glibc (2.38)
1 /*
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)queue.h 8.5 (Berkeley) 8/20/94
30 */
31
32 #ifndef _SYS_QUEUE_H_
33 #define _SYS_QUEUE_H_
34
35 /*
36 * This file defines five types of data structures: singly-linked lists,
37 * lists, simple queues, tail queues, and circular queues.
38 *
39 * A singly-linked list is headed by a single forward pointer. The
40 * elements are singly linked for minimum space and pointer manipulation
41 * overhead at the expense of O(n) removal for arbitrary elements. New
42 * elements can be added to the list after an existing element or at the
43 * head of the list. Elements being removed from the head of the list
44 * should use the explicit macro for this purpose for optimum
45 * efficiency. A singly-linked list may only be traversed in the forward
46 * direction. Singly-linked lists are ideal for applications with large
47 * datasets and few or no removals or for implementing a LIFO queue.
48 *
49 * A list is headed by a single forward pointer (or an array of forward
50 * pointers for a hash table header). The elements are doubly linked
51 * so that an arbitrary element can be removed without a need to
52 * traverse the list. New elements can be added to the list before
53 * or after an existing element or at the head of the list. A list
54 * may only be traversed in the forward direction.
55 *
56 * A simple queue is headed by a pair of pointers, one the head of the
57 * list and the other to the tail of the list. The elements are singly
58 * linked to save space, so elements can only be removed from the
59 * head of the list. New elements can be added to the list after
60 * an existing element, at the head of the list, or at the end of the
61 * list. A simple queue may only be traversed in the forward direction.
62 *
63 * A tail queue is headed by a pair of pointers, one to the head of the
64 * list and the other to the tail of the list. The elements are doubly
65 * linked so that an arbitrary element can be removed without a need to
66 * traverse the list. New elements can be added to the list before or
67 * after an existing element, at the head of the list, or at the end of
68 * the list. A tail queue may be traversed in either direction.
69 *
70 * A circle queue is headed by a pair of pointers, one to the head of the
71 * list and the other to the tail of the list. The elements are doubly
72 * linked so that an arbitrary element can be removed without a need to
73 * traverse the list. New elements can be added to the list before or after
74 * an existing element, at the head of the list, or at the end of the list.
75 * A circle queue may be traversed in either direction, but has a more
76 * complex end of list detection.
77 *
78 * For details on the use of these macros, see the queue(3) manual page.
79 */
80
81 /*
82 * List definitions.
83 */
84 #define LIST_HEAD(name, type) \
85 struct name { \
86 struct type *lh_first; /* first element */ \
87 }
88
89 #define LIST_HEAD_INITIALIZER(head) \
90 { NULL }
91
92 #define LIST_ENTRY(type) \
93 struct { \
94 struct type *le_next; /* next element */ \
95 struct type **le_prev; /* address of previous next element */ \
96 }
97
98 /*
99 * List functions.
100 */
101 #define LIST_INIT(head) do { \
102 (head)->lh_first = NULL; \
103 } while (/*CONSTCOND*/0)
104
105 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
106 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
107 (listelm)->field.le_next->field.le_prev = \
108 &(elm)->field.le_next; \
109 (listelm)->field.le_next = (elm); \
110 (elm)->field.le_prev = &(listelm)->field.le_next; \
111 } while (/*CONSTCOND*/0)
112
113 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
114 (elm)->field.le_prev = (listelm)->field.le_prev; \
115 (elm)->field.le_next = (listelm); \
116 *(listelm)->field.le_prev = (elm); \
117 (listelm)->field.le_prev = &(elm)->field.le_next; \
118 } while (/*CONSTCOND*/0)
119
120 #define LIST_INSERT_HEAD(head, elm, field) do { \
121 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
122 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
123 (head)->lh_first = (elm); \
124 (elm)->field.le_prev = &(head)->lh_first; \
125 } while (/*CONSTCOND*/0)
126
127 #define LIST_REMOVE(elm, field) do { \
128 if ((elm)->field.le_next != NULL) \
129 (elm)->field.le_next->field.le_prev = \
130 (elm)->field.le_prev; \
131 *(elm)->field.le_prev = (elm)->field.le_next; \
132 } while (/*CONSTCOND*/0)
133
134 #define LIST_FOREACH(var, head, field) \
135 for ((var) = ((head)->lh_first); \
136 (var); \
137 (var) = ((var)->field.le_next))
138
139 /*
140 * List access methods.
141 */
142 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
143 #define LIST_FIRST(head) ((head)->lh_first)
144 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
145
146
147 /*
148 * Singly-linked List definitions.
149 */
150 #define SLIST_HEAD(name, type) \
151 struct name { \
152 struct type *slh_first; /* first element */ \
153 }
154
155 #define SLIST_HEAD_INITIALIZER(head) \
156 { NULL }
157
158 #define SLIST_ENTRY(type) \
159 struct { \
160 struct type *sle_next; /* next element */ \
161 }
162
163 /*
164 * Singly-linked List functions.
165 */
166 #define SLIST_INIT(head) do { \
167 (head)->slh_first = NULL; \
168 } while (/*CONSTCOND*/0)
169
170 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
171 (elm)->field.sle_next = (slistelm)->field.sle_next; \
172 (slistelm)->field.sle_next = (elm); \
173 } while (/*CONSTCOND*/0)
174
175 #define SLIST_INSERT_HEAD(head, elm, field) do { \
176 (elm)->field.sle_next = (head)->slh_first; \
177 (head)->slh_first = (elm); \
178 } while (/*CONSTCOND*/0)
179
180 #define SLIST_REMOVE_HEAD(head, field) do { \
181 (head)->slh_first = (head)->slh_first->field.sle_next; \
182 } while (/*CONSTCOND*/0)
183
184 #define SLIST_REMOVE(head, elm, type, field) do { \
185 if ((head)->slh_first == (elm)) { \
186 SLIST_REMOVE_HEAD((head), field); \
187 } \
188 else { \
189 struct type *curelm = (head)->slh_first; \
190 while(curelm->field.sle_next != (elm)) \
191 curelm = curelm->field.sle_next; \
192 curelm->field.sle_next = \
193 curelm->field.sle_next->field.sle_next; \
194 } \
195 } while (/*CONSTCOND*/0)
196
197 #define SLIST_FOREACH(var, head, field) \
198 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
199
200 /*
201 * Singly-linked List access methods.
202 */
203 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
204 #define SLIST_FIRST(head) ((head)->slh_first)
205 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
206
207
208 /*
209 * Singly-linked Tail queue declarations.
210 */
211 #define STAILQ_HEAD(name, type) \
212 struct name { \
213 struct type *stqh_first; /* first element */ \
214 struct type **stqh_last; /* addr of last next element */ \
215 }
216
217 #define STAILQ_HEAD_INITIALIZER(head) \
218 { NULL, &(head).stqh_first }
219
220 #define STAILQ_ENTRY(type) \
221 struct { \
222 struct type *stqe_next; /* next element */ \
223 }
224
225 /*
226 * Singly-linked Tail queue functions.
227 */
228 #define STAILQ_INIT(head) do { \
229 (head)->stqh_first = NULL; \
230 (head)->stqh_last = &(head)->stqh_first; \
231 } while (/*CONSTCOND*/0)
232
233 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
234 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \
235 (head)->stqh_last = &(elm)->field.stqe_next; \
236 (head)->stqh_first = (elm); \
237 } while (/*CONSTCOND*/0)
238
239 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
240 (elm)->field.stqe_next = NULL; \
241 *(head)->stqh_last = (elm); \
242 (head)->stqh_last = &(elm)->field.stqe_next; \
243 } while (/*CONSTCOND*/0)
244
245 #define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
246 if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
247 (head)->stqh_last = &(elm)->field.stqe_next; \
248 (listelm)->field.stqe_next = (elm); \
249 } while (/*CONSTCOND*/0)
250
251 #define STAILQ_REMOVE_HEAD(head, field) do { \
252 if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
253 (head)->stqh_last = &(head)->stqh_first; \
254 } while (/*CONSTCOND*/0)
255
256 #define STAILQ_REMOVE(head, elm, type, field) do { \
257 if ((head)->stqh_first == (elm)) { \
258 STAILQ_REMOVE_HEAD((head), field); \
259 } else { \
260 struct type *curelm = (head)->stqh_first; \
261 while (curelm->field.stqe_next != (elm)) \
262 curelm = curelm->field.stqe_next; \
263 if ((curelm->field.stqe_next = \
264 curelm->field.stqe_next->field.stqe_next) == NULL) \
265 (head)->stqh_last = &(curelm)->field.stqe_next; \
266 } \
267 } while (/*CONSTCOND*/0)
268
269 #define STAILQ_FOREACH(var, head, field) \
270 for ((var) = ((head)->stqh_first); \
271 (var); \
272 (var) = ((var)->field.stqe_next))
273
274 #define STAILQ_CONCAT(head1, head2) do { \
275 if (!STAILQ_EMPTY((head2))) { \
276 *(head1)->stqh_last = (head2)->stqh_first; \
277 (head1)->stqh_last = (head2)->stqh_last; \
278 STAILQ_INIT((head2)); \
279 } \
280 } while (/*CONSTCOND*/0)
281
282 /*
283 * Singly-linked Tail queue access methods.
284 */
285 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
286 #define STAILQ_FIRST(head) ((head)->stqh_first)
287 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
288
289
290 /*
291 * Simple queue definitions.
292 */
293 #define SIMPLEQ_HEAD(name, type) \
294 struct name { \
295 struct type *sqh_first; /* first element */ \
296 struct type **sqh_last; /* addr of last next element */ \
297 }
298
299 #define SIMPLEQ_HEAD_INITIALIZER(head) \
300 { NULL, &(head).sqh_first }
301
302 #define SIMPLEQ_ENTRY(type) \
303 struct { \
304 struct type *sqe_next; /* next element */ \
305 }
306
307 /*
308 * Simple queue functions.
309 */
310 #define SIMPLEQ_INIT(head) do { \
311 (head)->sqh_first = NULL; \
312 (head)->sqh_last = &(head)->sqh_first; \
313 } while (/*CONSTCOND*/0)
314
315 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
316 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
317 (head)->sqh_last = &(elm)->field.sqe_next; \
318 (head)->sqh_first = (elm); \
319 } while (/*CONSTCOND*/0)
320
321 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
322 (elm)->field.sqe_next = NULL; \
323 *(head)->sqh_last = (elm); \
324 (head)->sqh_last = &(elm)->field.sqe_next; \
325 } while (/*CONSTCOND*/0)
326
327 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
328 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
329 (head)->sqh_last = &(elm)->field.sqe_next; \
330 (listelm)->field.sqe_next = (elm); \
331 } while (/*CONSTCOND*/0)
332
333 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \
334 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
335 (head)->sqh_last = &(head)->sqh_first; \
336 } while (/*CONSTCOND*/0)
337
338 #define SIMPLEQ_REMOVE(head, elm, type, field) do { \
339 if ((head)->sqh_first == (elm)) { \
340 SIMPLEQ_REMOVE_HEAD((head), field); \
341 } else { \
342 struct type *curelm = (head)->sqh_first; \
343 while (curelm->field.sqe_next != (elm)) \
344 curelm = curelm->field.sqe_next; \
345 if ((curelm->field.sqe_next = \
346 curelm->field.sqe_next->field.sqe_next) == NULL) \
347 (head)->sqh_last = &(curelm)->field.sqe_next; \
348 } \
349 } while (/*CONSTCOND*/0)
350
351 #define SIMPLEQ_FOREACH(var, head, field) \
352 for ((var) = ((head)->sqh_first); \
353 (var); \
354 (var) = ((var)->field.sqe_next))
355
356 /*
357 * Simple queue access methods.
358 */
359 #define SIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL)
360 #define SIMPLEQ_FIRST(head) ((head)->sqh_first)
361 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
362
363
364 /*
365 * Tail queue definitions.
366 */
367 #define _TAILQ_HEAD(name, type, qual) \
368 struct name { \
369 qual type *tqh_first; /* first element */ \
370 qual type *qual *tqh_last; /* addr of last next element */ \
371 }
372 #define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type,)
373
374 #define TAILQ_HEAD_INITIALIZER(head) \
375 { NULL, &(head).tqh_first }
376
377 #define _TAILQ_ENTRY(type, qual) \
378 struct { \
379 qual type *tqe_next; /* next element */ \
380 qual type *qual *tqe_prev; /* address of previous next element */\
381 }
382 #define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type,)
383
384 /*
385 * Tail queue functions.
386 */
387 #define TAILQ_INIT(head) do { \
388 (head)->tqh_first = NULL; \
389 (head)->tqh_last = &(head)->tqh_first; \
390 } while (/*CONSTCOND*/0)
391
392 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
393 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
394 (head)->tqh_first->field.tqe_prev = \
395 &(elm)->field.tqe_next; \
396 else \
397 (head)->tqh_last = &(elm)->field.tqe_next; \
398 (head)->tqh_first = (elm); \
399 (elm)->field.tqe_prev = &(head)->tqh_first; \
400 } while (/*CONSTCOND*/0)
401
402 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
403 (elm)->field.tqe_next = NULL; \
404 (elm)->field.tqe_prev = (head)->tqh_last; \
405 *(head)->tqh_last = (elm); \
406 (head)->tqh_last = &(elm)->field.tqe_next; \
407 } while (/*CONSTCOND*/0)
408
409 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
410 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
411 (elm)->field.tqe_next->field.tqe_prev = \
412 &(elm)->field.tqe_next; \
413 else \
414 (head)->tqh_last = &(elm)->field.tqe_next; \
415 (listelm)->field.tqe_next = (elm); \
416 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
417 } while (/*CONSTCOND*/0)
418
419 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
420 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
421 (elm)->field.tqe_next = (listelm); \
422 *(listelm)->field.tqe_prev = (elm); \
423 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
424 } while (/*CONSTCOND*/0)
425
426 #define TAILQ_REMOVE(head, elm, field) do { \
427 if (((elm)->field.tqe_next) != NULL) \
428 (elm)->field.tqe_next->field.tqe_prev = \
429 (elm)->field.tqe_prev; \
430 else \
431 (head)->tqh_last = (elm)->field.tqe_prev; \
432 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
433 } while (/*CONSTCOND*/0)
434
435 #define TAILQ_FOREACH(var, head, field) \
436 for ((var) = ((head)->tqh_first); \
437 (var); \
438 (var) = ((var)->field.tqe_next))
439
440 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
441 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \
442 (var); \
443 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
444
445 #define TAILQ_CONCAT(head1, head2, field) do { \
446 if (!TAILQ_EMPTY(head2)) { \
447 *(head1)->tqh_last = (head2)->tqh_first; \
448 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
449 (head1)->tqh_last = (head2)->tqh_last; \
450 TAILQ_INIT((head2)); \
451 } \
452 } while (/*CONSTCOND*/0)
453
454 /*
455 * Tail queue access methods.
456 */
457 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
458 #define TAILQ_FIRST(head) ((head)->tqh_first)
459 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
460
461 #define TAILQ_LAST(head, headname) \
462 (*(((struct headname *)((head)->tqh_last))->tqh_last))
463 #define TAILQ_PREV(elm, headname, field) \
464 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
465
466
467 /*
468 * Circular queue definitions.
469 */
470 #define CIRCLEQ_HEAD(name, type) \
471 struct name { \
472 struct type *cqh_first; /* first element */ \
473 struct type *cqh_last; /* last element */ \
474 }
475
476 #define CIRCLEQ_HEAD_INITIALIZER(head) \
477 { (void *)&head, (void *)&head }
478
479 #define CIRCLEQ_ENTRY(type) \
480 struct { \
481 struct type *cqe_next; /* next element */ \
482 struct type *cqe_prev; /* previous element */ \
483 }
484
485 /*
486 * Circular queue functions.
487 */
488 #define CIRCLEQ_INIT(head) do { \
489 (head)->cqh_first = (void *)(head); \
490 (head)->cqh_last = (void *)(head); \
491 } while (/*CONSTCOND*/0)
492
493 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
494 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
495 (elm)->field.cqe_prev = (listelm); \
496 if ((listelm)->field.cqe_next == (void *)(head)) \
497 (head)->cqh_last = (elm); \
498 else \
499 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
500 (listelm)->field.cqe_next = (elm); \
501 } while (/*CONSTCOND*/0)
502
503 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
504 (elm)->field.cqe_next = (listelm); \
505 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
506 if ((listelm)->field.cqe_prev == (void *)(head)) \
507 (head)->cqh_first = (elm); \
508 else \
509 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
510 (listelm)->field.cqe_prev = (elm); \
511 } while (/*CONSTCOND*/0)
512
513 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
514 (elm)->field.cqe_next = (head)->cqh_first; \
515 (elm)->field.cqe_prev = (void *)(head); \
516 if ((head)->cqh_last == (void *)(head)) \
517 (head)->cqh_last = (elm); \
518 else \
519 (head)->cqh_first->field.cqe_prev = (elm); \
520 (head)->cqh_first = (elm); \
521 } while (/*CONSTCOND*/0)
522
523 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
524 (elm)->field.cqe_next = (void *)(head); \
525 (elm)->field.cqe_prev = (head)->cqh_last; \
526 if ((head)->cqh_first == (void *)(head)) \
527 (head)->cqh_first = (elm); \
528 else \
529 (head)->cqh_last->field.cqe_next = (elm); \
530 (head)->cqh_last = (elm); \
531 } while (/*CONSTCOND*/0)
532
533 #define CIRCLEQ_REMOVE(head, elm, field) do { \
534 if ((elm)->field.cqe_next == (void *)(head)) \
535 (head)->cqh_last = (elm)->field.cqe_prev; \
536 else \
537 (elm)->field.cqe_next->field.cqe_prev = \
538 (elm)->field.cqe_prev; \
539 if ((elm)->field.cqe_prev == (void *)(head)) \
540 (head)->cqh_first = (elm)->field.cqe_next; \
541 else \
542 (elm)->field.cqe_prev->field.cqe_next = \
543 (elm)->field.cqe_next; \
544 } while (/*CONSTCOND*/0)
545
546 #define CIRCLEQ_FOREACH(var, head, field) \
547 for ((var) = ((head)->cqh_first); \
548 (var) != (const void *)(head); \
549 (var) = ((var)->field.cqe_next))
550
551 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
552 for ((var) = ((head)->cqh_last); \
553 (var) != (const void *)(head); \
554 (var) = ((var)->field.cqe_prev))
555
556 /*
557 * Circular queue access methods.
558 */
559 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
560 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
561 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
562 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
563 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
564
565 #define CIRCLEQ_LOOP_NEXT(head, elm, field) \
566 (((elm)->field.cqe_next == (void *)(head)) \
567 ? ((head)->cqh_first) \
568 : (elm->field.cqe_next))
569 #define CIRCLEQ_LOOP_PREV(head, elm, field) \
570 (((elm)->field.cqe_prev == (void *)(head)) \
571 ? ((head)->cqh_last) \
572 : (elm->field.cqe_prev))
573
574 #endif /* sys/queue.h */
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