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 | * |
14 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
24 | * SUCH DAMAGE. |
25 | * |
26 | * @(#)queue.h 8.5 (Berkeley) 8/20/94 |
27 | * $FreeBSD: src/sys/sys/queue.h,v 1.38 2000/05/26 02:06:56 jake Exp $ |
28 | */ |
29 | |
30 | #ifndef _SYS_QUEUE_H_ |
31 | #define _SYS_QUEUE_H_ |
32 | |
33 | /* |
34 | * This file defines five types of data structures: singly-linked lists, |
35 | * singly-linked tail queues, lists, tail queues, and circular queues. |
36 | * |
37 | * A singly-linked list is headed by a single forward pointer. The elements |
38 | * are singly linked for minimum space and pointer manipulation overhead at |
39 | * the expense of O(n) removal for arbitrary elements. New elements can be |
40 | * added to the list after an existing element or at the head of the list. |
41 | * Elements being removed from the head of the list should use the explicit |
42 | * macro for this purpose for optimum efficiency. A singly-linked list may |
43 | * only be traversed in the forward direction. Singly-linked lists are ideal |
44 | * for applications with large datasets and few or no removals or for |
45 | * implementing a LIFO queue. |
46 | * |
47 | * A singly-linked tail queue is headed by a pair of pointers, one to the |
48 | * head of the list and the other to the tail of the list. The elements are |
49 | * singly linked for minimum space and pointer manipulation overhead at the |
50 | * expense of O(n) removal for arbitrary elements. New elements can be added |
51 | * to the list after an existing element, at the head of the list, or at the |
52 | * end of the list. Elements being removed from the head of the tail queue |
53 | * should use the explicit macro for this purpose for optimum efficiency. |
54 | * A singly-linked tail queue may only be traversed in the forward direction. |
55 | * Singly-linked tail queues are ideal for applications with large datasets |
56 | * and few or no removals or for implementing a FIFO queue. |
57 | * |
58 | * A list is headed by a single forward pointer (or an array of forward |
59 | * pointers for a hash table header). The elements are doubly linked |
60 | * so that an arbitrary element can be removed without a need to |
61 | * traverse the list. New elements can be added to the list before |
62 | * or after an existing element or at the head of the list. A list |
63 | * may only be traversed in the forward direction. |
64 | * |
65 | * A tail queue is headed by a pair of pointers, one to the head of the |
66 | * list and the other to the tail of the list. The elements are doubly |
67 | * linked so that an arbitrary element can be removed without a need to |
68 | * traverse the list. New elements can be added to the list before or |
69 | * after an existing element, at the head of the list, or at the end of |
70 | * the list. A tail queue may be traversed in either direction. |
71 | * |
72 | * A circle queue is headed by a pair of pointers, one to the head of the |
73 | * list and the other to the tail of the list. The elements are doubly |
74 | * linked so that an arbitrary element can be removed without a need to |
75 | * traverse the list. New elements can be added to the list before or after |
76 | * an existing element, at the head of the list, or at the end of the list. |
77 | * A circle queue may be traversed in either direction, but has a more |
78 | * complex end of list detection. |
79 | * |
80 | * For details on the use of these macros, see the queue(3) manual page. |
81 | * |
82 | * |
83 | * SLIST LIST STAILQ TAILQ CIRCLEQ |
84 | * _HEAD + + + + + |
85 | * _HEAD_INITIALIZER + + + + + |
86 | * _ENTRY + + + + + |
87 | * _INIT + + + + + |
88 | * _EMPTY + + + + + |
89 | * _FIRST + + + + + |
90 | * _NEXT + + + + + |
91 | * _PREV - - - + + |
92 | * _LAST - - + + + |
93 | * _FOREACH + + + + + |
94 | * _FOREACH_REVERSE - - - + + |
95 | * _INSERT_HEAD + + + + + |
96 | * _INSERT_BEFORE - + - + + |
97 | * _INSERT_AFTER + + + + + |
98 | * _INSERT_TAIL - - + + + |
99 | * _REMOVE_HEAD + - + - - |
100 | * _REMOVE + + + + + |
101 | * |
102 | */ |
103 | |
104 | /* |
105 | * Singly-linked List declarations. |
106 | */ |
107 | #define SLIST_HEAD(name, type) \ |
108 | struct name { \ |
109 | struct type *slh_first; /* first element */ \ |
110 | } |
111 | |
112 | #define SLIST_HEAD_INITIALIZER(head) \ |
113 | { NULL } |
114 | |
115 | #define SLIST_ENTRY(type) \ |
116 | struct { \ |
117 | struct type *sle_next; /* next element */ \ |
118 | } |
119 | |
120 | /* |
121 | * Singly-linked List functions. |
122 | */ |
123 | #define SLIST_EMPTY(head) ((head)->slh_first == NULL) |
124 | |
125 | #define SLIST_FIRST(head) ((head)->slh_first) |
126 | |
127 | #define SLIST_FOREACH(var, head, field) \ |
128 | for ((var) = SLIST_FIRST((head)); \ |
129 | (var); \ |
130 | (var) = SLIST_NEXT((var), field)) |
131 | |
132 | #define SLIST_INIT(head) do { \ |
133 | SLIST_FIRST((head)) = NULL; \ |
134 | } while (0) |
135 | |
136 | #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ |
137 | SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ |
138 | SLIST_NEXT((slistelm), field) = (elm); \ |
139 | } while (0) |
140 | |
141 | #define SLIST_INSERT_HEAD(head, elm, field) do { \ |
142 | SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ |
143 | SLIST_FIRST((head)) = (elm); \ |
144 | } while (0) |
145 | |
146 | #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) |
147 | |
148 | #define SLIST_REMOVE(head, elm, type, field) do { \ |
149 | if (SLIST_FIRST((head)) == (elm)) { \ |
150 | SLIST_REMOVE_HEAD((head), field); \ |
151 | } \ |
152 | else { \ |
153 | struct type *curelm = SLIST_FIRST((head)); \ |
154 | while (SLIST_NEXT(curelm, field) != (elm)) \ |
155 | curelm = SLIST_NEXT(curelm, field); \ |
156 | SLIST_NEXT(curelm, field) = \ |
157 | SLIST_NEXT(SLIST_NEXT(curelm, field), field); \ |
158 | } \ |
159 | } while (0) |
160 | |
161 | #define SLIST_REMOVE_HEAD(head, field) do { \ |
162 | SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ |
163 | } while (0) |
164 | |
165 | /* |
166 | * Singly-linked Tail queue declarations. |
167 | */ |
168 | #define STAILQ_HEAD(name, type) \ |
169 | struct name { \ |
170 | struct type *stqh_first;/* first element */ \ |
171 | struct type **stqh_last;/* addr of last next element */ \ |
172 | } |
173 | |
174 | #define STAILQ_HEAD_INITIALIZER(head) \ |
175 | { NULL, &(head).stqh_first } |
176 | |
177 | #define STAILQ_ENTRY(type) \ |
178 | struct { \ |
179 | struct type *stqe_next; /* next element */ \ |
180 | } |
181 | |
182 | /* |
183 | * Singly-linked Tail queue functions. |
184 | */ |
185 | #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) |
186 | |
187 | #define STAILQ_FIRST(head) ((head)->stqh_first) |
188 | |
189 | #define STAILQ_FOREACH(var, head, field) \ |
190 | for((var) = STAILQ_FIRST((head)); \ |
191 | (var); \ |
192 | (var) = STAILQ_NEXT((var), field)) |
193 | |
194 | #define STAILQ_INIT(head) do { \ |
195 | STAILQ_FIRST((head)) = NULL; \ |
196 | (head)->stqh_last = &STAILQ_FIRST((head)); \ |
197 | } while (0) |
198 | |
199 | #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ |
200 | if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ |
201 | (head)->stqh_last = &STAILQ_NEXT((elm), field); \ |
202 | STAILQ_NEXT((tqelm), field) = (elm); \ |
203 | } while (0) |
204 | |
205 | #define STAILQ_INSERT_HEAD(head, elm, field) do { \ |
206 | if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ |
207 | (head)->stqh_last = &STAILQ_NEXT((elm), field); \ |
208 | STAILQ_FIRST((head)) = (elm); \ |
209 | } while (0) |
210 | |
211 | #define STAILQ_INSERT_TAIL(head, elm, field) do { \ |
212 | STAILQ_NEXT((elm), field) = NULL; \ |
213 | STAILQ_LAST((head)) = (elm); \ |
214 | (head)->stqh_last = &STAILQ_NEXT((elm), field); \ |
215 | } while (0) |
216 | |
217 | #define STAILQ_LAST(head) (*(head)->stqh_last) |
218 | |
219 | #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) |
220 | |
221 | #define STAILQ_REMOVE(head, elm, type, field) do { \ |
222 | if (STAILQ_FIRST((head)) == (elm)) { \ |
223 | STAILQ_REMOVE_HEAD(head, field); \ |
224 | } \ |
225 | else { \ |
226 | struct type *curelm = STAILQ_FIRST((head)); \ |
227 | while (STAILQ_NEXT(curelm, field) != (elm)) \ |
228 | curelm = STAILQ_NEXT(curelm, field); \ |
229 | if ((STAILQ_NEXT(curelm, field) = \ |
230 | STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\ |
231 | (head)->stqh_last = &STAILQ_NEXT((curelm), field);\ |
232 | } \ |
233 | } while (0) |
234 | |
235 | #define STAILQ_REMOVE_HEAD(head, field) do { \ |
236 | if ((STAILQ_FIRST((head)) = \ |
237 | STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ |
238 | (head)->stqh_last = &STAILQ_FIRST((head)); \ |
239 | } while (0) |
240 | |
241 | #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ |
242 | if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \ |
243 | (head)->stqh_last = &STAILQ_FIRST((head)); \ |
244 | } while (0) |
245 | |
246 | /* |
247 | * List declarations. |
248 | */ |
249 | #define BSD_LIST_HEAD(name, type) \ |
250 | struct name { \ |
251 | struct type *lh_first; /* first element */ \ |
252 | } |
253 | |
254 | #define LIST_HEAD_INITIALIZER(head) \ |
255 | { NULL } |
256 | |
257 | #define LIST_ENTRY(type) \ |
258 | struct { \ |
259 | struct type *le_next; /* next element */ \ |
260 | struct type **le_prev; /* address of previous next element */ \ |
261 | } |
262 | |
263 | /* |
264 | * List functions. |
265 | */ |
266 | |
267 | #define LIST_EMPTY(head) ((head)->lh_first == NULL) |
268 | |
269 | #define LIST_FIRST(head) ((head)->lh_first) |
270 | |
271 | #define LIST_FOREACH(var, head, field) \ |
272 | for ((var) = LIST_FIRST((head)); \ |
273 | (var); \ |
274 | (var) = LIST_NEXT((var), field)) |
275 | |
276 | #define LIST_INIT(head) do { \ |
277 | LIST_FIRST((head)) = NULL; \ |
278 | } while (0) |
279 | |
280 | #define LIST_INSERT_AFTER(listelm, elm, field) do { \ |
281 | if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ |
282 | LIST_NEXT((listelm), field)->field.le_prev = \ |
283 | &LIST_NEXT((elm), field); \ |
284 | LIST_NEXT((listelm), field) = (elm); \ |
285 | (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ |
286 | } while (0) |
287 | |
288 | #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ |
289 | (elm)->field.le_prev = (listelm)->field.le_prev; \ |
290 | LIST_NEXT((elm), field) = (listelm); \ |
291 | *(listelm)->field.le_prev = (elm); \ |
292 | (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ |
293 | } while (0) |
294 | |
295 | #define LIST_INSERT_HEAD(head, elm, field) do { \ |
296 | if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ |
297 | LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ |
298 | LIST_FIRST((head)) = (elm); \ |
299 | (elm)->field.le_prev = &LIST_FIRST((head)); \ |
300 | } while (0) |
301 | |
302 | #define LIST_NEXT(elm, field) ((elm)->field.le_next) |
303 | |
304 | #define LIST_REMOVE(elm, field) do { \ |
305 | if (LIST_NEXT((elm), field) != NULL) \ |
306 | LIST_NEXT((elm), field)->field.le_prev = \ |
307 | (elm)->field.le_prev; \ |
308 | *(elm)->field.le_prev = LIST_NEXT((elm), field); \ |
309 | } while (0) |
310 | |
311 | /* |
312 | * Tail queue declarations. |
313 | */ |
314 | #define TAILQ_HEAD(name, type) \ |
315 | struct name { \ |
316 | struct type *tqh_first; /* first element */ \ |
317 | struct type **tqh_last; /* addr of last next element */ \ |
318 | } |
319 | |
320 | #define TAILQ_HEAD_INITIALIZER(head) \ |
321 | { NULL, &(head).tqh_first } |
322 | |
323 | #define TAILQ_ENTRY(type) \ |
324 | struct { \ |
325 | struct type *tqe_next; /* next element */ \ |
326 | struct type **tqe_prev; /* address of previous next element */ \ |
327 | } |
328 | |
329 | /* |
330 | * Tail queue functions. |
331 | */ |
332 | #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) |
333 | |
334 | #define TAILQ_FIRST(head) ((head)->tqh_first) |
335 | |
336 | #define TAILQ_FOREACH(var, head, field) \ |
337 | for ((var) = TAILQ_FIRST((head)); \ |
338 | (var); \ |
339 | (var) = TAILQ_NEXT((var), field)) |
340 | |
341 | #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ |
342 | for ((var) = TAILQ_LAST((head), headname); \ |
343 | (var); \ |
344 | (var) = TAILQ_PREV((var), headname, field)) |
345 | |
346 | #define TAILQ_INIT(head) do { \ |
347 | TAILQ_FIRST((head)) = NULL; \ |
348 | (head)->tqh_last = &TAILQ_FIRST((head)); \ |
349 | } while (0) |
350 | |
351 | #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ |
352 | if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ |
353 | TAILQ_NEXT((elm), field)->field.tqe_prev = \ |
354 | &TAILQ_NEXT((elm), field); \ |
355 | else \ |
356 | (head)->tqh_last = &TAILQ_NEXT((elm), field); \ |
357 | TAILQ_NEXT((listelm), field) = (elm); \ |
358 | (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ |
359 | } while (0) |
360 | |
361 | #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ |
362 | (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ |
363 | TAILQ_NEXT((elm), field) = (listelm); \ |
364 | *(listelm)->field.tqe_prev = (elm); \ |
365 | (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ |
366 | } while (0) |
367 | |
368 | #define TAILQ_INSERT_HEAD(head, elm, field) do { \ |
369 | if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ |
370 | TAILQ_FIRST((head))->field.tqe_prev = \ |
371 | &TAILQ_NEXT((elm), field); \ |
372 | else \ |
373 | (head)->tqh_last = &TAILQ_NEXT((elm), field); \ |
374 | TAILQ_FIRST((head)) = (elm); \ |
375 | (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ |
376 | } while (0) |
377 | |
378 | #define TAILQ_INSERT_TAIL(head, elm, field) do { \ |
379 | TAILQ_NEXT((elm), field) = NULL; \ |
380 | (elm)->field.tqe_prev = (head)->tqh_last; \ |
381 | *(head)->tqh_last = (elm); \ |
382 | (head)->tqh_last = &TAILQ_NEXT((elm), field); \ |
383 | } while (0) |
384 | |
385 | #define TAILQ_LAST(head, headname) \ |
386 | (*(((struct headname *)((head)->tqh_last))->tqh_last)) |
387 | |
388 | #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) |
389 | |
390 | #define TAILQ_PREV(elm, headname, field) \ |
391 | (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) |
392 | |
393 | #define TAILQ_REMOVE(head, elm, field) do { \ |
394 | if ((TAILQ_NEXT((elm), field)) != NULL) \ |
395 | TAILQ_NEXT((elm), field)->field.tqe_prev = \ |
396 | (elm)->field.tqe_prev; \ |
397 | else \ |
398 | (head)->tqh_last = (elm)->field.tqe_prev; \ |
399 | *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ |
400 | } while (0) |
401 | |
402 | /* |
403 | * Circular queue declarations. |
404 | */ |
405 | #define CIRCLEQ_HEAD(name, type) \ |
406 | struct name { \ |
407 | struct type *cqh_first; /* first element */ \ |
408 | struct type *cqh_last; /* last element */ \ |
409 | } |
410 | |
411 | #define CIRCLEQ_HEAD_INITIALIZER(head) \ |
412 | { (void *)&(head), (void *)&(head) } |
413 | |
414 | #define CIRCLEQ_ENTRY(type) \ |
415 | struct { \ |
416 | struct type *cqe_next; /* next element */ \ |
417 | struct type *cqe_prev; /* previous element */ \ |
418 | } |
419 | |
420 | /* |
421 | * Circular queue functions. |
422 | */ |
423 | #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) |
424 | |
425 | #define CIRCLEQ_FIRST(head) ((head)->cqh_first) |
426 | |
427 | #define CIRCLEQ_FOREACH(var, head, field) \ |
428 | for ((var) = CIRCLEQ_FIRST((head)); \ |
429 | (var) != (void *)(head); \ |
430 | (var) = CIRCLEQ_NEXT((var), field)) |
431 | |
432 | #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ |
433 | for ((var) = CIRCLEQ_LAST((head)); \ |
434 | (var) != (void *)(head); \ |
435 | (var) = CIRCLEQ_PREV((var), field)) |
436 | |
437 | #define CIRCLEQ_INIT(head) do { \ |
438 | CIRCLEQ_FIRST((head)) = (void *)(head); \ |
439 | CIRCLEQ_LAST((head)) = (void *)(head); \ |
440 | } while (0) |
441 | |
442 | #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ |
443 | CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \ |
444 | CIRCLEQ_PREV((elm), field) = (listelm); \ |
445 | if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \ |
446 | CIRCLEQ_LAST((head)) = (elm); \ |
447 | else \ |
448 | CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\ |
449 | CIRCLEQ_NEXT((listelm), field) = (elm); \ |
450 | } while (0) |
451 | |
452 | #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ |
453 | CIRCLEQ_NEXT((elm), field) = (listelm); \ |
454 | CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \ |
455 | if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \ |
456 | CIRCLEQ_FIRST((head)) = (elm); \ |
457 | else \ |
458 | CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\ |
459 | CIRCLEQ_PREV((listelm), field) = (elm); \ |
460 | } while (0) |
461 | |
462 | #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ |
463 | CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \ |
464 | CIRCLEQ_PREV((elm), field) = (void *)(head); \ |
465 | if (CIRCLEQ_LAST((head)) == (void *)(head)) \ |
466 | CIRCLEQ_LAST((head)) = (elm); \ |
467 | else \ |
468 | CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \ |
469 | CIRCLEQ_FIRST((head)) = (elm); \ |
470 | } while (0) |
471 | |
472 | #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ |
473 | CIRCLEQ_NEXT((elm), field) = (void *)(head); \ |
474 | CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \ |
475 | if (CIRCLEQ_FIRST((head)) == (void *)(head)) \ |
476 | CIRCLEQ_FIRST((head)) = (elm); \ |
477 | else \ |
478 | CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \ |
479 | CIRCLEQ_LAST((head)) = (elm); \ |
480 | } while (0) |
481 | |
482 | #define CIRCLEQ_LAST(head) ((head)->cqh_last) |
483 | |
484 | #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) |
485 | |
486 | #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) |
487 | |
488 | #define CIRCLEQ_REMOVE(head, elm, field) do { \ |
489 | if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \ |
490 | CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \ |
491 | else \ |
492 | CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \ |
493 | CIRCLEQ_PREV((elm), field); \ |
494 | if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \ |
495 | CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \ |
496 | else \ |
497 | CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \ |
498 | CIRCLEQ_NEXT((elm), field); \ |
499 | } while (0) |
500 | |
501 | #endif /* !_SYS_QUEUE_H_ */ |
502 | |