1/* $OpenBSD: queue.h,v 1.46 2020/12/30 13:33:12 millert 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#include <sys/_null.h>
39
40/*
41 * This file defines five types of data structures: singly-linked lists,
42 * lists, simple queues, tail queues and XOR simple queues.
43 *
44 *
45 * A singly-linked list is headed by a single forward pointer. The elements
46 * are singly linked for minimum space and pointer manipulation overhead at
47 * the expense of O(n) removal for arbitrary elements. New elements can be
48 * added to the list after an existing element or at the head of the list.
49 * Elements being removed from the head of the list should use the explicit
50 * macro for this purpose for optimum efficiency. A singly-linked list may
51 * only be traversed in the forward direction. Singly-linked lists are ideal
52 * for applications with large datasets and few or no removals or for
53 * implementing a LIFO queue.
54 *
55 * A list is headed by a single forward pointer (or an array of forward
56 * pointers for a hash table header). The elements are doubly linked
57 * so that an arbitrary element can be removed without a need to
58 * traverse the list. New elements can be added to the list before
59 * or after an existing element or at the head of the list. A list
60 * may only be traversed in the forward direction.
61 *
62 * A simple queue is headed by a pair of pointers, one to the head of the
63 * list and the other to the tail of the list. The elements are singly
64 * linked to save space, so elements can only be removed from the
65 * head of the list. New elements can be added to the list before or after
66 * an existing element, at the head of the list, or at the end of the
67 * list. A simple queue may only be traversed in the forward direction.
68 *
69 * A tail queue is headed by a pair of pointers, one to the head of the
70 * list and the other to the tail of the list. The elements are doubly
71 * linked so that an arbitrary element can be removed without a need to
72 * traverse the list. New elements can be added to the list before or
73 * after an existing element, at the head of the list, or at the end of
74 * the list. A tail queue may be traversed in either direction.
75 *
76 * An XOR simple queue is used in the same way as a regular simple queue.
77 * The difference is that the head structure also includes a "cookie" that
78 * is XOR'd with the queue pointer (first, last or next) to generate the
79 * real pointer value.
80 *
81 * For details on the use of these macros, see the queue(3) manual page.
82 */
83
84#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
85#define _Q_INVALID ((void *)-1)
86#define _Q_INVALIDATE(a) (a) = _Q_INVALID
87#else
88#define _Q_INVALIDATE(a)
89#endif
90
91/*
92 * Singly-linked List definitions.
93 */
94#define SLIST_HEAD(name, type) \
95struct name { \
96 struct type *slh_first; /* first element */ \
97}
98
99#define SLIST_HEAD_INITIALIZER(head) \
100 { NULL }
101
102#define SLIST_ENTRY(type) \
103struct { \
104 struct type *sle_next; /* next element */ \
105}
106
107/*
108 * Singly-linked List access methods.
109 */
110#define SLIST_FIRST(head) ((head)->slh_first)
111#define SLIST_END(head) NULL
112#define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head))
113#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
114
115#define SLIST_FOREACH(var, head, field) \
116 for((var) = SLIST_FIRST(head); \
117 (var) != SLIST_END(head); \
118 (var) = SLIST_NEXT(var, field))
119
120#define SLIST_FOREACH_SAFE(var, head, field, tvar) \
121 for ((var) = SLIST_FIRST(head); \
122 (var) && ((tvar) = SLIST_NEXT(var, field), 1); \
123 (var) = (tvar))
124
125/*
126 * Singly-linked List functions.
127 */
128#define SLIST_INIT(head) { \
129 SLIST_FIRST(head) = SLIST_END(head); \
130}
131
132#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
133 (elm)->field.sle_next = (slistelm)->field.sle_next; \
134 (slistelm)->field.sle_next = (elm); \
135} while (0)
136
137#define SLIST_INSERT_HEAD(head, elm, field) do { \
138 (elm)->field.sle_next = (head)->slh_first; \
139 (head)->slh_first = (elm); \
140} while (0)
141
142#define SLIST_REMOVE_AFTER(elm, field) do { \
143 (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \
144} while (0)
145
146#define SLIST_REMOVE_HEAD(head, field) do { \
147 (head)->slh_first = (head)->slh_first->field.sle_next; \
148} while (0)
149
150#define SLIST_REMOVE(head, elm, type, field) do { \
151 if ((head)->slh_first == (elm)) { \
152 SLIST_REMOVE_HEAD((head), field); \
153 } else { \
154 struct type *curelm = (head)->slh_first; \
155 \
156 while (curelm->field.sle_next != (elm)) \
157 curelm = curelm->field.sle_next; \
158 curelm->field.sle_next = \
159 curelm->field.sle_next->field.sle_next; \
160 } \
161 _Q_INVALIDATE((elm)->field.sle_next); \
162} while (0)
163
164/*
165 * List definitions.
166 */
167#define LIST_HEAD(name, type) \
168struct name { \
169 struct type *lh_first; /* first element */ \
170}
171
172#define LIST_HEAD_INITIALIZER(head) \
173 { NULL }
174
175#define LIST_ENTRY(type) \
176struct { \
177 struct type *le_next; /* next element */ \
178 struct type **le_prev; /* address of previous next element */ \
179}
180
181/*
182 * List access methods.
183 */
184#define LIST_FIRST(head) ((head)->lh_first)
185#define LIST_END(head) NULL
186#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
187#define LIST_NEXT(elm, field) ((elm)->field.le_next)
188
189#define LIST_FOREACH(var, head, field) \
190 for((var) = LIST_FIRST(head); \
191 (var)!= LIST_END(head); \
192 (var) = LIST_NEXT(var, field))
193
194#define LIST_FOREACH_SAFE(var, head, field, tvar) \
195 for ((var) = LIST_FIRST(head); \
196 (var) && ((tvar) = LIST_NEXT(var, field), 1); \
197 (var) = (tvar))
198
199/*
200 * List functions.
201 */
202#define LIST_INIT(head) do { \
203 LIST_FIRST(head) = LIST_END(head); \
204} while (0)
205
206#define LIST_INSERT_AFTER(listelm, elm, field) do { \
207 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
208 (listelm)->field.le_next->field.le_prev = \
209 &(elm)->field.le_next; \
210 (listelm)->field.le_next = (elm); \
211 (elm)->field.le_prev = &(listelm)->field.le_next; \
212} while (0)
213
214#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
215 (elm)->field.le_prev = (listelm)->field.le_prev; \
216 (elm)->field.le_next = (listelm); \
217 *(listelm)->field.le_prev = (elm); \
218 (listelm)->field.le_prev = &(elm)->field.le_next; \
219} while (0)
220
221#define LIST_INSERT_HEAD(head, elm, field) do { \
222 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
223 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
224 (head)->lh_first = (elm); \
225 (elm)->field.le_prev = &(head)->lh_first; \
226} while (0)
227
228#define LIST_REMOVE(elm, field) do { \
229 if ((elm)->field.le_next != NULL) \
230 (elm)->field.le_next->field.le_prev = \
231 (elm)->field.le_prev; \
232 *(elm)->field.le_prev = (elm)->field.le_next; \
233 _Q_INVALIDATE((elm)->field.le_prev); \
234 _Q_INVALIDATE((elm)->field.le_next); \
235} while (0)
236
237#define LIST_REPLACE(elm, elm2, field) do { \
238 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
239 (elm2)->field.le_next->field.le_prev = \
240 &(elm2)->field.le_next; \
241 (elm2)->field.le_prev = (elm)->field.le_prev; \
242 *(elm2)->field.le_prev = (elm2); \
243 _Q_INVALIDATE((elm)->field.le_prev); \
244 _Q_INVALIDATE((elm)->field.le_next); \
245} while (0)
246
247/*
248 * Simple queue definitions.
249 */
250#define SIMPLEQ_HEAD(name, type) \
251struct name { \
252 struct type *sqh_first; /* first element */ \
253 struct type **sqh_last; /* addr of last next element */ \
254}
255
256#define SIMPLEQ_HEAD_INITIALIZER(head) \
257 { NULL, &(head).sqh_first }
258
259#define SIMPLEQ_ENTRY(type) \
260struct { \
261 struct type *sqe_next; /* next element */ \
262}
263
264/*
265 * Simple queue access methods.
266 */
267#define SIMPLEQ_FIRST(head) ((head)->sqh_first)
268#define SIMPLEQ_END(head) NULL
269#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
270#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
271
272#define SIMPLEQ_FOREACH(var, head, field) \
273 for((var) = SIMPLEQ_FIRST(head); \
274 (var) != SIMPLEQ_END(head); \
275 (var) = SIMPLEQ_NEXT(var, field))
276
277#define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \
278 for ((var) = SIMPLEQ_FIRST(head); \
279 (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1); \
280 (var) = (tvar))
281
282/*
283 * Simple queue functions.
284 */
285#define SIMPLEQ_INIT(head) do { \
286 (head)->sqh_first = NULL; \
287 (head)->sqh_last = &(head)->sqh_first; \
288} while (0)
289
290#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
291 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
292 (head)->sqh_last = &(elm)->field.sqe_next; \
293 (head)->sqh_first = (elm); \
294} while (0)
295
296#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
297 (elm)->field.sqe_next = NULL; \
298 *(head)->sqh_last = (elm); \
299 (head)->sqh_last = &(elm)->field.sqe_next; \
300} while (0)
301
302#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
303 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
304 (head)->sqh_last = &(elm)->field.sqe_next; \
305 (listelm)->field.sqe_next = (elm); \
306} while (0)
307
308#define SIMPLEQ_REMOVE_HEAD(head, field) do { \
309 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
310 (head)->sqh_last = &(head)->sqh_first; \
311} while (0)
312
313#define SIMPLEQ_REMOVE_AFTER(head, elm, field) do { \
314 if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
315 == NULL) \
316 (head)->sqh_last = &(elm)->field.sqe_next; \
317} while (0)
318
319#define SIMPLEQ_CONCAT(head1, head2) do { \
320 if (!SIMPLEQ_EMPTY((head2))) { \
321 *(head1)->sqh_last = (head2)->sqh_first; \
322 (head1)->sqh_last = (head2)->sqh_last; \
323 SIMPLEQ_INIT((head2)); \
324 } \
325} while (0)
326
327/*
328 * XOR Simple queue definitions.
329 */
330#define XSIMPLEQ_HEAD(name, type) \
331struct name { \
332 struct type *sqx_first; /* first element */ \
333 struct type **sqx_last; /* addr of last next element */ \
334 unsigned long sqx_cookie; \
335}
336
337#define XSIMPLEQ_ENTRY(type) \
338struct { \
339 struct type *sqx_next; /* next element */ \
340}
341
342/*
343 * XOR Simple queue access methods.
344 */
345#define XSIMPLEQ_XOR(head, ptr) ((__typeof(ptr))((head)->sqx_cookie ^ \
346 (unsigned long)(ptr)))
347#define XSIMPLEQ_FIRST(head) XSIMPLEQ_XOR(head, ((head)->sqx_first))
348#define XSIMPLEQ_END(head) NULL
349#define XSIMPLEQ_EMPTY(head) (XSIMPLEQ_FIRST(head) == XSIMPLEQ_END(head))
350#define XSIMPLEQ_NEXT(head, elm, field) XSIMPLEQ_XOR(head, ((elm)->field.sqx_next))
351
352
353#define XSIMPLEQ_FOREACH(var, head, field) \
354 for ((var) = XSIMPLEQ_FIRST(head); \
355 (var) != XSIMPLEQ_END(head); \
356 (var) = XSIMPLEQ_NEXT(head, var, field))
357
358#define XSIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \
359 for ((var) = XSIMPLEQ_FIRST(head); \
360 (var) && ((tvar) = XSIMPLEQ_NEXT(head, var, field), 1); \
361 (var) = (tvar))
362
363/*
364 * XOR Simple queue functions.
365 */
366#define XSIMPLEQ_INIT(head) do { \
367 arc4random_buf(&(head)->sqx_cookie, sizeof((head)->sqx_cookie)); \
368 (head)->sqx_first = XSIMPLEQ_XOR(head, NULL); \
369 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
370} while (0)
371
372#define XSIMPLEQ_INSERT_HEAD(head, elm, field) do { \
373 if (((elm)->field.sqx_next = (head)->sqx_first) == \
374 XSIMPLEQ_XOR(head, NULL)) \
375 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
376 (head)->sqx_first = XSIMPLEQ_XOR(head, (elm)); \
377} while (0)
378
379#define XSIMPLEQ_INSERT_TAIL(head, elm, field) do { \
380 (elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL); \
381 *(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \
382 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
383} while (0)
384
385#define XSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
386 if (((elm)->field.sqx_next = (listelm)->field.sqx_next) == \
387 XSIMPLEQ_XOR(head, NULL)) \
388 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
389 (listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm)); \
390} while (0)
391
392#define XSIMPLEQ_REMOVE_HEAD(head, field) do { \
393 if (((head)->sqx_first = XSIMPLEQ_XOR(head, \
394 (head)->sqx_first)->field.sqx_next) == XSIMPLEQ_XOR(head, NULL)) \
395 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \
396} while (0)
397
398#define XSIMPLEQ_REMOVE_AFTER(head, elm, field) do { \
399 if (((elm)->field.sqx_next = XSIMPLEQ_XOR(head, \
400 (elm)->field.sqx_next)->field.sqx_next) \
401 == XSIMPLEQ_XOR(head, NULL)) \
402 (head)->sqx_last = \
403 XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \
404} while (0)
405
406
407/*
408 * Tail queue definitions.
409 */
410#define TAILQ_HEAD(name, type) \
411struct name { \
412 struct type *tqh_first; /* first element */ \
413 struct type **tqh_last; /* addr of last next element */ \
414}
415
416#define TAILQ_HEAD_INITIALIZER(head) \
417 { NULL, &(head).tqh_first }
418
419#define TAILQ_ENTRY(type) \
420struct { \
421 struct type *tqe_next; /* next element */ \
422 struct type **tqe_prev; /* address of previous next element */ \
423}
424
425/*
426 * Tail queue access methods.
427 */
428#define TAILQ_FIRST(head) ((head)->tqh_first)
429#define TAILQ_END(head) NULL
430#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
431#define TAILQ_LAST(head, headname) \
432 (*(((struct headname *)((head)->tqh_last))->tqh_last))
433/* XXX */
434#define TAILQ_PREV(elm, headname, field) \
435 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
436#define TAILQ_EMPTY(head) \
437 (TAILQ_FIRST(head) == TAILQ_END(head))
438
439#define TAILQ_FOREACH(var, head, field) \
440 for((var) = TAILQ_FIRST(head); \
441 (var) != TAILQ_END(head); \
442 (var) = TAILQ_NEXT(var, field))
443
444#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
445 for ((var) = TAILQ_FIRST(head); \
446 (var) != TAILQ_END(head) && \
447 ((tvar) = TAILQ_NEXT(var, field), 1); \
448 (var) = (tvar))
449
450
451#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
452 for((var) = TAILQ_LAST(head, headname); \
453 (var) != TAILQ_END(head); \
454 (var) = TAILQ_PREV(var, headname, field))
455
456#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
457 for ((var) = TAILQ_LAST(head, headname); \
458 (var) != TAILQ_END(head) && \
459 ((tvar) = TAILQ_PREV(var, headname, field), 1); \
460 (var) = (tvar))
461
462/*
463 * Tail queue functions.
464 */
465#define TAILQ_INIT(head) do { \
466 (head)->tqh_first = NULL; \
467 (head)->tqh_last = &(head)->tqh_first; \
468} while (0)
469
470#define TAILQ_INSERT_HEAD(head, elm, field) do { \
471 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
472 (head)->tqh_first->field.tqe_prev = \
473 &(elm)->field.tqe_next; \
474 else \
475 (head)->tqh_last = &(elm)->field.tqe_next; \
476 (head)->tqh_first = (elm); \
477 (elm)->field.tqe_prev = &(head)->tqh_first; \
478} while (0)
479
480#define TAILQ_INSERT_TAIL(head, elm, field) do { \
481 (elm)->field.tqe_next = NULL; \
482 (elm)->field.tqe_prev = (head)->tqh_last; \
483 *(head)->tqh_last = (elm); \
484 (head)->tqh_last = &(elm)->field.tqe_next; \
485} while (0)
486
487#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
488 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
489 (elm)->field.tqe_next->field.tqe_prev = \
490 &(elm)->field.tqe_next; \
491 else \
492 (head)->tqh_last = &(elm)->field.tqe_next; \
493 (listelm)->field.tqe_next = (elm); \
494 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
495} while (0)
496
497#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
498 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
499 (elm)->field.tqe_next = (listelm); \
500 *(listelm)->field.tqe_prev = (elm); \
501 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
502} while (0)
503
504#define TAILQ_REMOVE(head, elm, field) do { \
505 if (((elm)->field.tqe_next) != NULL) \
506 (elm)->field.tqe_next->field.tqe_prev = \
507 (elm)->field.tqe_prev; \
508 else \
509 (head)->tqh_last = (elm)->field.tqe_prev; \
510 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
511 _Q_INVALIDATE((elm)->field.tqe_prev); \
512 _Q_INVALIDATE((elm)->field.tqe_next); \
513} while (0)
514
515#define TAILQ_REPLACE(head, elm, elm2, field) do { \
516 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
517 (elm2)->field.tqe_next->field.tqe_prev = \
518 &(elm2)->field.tqe_next; \
519 else \
520 (head)->tqh_last = &(elm2)->field.tqe_next; \
521 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
522 *(elm2)->field.tqe_prev = (elm2); \
523 _Q_INVALIDATE((elm)->field.tqe_prev); \
524 _Q_INVALIDATE((elm)->field.tqe_next); \
525} while (0)
526
527#define TAILQ_CONCAT(head1, head2, field) do { \
528 if (!TAILQ_EMPTY(head2)) { \
529 *(head1)->tqh_last = (head2)->tqh_first; \
530 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
531 (head1)->tqh_last = (head2)->tqh_last; \
532 TAILQ_INIT((head2)); \
533 } \
534} while (0)
535
536/*
537 * Singly-linked Tail queue declarations.
538 */
539#define STAILQ_HEAD(name, type) \
540struct name { \
541 struct type *stqh_first; /* first element */ \
542 struct type **stqh_last; /* addr of last next element */ \
543}
544
545#define STAILQ_HEAD_INITIALIZER(head) \
546 { NULL, &(head).stqh_first }
547
548#define STAILQ_ENTRY(type) \
549struct { \
550 struct type *stqe_next; /* next element */ \
551}
552
553/*
554 * Singly-linked Tail queue access methods.
555 */
556#define STAILQ_FIRST(head) ((head)->stqh_first)
557#define STAILQ_END(head) NULL
558#define STAILQ_EMPTY(head) (STAILQ_FIRST(head) == STAILQ_END(head))
559#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
560
561#define STAILQ_FOREACH(var, head, field) \
562 for ((var) = STAILQ_FIRST(head); \
563 (var) != STAILQ_END(head); \
564 (var) = STAILQ_NEXT(var, field))
565
566#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
567 for ((var) = STAILQ_FIRST(head); \
568 (var) && ((tvar) = STAILQ_NEXT(var, field), 1); \
569 (var) = (tvar))
570
571/*
572 * Singly-linked Tail queue functions.
573 */
574#define STAILQ_INIT(head) do { \
575 STAILQ_FIRST((head)) = NULL; \
576 (head)->stqh_last = &STAILQ_FIRST((head)); \
577} while (0)
578
579#define STAILQ_INSERT_HEAD(head, elm, field) do { \
580 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
581 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
582 STAILQ_FIRST((head)) = (elm); \
583} while (0)
584
585#define STAILQ_INSERT_TAIL(head, elm, field) do { \
586 STAILQ_NEXT((elm), field) = NULL; \
587 *(head)->stqh_last = (elm); \
588 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
589} while (0)
590
591#define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
592 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((elm), field)) == NULL)\
593 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
594 STAILQ_NEXT((elm), field) = (elm); \
595} while (0)
596
597#define STAILQ_REMOVE_HEAD(head, field) do { \
598 if ((STAILQ_FIRST((head)) = \
599 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
600 (head)->stqh_last = &STAILQ_FIRST((head)); \
601} while (0)
602
603#define STAILQ_REMOVE_AFTER(head, elm, field) do { \
604 if ((STAILQ_NEXT(elm, field) = \
605 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
606 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
607} while (0)
608
609#define STAILQ_REMOVE(head, elm, type, field) do { \
610 if (STAILQ_FIRST((head)) == (elm)) { \
611 STAILQ_REMOVE_HEAD((head), field); \
612 } else { \
613 struct type *curelm = (head)->stqh_first; \
614 while (STAILQ_NEXT(curelm, field) != (elm)) \
615 curelm = STAILQ_NEXT(curelm, field); \
616 STAILQ_REMOVE_AFTER(head, curelm, field); \
617 } \
618} while (0)
619
620#define STAILQ_CONCAT(head1, head2) do { \
621 if (!STAILQ_EMPTY((head2))) { \
622 *(head1)->stqh_last = (head2)->stqh_first; \
623 (head1)->stqh_last = (head2)->stqh_last; \
624 STAILQ_INIT((head2)); \
625 } \
626} while (0)
627
628#define STAILQ_LAST(head, type, field) \
629 (STAILQ_EMPTY((head)) ? NULL : \
630 ((struct type *)(void *) \
631 ((char *)((head)->stqh_last) - offsetof(struct type, field))))
632
633#endif /* !_SYS_QUEUE_H_ */