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
36 #include <sys/cdefs.h>
39 * This file defines four types of data structures: singly-linked lists,
40 * singly-linked tail queues, lists and tail queues.
42 * A singly-linked list is headed by a single forward pointer. The elements
43 * are singly linked for minimum space and pointer manipulation overhead at
44 * the expense of O(n) removal for arbitrary elements. New elements can be
45 * added to the list after an existing element or at the head of the list.
46 * Elements being removed from the head of the list should use the explicit
47 * macro for this purpose for optimum efficiency. A singly-linked list may
48 * only be traversed in the forward direction. Singly-linked lists are ideal
49 * for applications with large datasets and few or no removals or for
50 * implementing a LIFO queue.
52 * A singly-linked tail queue is headed by a pair of pointers, one to the
53 * head of the list and the other to the tail of the list. The elements are
54 * singly linked for minimum space and pointer manipulation overhead at the
55 * expense of O(n) removal for arbitrary elements. New elements can be added
56 * to the list after an existing element, at the head of the list, or at the
57 * end of the list. Elements being removed from the head of the tail queue
58 * should use the explicit macro for this purpose for optimum efficiency.
59 * A singly-linked tail queue may only be traversed in the forward direction.
60 * Singly-linked tail queues are ideal for applications with large datasets
61 * and few or no removals or for implementing a FIFO queue.
63 * A list is headed by a single forward pointer (or an array of forward
64 * pointers for a hash table header). The elements are doubly linked
65 * so that an arbitrary element can be removed without a need to
66 * traverse the list. New elements can be added to the list before
67 * or after an existing element or at the head of the list. A list
68 * may be traversed in either direction.
70 * A tail queue is headed by a pair of pointers, one to the head of the
71 * list and the other to the tail of the list. The elements are doubly
72 * linked so that an arbitrary element can be removed without a need to
73 * traverse the list. New elements can be added to the list before or
74 * after an existing element, at the head of the list, or at the end of
75 * the list. A tail queue may be traversed in either direction.
77 * For details on the use of these macros, see the queue(3) manual page.
80 * SLIST LIST STAILQ TAILQ
83 * _HEAD_INITIALIZER + + + +
85 * _CLASS_ENTRY + + + +
93 * _FOREACH_FROM + + + +
94 * _FOREACH_SAFE + + + +
95 * _FOREACH_FROM_SAFE + + + +
96 * _FOREACH_REVERSE - - - +
97 * _FOREACH_REVERSE_FROM - - - +
98 * _FOREACH_REVERSE_SAFE - - - +
99 * _FOREACH_REVERSE_FROM_SAFE - - - +
100 * _INSERT_HEAD + + + +
101 * _INSERT_BEFORE - + - +
102 * _INSERT_AFTER + + + +
103 * _INSERT_TAIL - - + +
105 * _REMOVE_AFTER + - + -
106 * _REMOVE_HEAD + - + -
111 #ifdef QUEUE_MACRO_DEBUG
112 /* Store the last 2 places the queue element or head was altered */
114 unsigned long lastline;
115 unsigned long prevline;
116 const char *lastfile;
117 const char *prevfile;
120 #define TRACEBUF struct qm_trace trace;
121 #define TRACEBUF_INITIALIZER { __LINE__, 0, __FILE__, NULL } ,
122 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
123 #define QMD_SAVELINK(name, link) void **name = (void *)&(link)
125 #define QMD_TRACE_HEAD(head) do { \
126 (head)->trace.prevline = (head)->trace.lastline; \
127 (head)->trace.prevfile = (head)->trace.lastfile; \
128 (head)->trace.lastline = __LINE__; \
129 (head)->trace.lastfile = __FILE__; \
132 #define QMD_TRACE_ELEM(elem) do { \
133 (elem)->trace.prevline = (elem)->trace.lastline; \
134 (elem)->trace.prevfile = (elem)->trace.lastfile; \
135 (elem)->trace.lastline = __LINE__; \
136 (elem)->trace.lastfile = __FILE__; \
140 #define QMD_TRACE_ELEM(elem)
141 #define QMD_TRACE_HEAD(head)
142 #define QMD_SAVELINK(name, link)
144 #define TRACEBUF_INITIALIZER
146 #endif /* QUEUE_MACRO_DEBUG */
150 * In C++ there can be structure lists and class lists:
152 #define QUEUE_TYPEOF(type) type
154 #define QUEUE_TYPEOF(type) struct type
158 * Singly-linked List declarations.
160 #define SLIST_HEAD(name, type) \
162 struct type *slh_first; /* first element */ \
165 #define SLIST_CLASS_HEAD(name, type) \
167 class type *slh_first; /* first element */ \
170 #define SLIST_HEAD_INITIALIZER(head) \
173 #define SLIST_ENTRY(type) \
175 struct type *sle_next; /* next element */ \
178 #define SLIST_CLASS_ENTRY(type) \
180 class type *sle_next; /* next element */ \
184 * Singly-linked List functions.
186 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
188 #define SLIST_FIRST(head) ((head)->slh_first)
190 #define SLIST_FOREACH(var, head, field) \
191 for ((var) = SLIST_FIRST((head)); \
193 (var) = SLIST_NEXT((var), field))
195 #define SLIST_FOREACH_FROM(var, head, field) \
196 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
198 (var) = SLIST_NEXT((var), field))
200 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
201 for ((var) = SLIST_FIRST((head)); \
202 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
205 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
206 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
207 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
210 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
211 for ((varp) = &SLIST_FIRST((head)); \
212 ((var) = *(varp)) != NULL; \
213 (varp) = &SLIST_NEXT((var), field))
215 #define SLIST_INIT(head) do { \
216 SLIST_FIRST((head)) = NULL; \
219 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
220 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
221 SLIST_NEXT((slistelm), field) = (elm); \
224 #define SLIST_INSERT_HEAD(head, elm, field) do { \
225 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
226 SLIST_FIRST((head)) = (elm); \
229 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
231 #define SLIST_REMOVE(head, elm, type, field) do { \
232 QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
233 if (SLIST_FIRST((head)) == (elm)) { \
234 SLIST_REMOVE_HEAD((head), field); \
237 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \
238 while (SLIST_NEXT(curelm, field) != (elm)) \
239 curelm = SLIST_NEXT(curelm, field); \
240 SLIST_REMOVE_AFTER(curelm, field); \
245 #define SLIST_REMOVE_AFTER(elm, field) do { \
246 SLIST_NEXT(elm, field) = \
247 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
250 #define SLIST_REMOVE_HEAD(head, field) do { \
251 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
254 #define SLIST_SWAP(head1, head2, type) do { \
255 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \
256 SLIST_FIRST(head1) = SLIST_FIRST(head2); \
257 SLIST_FIRST(head2) = swap_first; \
261 * Singly-linked Tail queue declarations.
263 #define STAILQ_HEAD(name, type) \
265 struct type *stqh_first;/* first element */ \
266 struct type **stqh_last;/* addr of last next element */ \
269 #define STAILQ_CLASS_HEAD(name, type) \
271 class type *stqh_first; /* first element */ \
272 class type **stqh_last; /* addr of last next element */ \
275 #define STAILQ_HEAD_INITIALIZER(head) \
276 { NULL, &(head).stqh_first }
278 #define STAILQ_ENTRY(type) \
280 struct type *stqe_next; /* next element */ \
283 #define STAILQ_CLASS_ENTRY(type) \
285 class type *stqe_next; /* next element */ \
289 * Singly-linked Tail queue functions.
291 #define STAILQ_CONCAT(head1, head2) do { \
292 if (!STAILQ_EMPTY((head2))) { \
293 *(head1)->stqh_last = (head2)->stqh_first; \
294 (head1)->stqh_last = (head2)->stqh_last; \
295 STAILQ_INIT((head2)); \
299 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
301 #define STAILQ_FIRST(head) ((head)->stqh_first)
303 #define STAILQ_FOREACH(var, head, field) \
304 for((var) = STAILQ_FIRST((head)); \
306 (var) = STAILQ_NEXT((var), field))
308 #define STAILQ_FOREACH_FROM(var, head, field) \
309 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
311 (var) = STAILQ_NEXT((var), field))
313 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
314 for ((var) = STAILQ_FIRST((head)); \
315 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
318 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
319 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
320 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
323 #define STAILQ_INIT(head) do { \
324 STAILQ_FIRST((head)) = NULL; \
325 (head)->stqh_last = &STAILQ_FIRST((head)); \
328 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
329 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
330 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
331 STAILQ_NEXT((tqelm), field) = (elm); \
334 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
335 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
336 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
337 STAILQ_FIRST((head)) = (elm); \
340 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
341 STAILQ_NEXT((elm), field) = NULL; \
342 *(head)->stqh_last = (elm); \
343 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
346 #define STAILQ_LAST(head, type, field) \
347 (STAILQ_EMPTY((head)) ? NULL : \
348 __containerof((head)->stqh_last, \
349 QUEUE_TYPEOF(type), field.stqe_next))
351 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
353 #define STAILQ_REMOVE(head, elm, type, field) do { \
354 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
355 if (STAILQ_FIRST((head)) == (elm)) { \
356 STAILQ_REMOVE_HEAD((head), field); \
359 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \
360 while (STAILQ_NEXT(curelm, field) != (elm)) \
361 curelm = STAILQ_NEXT(curelm, field); \
362 STAILQ_REMOVE_AFTER(head, curelm, field); \
367 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \
368 if ((STAILQ_NEXT(elm, field) = \
369 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
370 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
373 #define STAILQ_REMOVE_HEAD(head, field) do { \
374 if ((STAILQ_FIRST((head)) = \
375 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
376 (head)->stqh_last = &STAILQ_FIRST((head)); \
379 #define STAILQ_SWAP(head1, head2, type) do { \
380 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \
381 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \
382 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
383 (head1)->stqh_last = (head2)->stqh_last; \
384 STAILQ_FIRST(head2) = swap_first; \
385 (head2)->stqh_last = swap_last; \
386 if (STAILQ_EMPTY(head1)) \
387 (head1)->stqh_last = &STAILQ_FIRST(head1); \
388 if (STAILQ_EMPTY(head2)) \
389 (head2)->stqh_last = &STAILQ_FIRST(head2); \
396 #define LIST_HEAD(name, type) \
398 struct type *lh_first; /* first element */ \
401 #define LIST_CLASS_HEAD(name, type) \
403 class type *lh_first; /* first element */ \
406 #define LIST_HEAD_INITIALIZER(head) \
409 #define LIST_ENTRY(type) \
411 struct type *le_next; /* next element */ \
412 struct type **le_prev; /* address of previous next element */ \
415 #define LIST_CLASS_ENTRY(type) \
417 class type *le_next; /* next element */ \
418 class type **le_prev; /* address of previous next element */ \
425 #if (defined(_KERNEL) && defined(INVARIANTS))
426 #define QMD_LIST_CHECK_HEAD(head, field) do { \
427 if (LIST_FIRST((head)) != NULL && \
428 LIST_FIRST((head))->field.le_prev != \
429 &LIST_FIRST((head))) \
430 panic("Bad list head %p first->prev != head", (head)); \
433 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
434 if (LIST_NEXT((elm), field) != NULL && \
435 LIST_NEXT((elm), field)->field.le_prev != \
436 &((elm)->field.le_next)) \
437 panic("Bad link elm %p next->prev != elm", (elm)); \
440 #define QMD_LIST_CHECK_PREV(elm, field) do { \
441 if (*(elm)->field.le_prev != (elm)) \
442 panic("Bad link elm %p prev->next != elm", (elm)); \
445 #define QMD_LIST_CHECK_HEAD(head, field)
446 #define QMD_LIST_CHECK_NEXT(elm, field)
447 #define QMD_LIST_CHECK_PREV(elm, field)
448 #endif /* (_KERNEL && INVARIANTS) */
450 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
452 #define LIST_FIRST(head) ((head)->lh_first)
454 #define LIST_FOREACH(var, head, field) \
455 for ((var) = LIST_FIRST((head)); \
457 (var) = LIST_NEXT((var), field))
459 #define LIST_FOREACH_FROM(var, head, field) \
460 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
462 (var) = LIST_NEXT((var), field))
464 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
465 for ((var) = LIST_FIRST((head)); \
466 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
469 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
470 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
471 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
474 #define LIST_INIT(head) do { \
475 LIST_FIRST((head)) = NULL; \
478 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
479 QMD_LIST_CHECK_NEXT(listelm, field); \
480 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
481 LIST_NEXT((listelm), field)->field.le_prev = \
482 &LIST_NEXT((elm), field); \
483 LIST_NEXT((listelm), field) = (elm); \
484 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
487 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
488 QMD_LIST_CHECK_PREV(listelm, field); \
489 (elm)->field.le_prev = (listelm)->field.le_prev; \
490 LIST_NEXT((elm), field) = (listelm); \
491 *(listelm)->field.le_prev = (elm); \
492 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
495 #define LIST_INSERT_HEAD(head, elm, field) do { \
496 QMD_LIST_CHECK_HEAD((head), field); \
497 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
498 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
499 LIST_FIRST((head)) = (elm); \
500 (elm)->field.le_prev = &LIST_FIRST((head)); \
503 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
505 #define LIST_PREV(elm, head, type, field) \
506 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
507 __containerof((elm)->field.le_prev, \
508 QUEUE_TYPEOF(type), field.le_next))
510 #define LIST_REMOVE(elm, field) do { \
511 QMD_SAVELINK(oldnext, (elm)->field.le_next); \
512 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
513 QMD_LIST_CHECK_NEXT(elm, field); \
514 QMD_LIST_CHECK_PREV(elm, field); \
515 if (LIST_NEXT((elm), field) != NULL) \
516 LIST_NEXT((elm), field)->field.le_prev = \
517 (elm)->field.le_prev; \
518 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
523 #define LIST_SWAP(head1, head2, type, field) do { \
524 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \
525 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
526 LIST_FIRST((head2)) = swap_tmp; \
527 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
528 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
529 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
530 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
534 * Tail queue declarations.
536 #define TAILQ_HEAD(name, type) \
538 struct type *tqh_first; /* first element */ \
539 struct type **tqh_last; /* addr of last next element */ \
543 #define TAILQ_CLASS_HEAD(name, type) \
545 class type *tqh_first; /* first element */ \
546 class type **tqh_last; /* addr of last next element */ \
550 #define TAILQ_HEAD_INITIALIZER(head) \
551 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
553 #define TAILQ_ENTRY(type) \
555 struct type *tqe_next; /* next element */ \
556 struct type **tqe_prev; /* address of previous next element */ \
560 #define TAILQ_CLASS_ENTRY(type) \
562 class type *tqe_next; /* next element */ \
563 class type **tqe_prev; /* address of previous next element */ \
568 * Tail queue functions.
570 #if (defined(_KERNEL) && defined(INVARIANTS))
571 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \
572 if (!TAILQ_EMPTY(head) && \
573 TAILQ_FIRST((head))->field.tqe_prev != \
574 &TAILQ_FIRST((head))) \
575 panic("Bad tailq head %p first->prev != head", (head)); \
578 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \
579 if (*(head)->tqh_last != NULL) \
580 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
583 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
584 if (TAILQ_NEXT((elm), field) != NULL && \
585 TAILQ_NEXT((elm), field)->field.tqe_prev != \
586 &((elm)->field.tqe_next)) \
587 panic("Bad link elm %p next->prev != elm", (elm)); \
590 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \
591 if (*(elm)->field.tqe_prev != (elm)) \
592 panic("Bad link elm %p prev->next != elm", (elm)); \
595 #define QMD_TAILQ_CHECK_HEAD(head, field)
596 #define QMD_TAILQ_CHECK_TAIL(head, headname)
597 #define QMD_TAILQ_CHECK_NEXT(elm, field)
598 #define QMD_TAILQ_CHECK_PREV(elm, field)
599 #endif /* (_KERNEL && INVARIANTS) */
601 #define TAILQ_CONCAT(head1, head2, field) do { \
602 if (!TAILQ_EMPTY(head2)) { \
603 *(head1)->tqh_last = (head2)->tqh_first; \
604 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
605 (head1)->tqh_last = (head2)->tqh_last; \
606 TAILQ_INIT((head2)); \
607 QMD_TRACE_HEAD(head1); \
608 QMD_TRACE_HEAD(head2); \
612 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
614 #define TAILQ_FIRST(head) ((head)->tqh_first)
616 #define TAILQ_FOREACH(var, head, field) \
617 for ((var) = TAILQ_FIRST((head)); \
619 (var) = TAILQ_NEXT((var), field))
621 #define TAILQ_FOREACH_FROM(var, head, field) \
622 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
624 (var) = TAILQ_NEXT((var), field))
626 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
627 for ((var) = TAILQ_FIRST((head)); \
628 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
631 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
632 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
633 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
636 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
637 for ((var) = TAILQ_LAST((head), headname); \
639 (var) = TAILQ_PREV((var), headname, field))
641 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \
642 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
644 (var) = TAILQ_PREV((var), headname, field))
646 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
647 for ((var) = TAILQ_LAST((head), headname); \
648 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
651 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
652 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
653 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
656 #define TAILQ_INIT(head) do { \
657 TAILQ_FIRST((head)) = NULL; \
658 (head)->tqh_last = &TAILQ_FIRST((head)); \
659 QMD_TRACE_HEAD(head); \
662 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
663 QMD_TAILQ_CHECK_NEXT(listelm, field); \
664 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
665 TAILQ_NEXT((elm), field)->field.tqe_prev = \
666 &TAILQ_NEXT((elm), field); \
668 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
669 QMD_TRACE_HEAD(head); \
671 TAILQ_NEXT((listelm), field) = (elm); \
672 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
673 QMD_TRACE_ELEM(&(elm)->field); \
674 QMD_TRACE_ELEM(&(listelm)->field); \
677 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
678 QMD_TAILQ_CHECK_PREV(listelm, field); \
679 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
680 TAILQ_NEXT((elm), field) = (listelm); \
681 *(listelm)->field.tqe_prev = (elm); \
682 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
683 QMD_TRACE_ELEM(&(elm)->field); \
684 QMD_TRACE_ELEM(&(listelm)->field); \
687 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
688 QMD_TAILQ_CHECK_HEAD(head, field); \
689 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
690 TAILQ_FIRST((head))->field.tqe_prev = \
691 &TAILQ_NEXT((elm), field); \
693 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
694 TAILQ_FIRST((head)) = (elm); \
695 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
696 QMD_TRACE_HEAD(head); \
697 QMD_TRACE_ELEM(&(elm)->field); \
700 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
701 QMD_TAILQ_CHECK_TAIL(head, field); \
702 TAILQ_NEXT((elm), field) = NULL; \
703 (elm)->field.tqe_prev = (head)->tqh_last; \
704 *(head)->tqh_last = (elm); \
705 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
706 QMD_TRACE_HEAD(head); \
707 QMD_TRACE_ELEM(&(elm)->field); \
710 #define TAILQ_LAST(head, headname) \
711 (*(((struct headname *)((head)->tqh_last))->tqh_last))
713 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
715 #define TAILQ_PREV(elm, headname, field) \
716 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
718 #define TAILQ_REMOVE(head, elm, field) do { \
719 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
720 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
721 QMD_TAILQ_CHECK_NEXT(elm, field); \
722 QMD_TAILQ_CHECK_PREV(elm, field); \
723 if ((TAILQ_NEXT((elm), field)) != NULL) \
724 TAILQ_NEXT((elm), field)->field.tqe_prev = \
725 (elm)->field.tqe_prev; \
727 (head)->tqh_last = (elm)->field.tqe_prev; \
728 QMD_TRACE_HEAD(head); \
730 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
733 QMD_TRACE_ELEM(&(elm)->field); \
736 #define TAILQ_SWAP(head1, head2, type, field) do { \
737 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \
738 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \
739 (head1)->tqh_first = (head2)->tqh_first; \
740 (head1)->tqh_last = (head2)->tqh_last; \
741 (head2)->tqh_first = swap_first; \
742 (head2)->tqh_last = swap_last; \
743 if ((swap_first = (head1)->tqh_first) != NULL) \
744 swap_first->field.tqe_prev = &(head1)->tqh_first; \
746 (head1)->tqh_last = &(head1)->tqh_first; \
747 if ((swap_first = (head2)->tqh_first) != NULL) \
748 swap_first->field.tqe_prev = &(head2)->tqh_first; \
750 (head2)->tqh_last = &(head2)->tqh_first; \
753 #endif /* !_SYS_QUEUE_H_ */