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bsdqueue.h
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1 /* $OpenBSD: queue.h,v 1.31 2005/11/25 08:06:25 otto Exp $ */
2 /* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */
3 
4 /*
5  * Copyright (c) 1991, 1993
6  * The Regents of the University of California. All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer in the
15  * documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  * may be used to endorse or promote products derived from this software
18  * without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  * @(#)queue.h 8.5 (Berkeley) 8/20/94
33  */
34 
35 #ifndef _SYS_QUEUE_H_
36 #define _SYS_QUEUE_H_
37 
38 /*
39  * This file defines five types of data structures: singly-linked lists,
40  * lists, simple queues, tail queues, and circular queues.
41  *
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 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 list is headed by a single forward pointer (or an array of forward
54  * pointers for a hash table header). The elements are doubly linked
55  * so that an arbitrary element can be removed without a need to
56  * traverse the list. New elements can be added to the list before
57  * or after an existing element or at the head of the list. A list
58  * may only be traversed in the forward direction.
59  *
60  * A simple queue is headed by a pair of pointers, one the head of the
61  * list and the other to the tail of the list. The elements are singly
62  * linked to save space, so elements can only be removed from the
63  * head of the list. New elements can be added to the list before or after
64  * an existing element, at the head of the list, or at the end of the
65  * list. A simple queue may only be traversed in the forward direction.
66  *
67  * A tail queue is headed by a pair of pointers, one to the head of the
68  * list and the other to the tail of the list. The elements are doubly
69  * linked so that an arbitrary element can be removed without a need to
70  * traverse the list. New elements can be added to the list before or
71  * after an existing element, at the head of the list, or at the end of
72  * the list. A tail queue may be traversed in either direction.
73  *
74  * A circle 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 after
78  * an existing element, at the head of the list, or at the end of the list.
79  * A circle queue may be traversed in either direction, but has a more
80  * complex end of list detection.
81  *
82  * For details on the use of these macros, see the queue(3) manual page.
83  */
84 
85 #ifdef QUEUE_MACRO_DEBUG
86 #define _Q_INVALIDATE(a) (a) = ((void *)-1)
87 #else
88 #define _Q_INVALIDATE(a)
89 #endif
90 
91 /*
92  * Singly-linked List definitions.
93  */
94 #define SLIST_HEAD(name, type) \
95 struct name { \
96  struct type *slh_first; /* first element */ \
97 }
98 
99 #define SLIST_HEAD_INITIALIZER(head) \
100  { NULL }
101 
102 #ifdef SLIST_ENTRY
103 #undef SLIST_ENTRY
104 #endif
105 
106 #define SLIST_ENTRY(type) \
107 struct { \
108  struct type *sle_next; /* next element */ \
109 }
110 
111 /*
112  * Singly-linked List access methods.
113  */
114 #define SLIST_FIRST(head) ((head)->slh_first)
115 #define SLIST_END(head) NULL
116 #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head))
117 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
118 
119 #define SLIST_FOREACH(var, head, field) \
120  for((var) = SLIST_FIRST(head); \
121  (var) != SLIST_END(head); \
122  (var) = SLIST_NEXT(var, field))
123 
124 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
125  for ((varp) = &SLIST_FIRST((head)); \
126  ((var) = *(varp)) != SLIST_END(head); \
127  (varp) = &SLIST_NEXT((var), field))
128 
129 /*
130  * Singly-linked List functions.
131  */
132 #define SLIST_INIT(head) { \
133  SLIST_FIRST(head) = SLIST_END(head); \
134 }
135 
136 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
137  (elm)->field.sle_next = (slistelm)->field.sle_next; \
138  (slistelm)->field.sle_next = (elm); \
139 } while (0)
140 
141 #define SLIST_INSERT_HEAD(head, elm, field) do { \
142  (elm)->field.sle_next = (head)->slh_first; \
143  (head)->slh_first = (elm); \
144 } while (0)
145 
146 #define SLIST_REMOVE_NEXT(head, elm, field) do { \
147  (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \
148 } while (0)
149 
150 #define SLIST_REMOVE_HEAD(head, field) do { \
151  (head)->slh_first = (head)->slh_first->field.sle_next; \
152 } while (0)
153 
154 #define SLIST_REMOVE(head, elm, type, field) do { \
155  if ((head)->slh_first == (elm)) { \
156  SLIST_REMOVE_HEAD((head), field); \
157  } else { \
158  struct type *curelm = (head)->slh_first; \
159  \
160  while (curelm->field.sle_next != (elm)) \
161  curelm = curelm->field.sle_next; \
162  curelm->field.sle_next = \
163  curelm->field.sle_next->field.sle_next; \
164  _Q_INVALIDATE((elm)->field.sle_next); \
165  } \
166 } while (0)
167 
168 /*
169  * List definitions.
170  */
171 #define LIST_HEAD(name, type) \
172 struct name { \
173  struct type *lh_first; /* first element */ \
174 }
175 
176 #define LIST_HEAD_INITIALIZER(head) \
177  { NULL }
178 
179 #define LIST_ENTRY(type) \
180 struct { \
181  struct type *le_next; /* next element */ \
182  struct type **le_prev; /* address of previous next element */ \
183 }
184 
185 /*
186  * List access methods
187  */
188 #define LIST_FIRST(head) ((head)->lh_first)
189 #define LIST_END(head) NULL
190 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
191 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
192 
193 #define LIST_FOREACH(var, head, field) \
194  for((var) = LIST_FIRST(head); \
195  (var)!= LIST_END(head); \
196  (var) = LIST_NEXT(var, field))
197 
198 /*
199  * List functions.
200  */
201 #define LIST_INIT(head) do { \
202  LIST_FIRST(head) = LIST_END(head); \
203 } while (0)
204 
205 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
206  if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
207  (listelm)->field.le_next->field.le_prev = \
208  &(elm)->field.le_next; \
209  (listelm)->field.le_next = (elm); \
210  (elm)->field.le_prev = &(listelm)->field.le_next; \
211 } while (0)
212 
213 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
214  (elm)->field.le_prev = (listelm)->field.le_prev; \
215  (elm)->field.le_next = (listelm); \
216  *(listelm)->field.le_prev = (elm); \
217  (listelm)->field.le_prev = &(elm)->field.le_next; \
218 } while (0)
219 
220 #define LIST_INSERT_HEAD(head, elm, field) do { \
221  if (((elm)->field.le_next = (head)->lh_first) != NULL) \
222  (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
223  (head)->lh_first = (elm); \
224  (elm)->field.le_prev = &(head)->lh_first; \
225 } while (0)
226 
227 #define LIST_REMOVE(elm, field) do { \
228  if ((elm)->field.le_next != NULL) \
229  (elm)->field.le_next->field.le_prev = \
230  (elm)->field.le_prev; \
231  *(elm)->field.le_prev = (elm)->field.le_next; \
232  _Q_INVALIDATE((elm)->field.le_prev); \
233  _Q_INVALIDATE((elm)->field.le_next); \
234 } while (0)
235 
236 #define LIST_REPLACE(elm, elm2, field) do { \
237  if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
238  (elm2)->field.le_next->field.le_prev = \
239  &(elm2)->field.le_next; \
240  (elm2)->field.le_prev = (elm)->field.le_prev; \
241  *(elm2)->field.le_prev = (elm2); \
242  _Q_INVALIDATE((elm)->field.le_prev); \
243  _Q_INVALIDATE((elm)->field.le_next); \
244 } while (0)
245 
246 /*
247  * Simple queue definitions.
248  */
249 #define SIMPLEQ_HEAD(name, type) \
250 struct name { \
251  struct type *sqh_first; /* first element */ \
252  struct type **sqh_last; /* addr of last next element */ \
253 }
254 
255 #define SIMPLEQ_HEAD_INITIALIZER(head) \
256  { NULL, &(head).sqh_first }
257 
258 #define SIMPLEQ_ENTRY(type) \
259 struct { \
260  struct type *sqe_next; /* next element */ \
261 }
262 
263 /*
264  * Simple queue access methods.
265  */
266 #define SIMPLEQ_FIRST(head) ((head)->sqh_first)
267 #define SIMPLEQ_END(head) NULL
268 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
269 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
270 
271 #define SIMPLEQ_FOREACH(var, head, field) \
272  for((var) = SIMPLEQ_FIRST(head); \
273  (var) != SIMPLEQ_END(head); \
274  (var) = SIMPLEQ_NEXT(var, field))
275 
276 /*
277  * Simple queue functions.
278  */
279 #define SIMPLEQ_INIT(head) do { \
280  (head)->sqh_first = NULL; \
281  (head)->sqh_last = &(head)->sqh_first; \
282 } while (0)
283 
284 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
285  if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
286  (head)->sqh_last = &(elm)->field.sqe_next; \
287  (head)->sqh_first = (elm); \
288 } while (0)
289 
290 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
291  (elm)->field.sqe_next = NULL; \
292  *(head)->sqh_last = (elm); \
293  (head)->sqh_last = &(elm)->field.sqe_next; \
294 } while (0)
295 
296 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
297  if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
298  (head)->sqh_last = &(elm)->field.sqe_next; \
299  (listelm)->field.sqe_next = (elm); \
300 } while (0)
301 
302 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \
303  if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
304  (head)->sqh_last = &(head)->sqh_first; \
305 } while (0)
306 
307 /*
308  * Tail queue definitions.
309  */
310 #define TAILQ_HEAD(name, type) \
311 struct name { \
312  struct type *tqh_first; /* first element */ \
313  struct type **tqh_last; /* addr of last next element */ \
314 }
315 
316 #define TAILQ_HEAD_INITIALIZER(head) \
317  { NULL, &(head).tqh_first }
318 
319 #define TAILQ_ENTRY(type) \
320 struct { \
321  struct type *tqe_next; /* next element */ \
322  struct type **tqe_prev; /* address of previous next element */ \
323 }
324 
325 /*
326  * tail queue access methods
327  */
328 #define TAILQ_FIRST(head) ((head)->tqh_first)
329 #define TAILQ_END(head) NULL
330 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
331 #define TAILQ_LAST(head, headname) \
332  (*(((struct headname *)((head)->tqh_last))->tqh_last))
333 /* XXX */
334 #define TAILQ_PREV(elm, headname, field) \
335  (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
336 #define TAILQ_EMPTY(head) \
337  (TAILQ_FIRST(head) == TAILQ_END(head))
338 
339 #define TAILQ_FOREACH(var, head, field) \
340  for((var) = TAILQ_FIRST(head); \
341  (var) != TAILQ_END(head); \
342  (var) = TAILQ_NEXT(var, field))
343 
344 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
345  for((var) = TAILQ_LAST(head, headname); \
346  (var) != TAILQ_END(head); \
347  (var) = TAILQ_PREV(var, headname, field))
348 
349 /*
350  * Tail queue functions.
351  */
352 #define TAILQ_INIT(head) do { \
353  (head)->tqh_first = NULL; \
354  (head)->tqh_last = &(head)->tqh_first; \
355 } while (0)
356 
357 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
358  if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
359  (head)->tqh_first->field.tqe_prev = \
360  &(elm)->field.tqe_next; \
361  else \
362  (head)->tqh_last = &(elm)->field.tqe_next; \
363  (head)->tqh_first = (elm); \
364  (elm)->field.tqe_prev = &(head)->tqh_first; \
365 } while (0)
366 
367 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
368  (elm)->field.tqe_next = NULL; \
369  (elm)->field.tqe_prev = (head)->tqh_last; \
370  *(head)->tqh_last = (elm); \
371  (head)->tqh_last = &(elm)->field.tqe_next; \
372 } while (0)
373 
374 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
375  if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
376  (elm)->field.tqe_next->field.tqe_prev = \
377  &(elm)->field.tqe_next; \
378  else \
379  (head)->tqh_last = &(elm)->field.tqe_next; \
380  (listelm)->field.tqe_next = (elm); \
381  (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
382 } while (0)
383 
384 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
385  (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
386  (elm)->field.tqe_next = (listelm); \
387  *(listelm)->field.tqe_prev = (elm); \
388  (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
389 } while (0)
390 
391 #define TAILQ_REMOVE(head, elm, field) do { \
392  if (((elm)->field.tqe_next) != NULL) \
393  (elm)->field.tqe_next->field.tqe_prev = \
394  (elm)->field.tqe_prev; \
395  else \
396  (head)->tqh_last = (elm)->field.tqe_prev; \
397  *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
398  _Q_INVALIDATE((elm)->field.tqe_prev); \
399  _Q_INVALIDATE((elm)->field.tqe_next); \
400 } while (0)
401 
402 #define TAILQ_REPLACE(head, elm, elm2, field) do { \
403  if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
404  (elm2)->field.tqe_next->field.tqe_prev = \
405  &(elm2)->field.tqe_next; \
406  else \
407  (head)->tqh_last = &(elm2)->field.tqe_next; \
408  (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
409  *(elm2)->field.tqe_prev = (elm2); \
410  _Q_INVALIDATE((elm)->field.tqe_prev); \
411  _Q_INVALIDATE((elm)->field.tqe_next); \
412 } while (0)
413 
414 /*
415  * Circular queue definitions.
416  */
417 #define CIRCLEQ_HEAD(name, type) \
418 struct name { \
419  struct type *cqh_first; /* first element */ \
420  struct type *cqh_last; /* last element */ \
421 }
422 
423 #define CIRCLEQ_HEAD_INITIALIZER(head) \
424  { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
425 
426 #define CIRCLEQ_ENTRY(type) \
427 struct { \
428  struct type *cqe_next; /* next element */ \
429  struct type *cqe_prev; /* previous element */ \
430 }
431 
432 /*
433  * Circular queue access methods
434  */
435 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
436 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
437 #define CIRCLEQ_END(head) ((void *)(head))
438 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
439 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
440 #define CIRCLEQ_EMPTY(head) \
441  (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
442 
443 #define CIRCLEQ_FOREACH(var, head, field) \
444  for((var) = CIRCLEQ_FIRST(head); \
445  (var) != CIRCLEQ_END(head); \
446  (var) = CIRCLEQ_NEXT(var, field))
447 
448 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
449  for((var) = CIRCLEQ_LAST(head); \
450  (var) != CIRCLEQ_END(head); \
451  (var) = CIRCLEQ_PREV(var, field))
452 
453 /*
454  * Circular queue functions.
455  */
456 #define CIRCLEQ_INIT(head) do { \
457  (head)->cqh_first = CIRCLEQ_END(head); \
458  (head)->cqh_last = CIRCLEQ_END(head); \
459 } while (0)
460 
461 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
462  (elm)->field.cqe_next = (listelm)->field.cqe_next; \
463  (elm)->field.cqe_prev = (listelm); \
464  if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \
465  (head)->cqh_last = (elm); \
466  else \
467  (listelm)->field.cqe_next->field.cqe_prev = (elm); \
468  (listelm)->field.cqe_next = (elm); \
469 } while (0)
470 
471 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
472  (elm)->field.cqe_next = (listelm); \
473  (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
474  if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \
475  (head)->cqh_first = (elm); \
476  else \
477  (listelm)->field.cqe_prev->field.cqe_next = (elm); \
478  (listelm)->field.cqe_prev = (elm); \
479 } while (0)
480 
481 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
482  (elm)->field.cqe_next = (head)->cqh_first; \
483  (elm)->field.cqe_prev = CIRCLEQ_END(head); \
484  if ((head)->cqh_last == CIRCLEQ_END(head)) \
485  (head)->cqh_last = (elm); \
486  else \
487  (head)->cqh_first->field.cqe_prev = (elm); \
488  (head)->cqh_first = (elm); \
489 } while (0)
490 
491 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
492  (elm)->field.cqe_next = CIRCLEQ_END(head); \
493  (elm)->field.cqe_prev = (head)->cqh_last; \
494  if ((head)->cqh_first == CIRCLEQ_END(head)) \
495  (head)->cqh_first = (elm); \
496  else \
497  (head)->cqh_last->field.cqe_next = (elm); \
498  (head)->cqh_last = (elm); \
499 } while (0)
500 
501 #define CIRCLEQ_REMOVE(head, elm, field) do { \
502  if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \
503  (head)->cqh_last = (elm)->field.cqe_prev; \
504  else \
505  (elm)->field.cqe_next->field.cqe_prev = \
506  (elm)->field.cqe_prev; \
507  if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \
508  (head)->cqh_first = (elm)->field.cqe_next; \
509  else \
510  (elm)->field.cqe_prev->field.cqe_next = \
511  (elm)->field.cqe_next; \
512  _Q_INVALIDATE((elm)->field.cqe_prev); \
513  _Q_INVALIDATE((elm)->field.cqe_next); \
514 } while (0)
515 
516 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \
517  if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \
518  CIRCLEQ_END(head)) \
519  (head).cqh_last = (elm2); \
520  else \
521  (elm2)->field.cqe_next->field.cqe_prev = (elm2); \
522  if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \
523  CIRCLEQ_END(head)) \
524  (head).cqh_first = (elm2); \
525  else \
526  (elm2)->field.cqe_prev->field.cqe_next = (elm2); \
527  _Q_INVALIDATE((elm)->field.cqe_prev); \
528  _Q_INVALIDATE((elm)->field.cqe_next); \
529 } while (0)
530 
531 #endif /* !_SYS_QUEUE_H_ */