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queue.h
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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. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)queue.h 8.5 (Berkeley) 8/20/94
34 * $FreeBSD: src/sys/sys/queue.h,v 1.24.2.4 2000/05/05 01:41:41 archie Exp $
35 */
36
37#ifndef _SYS_QUEUE_H_
38#define _SYS_QUEUE_H_
39
40/*
41 * This file defines five types of data structures: singly-linked lists,
42 * singly-linked tail queues, lists, tail queues, and circular queues.
43 *
44 * A singly-linked list is headed by a single forward pointer. The elements
45 * are singly linked for minimum space and pointer manipulation overhead at
46 * the expense of O(n) removal for arbitrary elements. New elements can be
47 * added to the list after an existing element or at the head of the list.
48 * Elements being removed from the head of the list should use the explicit
49 * macro for this purpose for optimum efficiency. A singly-linked list may
50 * only be traversed in the forward direction. Singly-linked lists are ideal
51 * for applications with large datasets and few or no removals or for
52 * implementing a LIFO queue.
53 *
54 * A singly-linked tail queue is headed by a pair of pointers, one to the
55 * head of the list and the other to the tail of the list. The elements are
56 * singly linked for minimum space and pointer manipulation overhead at the
57 * expense of O(n) removal for arbitrary elements. New elements can be added
58 * to the list after an existing element, at the head of the list, or at the
59 * end of the list. Elements being removed from the head of the tail queue
60 * should use the explicit macro for this purpose for optimum efficiency.
61 * A singly-linked tail queue may only be traversed in the forward direction.
62 * Singly-linked tail queues are ideal for applications with large datasets
63 * and few or no removals or for implementing a FIFO queue.
64 *
65 * A list is headed by a single forward pointer (or an array of forward
66 * pointers for a hash table header). The elements are doubly linked
67 * 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
69 * or after an existing element or at the head of the list. A list
70 * may only be traversed in the forward direction.
71 *
72 * A tail 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
76 * after an existing element, at the head of the list, or at the end of
77 * the list. A tail queue may be traversed in either direction.
78 *
79 * A circle queue is headed by a pair of pointers, one to the head of the
80 * list and the other to the tail of the list. The elements are doubly
81 * linked so that an arbitrary element can be removed without a need to
82 * traverse the list. New elements can be added to the list before or after
83 * an existing element, at the head of the list, or at the end of the list.
84 * A circle queue may be traversed in either direction, but has a more
85 * complex end of list detection.
86 *
87 * For details on the use of these macros, see the queue(3) manual page.
88 *
89 *
90 * SLIST LIST STAILQ TAILQ CIRCLEQ
91 * _HEAD + + + + +
92 * _ENTRY + + + + +
93 * _INIT + + + + +
94 * _EMPTY + + + + +
95 * _FIRST + + + + +
96 * _NEXT + + + + +
97 * _PREV - - - + +
98 * _LAST - - + + +
99 * _FOREACH + + + + +
100 * _FOREACH_REVERSE - - - + +
101 * _INSERT_HEAD + + + + +
102 * _INSERT_BEFORE - + - + +
103 * _INSERT_AFTER + + + + +
104 * _INSERT_TAIL - - + + +
105 * _REMOVE_HEAD + - + - -
106 * _REMOVE + + + + +
107 *
108 */
109
110/*
111 * Singly-linked List definitions.
112 */
113#define SLIST_HEAD(name, type) \
114struct name { \
115 struct type *slh_first; /* first element */ \
116}
117
118#define SLIST_HEAD_INITIALIZER(head) \
119 { NULL }
120
121#define SLIST_ENTRY(type) \
122struct { \
123 struct type *sle_next; /* next element */ \
124}
125
126/*
127 * Singly-linked List functions.
128 */
129#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
130
131#define SLIST_FIRST(head) ((head)->slh_first)
132
133#define SLIST_FOREACH(var, head, field) \
134 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
135
136#define SLIST_INIT(head) { \
137 (head)->slh_first = NULL; \
138}
139
140#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
141 (elm)->field.sle_next = (slistelm)->field.sle_next; \
142 (slistelm)->field.sle_next = (elm); \
143} while (0)
144
145#define SLIST_INSERT_HEAD(head, elm, field) do { \
146 (elm)->field.sle_next = (head)->slh_first; \
147 (head)->slh_first = (elm); \
148} while (0)
149
150#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
151
152#define SLIST_REMOVE_HEAD(head, field) do { \
153 (head)->slh_first = (head)->slh_first->field.sle_next; \
154} while (0)
155
156#define SLIST_REMOVE(head, elm, type, field) do { \
157 if ((head)->slh_first == (elm)) { \
158 SLIST_REMOVE_HEAD((head), field); \
159 } \
160 else { \
161 struct type *curelm = (head)->slh_first; \
162 while( curelm->field.sle_next != (elm) ) \
163 curelm = curelm->field.sle_next; \
164 curelm->field.sle_next = \
165 curelm->field.sle_next->field.sle_next; \
166 } \
167} while (0)
168
169/*
170 * Singly-linked Tail queue definitions.
171 */
172#define STAILQ_HEAD(name, type) \
173struct name { \
174 struct type *stqh_first;/* first element */ \
175 struct type **stqh_last;/* addr of last next element */ \
176}
177
178#define STAILQ_HEAD_INITIALIZER(head) \
179 { NULL, &(head).stqh_first }
180
181#define STAILQ_ENTRY(type) \
182struct { \
183 struct type *stqe_next; /* next element */ \
184}
185
186/*
187 * Singly-linked Tail queue functions.
188 */
189#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
190
191#define STAILQ_INIT(head) do { \
192 (head)->stqh_first = NULL; \
193 (head)->stqh_last = &(head)->stqh_first; \
194} while (0)
195
196#define STAILQ_FIRST(head) ((head)->stqh_first)
197#define STAILQ_LAST(head) (*(head)->stqh_last)
198
199#define STAILQ_FOREACH(var, head, field) \
200 for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next)
201
202#define STAILQ_INSERT_HEAD(head, elm, field) do { \
203 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \
204 (head)->stqh_last = &(elm)->field.stqe_next; \
205 (head)->stqh_first = (elm); \
206} while (0)
207
208#define STAILQ_INSERT_TAIL(head, elm, field) do { \
209 (elm)->field.stqe_next = NULL; \
210 *(head)->stqh_last = (elm); \
211 (head)->stqh_last = &(elm)->field.stqe_next; \
212} while (0)
213
214#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
215 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
216 (head)->stqh_last = &(elm)->field.stqe_next; \
217 (tqelm)->field.stqe_next = (elm); \
218} while (0)
219
220#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
221
222#define STAILQ_REMOVE_HEAD(head, field) do { \
223 if (((head)->stqh_first = \
224 (head)->stqh_first->field.stqe_next) == NULL) \
225 (head)->stqh_last = &(head)->stqh_first; \
226} while (0)
227
228#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
229 if (((head)->stqh_first = (elm)->field.stqe_next) == NULL) \
230 (head)->stqh_last = &(head)->stqh_first; \
231} while (0)
232
233#define STAILQ_REMOVE(head, elm, type, field) do { \
234 if ((head)->stqh_first == (elm)) { \
235 STAILQ_REMOVE_HEAD(head, field); \
236 } \
237 else { \
238 struct type *curelm = (head)->stqh_first; \
239 while( curelm->field.stqe_next != (elm) ) \
240 curelm = curelm->field.stqe_next; \
241 if((curelm->field.stqe_next = \
242 curelm->field.stqe_next->field.stqe_next) == NULL) \
243 (head)->stqh_last = &(curelm)->field.stqe_next; \
244 } \
245} while (0)
246
247/*
248 * List definitions.
249 */
250#define LIST_HEAD(name, type) \
251struct name { \
252 struct type *lh_first; /* first element */ \
253}
254
255#define LIST_HEAD_INITIALIZER(head) \
256 { NULL }
257
258#define LIST_ENTRY(type) \
259struct { \
260 struct type *le_next; /* next element */ \
261 struct type **le_prev; /* address of previous next element */ \
262}
263
264/*
265 * List functions.
266 */
267
268#define LIST_EMPTY(head) ((head)->lh_first == NULL)
269
270#define LIST_FIRST(head) ((head)->lh_first)
271
272#define LIST_FOREACH(var, head, field) \
273 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)
274
275#define LIST_INIT(head) do { \
276 (head)->lh_first = NULL; \
277} while (0)
278
279#define LIST_INSERT_AFTER(listelm, elm, field) do { \
280 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
281 (listelm)->field.le_next->field.le_prev = \
282 &(elm)->field.le_next; \
283 (listelm)->field.le_next = (elm); \
284 (elm)->field.le_prev = &(listelm)->field.le_next; \
285} while (0)
286
287#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
288 (elm)->field.le_prev = (listelm)->field.le_prev; \
289 (elm)->field.le_next = (listelm); \
290 *(listelm)->field.le_prev = (elm); \
291 (listelm)->field.le_prev = &(elm)->field.le_next; \
292} while (0)
293
294#define LIST_INSERT_HEAD(head, elm, field) do { \
295 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
296 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
297 (head)->lh_first = (elm); \
298 (elm)->field.le_prev = &(head)->lh_first; \
299} while (0)
300
301#define LIST_NEXT(elm, field) ((elm)->field.le_next)
302
303#define LIST_REMOVE(elm, field) do { \
304 if ((elm)->field.le_next != NULL) \
305 (elm)->field.le_next->field.le_prev = \
306 (elm)->field.le_prev; \
307 *(elm)->field.le_prev = (elm)->field.le_next; \
308} while (0)
309
310/*
311 * Tail queue definitions.
312 */
313#define TAILQ_HEAD(name, type) \
314struct name { \
315 struct type *tqh_first; /* first element */ \
316 struct type **tqh_last; /* addr of last next element */ \
317}
318
319#define TAILQ_HEAD_INITIALIZER(head) \
320 { NULL, &(head).tqh_first }
321
322#define TAILQ_ENTRY(type) \
323struct { \
324 struct type *tqe_next; /* next element */ \
325 struct type **tqe_prev; /* address of previous next element */ \
326}
327
328/*
329 * Tail queue functions.
330 */
331#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
332
333#define TAILQ_FOREACH(var, head, field) \
334 for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field))
335
336#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
337 for ((var) = TAILQ_LAST((head), headname); \
338 (var); \
339 (var) = TAILQ_PREV((var), headname, field))
340
341#define TAILQ_FIRST(head) ((head)->tqh_first)
342
343#define TAILQ_LAST(head, headname) \
344 (*(((struct headname *)((head)->tqh_last))->tqh_last))
345
346#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
347
348#define TAILQ_PREV(elm, headname, field) \
349 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
350
351#define TAILQ_INIT(head) do { \
352 (head)->tqh_first = NULL; \
353 (head)->tqh_last = &(head)->tqh_first; \
354} while (0)
355
356#define TAILQ_INSERT_HEAD(head, elm, field) do { \
357 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
358 (head)->tqh_first->field.tqe_prev = \
359 &(elm)->field.tqe_next; \
360 else \
361 (head)->tqh_last = &(elm)->field.tqe_next; \
362 (head)->tqh_first = (elm); \
363 (elm)->field.tqe_prev = &(head)->tqh_first; \
364} while (0)
365
366#define TAILQ_INSERT_TAIL(head, elm, field) do { \
367 (elm)->field.tqe_next = NULL; \
368 (elm)->field.tqe_prev = (head)->tqh_last; \
369 *(head)->tqh_last = (elm); \
370 (head)->tqh_last = &(elm)->field.tqe_next; \
371} while (0)
372
373#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
374 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
375 (elm)->field.tqe_next->field.tqe_prev = \
376 &(elm)->field.tqe_next; \
377 else \
378 (head)->tqh_last = &(elm)->field.tqe_next; \
379 (listelm)->field.tqe_next = (elm); \
380 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
381} while (0)
382
383#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
384 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
385 (elm)->field.tqe_next = (listelm); \
386 *(listelm)->field.tqe_prev = (elm); \
387 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
388} while (0)
389
390#define TAILQ_REMOVE(head, elm, field) do { \
391 if (((elm)->field.tqe_next) != NULL) \
392 (elm)->field.tqe_next->field.tqe_prev = \
393 (elm)->field.tqe_prev; \
394 else \
395 (head)->tqh_last = (elm)->field.tqe_prev; \
396 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
397} while (0)
398
399/*
400 * Circular queue definitions.
401 */
402#define CIRCLEQ_HEAD(name, type) \
403struct name { \
404 struct type *cqh_first; /* first element */ \
405 struct type *cqh_last; /* last element */ \
406}
407
408#define CIRCLEQ_ENTRY(type) \
409struct { \
410 struct type *cqe_next; /* next element */ \
411 struct type *cqe_prev; /* previous element */ \
412}
413
414/*
415 * Circular queue functions.
416 */
417#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
418
419#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
420
421#define CIRCLEQ_FOREACH(var, head, field) \
422 for((var) = (head)->cqh_first; \
423 (var) != (void *)(head); \
424 (var) = (var)->field.cqe_next)
425
426#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
427 for((var) = (head)->cqh_last; \
428 (var) != (void *)(head); \
429 (var) = (var)->field.cqe_prev)
430
431#define CIRCLEQ_INIT(head) do { \
432 (head)->cqh_first = (void *)(head); \
433 (head)->cqh_last = (void *)(head); \
434} while (0)
435
436#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
437 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
438 (elm)->field.cqe_prev = (listelm); \
439 if ((listelm)->field.cqe_next == (void *)(head)) \
440 (head)->cqh_last = (elm); \
441 else \
442 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
443 (listelm)->field.cqe_next = (elm); \
444} while (0)
445
446#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
447 (elm)->field.cqe_next = (listelm); \
448 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
449 if ((listelm)->field.cqe_prev == (void *)(head)) \
450 (head)->cqh_first = (elm); \
451 else \
452 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
453 (listelm)->field.cqe_prev = (elm); \
454} while (0)
455
456#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
457 (elm)->field.cqe_next = (head)->cqh_first; \
458 (elm)->field.cqe_prev = (void *)(head); \
459 if ((head)->cqh_last == (void *)(head)) \
460 (head)->cqh_last = (elm); \
461 else \
462 (head)->cqh_first->field.cqe_prev = (elm); \
463 (head)->cqh_first = (elm); \
464} while (0)
465
466#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
467 (elm)->field.cqe_next = (void *)(head); \
468 (elm)->field.cqe_prev = (head)->cqh_last; \
469 if ((head)->cqh_first == (void *)(head)) \
470 (head)->cqh_first = (elm); \
471 else \
472 (head)->cqh_last->field.cqe_next = (elm); \
473 (head)->cqh_last = (elm); \
474} while (0)
475
476#define CIRCLEQ_LAST(head) ((head)->cqh_last)
477
478#define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
479
480#define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
481
482#define CIRCLEQ_REMOVE(head, elm, field) do { \
483 if ((elm)->field.cqe_next == (void *)(head)) \
484 (head)->cqh_last = (elm)->field.cqe_prev; \
485 else \
486 (elm)->field.cqe_next->field.cqe_prev = \
487 (elm)->field.cqe_prev; \
488 if ((elm)->field.cqe_prev == (void *)(head)) \
489 (head)->cqh_first = (elm)->field.cqe_next; \
490 else \
491 (elm)->field.cqe_prev->field.cqe_next = \
492 (elm)->field.cqe_next; \
493} while (0)
494
495#ifdef KERNEL
496
497/*
498 * XXX insque() and remque() are an old way of handling certain queues.
499 * They bogusly assumes that all queue heads look alike.
500 */
501
502struct quehead {
503 struct quehead *qh_link;
504 struct quehead *qh_rlink;
505};
506
507#ifdef __GNUC__
508
509static __inline void
510insque(void *a, void *b)
511{
512 struct quehead *element = a, *head = b;
513
514 element->qh_link = head->qh_link;
515 element->qh_rlink = head;
516 head->qh_link = element;
517 element->qh_link->qh_rlink = element;
518}
519
520static __inline void
521remque(void *a)
522{
523 struct quehead *element = a;
524
525 element->qh_link->qh_rlink = element->qh_rlink;
526 element->qh_rlink->qh_link = element->qh_link;
527 element->qh_rlink = 0;
528}
529
530#else /* !__GNUC__ */
531
532void insque __P((void *a, void *b));
533void remque __P((void *a));
534
535#endif /* __GNUC__ */
536
537#endif /* KERNEL */
538
539#endif /* !_SYS_QUEUE_H_ */
__P
#define __P(p)
Definition: include/solaris-compat/compat.h:8
b
static struct test_val b
Definition: test_linkedlists.c:47
a
static struct test_val a
Definition: test_linkedlists.c:46
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