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bf5f69f7 | 1 | /* $OpenBSD: queue.h,v 1.16 2000/09/07 19:47:59 art 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. All advertising materials mentioning features or use of this software | |
17 | * must display the following acknowledgement: | |
18 | * This product includes software developed by the University of | |
19 | * California, Berkeley and its contributors. | |
20 | * 4. Neither the name of the University nor the names of its contributors | |
21 | * may be used to endorse or promote products derived from this software | |
22 | * without specific prior written permission. | |
23 | * | |
24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
34 | * SUCH DAMAGE. | |
35 | * | |
36 | * @(#)queue.h 8.5 (Berkeley) 8/20/94 | |
37 | */ | |
38 | ||
39 | #ifndef _SYS_QUEUE_H_ | |
40 | #define _SYS_QUEUE_H_ | |
41 | ||
42 | /* | |
43 | * This file defines five types of data structures: singly-linked lists, | |
44 | * lists, simple queues, tail queues, and circular queues. | |
45 | * | |
46 | * | |
47 | * A singly-linked list is headed by a single forward pointer. The elements | |
48 | * are singly linked for minimum space and pointer manipulation overhead at | |
49 | * the expense of O(n) removal for arbitrary elements. New elements can be | |
50 | * added to the list after an existing element or at the head of the list. | |
51 | * Elements being removed from the head of the list should use the explicit | |
52 | * macro for this purpose for optimum efficiency. A singly-linked list may | |
53 | * only be traversed in the forward direction. Singly-linked lists are ideal | |
54 | * for applications with large datasets and few or no removals or for | |
55 | * implementing a LIFO queue. | |
56 | * | |
57 | * A list is headed by a single forward pointer (or an array of forward | |
58 | * pointers for a hash table header). The elements are doubly linked | |
59 | * so that an arbitrary element can be removed without a need to | |
60 | * traverse the list. New elements can be added to the list before | |
61 | * or after an existing element or at the head of the list. A list | |
62 | * may only be traversed in the forward direction. | |
63 | * | |
64 | * A simple queue is headed by a pair of pointers, one the head of the | |
65 | * list and the other to the tail of the list. The elements are singly | |
66 | * linked to save space, so elements can only be removed from the | |
67 | * head of the list. New elements can be added to the list before or after | |
68 | * an existing element, at the head of the list, or at the end of the | |
69 | * list. A simple queue may only be traversed in the forward direction. | |
70 | * | |
71 | * A tail queue is headed by a pair of pointers, one to the head of the | |
72 | * list and the other to the tail of the list. The elements are doubly | |
73 | * linked so that an arbitrary element can be removed without a need to | |
74 | * traverse the list. New elements can be added to the list before or | |
75 | * after an existing element, at the head of the list, or at the end of | |
76 | * the list. A tail queue may be traversed in either direction. | |
77 | * | |
78 | * A circle queue is headed by a pair of pointers, one to the head of the | |
79 | * list and the other to the tail of the list. The elements are doubly | |
80 | * linked so that an arbitrary element can be removed without a need to | |
81 | * traverse the list. New elements can be added to the list before or after | |
82 | * an existing element, at the head of the list, or at the end of the list. | |
83 | * A circle queue may be traversed in either direction, but has a more | |
84 | * complex end of list detection. | |
85 | * | |
86 | * For details on the use of these macros, see the queue(3) manual page. | |
87 | */ | |
88 | ||
89 | /* | |
90 | * Singly-linked List definitions. | |
91 | */ | |
92 | #define SLIST_HEAD(name, type) \ | |
93 | struct name { \ | |
94 | struct type *slh_first; /* first element */ \ | |
95 | } | |
96 | ||
97 | #define SLIST_HEAD_INITIALIZER(head) \ | |
98 | { NULL } | |
99 | ||
100 | #define SLIST_ENTRY(type) \ | |
101 | struct { \ | |
102 | struct type *sle_next; /* next element */ \ | |
103 | } | |
104 | ||
105 | /* | |
106 | * Singly-linked List access methods. | |
107 | */ | |
108 | #define SLIST_FIRST(head) ((head)->slh_first) | |
109 | #define SLIST_END(head) NULL | |
110 | #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) | |
111 | #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) | |
112 | ||
113 | #define SLIST_FOREACH(var, head, field) \ | |
114 | for((var) = SLIST_FIRST(head); \ | |
115 | (var) != SLIST_END(head); \ | |
116 | (var) = SLIST_NEXT(var, field)) | |
117 | ||
118 | /* | |
119 | * Singly-linked List functions. | |
120 | */ | |
121 | #define SLIST_INIT(head) { \ | |
122 | SLIST_FIRST(head) = SLIST_END(head); \ | |
123 | } | |
124 | ||
125 | #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ | |
126 | (elm)->field.sle_next = (slistelm)->field.sle_next; \ | |
127 | (slistelm)->field.sle_next = (elm); \ | |
128 | } while (0) | |
129 | ||
130 | #define SLIST_INSERT_HEAD(head, elm, field) do { \ | |
131 | (elm)->field.sle_next = (head)->slh_first; \ | |
132 | (head)->slh_first = (elm); \ | |
133 | } while (0) | |
134 | ||
135 | #define SLIST_REMOVE_HEAD(head, field) do { \ | |
136 | (head)->slh_first = (head)->slh_first->field.sle_next; \ | |
137 | } while (0) | |
138 | ||
139 | /* | |
140 | * List definitions. | |
141 | */ | |
142 | #define LIST_HEAD(name, type) \ | |
143 | struct name { \ | |
144 | struct type *lh_first; /* first element */ \ | |
145 | } | |
146 | ||
147 | #define LIST_HEAD_INITIALIZER(head) \ | |
148 | { NULL } | |
149 | ||
150 | #define LIST_ENTRY(type) \ | |
151 | struct { \ | |
152 | struct type *le_next; /* next element */ \ | |
153 | struct type **le_prev; /* address of previous next element */ \ | |
154 | } | |
155 | ||
156 | /* | |
157 | * List access methods | |
158 | */ | |
159 | #define LIST_FIRST(head) ((head)->lh_first) | |
160 | #define LIST_END(head) NULL | |
161 | #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) | |
162 | #define LIST_NEXT(elm, field) ((elm)->field.le_next) | |
163 | ||
164 | #define LIST_FOREACH(var, head, field) \ | |
165 | for((var) = LIST_FIRST(head); \ | |
166 | (var)!= LIST_END(head); \ | |
167 | (var) = LIST_NEXT(var, field)) | |
168 | ||
169 | /* | |
170 | * List functions. | |
171 | */ | |
172 | #define LIST_INIT(head) do { \ | |
173 | LIST_FIRST(head) = LIST_END(head); \ | |
174 | } while (0) | |
175 | ||
176 | #define LIST_INSERT_AFTER(listelm, elm, field) do { \ | |
177 | if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ | |
178 | (listelm)->field.le_next->field.le_prev = \ | |
179 | &(elm)->field.le_next; \ | |
180 | (listelm)->field.le_next = (elm); \ | |
181 | (elm)->field.le_prev = &(listelm)->field.le_next; \ | |
182 | } while (0) | |
183 | ||
184 | #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ | |
185 | (elm)->field.le_prev = (listelm)->field.le_prev; \ | |
186 | (elm)->field.le_next = (listelm); \ | |
187 | *(listelm)->field.le_prev = (elm); \ | |
188 | (listelm)->field.le_prev = &(elm)->field.le_next; \ | |
189 | } while (0) | |
190 | ||
191 | #define LIST_INSERT_HEAD(head, elm, field) do { \ | |
192 | if (((elm)->field.le_next = (head)->lh_first) != NULL) \ | |
193 | (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ | |
194 | (head)->lh_first = (elm); \ | |
195 | (elm)->field.le_prev = &(head)->lh_first; \ | |
196 | } while (0) | |
197 | ||
198 | #define LIST_REMOVE(elm, field) do { \ | |
199 | if ((elm)->field.le_next != NULL) \ | |
200 | (elm)->field.le_next->field.le_prev = \ | |
201 | (elm)->field.le_prev; \ | |
202 | *(elm)->field.le_prev = (elm)->field.le_next; \ | |
203 | } while (0) | |
204 | ||
205 | #define LIST_REPLACE(elm, elm2, field) do { \ | |
206 | if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ | |
207 | (elm2)->field.le_next->field.le_prev = \ | |
208 | &(elm2)->field.le_next; \ | |
209 | (elm2)->field.le_prev = (elm)->field.le_prev; \ | |
210 | *(elm2)->field.le_prev = (elm2); \ | |
211 | } while (0) | |
212 | ||
213 | /* | |
214 | * Simple queue definitions. | |
215 | */ | |
216 | #define SIMPLEQ_HEAD(name, type) \ | |
217 | struct name { \ | |
218 | struct type *sqh_first; /* first element */ \ | |
219 | struct type **sqh_last; /* addr of last next element */ \ | |
220 | } | |
221 | ||
222 | #define SIMPLEQ_HEAD_INITIALIZER(head) \ | |
223 | { NULL, &(head).sqh_first } | |
224 | ||
225 | #define SIMPLEQ_ENTRY(type) \ | |
226 | struct { \ | |
227 | struct type *sqe_next; /* next element */ \ | |
228 | } | |
229 | ||
230 | /* | |
231 | * Simple queue access methods. | |
232 | */ | |
233 | #define SIMPLEQ_FIRST(head) ((head)->sqh_first) | |
234 | #define SIMPLEQ_END(head) NULL | |
235 | #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) | |
236 | #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) | |
237 | ||
238 | #define SIMPLEQ_FOREACH(var, head, field) \ | |
239 | for((var) = SIMPLEQ_FIRST(head); \ | |
240 | (var) != SIMPLEQ_END(head); \ | |
241 | (var) = SIMPLEQ_NEXT(var, field)) | |
242 | ||
243 | /* | |
244 | * Simple queue functions. | |
245 | */ | |
246 | #define SIMPLEQ_INIT(head) do { \ | |
247 | (head)->sqh_first = NULL; \ | |
248 | (head)->sqh_last = &(head)->sqh_first; \ | |
249 | } while (0) | |
250 | ||
251 | #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ | |
252 | if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ | |
253 | (head)->sqh_last = &(elm)->field.sqe_next; \ | |
254 | (head)->sqh_first = (elm); \ | |
255 | } while (0) | |
256 | ||
257 | #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ | |
258 | (elm)->field.sqe_next = NULL; \ | |
259 | *(head)->sqh_last = (elm); \ | |
260 | (head)->sqh_last = &(elm)->field.sqe_next; \ | |
261 | } while (0) | |
262 | ||
263 | #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ | |
264 | if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ | |
265 | (head)->sqh_last = &(elm)->field.sqe_next; \ | |
266 | (listelm)->field.sqe_next = (elm); \ | |
267 | } while (0) | |
268 | ||
269 | #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \ | |
270 | if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \ | |
271 | (head)->sqh_last = &(head)->sqh_first; \ | |
272 | } while (0) | |
273 | ||
274 | /* | |
275 | * Tail queue definitions. | |
276 | */ | |
277 | #define TAILQ_HEAD(name, type) \ | |
278 | struct name { \ | |
279 | struct type *tqh_first; /* first element */ \ | |
280 | struct type **tqh_last; /* addr of last next element */ \ | |
281 | } | |
282 | ||
283 | #define TAILQ_HEAD_INITIALIZER(head) \ | |
284 | { NULL, &(head).tqh_first } | |
285 | ||
286 | #define TAILQ_ENTRY(type) \ | |
287 | struct { \ | |
288 | struct type *tqe_next; /* next element */ \ | |
289 | struct type **tqe_prev; /* address of previous next element */ \ | |
290 | } | |
291 | ||
292 | /* | |
293 | * tail queue access methods | |
294 | */ | |
295 | #define TAILQ_FIRST(head) ((head)->tqh_first) | |
296 | #define TAILQ_END(head) NULL | |
297 | #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) | |
298 | #define TAILQ_LAST(head, headname) \ | |
299 | (*(((struct headname *)((head)->tqh_last))->tqh_last)) | |
300 | /* XXX */ | |
301 | #define TAILQ_PREV(elm, headname, field) \ | |
302 | (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) | |
303 | #define TAILQ_EMPTY(head) \ | |
304 | (TAILQ_FIRST(head) == TAILQ_END(head)) | |
305 | ||
306 | #define TAILQ_FOREACH(var, head, field) \ | |
307 | for((var) = TAILQ_FIRST(head); \ | |
308 | (var) != TAILQ_END(head); \ | |
309 | (var) = TAILQ_NEXT(var, field)) | |
310 | ||
311 | #define TAILQ_FOREACH_REVERSE(var, head, field, headname) \ | |
312 | for((var) = TAILQ_LAST(head, headname); \ | |
313 | (var) != TAILQ_END(head); \ | |
314 | (var) = TAILQ_PREV(var, headname, field)) | |
315 | ||
316 | /* | |
317 | * Tail queue functions. | |
318 | */ | |
319 | #define TAILQ_INIT(head) do { \ | |
320 | (head)->tqh_first = NULL; \ | |
321 | (head)->tqh_last = &(head)->tqh_first; \ | |
322 | } while (0) | |
323 | ||
324 | #define TAILQ_INSERT_HEAD(head, elm, field) do { \ | |
325 | if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ | |
326 | (head)->tqh_first->field.tqe_prev = \ | |
327 | &(elm)->field.tqe_next; \ | |
328 | else \ | |
329 | (head)->tqh_last = &(elm)->field.tqe_next; \ | |
330 | (head)->tqh_first = (elm); \ | |
331 | (elm)->field.tqe_prev = &(head)->tqh_first; \ | |
332 | } while (0) | |
333 | ||
334 | #define TAILQ_INSERT_TAIL(head, elm, field) do { \ | |
335 | (elm)->field.tqe_next = NULL; \ | |
336 | (elm)->field.tqe_prev = (head)->tqh_last; \ | |
337 | *(head)->tqh_last = (elm); \ | |
338 | (head)->tqh_last = &(elm)->field.tqe_next; \ | |
339 | } while (0) | |
340 | ||
341 | #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ | |
342 | if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ | |
343 | (elm)->field.tqe_next->field.tqe_prev = \ | |
344 | &(elm)->field.tqe_next; \ | |
345 | else \ | |
346 | (head)->tqh_last = &(elm)->field.tqe_next; \ | |
347 | (listelm)->field.tqe_next = (elm); \ | |
348 | (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ | |
349 | } while (0) | |
350 | ||
351 | #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ | |
352 | (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ | |
353 | (elm)->field.tqe_next = (listelm); \ | |
354 | *(listelm)->field.tqe_prev = (elm); \ | |
355 | (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ | |
356 | } while (0) | |
357 | ||
358 | #define TAILQ_REMOVE(head, elm, field) do { \ | |
359 | if (((elm)->field.tqe_next) != NULL) \ | |
360 | (elm)->field.tqe_next->field.tqe_prev = \ | |
361 | (elm)->field.tqe_prev; \ | |
362 | else \ | |
363 | (head)->tqh_last = (elm)->field.tqe_prev; \ | |
364 | *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ | |
365 | } while (0) | |
366 | ||
367 | #define TAILQ_REPLACE(head, elm, elm2, field) do { \ | |
368 | if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ | |
369 | (elm2)->field.tqe_next->field.tqe_prev = \ | |
370 | &(elm2)->field.tqe_next; \ | |
371 | else \ | |
372 | (head)->tqh_last = &(elm2)->field.tqe_next; \ | |
373 | (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ | |
374 | *(elm2)->field.tqe_prev = (elm2); \ | |
375 | } while (0) | |
376 | ||
377 | /* | |
378 | * Circular queue definitions. | |
379 | */ | |
380 | #define CIRCLEQ_HEAD(name, type) \ | |
381 | struct name { \ | |
382 | struct type *cqh_first; /* first element */ \ | |
383 | struct type *cqh_last; /* last element */ \ | |
384 | } | |
385 | ||
386 | #define CIRCLEQ_HEAD_INITIALIZER(head) \ | |
387 | { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } | |
388 | ||
389 | #define CIRCLEQ_ENTRY(type) \ | |
390 | struct { \ | |
391 | struct type *cqe_next; /* next element */ \ | |
392 | struct type *cqe_prev; /* previous element */ \ | |
393 | } | |
394 | ||
395 | /* | |
396 | * Circular queue access methods | |
397 | */ | |
398 | #define CIRCLEQ_FIRST(head) ((head)->cqh_first) | |
399 | #define CIRCLEQ_LAST(head) ((head)->cqh_last) | |
400 | #define CIRCLEQ_END(head) ((void *)(head)) | |
401 | #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) | |
402 | #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) | |
403 | #define CIRCLEQ_EMPTY(head) \ | |
404 | (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) | |
405 | ||
406 | #define CIRCLEQ_FOREACH(var, head, field) \ | |
407 | for((var) = CIRCLEQ_FIRST(head); \ | |
408 | (var) != CIRCLEQ_END(head); \ | |
409 | (var) = CIRCLEQ_NEXT(var, field)) | |
410 | ||
411 | #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ | |
412 | for((var) = CIRCLEQ_LAST(head); \ | |
413 | (var) != CIRCLEQ_END(head); \ | |
414 | (var) = CIRCLEQ_PREV(var, field)) | |
415 | ||
416 | /* | |
417 | * Circular queue functions. | |
418 | */ | |
419 | #define CIRCLEQ_INIT(head) do { \ | |
420 | (head)->cqh_first = CIRCLEQ_END(head); \ | |
421 | (head)->cqh_last = CIRCLEQ_END(head); \ | |
422 | } while (0) | |
423 | ||
424 | #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ | |
425 | (elm)->field.cqe_next = (listelm)->field.cqe_next; \ | |
426 | (elm)->field.cqe_prev = (listelm); \ | |
427 | if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ | |
428 | (head)->cqh_last = (elm); \ | |
429 | else \ | |
430 | (listelm)->field.cqe_next->field.cqe_prev = (elm); \ | |
431 | (listelm)->field.cqe_next = (elm); \ | |
432 | } while (0) | |
433 | ||
434 | #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ | |
435 | (elm)->field.cqe_next = (listelm); \ | |
436 | (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ | |
437 | if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ | |
438 | (head)->cqh_first = (elm); \ | |
439 | else \ | |
440 | (listelm)->field.cqe_prev->field.cqe_next = (elm); \ | |
441 | (listelm)->field.cqe_prev = (elm); \ | |
442 | } while (0) | |
443 | ||
444 | #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ | |
445 | (elm)->field.cqe_next = (head)->cqh_first; \ | |
446 | (elm)->field.cqe_prev = CIRCLEQ_END(head); \ | |
447 | if ((head)->cqh_last == CIRCLEQ_END(head)) \ | |
448 | (head)->cqh_last = (elm); \ | |
449 | else \ | |
450 | (head)->cqh_first->field.cqe_prev = (elm); \ | |
451 | (head)->cqh_first = (elm); \ | |
452 | } while (0) | |
453 | ||
454 | #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ | |
455 | (elm)->field.cqe_next = CIRCLEQ_END(head); \ | |
456 | (elm)->field.cqe_prev = (head)->cqh_last; \ | |
457 | if ((head)->cqh_first == CIRCLEQ_END(head)) \ | |
458 | (head)->cqh_first = (elm); \ | |
459 | else \ | |
460 | (head)->cqh_last->field.cqe_next = (elm); \ | |
461 | (head)->cqh_last = (elm); \ | |
462 | } while (0) | |
463 | ||
464 | #define CIRCLEQ_REMOVE(head, elm, field) do { \ | |
465 | if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ | |
466 | (head)->cqh_last = (elm)->field.cqe_prev; \ | |
467 | else \ | |
468 | (elm)->field.cqe_next->field.cqe_prev = \ | |
469 | (elm)->field.cqe_prev; \ | |
470 | if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ | |
471 | (head)->cqh_first = (elm)->field.cqe_next; \ | |
472 | else \ | |
473 | (elm)->field.cqe_prev->field.cqe_next = \ | |
474 | (elm)->field.cqe_next; \ | |
475 | } while (0) | |
476 | ||
477 | #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ | |
478 | if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ | |
479 | CIRCLEQ_END(head)) \ | |
480 | (head).cqh_last = (elm2); \ | |
481 | else \ | |
482 | (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ | |
483 | if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ | |
484 | CIRCLEQ_END(head)) \ | |
485 | (head).cqh_first = (elm2); \ | |
486 | else \ | |
487 | (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ | |
488 | } while (0) | |
489 | ||
490 | #endif /* !_SYS_QUEUE_H_ */ |