2 * Copyright (c) 1991, 1993
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6 * modification, are permitted provided that the following conditions
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29 * @(#)queue.h 8.5 (Berkeley) 8/20/94
31 * Derived from FreeBSD src/sys/sys/queue.h:1.63.
32 * $P4: //depot/projects/trustedbsd/openbsm/compat/queue.h#3 $
35 #ifndef _COMPAT_QUEUE_H_
36 #define _COMPAT_QUEUE_H_
38 #include <sys/cdefs.h>
41 * This file defines four types of data structures: singly-linked lists,
42 * singly-linked tail queues, lists and tail queues.
44 * A singly-linked list is headed by a single forward pointer. The elements
45 * are singly linked for minimum space and pointer manipulation overhead at
46 * the expense of O(n) removal for arbitrary elements. New elements can be
47 * added to the list after an existing element or at the head of the list.
48 * Elements being removed from the head of the list should use the explicit
49 * macro for this purpose for optimum efficiency. A singly-linked list may
50 * only be traversed in the forward direction. Singly-linked lists are ideal
51 * for applications with large datasets and few or no removals or for
52 * implementing a LIFO queue.
54 * A singly-linked tail queue is headed by a pair of pointers, one to the
55 * head of the list and the other to the tail of the list. The elements are
56 * singly linked for minimum space and pointer manipulation overhead at the
57 * expense of O(n) removal for arbitrary elements. New elements can be added
58 * to the list after an existing element, at the head of the list, or at the
59 * end of the list. Elements being removed from the head of the tail queue
60 * should use the explicit macro for this purpose for optimum efficiency.
61 * A singly-linked tail queue may only be traversed in the forward direction.
62 * Singly-linked tail queues are ideal for applications with large datasets
63 * and few or no removals or for implementing a FIFO queue.
65 * A list is headed by a single forward pointer (or an array of forward
66 * pointers for a hash table header). The elements are doubly linked
67 * so that an arbitrary element can be removed without a need to
68 * traverse the list. New elements can be added to the list before
69 * or after an existing element or at the head of the list. A list
70 * may only be traversed in the forward direction.
72 * A tail queue is headed by a pair of pointers, one to the head of the
73 * list and the other to the tail of the list. The elements are doubly
74 * linked so that an arbitrary element can be removed without a need to
75 * traverse the list. New elements can be added to the list before or
76 * after an existing element, at the head of the list, or at the end of
77 * the list. A tail queue may be traversed in either direction.
79 * For details on the use of these macros, see the queue(3) manual page.
82 * SLIST LIST STAILQ TAILQ
84 * _HEAD_INITIALIZER + + + +
93 * _FOREACH_SAFE + + + +
94 * _FOREACH_REVERSE - - - +
95 * _FOREACH_REVERSE_SAFE - - - +
96 * _INSERT_HEAD + + + +
97 * _INSERT_BEFORE - + - +
98 * _INSERT_AFTER + + + +
99 * _INSERT_TAIL - - + +
101 * _REMOVE_HEAD + - + -
105 #ifdef QUEUE_MACRO_DEBUG
106 /* Store the last 2 places the queue element or head was altered */
114 #define TRACEBUF struct qm_trace trace;
115 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
117 #define QMD_TRACE_HEAD(head) do { \
118 (head)->trace.prevline = (head)->trace.lastline; \
119 (head)->trace.prevfile = (head)->trace.lastfile; \
120 (head)->trace.lastline = __LINE__; \
121 (head)->trace.lastfile = __FILE__; \
124 #define QMD_TRACE_ELEM(elem) do { \
125 (elem)->trace.prevline = (elem)->trace.lastline; \
126 (elem)->trace.prevfile = (elem)->trace.lastfile; \
127 (elem)->trace.lastline = __LINE__; \
128 (elem)->trace.lastfile = __FILE__; \
132 #define QMD_TRACE_ELEM(elem)
133 #define QMD_TRACE_HEAD(head)
136 #endif /* QUEUE_MACRO_DEBUG */
139 * Singly-linked List declarations.
141 #define SLIST_HEAD(name, type) \
143 struct type *slh_first; /* first element */ \
146 #define SLIST_HEAD_INITIALIZER(head) \
149 #define SLIST_ENTRY(type) \
151 struct type *sle_next; /* next element */ \
155 * Singly-linked List functions.
157 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
159 #define SLIST_FIRST(head) ((head)->slh_first)
161 #define SLIST_FOREACH(var, head, field) \
162 for ((var) = SLIST_FIRST((head)); \
164 (var) = SLIST_NEXT((var), field))
166 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
167 for ((var) = SLIST_FIRST((head)); \
168 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
171 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
172 for ((varp) = &SLIST_FIRST((head)); \
173 ((var) = *(varp)) != NULL; \
174 (varp) = &SLIST_NEXT((var), field))
176 #define SLIST_INIT(head) do { \
177 SLIST_FIRST((head)) = NULL; \
180 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
181 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
182 SLIST_NEXT((slistelm), field) = (elm); \
185 #define SLIST_INSERT_HEAD(head, elm, field) do { \
186 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
187 SLIST_FIRST((head)) = (elm); \
190 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
192 #define SLIST_REMOVE(head, elm, type, field) do { \
193 if (SLIST_FIRST((head)) == (elm)) { \
194 SLIST_REMOVE_HEAD((head), field); \
197 struct type *curelm = SLIST_FIRST((head)); \
198 while (SLIST_NEXT(curelm, field) != (elm)) \
199 curelm = SLIST_NEXT(curelm, field); \
200 SLIST_NEXT(curelm, field) = \
201 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
203 TRASHIT((elm)->field.sle_next); \
206 #define SLIST_REMOVE_HEAD(head, field) do { \
207 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
211 * Singly-linked Tail queue declarations.
213 #define STAILQ_HEAD(name, type) \
215 struct type *stqh_first;/* first element */ \
216 struct type **stqh_last;/* addr of last next element */ \
219 #define STAILQ_HEAD_INITIALIZER(head) \
220 { NULL, &(head).stqh_first }
222 #define STAILQ_ENTRY(type) \
224 struct type *stqe_next; /* next element */ \
228 * Singly-linked Tail queue functions.
230 #define STAILQ_CONCAT(head1, head2) do { \
231 if (!STAILQ_EMPTY((head2))) { \
232 *(head1)->stqh_last = (head2)->stqh_first; \
233 (head1)->stqh_last = (head2)->stqh_last; \
234 STAILQ_INIT((head2)); \
238 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
240 #define STAILQ_FIRST(head) ((head)->stqh_first)
242 #define STAILQ_FOREACH(var, head, field) \
243 for((var) = STAILQ_FIRST((head)); \
245 (var) = STAILQ_NEXT((var), field))
248 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
249 for ((var) = STAILQ_FIRST((head)); \
250 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
253 #define STAILQ_INIT(head) do { \
254 STAILQ_FIRST((head)) = NULL; \
255 (head)->stqh_last = &STAILQ_FIRST((head)); \
258 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
259 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
260 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
261 STAILQ_NEXT((tqelm), field) = (elm); \
264 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
265 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
266 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
267 STAILQ_FIRST((head)) = (elm); \
270 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
271 STAILQ_NEXT((elm), field) = NULL; \
272 *(head)->stqh_last = (elm); \
273 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
276 #define STAILQ_LAST(head, type, field) \
277 (STAILQ_EMPTY((head)) ? \
280 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
282 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
284 #define STAILQ_REMOVE(head, elm, type, field) do { \
285 if (STAILQ_FIRST((head)) == (elm)) { \
286 STAILQ_REMOVE_HEAD((head), field); \
289 struct type *curelm = STAILQ_FIRST((head)); \
290 while (STAILQ_NEXT(curelm, field) != (elm)) \
291 curelm = STAILQ_NEXT(curelm, field); \
292 if ((STAILQ_NEXT(curelm, field) = \
293 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
294 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\
296 TRASHIT((elm)->field.stqe_next); \
299 #define STAILQ_REMOVE_HEAD(head, field) do { \
300 if ((STAILQ_FIRST((head)) = \
301 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
302 (head)->stqh_last = &STAILQ_FIRST((head)); \
305 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
306 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
307 (head)->stqh_last = &STAILQ_FIRST((head)); \
313 #define LIST_HEAD(name, type) \
315 struct type *lh_first; /* first element */ \
318 #define LIST_HEAD_INITIALIZER(head) \
321 #define LIST_ENTRY(type) \
323 struct type *le_next; /* next element */ \
324 struct type **le_prev; /* address of previous next element */ \
331 #if (defined(_KERNEL) && defined(INVARIANTS)) || defined(QUEUE_MACRO_DEBUG)
332 #define QMD_LIST_CHECK_HEAD(head, field) do { \
333 if (LIST_FIRST((head)) != NULL && \
334 LIST_FIRST((head))->field.le_prev != \
335 &LIST_FIRST((head))) \
336 panic("Bad list head %p first->prev != head", (head)); \
339 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
340 if (LIST_NEXT((elm), field) != NULL && \
341 LIST_NEXT((elm), field)->field.le_prev != \
342 &((elm)->field.le_next)) \
343 panic("Bad link elm %p next->prev != elm", (elm)); \
346 #define QMD_LIST_CHECK_PREV(elm, field) do { \
347 if (*(elm)->field.le_prev != (elm)) \
348 panic("Bad link elm %p prev->next != elm", (elm)); \
351 #define QMD_LIST_CHECK_HEAD(head, field)
352 #define QMD_LIST_CHECK_NEXT(elm, field)
353 #define QMD_LIST_CHECK_PREV(elm, field)
354 #endif /* (_KERNEL && INVARIANTS) || QUEUE_MACRO_DEBUG */
356 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
358 #define LIST_FIRST(head) ((head)->lh_first)
360 #define LIST_FOREACH(var, head, field) \
361 for ((var) = LIST_FIRST((head)); \
363 (var) = LIST_NEXT((var), field))
365 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
366 for ((var) = LIST_FIRST((head)); \
367 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
370 #define LIST_INIT(head) do { \
371 LIST_FIRST((head)) = NULL; \
374 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
375 QMD_LIST_CHECK_NEXT(listelm, field); \
376 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
377 LIST_NEXT((listelm), field)->field.le_prev = \
378 &LIST_NEXT((elm), field); \
379 LIST_NEXT((listelm), field) = (elm); \
380 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
383 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
384 QMD_LIST_CHECK_PREV(listelm, field); \
385 (elm)->field.le_prev = (listelm)->field.le_prev; \
386 LIST_NEXT((elm), field) = (listelm); \
387 *(listelm)->field.le_prev = (elm); \
388 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
391 #define LIST_INSERT_HEAD(head, elm, field) do { \
392 QMD_LIST_CHECK_HEAD((head), field); \
393 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
394 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
395 LIST_FIRST((head)) = (elm); \
396 (elm)->field.le_prev = &LIST_FIRST((head)); \
399 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
401 #define LIST_REMOVE(elm, field) do { \
402 QMD_LIST_CHECK_NEXT(elm, field); \
403 QMD_LIST_CHECK_PREV(elm, field); \
404 if (LIST_NEXT((elm), field) != NULL) \
405 LIST_NEXT((elm), field)->field.le_prev = \
406 (elm)->field.le_prev; \
407 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
408 TRASHIT((elm)->field.le_next); \
409 TRASHIT((elm)->field.le_prev); \
413 * Tail queue declarations.
415 #define TAILQ_HEAD(name, type) \
417 struct type *tqh_first; /* first element */ \
418 struct type **tqh_last; /* addr of last next element */ \
422 #define TAILQ_HEAD_INITIALIZER(head) \
423 { NULL, &(head).tqh_first }
425 #define TAILQ_ENTRY(type) \
427 struct type *tqe_next; /* next element */ \
428 struct type **tqe_prev; /* address of previous next element */ \
433 * Tail queue functions.
435 #define TAILQ_CONCAT(head1, head2, field) do { \
436 if (!TAILQ_EMPTY(head2)) { \
437 *(head1)->tqh_last = (head2)->tqh_first; \
438 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
439 (head1)->tqh_last = (head2)->tqh_last; \
440 TAILQ_INIT((head2)); \
441 QMD_TRACE_HEAD(head1); \
442 QMD_TRACE_HEAD(head2); \
446 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
448 #define TAILQ_FIRST(head) ((head)->tqh_first)
450 #define TAILQ_FOREACH(var, head, field) \
451 for ((var) = TAILQ_FIRST((head)); \
453 (var) = TAILQ_NEXT((var), field))
455 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
456 for ((var) = TAILQ_FIRST((head)); \
457 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
460 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
461 for ((var) = TAILQ_LAST((head), headname); \
463 (var) = TAILQ_PREV((var), headname, field))
465 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
466 for ((var) = TAILQ_LAST((head), headname); \
467 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
470 #define TAILQ_INIT(head) do { \
471 TAILQ_FIRST((head)) = NULL; \
472 (head)->tqh_last = &TAILQ_FIRST((head)); \
473 QMD_TRACE_HEAD(head); \
476 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
477 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
478 TAILQ_NEXT((elm), field)->field.tqe_prev = \
479 &TAILQ_NEXT((elm), field); \
481 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
482 QMD_TRACE_HEAD(head); \
484 TAILQ_NEXT((listelm), field) = (elm); \
485 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
486 QMD_TRACE_ELEM(&(elm)->field); \
487 QMD_TRACE_ELEM(&listelm->field); \
490 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
491 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
492 TAILQ_NEXT((elm), field) = (listelm); \
493 *(listelm)->field.tqe_prev = (elm); \
494 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
495 QMD_TRACE_ELEM(&(elm)->field); \
496 QMD_TRACE_ELEM(&listelm->field); \
499 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
500 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
501 TAILQ_FIRST((head))->field.tqe_prev = \
502 &TAILQ_NEXT((elm), field); \
504 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
505 TAILQ_FIRST((head)) = (elm); \
506 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
507 QMD_TRACE_HEAD(head); \
508 QMD_TRACE_ELEM(&(elm)->field); \
511 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
512 TAILQ_NEXT((elm), field) = NULL; \
513 (elm)->field.tqe_prev = (head)->tqh_last; \
514 *(head)->tqh_last = (elm); \
515 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
516 QMD_TRACE_HEAD(head); \
517 QMD_TRACE_ELEM(&(elm)->field); \
520 #define TAILQ_LAST(head, headname) \
521 (*(((struct headname *)((head)->tqh_last))->tqh_last))
523 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
525 #define TAILQ_PREV(elm, headname, field) \
526 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
528 #define TAILQ_REMOVE(head, elm, field) do { \
529 if ((TAILQ_NEXT((elm), field)) != NULL) \
530 TAILQ_NEXT((elm), field)->field.tqe_prev = \
531 (elm)->field.tqe_prev; \
533 (head)->tqh_last = (elm)->field.tqe_prev; \
534 QMD_TRACE_HEAD(head); \
536 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
537 TRASHIT((elm)->field.tqe_next); \
538 TRASHIT((elm)->field.tqe_prev); \
539 QMD_TRACE_ELEM(&(elm)->field); \
542 #endif /* !_COMPAT_QUEUE_H_ */