1 /* $OpenBSD: queue.h,v 1.22 2001/06/23 04:39:35 angelos Exp $ */
2 /* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */
5 * University of California, Berkeley "advertising clause" removed as per
6 * authorisation given by William Hoskins, Director, Office of Technology
7 * Licensing, University of California, Berkeley, on the 22nd day of July
12 * Copyright (c) 1991, 1993
13 * The Regents of the University of California. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 * 3. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * @(#)queue.h 8.5 (Berkeley) 8/20/94
42 #ifndef _LOCAL_SYS_QUEUE_H_
43 #define _LOCAL_SYS_QUEUE_H_
46 * This file defines five types of data structures: singly-linked lists,
47 * lists, simple queues, tail queues, and circular queues.
50 * A singly-linked list is headed by a single forward pointer. The elements
51 * are singly linked for minimum space and pointer manipulation overhead at
52 * the expense of O(n) removal for arbitrary elements. New elements can be
53 * added to the list after an existing element or at the head of the list.
54 * Elements being removed from the head of the list should use the explicit
55 * macro for this purpose for optimum efficiency. A singly-linked list may
56 * only be traversed in the forward direction. Singly-linked lists are ideal
57 * for applications with large datasets and few or no removals or for
58 * implementing a LIFO queue.
60 * A list is headed by a single forward pointer (or an array of forward
61 * pointers for a hash table header). The elements are doubly linked
62 * so that an arbitrary element can be removed without a need to
63 * traverse the list. New elements can be added to the list before
64 * or after an existing element or at the head of the list. A list
65 * may only be traversed in the forward direction.
67 * A simple queue is headed by a pair of pointers, one the head of the
68 * list and the other to the tail of the list. The elements are singly
69 * linked to save space, so elements can only be removed from the
70 * head of the list. New elements can be added to the list before or after
71 * an existing element, at the head of the list, or at the end of the
72 * list. A simple queue may only be traversed in the forward direction.
74 * A tail queue is headed by a pair of pointers, one to the head of the
75 * list and the other to the tail of the list. The elements are doubly
76 * linked so that an arbitrary element can be removed without a need to
77 * traverse the list. New elements can be added to the list before or
78 * after an existing element, at the head of the list, or at the end of
79 * the list. A tail queue may be traversed in either direction.
81 * A circle queue is headed by a pair of pointers, one to the head of the
82 * list and the other to the tail of the list. The elements are doubly
83 * linked so that an arbitrary element can be removed without a need to
84 * traverse the list. New elements can be added to the list before or after
85 * an existing element, at the head of the list, or at the end of the list.
86 * A circle queue may be traversed in either direction, but has a more
87 * complex end of list detection.
89 * For details on the use of these macros, see the queue(3) manual page.
93 * Singly-linked List definitions.
95 #define SLIST_HEAD(name, type) \
97 struct type *slh_first; /* first element */ \
100 #define SLIST_HEAD_INITIALIZER(head) \
103 /* Conflicts with winnt.h */
104 #define bSLIST_ENTRY(type) \
106 struct type *sle_next; /* next element */ \
110 * Singly-linked List access methods.
112 #define SLIST_FIRST(head) ((head)->slh_first)
113 #define SLIST_END(head) NULL
114 #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head))
115 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
117 #define SLIST_FOREACH(var, head, field) \
118 for((var) = SLIST_FIRST(head); \
119 (var) != SLIST_END(head); \
120 (var) = SLIST_NEXT(var, field))
122 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
123 for((var) = SLIST_FIRST(head); \
124 (var) != SLIST_END(head) && \
125 ((tvar) = SLIST_NEXT(var, field), 1); \
129 * Singly-linked List functions.
131 #define SLIST_INIT(head) { \
132 SLIST_FIRST(head) = SLIST_END(head); \
135 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
136 (elm)->field.sle_next = (slistelm)->field.sle_next; \
137 (slistelm)->field.sle_next = (elm); \
140 #define SLIST_INSERT_HEAD(head, elm, field) do { \
141 (elm)->field.sle_next = (head)->slh_first; \
142 (head)->slh_first = (elm); \
145 #define SLIST_REMOVE_HEAD(head, field) do { \
146 (head)->slh_first = (head)->slh_first->field.sle_next; \
149 #define SLIST_REMOVE(head, elm, type, field) do { \
150 if ((head)->slh_first == (elm)) { \
151 SLIST_REMOVE_HEAD((head), field); \
154 struct type *curelm = (head)->slh_first; \
155 while( curelm->field.sle_next != (elm) ) \
156 curelm = curelm->field.sle_next; \
157 curelm->field.sle_next = \
158 curelm->field.sle_next->field.sle_next; \
165 #define LIST_HEAD(name, type) \
167 struct type *lh_first; /* first element */ \
170 #define LIST_HEAD_INITIALIZER(head) \
173 #define LIST_ENTRY(type) \
175 struct type *le_next; /* next element */ \
176 struct type **le_prev; /* address of previous next element */ \
180 * List access methods
182 #define LIST_FIRST(head) ((head)->lh_first)
183 #define LIST_END(head) NULL
184 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
185 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
187 #define LIST_FOREACH(var, head, field) \
188 for((var) = LIST_FIRST(head); \
189 (var)!= LIST_END(head); \
190 (var) = LIST_NEXT(var, field))
192 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
193 for((var) = LIST_FIRST(head); \
194 (var)!= LIST_END(head) && \
195 ((tvar) = LIST_NEXT(var, field), 1); \
202 #define LIST_INIT(head) do { \
203 LIST_FIRST(head) = LIST_END(head); \
206 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
207 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
208 (listelm)->field.le_next->field.le_prev = \
209 &(elm)->field.le_next; \
210 (listelm)->field.le_next = (elm); \
211 (elm)->field.le_prev = &(listelm)->field.le_next; \
214 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
215 (elm)->field.le_prev = (listelm)->field.le_prev; \
216 (elm)->field.le_next = (listelm); \
217 *(listelm)->field.le_prev = (elm); \
218 (listelm)->field.le_prev = &(elm)->field.le_next; \
221 #define LIST_INSERT_HEAD(head, elm, field) do { \
222 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
223 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
224 (head)->lh_first = (elm); \
225 (elm)->field.le_prev = &(head)->lh_first; \
228 #define LIST_REMOVE(elm, field) do { \
229 if ((elm)->field.le_next != NULL) \
230 (elm)->field.le_next->field.le_prev = \
231 (elm)->field.le_prev; \
232 *(elm)->field.le_prev = (elm)->field.le_next; \
235 #define LIST_REPLACE(elm, elm2, field) do { \
236 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
237 (elm2)->field.le_next->field.le_prev = \
238 &(elm2)->field.le_next; \
239 (elm2)->field.le_prev = (elm)->field.le_prev; \
240 *(elm2)->field.le_prev = (elm2); \
244 * Simple queue definitions.
246 #define SIMPLEQ_HEAD(name, type) \
248 struct type *sqh_first; /* first element */ \
249 struct type **sqh_last; /* addr of last next element */ \
252 #define SIMPLEQ_HEAD_INITIALIZER(head) \
253 { NULL, &(head).sqh_first }
255 #define SIMPLEQ_ENTRY(type) \
257 struct type *sqe_next; /* next element */ \
261 * Simple queue access methods.
263 #define SIMPLEQ_FIRST(head) ((head)->sqh_first)
264 #define SIMPLEQ_END(head) NULL
265 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
266 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
268 #define SIMPLEQ_FOREACH(var, head, field) \
269 for((var) = SIMPLEQ_FIRST(head); \
270 (var) != SIMPLEQ_END(head); \
271 (var) = SIMPLEQ_NEXT(var, field))
273 #define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \
274 for((var) = SIMPLEQ_FIRST(head); \
275 (var) != SIMPLEQ_END(head) && \
276 ((tvar) = SIMPLEQ_NEXT(var, field), 1); \
280 * Simple queue functions.
282 #define SIMPLEQ_INIT(head) do { \
283 (head)->sqh_first = NULL; \
284 (head)->sqh_last = &(head)->sqh_first; \
287 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
288 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
289 (head)->sqh_last = &(elm)->field.sqe_next; \
290 (head)->sqh_first = (elm); \
293 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
294 (elm)->field.sqe_next = NULL; \
295 *(head)->sqh_last = (elm); \
296 (head)->sqh_last = &(elm)->field.sqe_next; \
299 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
300 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
301 (head)->sqh_last = &(elm)->field.sqe_next; \
302 (listelm)->field.sqe_next = (elm); \
305 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \
306 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \
307 (head)->sqh_last = &(head)->sqh_first; \
311 * Tail queue definitions.
313 #define TAILQ_HEAD(name, type) \
315 struct type *tqh_first; /* first element */ \
316 struct type **tqh_last; /* addr of last next element */ \
319 #define TAILQ_HEAD_INITIALIZER(head) \
320 { NULL, &(head).tqh_first }
322 #define TAILQ_ENTRY(type) \
324 struct type *tqe_next; /* next element */ \
325 struct type **tqe_prev; /* address of previous next element */ \
329 * tail queue access methods
331 #define TAILQ_FIRST(head) ((head)->tqh_first)
332 #define TAILQ_END(head) NULL
333 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
334 #define TAILQ_LAST(head, headname) \
335 (*(((struct headname *)((head)->tqh_last))->tqh_last))
337 #define TAILQ_PREV(elm, headname, field) \
338 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
339 #define TAILQ_EMPTY(head) \
340 (TAILQ_FIRST(head) == TAILQ_END(head))
342 #define TAILQ_FOREACH(var, head, field) \
343 for((var) = TAILQ_FIRST(head); \
344 (var) != TAILQ_END(head); \
345 (var) = TAILQ_NEXT(var, field))
347 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
348 for((var) = TAILQ_FIRST(head); \
349 (var) != TAILQ_END(head) && \
350 ((tvar) = TAILQ_NEXT(var, field), 1); \
353 #define TAILQ_FOREACH_REVERSE(var, head, field, headname) \
354 for((var) = TAILQ_LAST(head, headname); \
355 (var) != TAILQ_END(head); \
356 (var) = TAILQ_PREV(var, headname, field))
358 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, field, headname, tvar) \
359 for((var) = TAILQ_LAST(head, headname); \
360 (var) != TAILQ_END(head) && \
361 ((tvar) = TAILQ_PREV(var, headname, field), 1); \
365 * Tail queue functions.
367 #define TAILQ_INIT(head) do { \
368 (head)->tqh_first = NULL; \
369 (head)->tqh_last = &(head)->tqh_first; \
372 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
373 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
374 (head)->tqh_first->field.tqe_prev = \
375 &(elm)->field.tqe_next; \
377 (head)->tqh_last = &(elm)->field.tqe_next; \
378 (head)->tqh_first = (elm); \
379 (elm)->field.tqe_prev = &(head)->tqh_first; \
382 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
383 (elm)->field.tqe_next = NULL; \
384 (elm)->field.tqe_prev = (head)->tqh_last; \
385 *(head)->tqh_last = (elm); \
386 (head)->tqh_last = &(elm)->field.tqe_next; \
389 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
390 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
391 (elm)->field.tqe_next->field.tqe_prev = \
392 &(elm)->field.tqe_next; \
394 (head)->tqh_last = &(elm)->field.tqe_next; \
395 (listelm)->field.tqe_next = (elm); \
396 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
399 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
400 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
401 (elm)->field.tqe_next = (listelm); \
402 *(listelm)->field.tqe_prev = (elm); \
403 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
406 #define TAILQ_REMOVE(head, elm, field) do { \
407 if (((elm)->field.tqe_next) != NULL) \
408 (elm)->field.tqe_next->field.tqe_prev = \
409 (elm)->field.tqe_prev; \
411 (head)->tqh_last = (elm)->field.tqe_prev; \
412 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
415 #define TAILQ_REPLACE(head, elm, elm2, field) do { \
416 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
417 (elm2)->field.tqe_next->field.tqe_prev = \
418 &(elm2)->field.tqe_next; \
420 (head)->tqh_last = &(elm2)->field.tqe_next; \
421 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
422 *(elm2)->field.tqe_prev = (elm2); \
426 * Circular queue definitions.
428 #define CIRCLEQ_HEAD(name, type) \
430 struct type *cqh_first; /* first element */ \
431 struct type *cqh_last; /* last element */ \
434 #define CIRCLEQ_HEAD_INITIALIZER(head) \
435 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
437 #define CIRCLEQ_ENTRY(type) \
439 struct type *cqe_next; /* next element */ \
440 struct type *cqe_prev; /* previous element */ \
444 * Circular queue access methods
446 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
447 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
448 #define CIRCLEQ_END(head) ((void *)(head))
449 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
450 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
451 #define CIRCLEQ_EMPTY(head) \
452 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
454 #define CIRCLEQ_FOREACH(var, head, field) \
455 for((var) = CIRCLEQ_FIRST(head); \
456 (var) != CIRCLEQ_END(head); \
457 (var) = CIRCLEQ_NEXT(var, field))
459 #define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar) \
460 for((var) = CIRCLEQ_FIRST(head); \
461 (var) != CIRCLEQ_END(head) && \
462 ((tvar) = CIRCLEQ_NEXT(var, field), 1); \
465 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
466 for((var) = CIRCLEQ_LAST(head); \
467 (var) != CIRCLEQ_END(head); \
468 (var) = CIRCLEQ_PREV(var, field))
470 #define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, field, tvar) \
471 for((var) = CIRCLEQ_LAST(head); \
472 (var) != CIRCLEQ_END(head) && \
473 ((tvar) = CIRCLEQ_PREV(var, field), 1); \
477 * Circular queue functions.
479 #define CIRCLEQ_INIT(head) do { \
480 (head)->cqh_first = CIRCLEQ_END(head); \
481 (head)->cqh_last = CIRCLEQ_END(head); \
484 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
485 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
486 (elm)->field.cqe_prev = (listelm); \
487 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \
488 (head)->cqh_last = (elm); \
490 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
491 (listelm)->field.cqe_next = (elm); \
494 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
495 (elm)->field.cqe_next = (listelm); \
496 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
497 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \
498 (head)->cqh_first = (elm); \
500 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
501 (listelm)->field.cqe_prev = (elm); \
504 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
505 (elm)->field.cqe_next = (head)->cqh_first; \
506 (elm)->field.cqe_prev = CIRCLEQ_END(head); \
507 if ((head)->cqh_last == CIRCLEQ_END(head)) \
508 (head)->cqh_last = (elm); \
510 (head)->cqh_first->field.cqe_prev = (elm); \
511 (head)->cqh_first = (elm); \
514 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
515 (elm)->field.cqe_next = CIRCLEQ_END(head); \
516 (elm)->field.cqe_prev = (head)->cqh_last; \
517 if ((head)->cqh_first == CIRCLEQ_END(head)) \
518 (head)->cqh_first = (elm); \
520 (head)->cqh_last->field.cqe_next = (elm); \
521 (head)->cqh_last = (elm); \
524 #define CIRCLEQ_REMOVE(head, elm, field) do { \
525 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \
526 (head)->cqh_last = (elm)->field.cqe_prev; \
528 (elm)->field.cqe_next->field.cqe_prev = \
529 (elm)->field.cqe_prev; \
530 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \
531 (head)->cqh_first = (elm)->field.cqe_next; \
533 (elm)->field.cqe_prev->field.cqe_next = \
534 (elm)->field.cqe_next; \
537 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \
538 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \
540 (head).cqh_last = (elm2); \
542 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \
543 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \
545 (head).cqh_first = (elm2); \
547 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \
550 #endif /* !_LOCAL_SYS_QUEUE_H_ */