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This source file includes following definitions.
- insque
- remque
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 * $FreeBSD: src/sys/sys/queue.h,v 1.32.2.4 2001/03/31 03:33:39 hsu Exp $
31 */
32
33 #ifndef _SYS_QUEUE_H_
34 #define _SYS_QUEUE_H_
35
36 /* #include <machine/ansi.h>*/ /* for __offsetof */
37
38 /**
39 * @file
40 * This file defines five types of data structures: singly-linked lists,
41 * singly-linked tail queues, lists, tail queues, and circular queues.
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 @CODE{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 singly-linked tail queue is headed by a pair of pointers, one to the
54 * head of the list and the other to the tail of the list. The elements are
55 * singly linked for minimum space and pointer manipulation overhead at the
56 * expense of @CODE{O(n)} removal for arbitrary elements. New elements can be added
57 * to the list after an existing element, at the head of the list, or at the
58 * end of the list. Elements being removed from the head of the tail queue
59 * should use the explicit macro for this purpose for optimum efficiency.
60 * A singly-linked tail queue may only be traversed in the forward direction.
61 * Singly-linked tail queues are ideal for applications with large datasets
62 * and few or no removals or for implementing a FIFO queue.
63 *
64 * A list is headed by a single forward pointer (or an array of forward
65 * pointers for a hash table header). The elements are doubly linked
66 * so that an arbitrary element can be removed without a need to
67 * traverse the list. New elements can be added to the list before
68 * or after an existing element or at the head of the list. A list
69 * 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 @XREF{queue,3} manual page.
87 *
88 * @code{.txt}
89 * SLIST LIST STAILQ TAILQ CIRCLEQ
90 * _HEAD + + + + +
91 * _ENTRY + + + + +
92 * _INIT + + + + +
93 * _EMPTY + + + + +
94 * _FIRST + + + + +
95 * _NEXT + + + + +
96 * _PREV - - - + +
97 * _LAST - - + + +
98 * _FOREACH + + + + +
99 * _FOREACH_REVERSE - - - + +
100 * _INSERT_HEAD + + + + +
101 * _INSERT_BEFORE - + - + +
102 * _INSERT_AFTER + + + + +
103 * _INSERT_TAIL - - + + +
104 * _REMOVE_HEAD + - + - -
105 * _REMOVE + + + + +
106 * @endcode
107 */
108
109 /**
110 * Singly-linked List definitions.
111 */
112 /** @{ */
113 #define SLIST_HEAD(name, type) \
114 struct name { \
115 struct type *slh_first; /**< first element */ \
116 }
117
118 #define SLIST_HEAD_INITIALIZER(head) \
119 { NULL }
120
121 #define SLIST_ENTRY(type) \
122 struct { \
123 struct type *sle_next; /**< next element */ \
124 }
125 /** @} */
126
127 /**
128 * Singly-linked List functions.
129 */
130 /** @{ */
131 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
132
133 #define SLIST_FIRST(head) ((head)->slh_first)
134
135 #define SLIST_FOREACH(var, head, field) \
136 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
137
138 #define SLIST_INIT(head) { \
139 (head)->slh_first = NULL; \
140 }
141
142 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
143 (elm)->field.sle_next = (slistelm)->field.sle_next; \
144 (slistelm)->field.sle_next = (elm); \
145 } while (0)
146
147 #define SLIST_INSERT_HEAD(head, elm, field) do { \
148 (elm)->field.sle_next = (head)->slh_first; \
149 (head)->slh_first = (elm); \
150 } while (0)
151
152 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
153
154 #define SLIST_REMOVE_HEAD(head, field) do { \
155 (head)->slh_first = (head)->slh_first->field.sle_next; \
156 } while (0)
157
158 #define SLIST_REMOVE(head, elm, type, field) do { \
159 if ((head)->slh_first == (elm)) { \
160 SLIST_REMOVE_HEAD((head), field); \
161 } \
162 else { \
163 struct type *curelm = (head)->slh_first; \
164 while( curelm->field.sle_next != (elm) ) \
165 curelm = curelm->field.sle_next; \
166 curelm->field.sle_next = \
167 curelm->field.sle_next->field.sle_next; \
168 } \
169 } while (0)
170 /** @} */
171
172 /**
173 * Singly-linked Tail queue definitions.
174 */
175 /** @{ */
176 #define STAILQ_HEAD(name, type) \
177 struct name { \
178 struct type *stqh_first;/**< first element */ \
179 struct type **stqh_last;/**< addr of last next element */ \
180 }
181
182 #define STAILQ_HEAD_INITIALIZER(head) \
183 { NULL, &(head).stqh_first }
184
185 #define STAILQ_ENTRY(type) \
186 struct { \
187 struct type *stqe_next; /**< next element */ \
188 }
189 /** @} */
190
191 /**
192 * Singly-linked Tail queue functions.
193 */
194 /** @{ */
195 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
196
197 #define STAILQ_INIT(head) do { \
198 (head)->stqh_first = NULL; \
199 (head)->stqh_last = &(head)->stqh_first; \
200 } while (0)
201
202 #define STAILQ_FIRST(head) ((head)->stqh_first)
203
204 #define STAILQ_LAST(head, type, field) \
205 (STAILQ_EMPTY(head) ? \
206 NULL : \
207 ((struct type *) \
208 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
209
210 #define STAILQ_FOREACH(var, head, field) \
211 for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next)
212
213 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
214 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \
215 (head)->stqh_last = &(elm)->field.stqe_next; \
216 (head)->stqh_first = (elm); \
217 } while (0)
218
219 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
220 (elm)->field.stqe_next = NULL; \
221 *(head)->stqh_last = (elm); \
222 (head)->stqh_last = &(elm)->field.stqe_next; \
223 } while (0)
224
225 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
226 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
227 (head)->stqh_last = &(elm)->field.stqe_next; \
228 (tqelm)->field.stqe_next = (elm); \
229 } while (0)
230
231 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
232
233 #define STAILQ_REMOVE_HEAD(head, field) do { \
234 if (((head)->stqh_first = \
235 (head)->stqh_first->field.stqe_next) == NULL) \
236 (head)->stqh_last = &(head)->stqh_first; \
237 } while (0)
238
239 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
240 if (((head)->stqh_first = (elm)->field.stqe_next) == NULL) \
241 (head)->stqh_last = &(head)->stqh_first; \
242 } while (0)
243
244 #define STAILQ_REMOVE(head, elm, type, field) do { \
245 if ((head)->stqh_first == (elm)) { \
246 STAILQ_REMOVE_HEAD(head, field); \
247 } \
248 else { \
249 struct type *curelm = (head)->stqh_first; \
250 while( curelm->field.stqe_next != (elm) ) \
251 curelm = curelm->field.stqe_next; \
252 if((curelm->field.stqe_next = \
253 curelm->field.stqe_next->field.stqe_next) == NULL) \
254 (head)->stqh_last = &(curelm)->field.stqe_next; \
255 } \
256 } while (0)
257 /** @} */
258
259 /**
260 * List definitions.
261 */
262 /** @{ */
263 #define LIST_HEAD(name, type) \
264 struct name { \
265 struct type *lh_first; /**< first element */ \
266 }
267
268 #define LIST_HEAD_INITIALIZER(head) \
269 { NULL }
270
271 #define LIST_ENTRY(type) \
272 struct { \
273 struct type *le_next; /**< next element */ \
274 struct type **le_prev; /**< address of previous next element */ \
275 }
276 /** @} */
277
278 /**
279 * List functions.
280 */
281 /** @{ */
282 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
283
284 #define LIST_FIRST(head) ((head)->lh_first)
285
286 #define LIST_FOREACH(var, head, field) \
287 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)
288
289 #define LIST_INIT(head) do { \
290 (head)->lh_first = NULL; \
291 } while (0)
292
293 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
294 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
295 (listelm)->field.le_next->field.le_prev = \
296 &(elm)->field.le_next; \
297 (listelm)->field.le_next = (elm); \
298 (elm)->field.le_prev = &(listelm)->field.le_next; \
299 } while (0)
300
301 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
302 (elm)->field.le_prev = (listelm)->field.le_prev; \
303 (elm)->field.le_next = (listelm); \
304 *(listelm)->field.le_prev = (elm); \
305 (listelm)->field.le_prev = &(elm)->field.le_next; \
306 } while (0)
307
308 #define LIST_INSERT_HEAD(head, elm, field) do { \
309 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
310 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
311 (head)->lh_first = (elm); \
312 (elm)->field.le_prev = &(head)->lh_first; \
313 } while (0)
314
315 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
316
317 #define LIST_REMOVE(elm, field) do { \
318 if ((elm)->field.le_next != NULL) \
319 (elm)->field.le_next->field.le_prev = \
320 (elm)->field.le_prev; \
321 *(elm)->field.le_prev = (elm)->field.le_next; \
322 } while (0)
323 /** @} */
324
325 /**
326 * Tail queue definitions.
327 */
328 /** @{ */
329 #define TAILQ_HEAD(name, type) \
330 struct name { \
331 struct type *tqh_first; /**< first element */ \
332 struct type **tqh_last; /**< addr of last next element */ \
333 }
334
335 #define TAILQ_HEAD_INITIALIZER(head) \
336 { NULL, &(head).tqh_first }
337
338 #define TAILQ_ENTRY(type) \
339 struct { \
340 struct type *tqe_next; /**< next element */ \
341 struct type **tqe_prev; /**< address of previous next element */ \
342 }
343 /** @} */
344
345 /**
346 * Tail queue functions.
347 */
348 /** @{ */
349 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
350
351 #define TAILQ_FOREACH(var, head, field) \
352 for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field))
353
354 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
355 for ((var) = TAILQ_LAST((head), headname); \
356 (var); \
357 (var) = TAILQ_PREV((var), headname, field))
358
359 #define TAILQ_FIRST(head) ((head)->tqh_first)
360
361 #define TAILQ_LAST(head, headname) \
362 (*(((struct headname *)((head)->tqh_last))->tqh_last))
363
364 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
365
366 #define TAILQ_PREV(elm, headname, field) \
367 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
368
369 #define TAILQ_INIT(head) do { \
370 (head)->tqh_first = NULL; \
371 (head)->tqh_last = &(head)->tqh_first; \
372 } while (0)
373
374 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
375 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
376 (head)->tqh_first->field.tqe_prev = \
377 &(elm)->field.tqe_next; \
378 else \
379 (head)->tqh_last = &(elm)->field.tqe_next; \
380 (head)->tqh_first = (elm); \
381 (elm)->field.tqe_prev = &(head)->tqh_first; \
382 } while (0)
383
384 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
385 (elm)->field.tqe_next = NULL; \
386 (elm)->field.tqe_prev = (head)->tqh_last; \
387 *(head)->tqh_last = (elm); \
388 (head)->tqh_last = &(elm)->field.tqe_next; \
389 } while (0)
390
391 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
392 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
393 (elm)->field.tqe_next->field.tqe_prev = \
394 &(elm)->field.tqe_next; \
395 else \
396 (head)->tqh_last = &(elm)->field.tqe_next; \
397 (listelm)->field.tqe_next = (elm); \
398 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
399 } while (0)
400
401 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
402 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
403 (elm)->field.tqe_next = (listelm); \
404 *(listelm)->field.tqe_prev = (elm); \
405 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
406 } while (0)
407
408 #define TAILQ_REMOVE(head, elm, field) do { \
409 if (((elm)->field.tqe_next) != NULL) \
410 (elm)->field.tqe_next->field.tqe_prev = \
411 (elm)->field.tqe_prev; \
412 else \
413 (head)->tqh_last = (elm)->field.tqe_prev; \
414 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
415 } while (0)
416 /** @} */
417
418 /**
419 * Circular queue definitions.
420 */
421 /** @{ */
422 #define CIRCLEQ_HEAD(name, type) \
423 struct name { \
424 struct type *cqh_first; /**< first element */ \
425 struct type *cqh_last; /**< last element */ \
426 }
427
428 #define CIRCLEQ_ENTRY(type) \
429 struct { \
430 struct type *cqe_next; /**< next element */ \
431 struct type *cqe_prev; /**< previous element */ \
432 }
433 /** @} */
434
435 /**
436 * Circular queue functions.
437 */
438 /** @{ */
439 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
440
441 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
442
443 #define CIRCLEQ_FOREACH(var, head, field) \
444 for((var) = (head)->cqh_first; \
445 (var) != (void *)(head); \
446 (var) = (var)->field.cqe_next)
447
448 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
449 for((var) = (head)->cqh_last; \
450 (var) != (void *)(head); \
451 (var) = (var)->field.cqe_prev)
452
453 #define CIRCLEQ_INIT(head) do { \
454 (head)->cqh_first = (void *)(head); \
455 (head)->cqh_last = (void *)(head); \
456 } while (0)
457
458 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
459 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
460 (elm)->field.cqe_prev = (listelm); \
461 if ((listelm)->field.cqe_next == (void *)(head)) \
462 (head)->cqh_last = (elm); \
463 else \
464 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
465 (listelm)->field.cqe_next = (elm); \
466 } while (0)
467
468 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
469 (elm)->field.cqe_next = (listelm); \
470 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
471 if ((listelm)->field.cqe_prev == (void *)(head)) \
472 (head)->cqh_first = (elm); \
473 else \
474 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
475 (listelm)->field.cqe_prev = (elm); \
476 } while (0)
477
478 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
479 (elm)->field.cqe_next = (head)->cqh_first; \
480 (elm)->field.cqe_prev = (void *)(head); \
481 if ((head)->cqh_last == (void *)(head)) \
482 (head)->cqh_last = (elm); \
483 else \
484 (head)->cqh_first->field.cqe_prev = (elm); \
485 (head)->cqh_first = (elm); \
486 } while (0)
487
488 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
489 (elm)->field.cqe_next = (void *)(head); \
490 (elm)->field.cqe_prev = (head)->cqh_last; \
491 if ((head)->cqh_first == (void *)(head)) \
492 (head)->cqh_first = (elm); \
493 else \
494 (head)->cqh_last->field.cqe_next = (elm); \
495 (head)->cqh_last = (elm); \
496 } while (0)
497
498 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
499
500 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
501
502 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
503
504 #define CIRCLEQ_REMOVE(head, elm, field) do { \
505 if ((elm)->field.cqe_next == (void *)(head)) \
506 (head)->cqh_last = (elm)->field.cqe_prev; \
507 else \
508 (elm)->field.cqe_next->field.cqe_prev = \
509 (elm)->field.cqe_prev; \
510 if ((elm)->field.cqe_prev == (void *)(head)) \
511 (head)->cqh_first = (elm)->field.cqe_next; \
512 else \
513 (elm)->field.cqe_prev->field.cqe_next = \
514 (elm)->field.cqe_next; \
515 } while (0)
516 /** @} */
517
518 #ifdef _KERNEL
519
520 /*
521 * @par XXX
522 * @NAME{insque()} and @NAME{remque()} are an old way of handling certain queues.
523 * They bogusly assumes that all queue heads look alike.
524 */
525
526 struct quehead {
527 struct quehead *qh_link;
528 struct quehead *qh_rlink;
529 };
530
531 #ifdef __GNUC__
532
533 static __inline void
534 insque(void *a, void *b)
535 {
536 struct quehead *element = a, *head = b;
537
538 element->qh_link = head->qh_link;
539 element->qh_rlink = head;
540 head->qh_link = element;
541 element->qh_link->qh_rlink = element;
542 }
543
544 static __inline void
545 remque(void *a)
546 {
547 struct quehead *element = a;
548
549 element->qh_link->qh_rlink = element->qh_rlink;
550 element->qh_rlink->qh_link = element->qh_link;
551 element->qh_rlink = 0;
552 }
553
554 #else /* !__GNUC__ */
555
556 void insque __P((void *a, void *b));
557 void remque __P((void *a));
558
559 #endif /* __GNUC__ */
560
561 #endif /* _KERNEL */
562
563 #endif /* !_SYS_QUEUE_H_ */
/* ![[top]](../icons/top.png)
![[bottom]](../icons/n_bottom.png)
*/