↑ 1 /* $OpenBSD: queue.h,v 1.16 2000/09/07 19:47:59 art 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 /*
↑ 86 * Singly-linked List definitions.
↑ 87 */
↑ 88 #define SLIST_HEAD(name, type) \
↑ 89 struct name { \
↑ 90 struct type *slh_first; /* first element */ \
↑ 91 }
↑ 92
↑ 93 #define SLIST_HEAD_INITIALIZER(head) \
↑ 94 { NULL }
↑ 95
↑ 96 #ifndef WIN32
↑ 97 #define SLIST_ENTRY(type) \
↑ 98 struct { \
↑ 99 struct type *sle_next; /* next element */ \
↑100 }
↑101 #endif
↑102
↑103 /*
↑104 * Singly-linked List access methods.
↑105 */
↑106 #define SLIST_FIRST(head) ((head)->slh_first)
↑107 #define SLIST_END(head) NULL
↑108 #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head))
↑109 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
↑110
↑111 #define SLIST_FOREACH(var, head, field) \
↑112 for((var) = SLIST_FIRST(head); \
↑113 (var) != SLIST_END(head); \
↑114 (var) = SLIST_NEXT(var, field))
↑115
↑116 /*
↑117 * Singly-linked List functions.
↑118 */
↑119 #define SLIST_INIT(head) { \
↑120 SLIST_FIRST(head) = SLIST_END(head); \
↑121 }
↑122
↑123 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
↑124 (elm)->field.sle_next = (slistelm)->field.sle_next; \
↑125 (slistelm)->field.sle_next = (elm); \
↑126 } while (0)
↑127
↑128 #define SLIST_INSERT_HEAD(head, elm, field) do { \
↑129 (elm)->field.sle_next = (head)->slh_first; \
↑130 (head)->slh_first = (elm); \
↑131 } while (0)
↑132
↑133 #define SLIST_REMOVE_HEAD(head, field) do { \
↑134 (head)->slh_first = (head)->slh_first->field.sle_next; \
↑135 } while (0)
↑136
↑137 /*
↑138 * List definitions.
↑139 */
↑140 #define LIST_HEAD(name, type) \
↑141 struct name { \
↑142 struct type *lh_first; /* first element */ \
↑143 }
↑144
↑145 #define LIST_HEAD_INITIALIZER(head) \
↑146 { NULL }
↑147
↑148 #define LIST_ENTRY(type) \
↑149 struct { \
↑150 struct type *le_next; /* next element */ \
↑151 struct type **le_prev; /* address of previous next element */ \
↑152 }
↑153
↑154 /*
↑155 * List access methods
↑156 */
↑157 #define LIST_FIRST(head) ((head)->lh_first)
↑158 #define LIST_END(head) NULL
↑159 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
↑160 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
↑161
↑162 #define LIST_FOREACH(var, head, field) \
↑163 for((var) = LIST_FIRST(head); \
↑164 (var)!= LIST_END(head); \
↑165 (var) = LIST_NEXT(var, field))
↑166
↑167 /*
↑168 * List functions.
↑169 */
↑170 #define LIST_INIT(head) do { \
↑171 LIST_FIRST(head) = LIST_END(head); \
↑172 } while (0)
↑173
↑174 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
↑175 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
↑176 (listelm)->field.le_next->field.le_prev = \
↑177 &(elm)->field.le_next; \
↑178 (listelm)->field.le_next = (elm); \
↑179 (elm)->field.le_prev = &(listelm)->field.le_next; \
↑180 } while (0)
↑181
↑182 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
↑183 (elm)->field.le_prev = (listelm)->field.le_prev; \
↑184 (elm)->field.le_next = (listelm); \
↑185 *(listelm)->field.le_prev = (elm); \
↑186 (listelm)->field.le_prev = &(elm)->field.le_next; \
↑187 } while (0)
↑188
↑189 #define LIST_INSERT_HEAD(head, elm, field) do { \
↑190 if (((elm)->field.le_next = (head)->lh_first) != NULL) \
↑191 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
↑192 (head)->lh_first = (elm); \
↑193 (elm)->field.le_prev = &(head)->lh_first; \
↑194 } while (0)
↑195
↑196 #define LIST_REMOVE(elm, field) do { \
↑197 if ((elm)->field.le_next != NULL) \
↑198 (elm)->field.le_next->field.le_prev = \
↑199 (elm)->field.le_prev; \
↑200 *(elm)->field.le_prev = (elm)->field.le_next; \
↑201 } while (0)
↑202
↑203 #define LIST_REPLACE(elm, elm2, field) do { \
↑204 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
↑205 (elm2)->field.le_next->field.le_prev = \
↑206 &(elm2)->field.le_next; \
↑207 (elm2)->field.le_prev = (elm)->field.le_prev; \
↑208 *(elm2)->field.le_prev = (elm2); \
↑209 } while (0)
↑210
↑211 /*
↑212 * Simple queue definitions.
↑213 */
↑214 #define SIMPLEQ_HEAD(name, type) \
↑215 struct name { \
↑216 struct type *sqh_first; /* first element */ \
↑217 struct type **sqh_last; /* addr of last next element */ \
↑218 }
↑219
↑220 #define SIMPLEQ_HEAD_INITIALIZER(head) \
↑221 { NULL, &(head).sqh_first }
↑222
↑223 #define SIMPLEQ_ENTRY(type) \
↑224 struct { \
↑225 struct type *sqe_next; /* next element */ \
↑226 }
↑227
↑228 /*
↑229 * Simple queue access methods.
↑230 */
↑231 #define SIMPLEQ_FIRST(head) ((head)->sqh_first)
↑232 #define SIMPLEQ_END(head) NULL
↑233 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
↑234 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
↑235
↑236 #define SIMPLEQ_FOREACH(var, head, field) \
↑237 for((var) = SIMPLEQ_FIRST(head); \
↑238 (var) != SIMPLEQ_END(head); \
↑239 (var) = SIMPLEQ_NEXT(var, field))
↑240
↑241 /*
↑242 * Simple queue functions.
↑243 */
↑244 #define SIMPLEQ_INIT(head) do { \
↑245 (head)->sqh_first = NULL; \
↑246 (head)->sqh_last = &(head)->sqh_first; \
↑247 } while (0)
↑248
↑249 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
↑250 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
↑251 (head)->sqh_last = &(elm)->field.sqe_next; \
↑252 (head)->sqh_first = (elm); \
↑253 } while (0)
↑254
↑255 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
↑256 (elm)->field.sqe_next = NULL; \
↑257 *(head)->sqh_last = (elm); \
↑258 (head)->sqh_last = &(elm)->field.sqe_next; \
↑259 } while (0)
↑260
↑261 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
↑262 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
↑263 (head)->sqh_last = &(elm)->field.sqe_next; \
↑264 (listelm)->field.sqe_next = (elm); \
↑265 } while (0)
↑266
↑267 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \
↑268 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \
↑269 (head)->sqh_last = &(head)->sqh_first; \
↑270 } while (0)
↑271
↑272 /*
↑273 * Tail queue definitions.
↑274 */
↑275 #define TAILQ_HEAD(name, type) \
↑276 struct name { \
↑277 struct type *tqh_first; /* first element */ \
↑278 struct type **tqh_last; /* addr of last next element */ \
↑279 }
↑280
↑281 #define TAILQ_HEAD_INITIALIZER(head) \
↑282 { NULL, &(head).tqh_first }
↑283
↑284 #define TAILQ_ENTRY(type) \
↑285 struct { \
↑286 struct type *tqe_next; /* next element */ \
↑287 struct type **tqe_prev; /* address of previous next element */ \
↑288 }
↑289
↑290 /*
↑291 * tail queue access methods
↑292 */
↑293 #define TAILQ_FIRST(head) ((head)->tqh_first)
↑294 #define TAILQ_END(head) NULL
↑295 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
↑296 #define TAILQ_LAST(head, headname) \
↑297 (*(((struct headname *)((head)->tqh_last))->tqh_last))
↑298 /* XXX */
↑299 #define TAILQ_PREV(elm, headname, field) \
↑300 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
↑301 #define TAILQ_EMPTY(head) \
↑302 (TAILQ_FIRST(head) == TAILQ_END(head))
↑303
↑304 #define TAILQ_FOREACH(var, head, field) \
↑305 for((var) = TAILQ_FIRST(head); \
↑306 (var) != TAILQ_END(head); \
↑307 (var) = TAILQ_NEXT(var, field))
↑308
↑309 #define TAILQ_FOREACH_REVERSE(var, head, field, headname) \
↑310 for((var) = TAILQ_LAST(head, headname); \
↑311 (var) != TAILQ_END(head); \
↑312 (var) = TAILQ_PREV(var, headname, field))
↑313
↑314 /*
↑315 * Tail queue functions.
↑316 */
↑317 #define TAILQ_INIT(head) do { \
↑318 (head)->tqh_first = NULL; \
↑319 (head)->tqh_last = &(head)->tqh_first; \
↑320 } while (0)
↑321
↑322 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
↑323 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
↑324 (head)->tqh_first->field.tqe_prev = \
↑325 &(elm)->field.tqe_next; \
↑326 else \
↑327 (head)->tqh_last = &(elm)->field.tqe_next; \
↑328 (head)->tqh_first = (elm); \
↑329 (elm)->field.tqe_prev = &(head)->tqh_first; \
↑330 } while (0)
↑331
↑332 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
↑333 (elm)->field.tqe_next = NULL; \
↑334 (elm)->field.tqe_prev = (head)->tqh_last; \
↑335 *(head)->tqh_last = (elm); \
↑336 (head)->tqh_last = &(elm)->field.tqe_next; \
↑337 } while (0)
↑338
↑339 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
↑340 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
↑341 (elm)->field.tqe_next->field.tqe_prev = \
↑342 &(elm)->field.tqe_next; \
↑343 else \
↑344 (head)->tqh_last = &(elm)->field.tqe_next; \
↑345 (listelm)->field.tqe_next = (elm); \
↑346 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
↑347 } while (0)
↑348
↑349 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
↑350 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
↑351 (elm)->field.tqe_next = (listelm); \
↑352 *(listelm)->field.tqe_prev = (elm); \
↑353 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
↑354 } while (0)
↑355
↑356 #define TAILQ_REMOVE(head, elm, field) do { \
↑357 if (((elm)->field.tqe_next) != NULL) \
↑358 (elm)->field.tqe_next->field.tqe_prev = \
↑359 (elm)->field.tqe_prev; \
↑360 else \
↑361 (head)->tqh_last = (elm)->field.tqe_prev; \
↑362 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
↑363 } while (0)
↑364
↑365 #define TAILQ_REPLACE(head, elm, elm2, field) do { \
↑366 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \
↑367 (elm2)->field.tqe_next->field.tqe_prev = \
↑368 &(elm2)->field.tqe_next; \
↑369 else \
↑370 (head)->tqh_last = &(elm2)->field.tqe_next; \
↑371 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \
↑372 *(elm2)->field.tqe_prev = (elm2); \
↑373 } while (0)
↑374
↑375 /*
↑376 * Circular queue definitions.
↑377 */
↑378 #define CIRCLEQ_HEAD(name, type) \
↑379 struct name { \
↑380 struct type *cqh_first; /* first element */ \
↑381 struct type *cqh_last; /* last element */ \
↑382 }
↑383
↑384 #define CIRCLEQ_HEAD_INITIALIZER(head) \
↑385 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
↑386
↑387 #define CIRCLEQ_ENTRY(type) \
↑388 struct { \
↑389 struct type *cqe_next; /* next element */ \
↑390 struct type *cqe_prev; /* previous element */ \
↑391 }
↑392
↑393 /*
↑394 * Circular queue access methods
↑395 */
↑396 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
↑397 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
↑398 #define CIRCLEQ_END(head) ((void *)(head))
↑399 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
↑400 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
↑401 #define CIRCLEQ_EMPTY(head) \
↑402 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head))
↑403
↑404 #define CIRCLEQ_FOREACH(var, head, field) \
↑405 for((var) = CIRCLEQ_FIRST(head); \
↑406 (var) != CIRCLEQ_END(head); \
↑407 (var) = CIRCLEQ_NEXT(var, field))
↑408
↑409 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
↑410 for((var) = CIRCLEQ_LAST(head); \
↑411 (var) != CIRCLEQ_END(head); \
↑412 (var) = CIRCLEQ_PREV(var, field))
↑413
↑414 /*
↑415 * Circular queue functions.
↑416 */
↑417 #define CIRCLEQ_INIT(head) do { \
↑418 (head)->cqh_first = CIRCLEQ_END(head); \
↑419 (head)->cqh_last = CIRCLEQ_END(head); \
↑420 } while (0)
↑421
↑422 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
↑423 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
↑424 (elm)->field.cqe_prev = (listelm); \
↑425 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \
↑426 (head)->cqh_last = (elm); \
↑427 else \
↑428 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
↑429 (listelm)->field.cqe_next = (elm); \
↑430 } while (0)
↑431
↑432 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
↑433 (elm)->field.cqe_next = (listelm); \
↑434 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
↑435 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \
↑436 (head)->cqh_first = (elm); \
↑437 else \
↑438 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
↑439 (listelm)->field.cqe_prev = (elm); \
↑440 } while (0)
↑441
↑442 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
↑443 (elm)->field.cqe_next = (head)->cqh_first; \
↑444 (elm)->field.cqe_prev = CIRCLEQ_END(head); \
↑445 if ((head)->cqh_last == CIRCLEQ_END(head)) \
↑446 (head)->cqh_last = (elm); \
↑447 else \
↑448 (head)->cqh_first->field.cqe_prev = (elm); \
↑449 (head)->cqh_first = (elm); \
↑450 } while (0)
↑451
↑452 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
↑453 (elm)->field.cqe_next = CIRCLEQ_END(head); \
↑454 (elm)->field.cqe_prev = (head)->cqh_last; \
↑455 if ((head)->cqh_first == CIRCLEQ_END(head)) \
↑456 (head)->cqh_first = (elm); \
↑457 else \
↑458 (head)->cqh_last->field.cqe_next = (elm); \
↑459 (head)->cqh_last = (elm); \
↑460 } while (0)
↑461
↑462 #define CIRCLEQ_REMOVE(head, elm, field) do { \
↑463 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \
↑464 (head)->cqh_last = (elm)->field.cqe_prev; \
↑465 else \
↑466 (elm)->field.cqe_next->field.cqe_prev = \
↑467 (elm)->field.cqe_prev; \
↑468 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \
↑469 (head)->cqh_first = (elm)->field.cqe_next; \
↑470 else \
↑471 (elm)->field.cqe_prev->field.cqe_next = \
↑472 (elm)->field.cqe_next; \
↑473 } while (0)
↑474
↑475 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \
↑476 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \
↑477 CIRCLEQ_END(head)) \
↑478 (head).cqh_last = (elm2); \
↑479 else \
↑480 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \
↑481 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \
↑482 CIRCLEQ_END(head)) \
↑483 (head).cqh_first = (elm2); \
↑484 else