEXT(var, field))
190
191#define LIST_FOREACH_SAFE(var, head, field, tvar) \
192 for ((var) = LIST_FIRST(head); (var) && ((tvar) = LIST_NEXT(var, field), 1); (var) = (tvar))
193
194/*
195 * List functions.
196 */
197#define LIST_INIT(head) \
198 do { \
199 LIST_FIRST(head) = LIST_END(head); \
200 } while (0)
201
202#define LIST_INSERT_AFTER(listelm, elm, field) \
203 do { \
204 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
205 (listelm)->field.le_next->field.le_prev = &(elm)->field.le_next; \
206 (listelm)->field.le_next = (elm); \
207 (elm)->field.le_prev = &(listelm)->field.le_next; \
208 } while (0)
209
210#define LIST_INSERT_BEFORE(listelm, elm, field) \
211 do { \
212 (elm)->field.le_prev = (listelm)->field.le_prev; \
213 (elm)->field.le_next = (listelm); \
214 *(listelm)->field.le_prev = (elm); \
215 (listelm)->field.le_prev = &(elm)->field.le_next; \
216 } while (0)
217
218#define LIST_INSERT_HEAD(head, elm, field) \
219 do { \
220 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
221 (head)->lh_first->field.le_prev = &(elm)->field.le_next; \
222 (head)->lh_first = (elm); \
223 (elm)->field.le_prev = &(head)->lh_first; \
224 } while (0)
225
226#define LIST_REMOVE(elm, field) \
227 do { \
228 if ((elm)->field.le_next != NULL) \
229 (elm)->field.le_next->field.le_prev = (elm)->field.le_prev; \
230 *(elm)->field.le_prev = (elm)->field.le_next; \
231 _Q_INVALIDATE((elm)->field.le_prev); \
232 _Q_INVALIDATE((elm)->field.le_next); \
233 } while (0)
234
235#define LIST_REPLACE(elm, elm2, field) \
236 do { \
237 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
238 (elm2)->field.le_next->field.le_prev = &(elm2)->field.le_next; \
239 (elm2)->field.le_prev = (elm)->field.le_prev; \
240 *(elm2)->field.le_prev = (elm2); \
241 _Q_INVALIDATE((elm)->field.le_prev); \
242 _Q_INVALIDATE((elm)->field.le_next); \
243 } while (0)
244
245/*
246 * Simple queue definitions.
247 */
248#define SIMPLEQ_HEAD(name, type) \
249 struct name { \
250 struct type *sqh_first; /* first element */ \
251 struct type **sqh_last; /* addr of last next element */ \
252 }
253
254#define SIMPLEQ_HEAD_INITIALIZER(head) {NULL, &(head).sqh_first}
255
256#define SIMPLEQ_ENTRY(type) \
257 struct { \
258 struct type *sqe_next; /* next element */ \
259 }
260
261/*
262 * Simple queue access methods.
263 */
264#define SIMPLEQ_FIRST(head) ((head)->sqh_first)
265#define SIMPLEQ_END(head) NULL
266#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
267#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
268
269#define SIMPLEQ_FOREACH(var, head, field) \
270 for ((var) = SIMPLEQ_FIRST(head); (var) != SIMPLEQ_END(head); (var) = SIMPLEQ_NEXT(var, field))
271
272#define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \
273 for ((var) = SIMPLEQ_FIRST(head); (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1); (var) = (tvar))
274
275/*
276 * Simple queue functions.
277 */
278#define SIMPLEQ_INIT(head) \
279 do { \
280 (head)->sqh_first = NULL; \
281 (head)->sqh_last = &(head)->sqh_first; \
282 } while (0)
283
284#define SIMPLEQ_INSERT_HEAD(head, elm, field) \
285 do { \
286 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
287 (head)->sqh_last = &(elm)->field.sqe_next; \
288 (head)->sqh_first = (elm); \
289 } while (0)
290
291#define SIMPLEQ_INSERT_TAIL(head, elm, field) \
292 do { \
293 (elm)->field.sqe_next = NULL; \
294 *(head)->sqh_last = (elm); \
295 (head)->sqh_last = &(elm)->field.sqe_next; \
296 } while (0)
297
298#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) \
299 do { \
300 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \
301 (head)->sqh_last = &(elm)->field.sqe_next; \
302 (listelm)->field.sqe_next = (elm); \
303 } while (0)
304
305#define SIMPLEQ_REMOVE_HEAD(head, field) \
306 do { \
307 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
308 (head)->sqh_last = &(head)->sqh_first; \
309 } while (0)
310
311#define SIMPLEQ_REMOVE_AFTER(head, elm, field) \
312 do { \
313 if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) == NULL) \
314 (head)->sqh_last = &(elm)->field.sqe_next; \
315 } while (0)
316
317/*
318 * XOR Simple queue definitions.
319 */
320#define XSIMPLEQ_HEAD(name, type) \
321 struct name { \
322 struct type *sqx_first; /* first element */ \
323 struct type **sqx_last; /* addr of last next element */ \
324 unsigned long sqx_cookie; \
325 }
326
327#define XSIMPLEQ_ENTRY(type) \
328 struct { \
329 struct type *sqx_next; /* next element */ \
330 }
331
332/*
333 * XOR Simple queue access methods.
334 */
335#define XSIMPLEQ_XOR(head, ptr) ((__typeof(ptr))((head)->sqx_cookie ^ (unsigned long)(ptr)))
336#define XSIMPLEQ_FIRST(head) XSIMPLEQ_XOR(head, ((head)->sqx_first))
337#define XSIMPLEQ_END(head) NULL
338#define XSIMPLEQ_EMPTY(head) (XSIMPLEQ_FIRST(head) == XSIMPLEQ_END(head))
339#define XSIMPLEQ_NEXT(head, elm, field) XSIMPLEQ_XOR(head, ((elm)->field.sqx_next))
340
341#define XSIMPLEQ_FOREACH(var, head, field) \
342 for ((var) = XSIMPLEQ_FIRST(head); (var) != XSIMPLEQ_END(head); \
343 (var) = XSIMPLEQ_NEXT(head, var, field))
344
345#define XSIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \
346 for ((var) = XSIMPLEQ_FIRST(head); (var) && ((tvar) = XSIMPLEQ_NEXT(head, var, field), 1); \
347 (var) = (tvar))
348
349/*
350 * XOR Simple queue functions.
351 */
352#define XSIMPLEQ_INIT(head) \
353 do { \
354 arc4random_buf(&(head)->sqx_cookie, sizeof((head)->sqx_cookie)); \
355 (head)->sqx_first = XSIMPLEQ_XOR(head, NULL); \
356 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
357 } while (0)
358
359#define XSIMPLEQ_INSERT_HEAD(head, elm, field) \
360 do { \
361 if (((elm)->field.sqx_next = (head)->sqx_first) == XSIMPLEQ_XOR(head, NULL)) \
362 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
363 (head)->sqx_first = XSIMPLEQ_XOR(head, (elm)); \
364 } while (0)
365
366#define XSIMPLEQ_INSERT_TAIL(head, elm, field) \
367 do { \
368 (elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL); \
369 *(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \
370 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
371 } while (0)
372
373#define XSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) \
374 do { \
375 if (((elm)->field.sqx_next = (listelm)->field.sqx_next) == XSIMPLEQ_XOR(head, NULL)) \
376 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
377 (listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm)); \
378 } while (0)
379
380#define XSIMPLEQ_REMOVE_HEAD(head, field) \
381 do { \
382 if (((head)->sqx_first = XSIMPLEQ_XOR(head, (head)->sqx_first)->field.sqx_next) \
383 == XSIMPLEQ_XOR(head, NULL)) \
384 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
385 } while (0)
386
387#define XSIMPLEQ_REMOVE_AFTER(head, elm, field) \
388 do { \
389 if (((elm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm)->field.sqx_next)->field.sqx_next) \
390 == XSIMPLEQ_XOR(head, NULL)) \
391 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
392 } while (0)
393
394/*
395 * Tail queue definitions.
396 */
397#define TAILQ_HEAD(name, type) \
398 struct name { \
399 struct type *tqh_first; /* first element */ \
400 struct type **tqh_last; /* addr of last next element */ \
401 }
402
403#define TAILQ_HEAD_INITIALIZER(head) {NULL, &(head).tqh_first}
404
405#define TAILQ_ENTRY(type) \
406 struct { \
407 struct type *tqe_next; /* next element */ \
408 struct type **tqe_prev; /* address of previous next element */ \
409 }
410
411/*
412 * tail queue access methods
413 */
414#define TAILQ_FIRST(head) ((head)->tqh_first)
415#define TAILQ_END(head) NULL
416#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
417#define TAILQ_LAST(head, headname) (*(((struct headname *)((head)->tqh_last))->tqh_last))
418/* XXX */
419#define TAILQ_PREV(elm, headname, field) (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
420#define TAILQ_EMPTY(head) (TAILQ_FIRST(head) == TAILQ_END(head))
421
422#define TAILQ_FOREACH(var, head, field) \
423 for ((var) = TAILQ_FIRST(head); (var) != TAILQ_END(head); (var) = TAILQ_NEXT(var, field))
424
425#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
426 for ((var) = TAILQ_FIRST(head); \
427 (var) != TAILQ_END(head) && ((tvar) = TAILQ_NEXT(var, field), 1); \
428 (var) = (tvar))
429
430#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
431 for ((var) = TAILQ_LAST(head, headname); (var) != TAILQ_END(head); \
432 (var) = TAILQ_PREV(var, headname, field))
433
434#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
435 for ((var) = TAILQ_LAST(head, headname); \
436 (var) != TAILQ_END(head) && ((tvar) = TAILQ_PREV(var, headname, field), 1); \
437 (var) = (tvar))
438
439/*
440 * Tail queue functions.
441 */
442#define TAILQ_INIT(head) \
443 do { \
444 (head)->tqh_first = NULL; \
445 (head)->tqh_last = &(head)->tqh_first; \
446 } while (0)
447
448#define TAILQ_INSERT_HEAD(head, elm, field) \
449 do { \
450 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
451 (head)->tqh_first->field.tqe_prev = &(elm)->field.tqe_next; \
452 else \
453 (head)->tqh_last = &(elm)->field.tqe_next; \
454 (head)->tqh_first = (elm); \
455 (elm)->field.tqe_prev = &(head)->tqh_first; \
456 } while (0)
457
458#define TAILQ_INSERT_TAIL(head, elm, field) \
459 do { \
460 (elm)->field.tqe_next = NULL; \
461 (elm)->field.tqe_prev = (head)->tqh_last; \
462 *(head)->tqh_last = (elm); \
463 (head)->tqh_last = &(elm)->field.tqe_next; \
464 } while (0)
465
466#define TAILQ_INSERT_AFTER(head, listelm, elm, field) \
467 do { \
468 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL) \
469 (elm)->field.tqe_next->field.tqe_prev = &(elm)->field.tqe_next; \
470 else \
471 (head)->tqh_last = &(elm)->field.tqe_next; \
472 (listelm)->field.tqe_next = (elm); \
473 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
474 } while (0)
475
476#define TAILQ_INSERT_BEFORE(listelm, elm, field) \
477 do { \
478 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
479 (elm)->field.tqe_next = (listelm); \
480 *(listelm)->field.tqe_prev = (elm); \
481 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
482 } while (0)
483
484#define TAILQ_REMOVE(head, elm, field) \
485 do { \
486 if (((elm)->field.tqe_next) != NULL) \
487 (elm)->field.tqe_next->field.tqe_prev = (elm)->field.tqe_prev; \
488 else \
489 (head)->tqh_last = (elm)->field.tqe_prev; \
490 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
491 _Q_INVALIDATE((elm)->field.tqe_prev); \
492 _Q_INVALIDATE((elm)->field.tqe_next); \
493 } while (0)
494
495#define TAILQ_REPLACE(head, elm, elm2, field) \
496 do { \
497 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
498 (elm2)->field.tqe_next->field.tqe_prev = &(elm2)->field.tqe_next; \
499 else \
500 (head)->tqh_last = &(elm2)->field.tqe_next; \
501 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
502 *(elm2)->field.tqe_prev = (elm2); \
503 _Q_INVALIDATE((elm)->field.tqe_prev); \
504 _Q_INVALIDATE((elm)->field.tqe_next); \
505 } while (0)
506
507/*
508 * Circular queue definitions.
509 */
510#define CIRCLEQ_HEAD(name, type) \
511 struct name { \
512 struct type *cqh_first; /* first element */ \
513 struct type *cqh_last; /* last element */ \
514 }
515
516#define CIRCLEQ_HEAD_INITIALIZER(head) {CIRCLEQ_END(&head), CIRCLEQ_END(&head)}
517
518#define CIRCLEQ_ENTRY(type) \
519 struct { \
520 struct type *cqe_next; /* next element */ \
521 struct type *cqe_prev; /* previous element */ \
522 }
523
524/*
525 * Circular queue access methods
526 */
527#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
528#define CIRCLEQ_LAST(head) ((head)->cqh_last)
529#define CIRCLEQ_END(head) ((void *)(head))
530#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
531#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
532#define CIRCLEQ_EMPTY(head) (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
533
534#define CIRCLEQ_FOREACH(var, head, field) \
535 for ((var) = CIRCLEQ_FIRST(head); (var) != CIRCLEQ_END(head); (var) = CIRCLEQ_NEXT(var, field))
536
537#define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar) \
538 for ((var) = CIRCLEQ_FIRST(head); \
539 (var) != CIRCLEQ_END(head) && ((tvar) = CIRCLEQ_NEXT(var, field), 1); \
540 (var) = (tvar))
541
542#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
543 for ((var) = CIRCLEQ_LAST(head); (var) != CIRCLEQ_END(head); (var) = CIRCLEQ_PREV(var, field))
544
545#define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
546 for ((var) = CIRCLEQ_LAST(head, headname); \
547 (var) != CIRCLEQ_END(head) && ((tvar) = CIRCLEQ_PREV(var, headname, field), 1); \
548 (var) = (tvar))
549
550/*
551 * Circular queue functions.
552 */
553#define CIRCLEQ_INIT(head) \
554 do { \
555 (head)->cqh_first = CIRCLEQ_END(head); \
556 (head)->cqh_last = CIRCLEQ_END(head); \
557 } while (0)
558
559#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) \
560 do { \
561 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
562 (elm)->field.cqe_prev = (listelm); \
563 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \
564 (head)->cqh_last = (elm); \
565 else \
566 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
567 (listelm)->field.cqe_next = (elm); \
568 } while (0)
569
570#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) \
571 do { \
572 (elm)->field.cqe_next = (listelm); \
573 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
574 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \
575 (head)->cqh_first = (elm); \
576 else \
577 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
578 (listelm)->field.cqe_prev = (elm); \
579 } while (0)
580
581#define CIRCLEQ_INSERT_HEAD(head, elm, field) \
582 do { \
583 (elm)->field.cqe_next = (head)->cqh_first; \
584 (elm)->field.cqe_prev = CIRCLEQ_END(head); \
585 if ((head)->cqh_last == CIRCLEQ_END(head)) \
586 (head)->cqh_last = (elm); \
587 else \
588 (head)->cqh_first->field.cqe_prev = (elm); \
589 (head)->cqh_first = (elm); \
590 } while (0)
591
592#define CIRCLEQ_INSERT_TAIL(head, elm, field) \
593 do { \
594 (elm)->field.cqe_next = CIRCLEQ_END(head); \
595 (elm)->field.cqe_prev = (head)->cqh_last; \
596 if ((head)->cqh_first == CIRCLEQ_END(head)) \
597 (head)->cqh_first = (elm); \
598 else \
599 (head)->cqh_last->field.cqe_next = (elm); \
600 (head)->cqh_last = (elm); \
601 } while (0)
602
603#define CIRCLEQ_REMOVE(head, elm, field) \
604 do { \
605 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \
606 (head)->cqh_last = (elm)->field.cqe_prev; \
607 else \
608 (elm)->field.cqe_next->field.cqe_prev = (elm)->field.cqe_prev; \
609 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \
610 (head)->cqh_first = (elm)->field.cqe_next; \
611 else \
612 (elm)->field.cqe_prev->field.cqe_next = (elm)->field.cqe_next; \
613 _Q_INVALIDATE((elm)->field.cqe_prev); \
614 _Q_INVALIDATE((elm)->field.cqe_next); \
615 } while (0)
616
617#define CIRCLEQ_REPLACE(head, elm, elm2, field) \
618 do { \
619 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == CIRCLEQ_END(head)) \
620 (head)->cqh_last = (elm2); \
621 else \
622 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \
623 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == CIRCLEQ_END(head)) \
624 (head)->cqh_first = (elm2); \
625 else \
626 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \
627 _Q_INVALIDATE((elm)->field.cqe_prev); \
628 _Q_INVALIDATE((elm)->field.cqe_next); \
629 } while (0)
630
631#endif /* !_SYS_QUEUE_H_ */
