1 /* $NetBSD: queue.h,v 1.4 2006/09/09 16:22:09 manu Exp $ */
2
3 /*
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)queue.h 8.5 (Berkeley) 8/20/94
32 * $FreeBSD: src/sys/sys/queue.h,v 1.58 2004/04/07 04:19:49 imp Exp $
33 *
34 * 04/24/2004 Backport to v1.45 functionality for ipsec-tools
35 * Heiko Hund <heiko@ist.eigentlich.net>
36 */
37
38 #ifndef _SYS_QUEUE_H_
39 #define _SYS_QUEUE_H_
40
41 //#include <sys/cdefs.h>
42
43 /*
44 * This file defines four types of data structures: singly-linked lists,
45 * singly-linked tail queues, lists and tail queues.
46 *
47 * A singly-linked list is headed by a single forward pointer. The elements
48 * are singly linked for minimum space and pointer manipulation overhead at
49 * the expense of O(n) removal for arbitrary elements. New elements can be
50 * added to the list after an existing element or at the head of the list.
51 * Elements being removed from the head of the list should use the explicit
52 * macro for this purpose for optimum efficiency. A singly-linked list may
53 * only be traversed in the forward direction. Singly-linked lists are ideal
54 * for applications with large datasets and few or no removals or for
55 * implementing a LIFO queue.
56 *
57 * A singly-linked tail queue is headed by a pair of pointers, one to the
58 * head of the list and the other to the tail of the list. The elements are
59 * singly linked for minimum space and pointer manipulation overhead at the
60 * expense of O(n) removal for arbitrary elements. New elements can be added
61 * to the list after an existing element, at the head of the list, or at the
62 * end of the list. Elements being removed from the head of the tail queue
63 * should use the explicit macro for this purpose for optimum efficiency.
64 * A singly-linked tail queue may only be traversed in the forward direction.
65 * Singly-linked tail queues are ideal for applications with large datasets
66 * and few or no removals or for implementing a FIFO queue.
67 *
68 * A list is headed by a single forward pointer (or an array of forward
69 * pointers for a hash table header). The elements are doubly linked
70 * so that an arbitrary element can be removed without a need to
71 * traverse the list. New elements can be added to the list before
72 * or after an existing element or at the head of the list. A list
73 * may only be traversed in the forward direction.
74 *
75 * A tail queue is headed by a pair of pointers, one to the head of the
76 * list and the other to the tail of the list. The elements are doubly
77 * linked so that an arbitrary element can be removed without a need to
78 * traverse the list. New elements can be added to the list before or
79 * after an existing element, at the head of the list, or at the end of
80 * the list. A tail queue may be traversed in either direction.
81 *
82 * For details on the use of these macros, see the queue(3) manual page.
83 *
84 *
85 * SLIST LIST STAILQ TAILQ
86 * _HEAD + + + +
87 * _HEAD_INITIALIZER + + + +
88 * _ENTRY + + + +
89 * _INIT + + + +
90 * _EMPTY + + + +
91 * _FIRST + + + +
92 * _NEXT + + + +
93 * _PREV - - - +
94 * _LAST - - + +
95 * _FOREACH + + + +
96 * _FOREACH_REVERSE - - - +
97 * _INSERT_HEAD + + + +
98 * _INSERT_BEFORE - + - +
99 * _INSERT_AFTER + + + +
100 * _INSERT_TAIL - - + +
101 * _REMOVE_HEAD + - + -
102 * _REMOVE + + + +
103 *
104 */
105
106 /*
107 * Singly-linked List declarations.
108 */
109 #define SLIST_HEAD(name, type) \
110 struct name { \
111 struct type *slh_first; /* first element */ \
112 }
113
114 #define SLIST_HEAD_INITIALIZER(head) \
115 { NULL }
116
117 #define SLIST_ENTRY(type) \
118 struct { \
119 struct type *sle_next; /* next element */ \
120 }
121
122 /*
123 * Singly-linked List functions.
124 */
125 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
126
127 #define SLIST_FIRST(head) ((head)->slh_first)
128
129 #define SLIST_FOREACH(var, head, field) \
130 for ((var) = SLIST_FIRST((head)); \
131 (var); \
132 (var) = SLIST_NEXT((var), field))
133
134 #define SLIST_INIT(head) do { \
135 SLIST_FIRST((head)) = NULL; \
136 } while (0)
137
138 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
139 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
140 SLIST_NEXT((slistelm), field) = (elm); \
141 } while (0)
142
143 #define SLIST_INSERT_HEAD(head, elm, field) do { \
144 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
145 SLIST_FIRST((head)) = (elm); \
146 } while (0)
147
148 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
149
150 #define SLIST_REMOVE(head, elm, type, field) do { \
151 if (SLIST_FIRST((head)) == (elm)) { \
152 SLIST_REMOVE_HEAD((head), field); \
153 } \
154 else { \
155 struct type *curelm = SLIST_FIRST((head)); \
156 while (SLIST_NEXT(curelm, field) != (elm)) \
157 curelm = SLIST_NEXT(curelm, field); \
158 SLIST_NEXT(curelm, field) = \
159 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
160 } \
161 } while (0)
162
163 #define SLIST_REMOVE_HEAD(head, field) do { \
164 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
165 } while (0)
166
167 /*
168 * Singly-linked Tail queue declarations.
169 */
170 #define STAILQ_HEAD(name, type) \
171 struct name { \
172 struct type *stqh_first;/* first element */ \
173 struct type **stqh_last;/* addr of last next element */ \
174 }
175
176 #define STAILQ_HEAD_INITIALIZER(head) \
177 { NULL, &(head).stqh_first }
178
179 #define STAILQ_ENTRY(type) \
180 struct { \
181 struct type *stqe_next; /* next element */ \
182 }
183
184 /*
185 * Singly-linked Tail queue functions.
186 */
187 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
188
189 #define STAILQ_FIRST(head) ((head)->stqh_first)
190
191 #define STAILQ_FOREACH(var, head, field) \
192 for((var) = STAILQ_FIRST((head)); \
193 (var); \
194 (var) = STAILQ_NEXT((var), field))
195
196 #define STAILQ_INIT(head) do { \
197 STAILQ_FIRST((head)) = NULL; \
198 (head)->stqh_last = &STAILQ_FIRST((head)); \
199 } while (0)
200
201 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
202 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
203 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
204 STAILQ_NEXT((tqelm), field) = (elm); \
205 } while (0)
206
207 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
208 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
209 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
210 STAILQ_FIRST((head)) = (elm); \
211 } while (0)
212
213 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
214 STAILQ_NEXT((elm), field) = NULL; \
215 *(head)->stqh_last = (elm); \
216 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
217 } while (0)
218
219 #define STAILQ_LAST(head, type, field) \
220 (STAILQ_EMPTY(head) ? \
221 NULL : \
222 ((struct type *) \
223 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
224
225 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
226
227 #define STAILQ_REMOVE(head, elm, type, field) do { \
228 if (STAILQ_FIRST((head)) == (elm)) { \
229 STAILQ_REMOVE_HEAD(head, field); \
230 } \
231 else { \
232 struct type *curelm = STAILQ_FIRST((head)); \
233 while (STAILQ_NEXT(curelm, field) != (elm)) \
234 curelm = STAILQ_NEXT(curelm, field); \
235 if ((STAILQ_NEXT(curelm, field) = \
236 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
237 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\
238 } \
239 } while (0)
240
241 #define STAILQ_REMOVE_HEAD(head, field) do { \
242 if ((STAILQ_FIRST((head)) = \
243 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
244 (head)->stqh_last = &STAILQ_FIRST((head)); \
245 } while (0)
246
247 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
248 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
249 (head)->stqh_last = &STAILQ_FIRST((head)); \
250 } while (0)
251
252 /*
253 * List declarations.
254 */
255 #define LIST_HEAD(name, type) \
256 struct name { \
257 struct type *lh_first; /* first element */ \
258 }
259
260 #define LIST_HEAD_INITIALIZER(head) \
261 { NULL }
262
263 #define LIST_ENTRY(type) \
264 struct { \
265 struct type *le_next; /* next element */ \
266 struct type **le_prev; /* address of previous next element */ \
267 }
268
269 /*
270 * List functions.
271 */
272
273 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
274
275 #define LIST_FIRST(head) ((head)->lh_first)
276
277 #define LIST_FOREACH(var, head, field) \
278 for ((var) = LIST_FIRST((head)); \
279 (var); \
280 (var) = LIST_NEXT((var), field))
281
282 #define LIST_INIT(head) do { \
283 LIST_FIRST((head)) = NULL; \
284 } while (0)
285
286 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
287 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
288 LIST_NEXT((listelm), field)->field.le_prev = \
289 &LIST_NEXT((elm), field); \
290 LIST_NEXT((listelm), field) = (elm); \
291 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
292 } while (0)
293
294 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
295 (elm)->field.le_prev = (listelm)->field.le_prev; \
296 LIST_NEXT((elm), field) = (listelm); \
297 *(listelm)->field.le_prev = (elm); \
298 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
299 } while (0)
300
301 #define LIST_INSERT_HEAD(head, elm, field) do { \
302 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
303 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
304 LIST_FIRST((head)) = (elm); \
305 (elm)->field.le_prev = &LIST_FIRST((head)); \
306 } while (0)
307
308 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
309
310 #define LIST_REMOVE(elm, field) do { \
311 if (LIST_NEXT((elm), field) != NULL) \
312 LIST_NEXT((elm), field)->field.le_prev = \
313 (elm)->field.le_prev; \
314 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
315 } while (0)
316
317 /*
318 * Tail queue declarations.
319 */
320 #define TAILQ_HEAD(name, type) \
321 struct name { \
322 struct type *tqh_first; /* first element */ \
323 struct type **tqh_last; /* addr of last next element */ \
324 }
325
326 #define TAILQ_HEAD_INITIALIZER(head) \
327 { NULL, &(head).tqh_first }
328
329 #define TAILQ_ENTRY(type) \
330 struct { \
331 struct type *tqe_next; /* next element */ \
332 struct type **tqe_prev; /* address of previous next element */ \
333 }
334
335 /*
336 * Tail queue functions.
337 */
338 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
339
340 #define TAILQ_FIRST(head) ((head)->tqh_first)
341
342 #define TAILQ_FOREACH(var, head, field) \
343 for ((var) = TAILQ_FIRST((head)); \
344 (var); \
345 (var) = TAILQ_NEXT((var), field))
346
347 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
348 for ((var) = TAILQ_LAST((head), headname); \
349 (var); \
350 (var) = TAILQ_PREV((var), headname, field))
351
352 #define TAILQ_INIT(head) do { \
353 TAILQ_FIRST((head)) = NULL; \
354 (head)->tqh_last = &TAILQ_FIRST((head)); \
355 } while (0)
356
357 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
358 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
359 TAILQ_NEXT((elm), field)->field.tqe_prev = \
360 &TAILQ_NEXT((elm), field); \
361 else \
362 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
363 TAILQ_NEXT((listelm), field) = (elm); \
364 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
365 } while (0)
366
367 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
368 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
369 TAILQ_NEXT((elm), field) = (listelm); \
370 *(listelm)->field.tqe_prev = (elm); \
371 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
372 } while (0)
373
374 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
375 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
376 TAILQ_FIRST((head))->field.tqe_prev = \
377 &TAILQ_NEXT((elm), field); \
378 else \
379 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
380 TAILQ_FIRST((head)) = (elm); \
381 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
382 } while (0)
383
384 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
385 TAILQ_NEXT((elm), field) = NULL; \
386 (elm)->field.tqe_prev = (head)->tqh_last; \
387 *(head)->tqh_last = (elm); \
388 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
389 } while (0)
390
391 #define TAILQ_LAST(head, headname) \
392 (*(((struct headname *)((head)->tqh_last))->tqh_last))
393
394 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
395
396 #define TAILQ_PREV(elm, headname, field) \
397 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
398
399 #define TAILQ_REMOVE(head, elm, field) do { \
400 if ((TAILQ_NEXT((elm), field)) != NULL) \
401 TAILQ_NEXT((elm), field)->field.tqe_prev = \
402 (elm)->field.tqe_prev; \
403 else \
404 (head)->tqh_last = (elm)->field.tqe_prev; \
405 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
406 } while (0)
407
408
409 #ifdef _KERNEL
410
411 /*
412 * XXX insque() and remque() are an old way of handling certain queues.
413 * They bogusly assumes that all queue heads look alike.
414 */
415
416 struct quehead {
417 struct quehead *qh_link;
418 struct quehead *qh_rlink;
419 };
420
421 #ifdef __GNUC__
422
423 static __inline void
insque(void * a,void * b)424 insque(void *a, void *b)
425 {
426 struct quehead *element = (struct quehead *)a,
427 *head = (struct quehead *)b;
428
429 element->qh_link = head->qh_link;
430 element->qh_rlink = head;
431 head->qh_link = element;
432 element->qh_link->qh_rlink = element;
433 }
434
435 static __inline void
remque(void * a)436 remque(void *a)
437 {
438 struct quehead *element = (struct quehead *)a;
439
440 element->qh_link->qh_rlink = element->qh_rlink;
441 element->qh_rlink->qh_link = element->qh_link;
442 element->qh_rlink = 0;
443 }
444
445 #else /* !__GNUC__ */
446
447 void insque __P((void *a, void *b));
448 void remque __P((void *a));
449
450 #endif /* __GNUC__ */
451
452 #endif /* _KERNEL */
453
454 #endif /* !_SYS_QUEUE_H_ */
455