2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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15 * This product includes software developed by the University of
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33 * @(#)queue.h 8.5 (Berkeley) 8/20/94
34 * $FreeBSD: src/sys/sys/queue.h,v 1.32.2.7 2002/04/17 14:21:02 des Exp $
35 * $DragonFly: src/sys/sys/queue.h,v 1.7 2005/03/04 02:21:49 hsu Exp $
41 #ifndef _MACHINE_STDINT_H_
42 #include <machine/stdint.h> /* for __offsetof */
46 * This file defines five types of data structures: singly-linked lists,
47 * singly-linked tail queues, lists, tail queues, and circular queues.
49 * A singly-linked list is headed by a single forward pointer. The elements
50 * are singly linked for minimum space and pointer manipulation overhead at
51 * the expense of O(n) removal for arbitrary elements. New elements can be
52 * added to the list after an existing element or at the head of the list.
53 * Elements being removed from the head of the list should use the explicit
54 * macro for this purpose for optimum efficiency. A singly-linked list may
55 * only be traversed in the forward direction. Singly-linked lists are ideal
56 * for applications with large datasets and few or no removals or for
57 * implementing a LIFO queue.
59 * A singly-linked tail queue is headed by a pair of pointers, one to the
60 * head of the list and the other to the tail of the list. The elements are
61 * singly linked for minimum space and pointer manipulation overhead at the
62 * expense of O(n) removal for arbitrary elements. New elements can be added
63 * to the list after an existing element, at the head of the list, or at the
64 * end of the list. Elements being removed from the head of the tail queue
65 * should use the explicit macro for this purpose for optimum efficiency.
66 * A singly-linked tail queue may only be traversed in the forward direction.
67 * Singly-linked tail queues are ideal for applications with large datasets
68 * and few or no removals or for implementing a FIFO queue.
70 * A list is headed by a single forward pointer (or an array of forward
71 * pointers for a hash table header). The elements are doubly linked
72 * so that an arbitrary element can be removed without a need to
73 * traverse the list. New elements can be added to the list before
74 * or after an existing element or at the head of the list. A list
75 * may only be traversed in the forward direction.
77 * A tail queue is headed by a pair of pointers, one to the head of the
78 * list and the other to the tail of the list. The elements are doubly
79 * linked so that an arbitrary element can be removed without a need to
80 * traverse the list. New elements can be added to the list before or
81 * after an existing element, at the head of the list, or at the end of
82 * the list. A tail queue may be traversed in either direction.
84 * A circle queue is headed by a pair of pointers, one to the head of the
85 * list and the other to the tail of the list. The elements are doubly
86 * linked so that an arbitrary element can be removed without a need to
87 * traverse the list. New elements can be added to the list before or after
88 * an existing element, at the head of the list, or at the end of the list.
89 * A circle queue may be traversed in either direction, but has a more
90 * complex end of list detection.
92 * For details on the use of these macros, see the queue(3) manual page.
95 * SLIST LIST STAILQ TAILQ CIRCLEQ
97 * _HEAD_INITIALIZER + + + + +
106 * _FOREACH_REVERSE - - - + +
107 * _INSERT_HEAD + + + + +
108 * _INSERT_BEFORE - + - + +
109 * _INSERT_AFTER + + + + +
110 * _INSERT_TAIL - - + + +
111 * _REMOVE_HEAD + - + - -
117 * Singly-linked List declarations.
119 #define SLIST_HEAD(name, type) \
121 struct type *slh_first; /* first element */ \
124 #define SLIST_HEAD_INITIALIZER(head) \
127 #define SLIST_ENTRY(type) \
129 struct type *sle_next; /* next element */ \
132 #define SLIST_ENTRY_INITIALIZER { NULL }
135 * Singly-linked List functions.
137 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
139 #define SLIST_FIRST(head) ((head)->slh_first)
141 #define SLIST_FOREACH(var, head, field) \
142 for ((var) = SLIST_FIRST((head)); \
144 (var) = SLIST_NEXT((var), field))
146 #define SLIST_INIT(head) do { \
147 SLIST_FIRST((head)) = NULL; \
150 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
151 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
152 SLIST_NEXT((slistelm), field) = (elm); \
155 #define SLIST_INSERT_HEAD(head, elm, field) do { \
156 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
157 SLIST_FIRST((head)) = (elm); \
160 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
162 #define SLIST_REMOVE(head, elm, type, field) do { \
163 if (SLIST_FIRST((head)) == (elm)) { \
164 SLIST_REMOVE_HEAD((head), field); \
167 struct type *curelm = SLIST_FIRST((head)); \
168 while (SLIST_NEXT(curelm, field) != (elm)) \
169 curelm = SLIST_NEXT(curelm, field); \
170 SLIST_NEXT(curelm, field) = \
171 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
175 #define SLIST_REMOVE_HEAD(head, field) do { \
176 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
180 * Singly-linked Tail queue declarations.
182 #define STAILQ_HEAD(name, type) \
184 struct type *stqh_first;/* first element */ \
185 struct type **stqh_last;/* addr of last next element */ \
188 #define STAILQ_HEAD_INITIALIZER(head) \
189 { NULL, &(head).stqh_first }
191 #define STAILQ_ENTRY(type) \
193 struct type *stqe_next; /* next element */ \
197 * Singly-linked Tail queue functions.
199 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
201 #define STAILQ_FIRST(head) ((head)->stqh_first)
203 #define STAILQ_FOREACH(var, head, field) \
204 for((var) = STAILQ_FIRST((head)); \
206 (var) = STAILQ_NEXT((var), field))
208 #define STAILQ_INIT(head) do { \
209 STAILQ_FIRST((head)) = NULL; \
210 (head)->stqh_last = &STAILQ_FIRST((head)); \
213 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
214 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
215 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
216 STAILQ_NEXT((tqelm), field) = (elm); \
219 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
220 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
221 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
222 STAILQ_FIRST((head)) = (elm); \
225 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
226 STAILQ_NEXT((elm), field) = NULL; \
227 *(head)->stqh_last = (elm); \
228 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
231 #define STAILQ_LAST(head, type, field) \
232 (STAILQ_EMPTY(head) ? \
235 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
237 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
239 #define STAILQ_REMOVE(head, elm, type, field) do { \
240 if (STAILQ_FIRST((head)) == (elm)) { \
241 STAILQ_REMOVE_HEAD(head, field); \
244 struct type *curelm = STAILQ_FIRST((head)); \
245 while (STAILQ_NEXT(curelm, field) != (elm)) \
246 curelm = STAILQ_NEXT(curelm, field); \
247 if ((STAILQ_NEXT(curelm, field) = \
248 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
249 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\
253 #define STAILQ_REMOVE_HEAD(head, field) do { \
254 if ((STAILQ_FIRST((head)) = \
255 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
256 (head)->stqh_last = &STAILQ_FIRST((head)); \
259 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
260 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
261 (head)->stqh_last = &STAILQ_FIRST((head)); \
267 #define LIST_HEAD(name, type) \
269 struct type *lh_first; /* first element */ \
272 #define LIST_HEAD_INITIALIZER(head) \
275 #define LIST_ENTRY(type) \
277 struct type *le_next; /* next element */ \
278 struct type **le_prev; /* address of previous next element */ \
285 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
287 #define LIST_FIRST(head) ((head)->lh_first)
289 #define LIST_FOREACH(var, head, field) \
290 for ((var) = LIST_FIRST((head)); \
292 (var) = LIST_NEXT((var), field))
294 #define LIST_FOREACH_MUTABLE(var, head, field, nvar) \
295 for ((var) = LIST_FIRST((head)); \
296 (var) && ((nvar) = LIST_NEXT((var), field), (var)); \
299 #define LIST_INIT(head) do { \
300 LIST_FIRST((head)) = NULL; \
303 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
304 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
305 LIST_NEXT((listelm), field)->field.le_prev = \
306 &LIST_NEXT((elm), field); \
307 LIST_NEXT((listelm), field) = (elm); \
308 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
311 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
312 (elm)->field.le_prev = (listelm)->field.le_prev; \
313 LIST_NEXT((elm), field) = (listelm); \
314 *(listelm)->field.le_prev = (elm); \
315 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
318 #define LIST_INSERT_HEAD(head, elm, field) do { \
319 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
320 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
321 LIST_FIRST((head)) = (elm); \
322 (elm)->field.le_prev = &LIST_FIRST((head)); \
325 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
327 #define LIST_REMOVE(elm, field) do { \
328 if (LIST_NEXT((elm), field) != NULL) \
329 LIST_NEXT((elm), field)->field.le_prev = \
330 (elm)->field.le_prev; \
331 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
335 * Tail queue declarations.
337 #define TAILQ_HEAD(name, type) \
339 struct type *tqh_first; /* first element */ \
340 struct type **tqh_last; /* addr of last next element */ \
343 #define TAILQ_HEAD_INITIALIZER(head) \
344 { NULL, &(head).tqh_first }
346 #define TAILQ_ENTRY(type) \
348 struct type *tqe_next; /* next element */ \
349 struct type **tqe_prev; /* address of previous next element */ \
353 * Tail queue functions.
355 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
357 #define TAILQ_FIRST(head) ((head)->tqh_first)
359 #define TAILQ_FOREACH(var, head, field) \
360 for ((var) = TAILQ_FIRST((head)); \
362 (var) = TAILQ_NEXT((var), field))
364 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
365 for ((var) = TAILQ_LAST((head), headname); \
367 (var) = TAILQ_PREV((var), headname, field))
369 #define TAILQ_FOREACH_MUTABLE(var, head, field, nvar) \
370 for ((var) = TAILQ_FIRST((head)); \
371 (var) && ((nvar) = TAILQ_NEXT((var), field), (var)); \
374 #define TAILQ_INIT(head) do { \
375 TAILQ_FIRST((head)) = NULL; \
376 (head)->tqh_last = &TAILQ_FIRST((head)); \
379 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
380 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
381 TAILQ_NEXT((elm), field)->field.tqe_prev = \
382 &TAILQ_NEXT((elm), field); \
384 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
385 TAILQ_NEXT((listelm), field) = (elm); \
386 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
389 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
390 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
391 TAILQ_NEXT((elm), field) = (listelm); \
392 *(listelm)->field.tqe_prev = (elm); \
393 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
396 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
397 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
398 TAILQ_FIRST((head))->field.tqe_prev = \
399 &TAILQ_NEXT((elm), field); \
401 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
402 TAILQ_FIRST((head)) = (elm); \
403 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
406 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
407 TAILQ_NEXT((elm), field) = NULL; \
408 (elm)->field.tqe_prev = (head)->tqh_last; \
409 *(head)->tqh_last = (elm); \
410 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
413 #define TAILQ_LAST(head, headname) \
414 (*(((struct headname *)((head)->tqh_last))->tqh_last))
416 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
418 #define TAILQ_PREV(elm, headname, field) \
419 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
421 #define TAILQ_REMOVE(head, elm, field) do { \
422 if ((TAILQ_NEXT((elm), field)) != NULL) \
423 TAILQ_NEXT((elm), field)->field.tqe_prev = \
424 (elm)->field.tqe_prev; \
426 (head)->tqh_last = (elm)->field.tqe_prev; \
427 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
431 * Circular queue declarations.
433 #define CIRCLEQ_HEAD(name, type) \
435 struct type *cqh_first; /* first element */ \
436 struct type *cqh_last; /* last element */ \
439 #define CIRCLEQ_HEAD_INITIALIZER(head) \
440 { (void *)&(head), (void *)&(head) }
442 #define CIRCLEQ_ENTRY(type) \
444 struct type *cqe_next; /* next element */ \
445 struct type *cqe_prev; /* previous element */ \
449 * Circular queue functions.
451 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
453 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
455 #define CIRCLEQ_FOREACH(var, head, field) \
456 for ((var) = CIRCLEQ_FIRST((head)); \
457 (var) != (void *)(head) || ((var) = NULL); \
458 (var) = CIRCLEQ_NEXT((var), field))
460 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
461 for ((var) = CIRCLEQ_LAST((head)); \
462 (var) != (void *)(head) || ((var) = NULL); \
463 (var) = CIRCLEQ_PREV((var), field))
465 #define CIRCLEQ_INIT(head) do { \
466 CIRCLEQ_FIRST((head)) = (void *)(head); \
467 CIRCLEQ_LAST((head)) = (void *)(head); \
470 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
471 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \
472 CIRCLEQ_PREV((elm), field) = (listelm); \
473 if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \
474 CIRCLEQ_LAST((head)) = (elm); \
476 CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\
477 CIRCLEQ_NEXT((listelm), field) = (elm); \
480 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
481 CIRCLEQ_NEXT((elm), field) = (listelm); \
482 CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \
483 if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \
484 CIRCLEQ_FIRST((head)) = (elm); \
486 CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\
487 CIRCLEQ_PREV((listelm), field) = (elm); \
490 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
491 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \
492 CIRCLEQ_PREV((elm), field) = (void *)(head); \
493 if (CIRCLEQ_LAST((head)) == (void *)(head)) \
494 CIRCLEQ_LAST((head)) = (elm); \
496 CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \
497 CIRCLEQ_FIRST((head)) = (elm); \
500 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
501 CIRCLEQ_NEXT((elm), field) = (void *)(head); \
502 CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \
503 if (CIRCLEQ_FIRST((head)) == (void *)(head)) \
504 CIRCLEQ_FIRST((head)) = (elm); \
506 CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \
507 CIRCLEQ_LAST((head)) = (elm); \
510 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
512 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
514 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
516 #define CIRCLEQ_REMOVE(head, elm, field) do { \
517 if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \
518 CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \
520 CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \
521 CIRCLEQ_PREV((elm), field); \
522 if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \
523 CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \
525 CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \
526 CIRCLEQ_NEXT((elm), field); \
532 * XXX insque() and remque() are an old way of handling certain queues.
533 * They bogusly assumes that all queue heads look alike.
537 struct quehead *qh_link;
538 struct quehead *qh_rlink;
544 insque(void *a, void *b)
546 struct quehead *element = (struct quehead *)a,
547 *head = (struct quehead *)b;
549 element->qh_link = head->qh_link;
550 element->qh_rlink = head;
551 head->qh_link = element;
552 element->qh_link->qh_rlink = element;
558 struct quehead *element = (struct quehead *)a;
560 element->qh_link->qh_rlink = element->qh_rlink;
561 element->qh_rlink->qh_link = element->qh_link;
562 element->qh_rlink = 0;
565 #else /* !__GNUC__ */
567 void insque (void *a, void *b);
568 void remque (void *a);
570 #endif /* __GNUC__ */
574 #endif /* !_SYS_QUEUE_H_ */