2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
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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 $
37 #ifndef _AVERSIVE_QUEUE_H_
38 #define _AVERSIVE_QUEUE_H_
41 #define __offsetof(type, field) ((size_t)(&(type *)0)->field))
45 * This file defines five types of data structures: singly-linked lists,
46 * singly-linked tail queues, lists, tail queues, and circular queues.
48 * A singly-linked list is headed by a single forward pointer. The elements
49 * are singly linked for minimum space and pointer manipulation overhead at
50 * the expense of O(n) removal for arbitrary elements. New elements can be
51 * added to the list after an existing element or at the head of the list.
52 * Elements being removed from the head of the list should use the explicit
53 * macro for this purpose for optimum efficiency. A singly-linked list may
54 * only be traversed in the forward direction. Singly-linked lists are ideal
55 * for applications with large datasets and few or no removals or for
56 * implementing a LIFO queue.
58 * A singly-linked tail queue is headed by a pair of pointers, one to the
59 * head of the list and the other to the tail of the list. The elements are
60 * singly linked for minimum space and pointer manipulation overhead at the
61 * expense of O(n) removal for arbitrary elements. New elements can be added
62 * to the list after an existing element, at the head of the list, or at the
63 * end of the list. Elements being removed from the head of the tail queue
64 * should use the explicit macro for this purpose for optimum efficiency.
65 * A singly-linked tail queue may only be traversed in the forward direction.
66 * Singly-linked tail queues are ideal for applications with large datasets
67 * and few or no removals or for implementing a FIFO queue.
69 * A list is headed by a single forward pointer (or an array of forward
70 * pointers for a hash table header). The elements are doubly linked
71 * so that an arbitrary element can be removed without a need to
72 * traverse the list. New elements can be added to the list before
73 * or after an existing element or at the head of the list. A list
74 * may only be traversed in the forward direction.
76 * A tail queue is headed by a pair of pointers, one to the head of the
77 * list and the other to the tail of the list. The elements are doubly
78 * linked so that an arbitrary element can be removed without a need to
79 * traverse the list. New elements can be added to the list before or
80 * after an existing element, at the head of the list, or at the end of
81 * the list. A tail queue may be traversed in either direction.
83 * A circle queue is headed by a pair of pointers, one to the head of the
84 * list and the other to the tail of the list. The elements are doubly
85 * linked so that an arbitrary element can be removed without a need to
86 * traverse the list. New elements can be added to the list before or after
87 * an existing element, at the head of the list, or at the end of the list.
88 * A circle queue may be traversed in either direction, but has a more
89 * complex end of list detection.
91 * For details on the use of these macros, see the queue(3) manual page.
94 * SLIST LIST STAILQ TAILQ CIRCLEQ
96 * _HEAD_INITIALIZER + + + + +
105 * _FOREACH_REVERSE - - - + +
106 * _INSERT_HEAD + + + + +
107 * _INSERT_BEFORE - + - + +
108 * _INSERT_AFTER + + + + +
109 * _INSERT_TAIL - - + + +
110 * _REMOVE_HEAD + - + - -
116 * Singly-linked List declarations.
118 #define SLIST_HEAD(name, type) \
120 struct type *slh_first; /* first element */ \
123 #define SLIST_HEAD_INITIALIZER(head) \
126 #define SLIST_ENTRY(type) \
128 struct type *sle_next; /* next element */ \
132 * Singly-linked List functions.
134 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
136 #define SLIST_FIRST(head) ((head)->slh_first)
138 #define SLIST_FOREACH(var, head, field) \
139 for ((var) = SLIST_FIRST((head)); \
141 (var) = SLIST_NEXT((var), field))
143 #define SLIST_INIT(head) do { \
144 SLIST_FIRST((head)) = NULL; \
147 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
148 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
149 SLIST_NEXT((slistelm), field) = (elm); \
152 #define SLIST_INSERT_HEAD(head, elm, field) do { \
153 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
154 SLIST_FIRST((head)) = (elm); \
157 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
159 #define SLIST_REMOVE(head, elm, type, field) do { \
160 if (SLIST_FIRST((head)) == (elm)) { \
161 SLIST_REMOVE_HEAD((head), field); \
164 struct type *curelm = SLIST_FIRST((head)); \
165 while (SLIST_NEXT(curelm, field) != (elm)) \
166 curelm = SLIST_NEXT(curelm, field); \
167 SLIST_NEXT(curelm, field) = \
168 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
172 #define SLIST_REMOVE_HEAD(head, field) do { \
173 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
177 * Singly-linked Tail queue declarations.
179 #define STAILQ_HEAD(name, type) \
181 struct type *stqh_first;/* first element */ \
182 struct type **stqh_last;/* addr of last next element */ \
185 #define STAILQ_HEAD_INITIALIZER(head) \
186 { NULL, &(head).stqh_first }
188 #define STAILQ_ENTRY(type) \
190 struct type *stqe_next; /* next element */ \
194 * Singly-linked Tail queue functions.
196 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
198 #define STAILQ_FIRST(head) ((head)->stqh_first)
200 #define STAILQ_FOREACH(var, head, field) \
201 for((var) = STAILQ_FIRST((head)); \
203 (var) = STAILQ_NEXT((var), field))
205 #define STAILQ_INIT(head) do { \
206 STAILQ_FIRST((head)) = NULL; \
207 (head)->stqh_last = &STAILQ_FIRST((head)); \
210 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
211 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
212 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
213 STAILQ_NEXT((tqelm), field) = (elm); \
216 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
217 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
218 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
219 STAILQ_FIRST((head)) = (elm); \
222 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
223 STAILQ_NEXT((elm), field) = NULL; \
224 *(head)->stqh_last = (elm); \
225 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
228 #define STAILQ_LAST(head, type, field) \
229 (STAILQ_EMPTY(head) ? \
232 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
234 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
236 #define STAILQ_REMOVE(head, elm, type, field) do { \
237 if (STAILQ_FIRST((head)) == (elm)) { \
238 STAILQ_REMOVE_HEAD(head, field); \
241 struct type *curelm = STAILQ_FIRST((head)); \
242 while (STAILQ_NEXT(curelm, field) != (elm)) \
243 curelm = STAILQ_NEXT(curelm, field); \
244 if ((STAILQ_NEXT(curelm, field) = \
245 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
246 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\
250 #define STAILQ_REMOVE_HEAD(head, field) do { \
251 if ((STAILQ_FIRST((head)) = \
252 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
253 (head)->stqh_last = &STAILQ_FIRST((head)); \
256 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
257 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
258 (head)->stqh_last = &STAILQ_FIRST((head)); \
264 #define LIST_HEAD(name, type) \
266 struct type *lh_first; /* first element */ \
269 #define LIST_HEAD_INITIALIZER(head) \
272 #define LIST_ENTRY(type) \
274 struct type *le_next; /* next element */ \
275 struct type **le_prev; /* address of previous next element */ \
282 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
284 #define LIST_FIRST(head) ((head)->lh_first)
286 #define LIST_FOREACH(var, head, field) \
287 for ((var) = LIST_FIRST((head)); \
289 (var) = LIST_NEXT((var), field))
291 #define LIST_INIT(head) do { \
292 LIST_FIRST((head)) = NULL; \
295 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
296 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
297 LIST_NEXT((listelm), field)->field.le_prev = \
298 &LIST_NEXT((elm), field); \
299 LIST_NEXT((listelm), field) = (elm); \
300 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
303 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
304 (elm)->field.le_prev = (listelm)->field.le_prev; \
305 LIST_NEXT((elm), field) = (listelm); \
306 *(listelm)->field.le_prev = (elm); \
307 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
310 #define LIST_INSERT_HEAD(head, elm, field) do { \
311 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
312 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
313 LIST_FIRST((head)) = (elm); \
314 (elm)->field.le_prev = &LIST_FIRST((head)); \
317 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
319 #define LIST_REMOVE(elm, field) do { \
320 if (LIST_NEXT((elm), field) != NULL) \
321 LIST_NEXT((elm), field)->field.le_prev = \
322 (elm)->field.le_prev; \
323 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
327 * Tail queue declarations.
329 #define TAILQ_HEAD(name, type) \
331 struct type *tqh_first; /* first element */ \
332 struct type **tqh_last; /* addr of last next element */ \
335 #define TAILQ_HEAD_INITIALIZER(head) \
336 { NULL, &(head).tqh_first }
338 #define TAILQ_ENTRY(type) \
340 struct type *tqe_next; /* next element */ \
341 struct type **tqe_prev; /* address of previous next element */ \
345 * Tail queue functions.
347 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
349 #define TAILQ_FIRST(head) ((head)->tqh_first)
351 #define TAILQ_FOREACH(var, head, field) \
352 for ((var) = TAILQ_FIRST((head)); \
354 (var) = TAILQ_NEXT((var), field))
356 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
357 for ((var) = TAILQ_LAST((head), headname); \
359 (var) = TAILQ_PREV((var), headname, field))
361 #define TAILQ_INIT(head) do { \
362 TAILQ_FIRST((head)) = NULL; \
363 (head)->tqh_last = &TAILQ_FIRST((head)); \
366 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
367 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
368 TAILQ_NEXT((elm), field)->field.tqe_prev = \
369 &TAILQ_NEXT((elm), field); \
371 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
372 TAILQ_NEXT((listelm), field) = (elm); \
373 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
376 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
377 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
378 TAILQ_NEXT((elm), field) = (listelm); \
379 *(listelm)->field.tqe_prev = (elm); \
380 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
383 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
384 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
385 TAILQ_FIRST((head))->field.tqe_prev = \
386 &TAILQ_NEXT((elm), field); \
388 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
389 TAILQ_FIRST((head)) = (elm); \
390 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
393 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
394 TAILQ_NEXT((elm), field) = NULL; \
395 (elm)->field.tqe_prev = (head)->tqh_last; \
396 *(head)->tqh_last = (elm); \
397 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
400 #define TAILQ_LAST(head, headname) \
401 (*(((struct headname *)((head)->tqh_last))->tqh_last))
403 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
405 #define TAILQ_PREV(elm, headname, field) \
406 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
408 #define TAILQ_REMOVE(head, elm, field) do { \
409 if ((TAILQ_NEXT((elm), field)) != NULL) \
410 TAILQ_NEXT((elm), field)->field.tqe_prev = \
411 (elm)->field.tqe_prev; \
413 (head)->tqh_last = (elm)->field.tqe_prev; \
414 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
418 * Circular queue declarations.
420 #define CIRCLEQ_HEAD(name, type) \
422 struct type *cqh_first; /* first element */ \
423 struct type *cqh_last; /* last element */ \
426 #define CIRCLEQ_HEAD_INITIALIZER(head) \
427 { (void *)&(head), (void *)&(head) }
429 #define CIRCLEQ_ENTRY(type) \
431 struct type *cqe_next; /* next element */ \
432 struct type *cqe_prev; /* previous element */ \
436 * Circular queue functions.
438 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
440 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
442 #define CIRCLEQ_FOREACH(var, head, field) \
443 for ((var) = CIRCLEQ_FIRST((head)); \
444 (var) != (void *)(head) || ((var) = NULL); \
445 (var) = CIRCLEQ_NEXT((var), field))
447 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
448 for ((var) = CIRCLEQ_LAST((head)); \
449 (var) != (void *)(head) || ((var) = NULL); \
450 (var) = CIRCLEQ_PREV((var), field))
452 #define CIRCLEQ_INIT(head) do { \
453 CIRCLEQ_FIRST((head)) = (void *)(head); \
454 CIRCLEQ_LAST((head)) = (void *)(head); \
457 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
458 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \
459 CIRCLEQ_PREV((elm), field) = (listelm); \
460 if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \
461 CIRCLEQ_LAST((head)) = (elm); \
463 CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\
464 CIRCLEQ_NEXT((listelm), field) = (elm); \
467 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
468 CIRCLEQ_NEXT((elm), field) = (listelm); \
469 CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \
470 if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \
471 CIRCLEQ_FIRST((head)) = (elm); \
473 CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\
474 CIRCLEQ_PREV((listelm), field) = (elm); \
477 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
478 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \
479 CIRCLEQ_PREV((elm), field) = (void *)(head); \
480 if (CIRCLEQ_LAST((head)) == (void *)(head)) \
481 CIRCLEQ_LAST((head)) = (elm); \
483 CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \
484 CIRCLEQ_FIRST((head)) = (elm); \
487 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
488 CIRCLEQ_NEXT((elm), field) = (void *)(head); \
489 CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \
490 if (CIRCLEQ_FIRST((head)) == (void *)(head)) \
491 CIRCLEQ_FIRST((head)) = (elm); \
493 CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \
494 CIRCLEQ_LAST((head)) = (elm); \
497 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
499 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
501 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
503 #define CIRCLEQ_REMOVE(head, elm, field) do { \
504 if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \
505 CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \
507 CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \
508 CIRCLEQ_PREV((elm), field); \
509 if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \
510 CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \
512 CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \
513 CIRCLEQ_NEXT((elm), field); \
517 #endif /* !_AVERSIVE_QUEUE_H_ */