1/* $OpenBSD: queue.h,v 1.22 2001/06/23 04:39:35 angelos Exp $ */ 2/* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */ 3 4#ifndef _SYS_QUEUE_H 5#define _SYS_QUEUE_H 6 7#pragma ident "%Z%%M% %I% %E% SMI" 8 9#ifdef __cplusplus 10extern "C" { 11#endif 12 13 14/* 15 * Copyright (c) 1991, 1993 16 * The Regents of the University of California. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. All advertising materials mentioning features or use of this software 27 * must display the following acknowledgement: 28 * This product includes software developed by the University of 29 * California, Berkeley and its contributors. 30 * 4. Neither the name of the University nor the names of its contributors 31 * may be used to endorse or promote products derived from this software 32 * without specific prior written permission. 33 * 34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 37 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 44 * SUCH DAMAGE. 45 * 46 * @(#)queue.h 8.5 (Berkeley) 8/20/94 47 */ 48 49/* 50 * Ignore all <sys/queue.h> since older platforms have broken/incomplete 51 * <sys/queue.h> that are too hard to work around. 52 */ 53#undef SLIST_HEAD 54#undef SLIST_HEAD_INITIALIZER 55#undef SLIST_ENTRY 56#undef SLIST_FIRST 57#undef SLIST_END 58#undef SLIST_EMPTY 59#undef SLIST_NEXT 60#undef SLIST_FOREACH 61#undef SLIST_INIT 62#undef SLIST_INSERT_AFTER 63#undef SLIST_INSERT_HEAD 64#undef SLIST_REMOVE_HEAD 65#undef SLIST_REMOVE 66#undef LIST_HEAD 67#undef LIST_HEAD_INITIALIZER 68#undef LIST_ENTRY 69#undef LIST_FIRST 70#undef LIST_END 71#undef LIST_EMPTY 72#undef LIST_NEXT 73#undef LIST_FOREACH 74#undef LIST_INIT 75#undef LIST_INSERT_AFTER 76#undef LIST_INSERT_BEFORE 77#undef LIST_INSERT_HEAD 78#undef LIST_REMOVE 79#undef LIST_REPLACE 80#undef SIMPLEQ_HEAD 81#undef SIMPLEQ_HEAD_INITIALIZER 82#undef SIMPLEQ_ENTRY 83#undef SIMPLEQ_FIRST 84#undef SIMPLEQ_END 85#undef SIMPLEQ_EMPTY 86#undef SIMPLEQ_NEXT 87#undef SIMPLEQ_FOREACH 88#undef SIMPLEQ_INIT 89#undef SIMPLEQ_INSERT_HEAD 90#undef SIMPLEQ_INSERT_TAIL 91#undef SIMPLEQ_INSERT_AFTER 92#undef SIMPLEQ_REMOVE_HEAD 93#undef TAILQ_HEAD 94#undef TAILQ_HEAD_INITIALIZER 95#undef TAILQ_ENTRY 96#undef TAILQ_FIRST 97#undef TAILQ_END 98#undef TAILQ_NEXT 99#undef TAILQ_LAST 100#undef TAILQ_PREV 101#undef TAILQ_EMPTY 102#undef TAILQ_FOREACH 103#undef TAILQ_FOREACH_REVERSE 104#undef TAILQ_INIT 105#undef TAILQ_INSERT_HEAD 106#undef TAILQ_INSERT_TAIL 107#undef TAILQ_INSERT_AFTER 108#undef TAILQ_INSERT_BEFORE 109#undef TAILQ_REMOVE 110#undef TAILQ_REPLACE 111#undef CIRCLEQ_HEAD 112#undef CIRCLEQ_HEAD_INITIALIZER 113#undef CIRCLEQ_ENTRY 114#undef CIRCLEQ_FIRST 115#undef CIRCLEQ_LAST 116#undef CIRCLEQ_END 117#undef CIRCLEQ_NEXT 118#undef CIRCLEQ_PREV 119#undef CIRCLEQ_EMPTY 120#undef CIRCLEQ_FOREACH 121#undef CIRCLEQ_FOREACH_REVERSE 122#undef CIRCLEQ_INIT 123#undef CIRCLEQ_INSERT_AFTER 124#undef CIRCLEQ_INSERT_BEFORE 125#undef CIRCLEQ_INSERT_HEAD 126#undef CIRCLEQ_INSERT_TAIL 127#undef CIRCLEQ_REMOVE 128#undef CIRCLEQ_REPLACE 129 130/* 131 * This file defines five types of data structures: singly-linked lists, 132 * lists, simple queues, tail queues, and circular queues. 133 * 134 * 135 * A singly-linked list is headed by a single forward pointer. The elements 136 * are singly linked for minimum space and pointer manipulation overhead at 137 * the expense of O(n) removal for arbitrary elements. New elements can be 138 * added to the list after an existing element or at the head of the list. 139 * Elements being removed from the head of the list should use the explicit 140 * macro for this purpose for optimum efficiency. A singly-linked list may 141 * only be traversed in the forward direction. Singly-linked lists are ideal 142 * for applications with large datasets and few or no removals or for 143 * implementing a LIFO queue. 144 * 145 * A list is headed by a single forward pointer (or an array of forward 146 * pointers for a hash table header). The elements are doubly linked 147 * so that an arbitrary element can be removed without a need to 148 * traverse the list. New elements can be added to the list before 149 * or after an existing element or at the head of the list. A list 150 * may only be traversed in the forward direction. 151 * 152 * A simple queue is headed by a pair of pointers, one the head of the 153 * list and the other to the tail of the list. The elements are singly 154 * linked to save space, so elements can only be removed from the 155 * head of the list. New elements can be added to the list before or after 156 * an existing element, at the head of the list, or at the end of the 157 * list. A simple queue may only be traversed in the forward direction. 158 * 159 * A tail queue is headed by a pair of pointers, one to the head of the 160 * list and the other to the tail of the list. The elements are doubly 161 * linked so that an arbitrary element can be removed without a need to 162 * traverse the list. New elements can be added to the list before or 163 * after an existing element, at the head of the list, or at the end of 164 * the list. A tail queue may be traversed in either direction. 165 * 166 * A circle queue is headed by a pair of pointers, one to the head of the 167 * list and the other to the tail of the list. The elements are doubly 168 * linked so that an arbitrary element can be removed without a need to 169 * traverse the list. New elements can be added to the list before or after 170 * an existing element, at the head of the list, or at the end of the list. 171 * A circle queue may be traversed in either direction, but has a more 172 * complex end of list detection. 173 * 174 * For details on the use of these macros, see the queue(3) manual page. 175 */ 176 177/* 178 * Singly-linked List definitions. 179 */ 180#define SLIST_HEAD(name, type) \ 181struct name { \ 182 struct type *slh_first; /* first element */ \ 183} 184 185#define SLIST_HEAD_INITIALIZER(head) \ 186 { NULL } 187 188#define SLIST_ENTRY(type) \ 189struct { \ 190 struct type *sle_next; /* next element */ \ 191} 192 193/* 194 * Singly-linked List access methods. 195 */ 196#define SLIST_FIRST(head) ((head)->slh_first) 197#define SLIST_END(head) NULL 198#define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) 199#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 200 201#define SLIST_FOREACH(var, head, field) \ 202 for((var) = SLIST_FIRST(head); \ 203 (var) != SLIST_END(head); \ 204 (var) = SLIST_NEXT(var, field)) 205 206/* 207 * Singly-linked List functions. 208 */ 209#define SLIST_INIT(head) { \ 210 SLIST_FIRST(head) = SLIST_END(head); \ 211} 212 213#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 214 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 215 (slistelm)->field.sle_next = (elm); \ 216} while (0) 217 218#define SLIST_INSERT_HEAD(head, elm, field) do { \ 219 (elm)->field.sle_next = (head)->slh_first; \ 220 (head)->slh_first = (elm); \ 221} while (0) 222 223#define SLIST_REMOVE_HEAD(head, field) do { \ 224 (head)->slh_first = (head)->slh_first->field.sle_next; \ 225} while (0) 226 227#define SLIST_REMOVE(head, elm, type, field) do { \ 228 if ((head)->slh_first == (elm)) { \ 229 SLIST_REMOVE_HEAD((head), field); \ 230 } \ 231 else { \ 232 struct type *curelm = (head)->slh_first; \ 233 while( curelm->field.sle_next != (elm) ) \ 234 curelm = curelm->field.sle_next; \ 235 curelm->field.sle_next = \ 236 curelm->field.sle_next->field.sle_next; \ 237 } \ 238} while (0) 239 240/* 241 * List definitions. 242 */ 243#define LIST_HEAD(name, type) \ 244struct name { \ 245 struct type *lh_first; /* first element */ \ 246} 247 248#define LIST_HEAD_INITIALIZER(head) \ 249 { NULL } 250 251#define LIST_ENTRY(type) \ 252struct { \ 253 struct type *le_next; /* next element */ \ 254 struct type **le_prev; /* address of previous next element */ \ 255} 256 257/* 258 * List access methods 259 */ 260#define LIST_FIRST(head) ((head)->lh_first) 261#define LIST_END(head) NULL 262#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 263#define LIST_NEXT(elm, field) ((elm)->field.le_next) 264 265#define LIST_FOREACH(var, head, field) \ 266 for((var) = LIST_FIRST(head); \ 267 (var)!= LIST_END(head); \ 268 (var) = LIST_NEXT(var, field)) 269 270/* 271 * List functions. 272 */ 273#define LIST_INIT(head) do { \ 274 LIST_FIRST(head) = LIST_END(head); \ 275} while (0) 276 277#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 278 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 279 (listelm)->field.le_next->field.le_prev = \ 280 &(elm)->field.le_next; \ 281 (listelm)->field.le_next = (elm); \ 282 (elm)->field.le_prev = &(listelm)->field.le_next; \ 283} while (0) 284 285#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 286 (elm)->field.le_prev = (listelm)->field.le_prev; \ 287 (elm)->field.le_next = (listelm); \ 288 *(listelm)->field.le_prev = (elm); \ 289 (listelm)->field.le_prev = &(elm)->field.le_next; \ 290} while (0) 291 292#define LIST_INSERT_HEAD(head, elm, field) do { \ 293 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 294 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 295 (head)->lh_first = (elm); \ 296 (elm)->field.le_prev = &(head)->lh_first; \ 297} while (0) 298 299#define LIST_REMOVE(elm, field) do { \ 300 if ((elm)->field.le_next != NULL) \ 301 (elm)->field.le_next->field.le_prev = \ 302 (elm)->field.le_prev; \ 303 *(elm)->field.le_prev = (elm)->field.le_next; \ 304} while (0) 305 306#define LIST_REPLACE(elm, elm2, field) do { \ 307 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 308 (elm2)->field.le_next->field.le_prev = \ 309 &(elm2)->field.le_next; \ 310 (elm2)->field.le_prev = (elm)->field.le_prev; \ 311 *(elm2)->field.le_prev = (elm2); \ 312} while (0) 313 314/* 315 * Simple queue definitions. 316 */ 317#define SIMPLEQ_HEAD(name, type) \ 318struct name { \ 319 struct type *sqh_first; /* first element */ \ 320 struct type **sqh_last; /* addr of last next element */ \ 321} 322 323#define SIMPLEQ_HEAD_INITIALIZER(head) \ 324 { NULL, &(head).sqh_first } 325 326#define SIMPLEQ_ENTRY(type) \ 327struct { \ 328 struct type *sqe_next; /* next element */ \ 329} 330 331/* 332 * Simple queue access methods. 333 */ 334#define SIMPLEQ_FIRST(head) ((head)->sqh_first) 335#define SIMPLEQ_END(head) NULL 336#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 337#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 338 339#define SIMPLEQ_FOREACH(var, head, field) \ 340 for((var) = SIMPLEQ_FIRST(head); \ 341 (var) != SIMPLEQ_END(head); \ 342 (var) = SIMPLEQ_NEXT(var, field)) 343 344/* 345 * Simple queue functions. 346 */ 347#define SIMPLEQ_INIT(head) do { \ 348 (head)->sqh_first = NULL; \ 349 (head)->sqh_last = &(head)->sqh_first; \ 350} while (0) 351 352#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 353 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 354 (head)->sqh_last = &(elm)->field.sqe_next; \ 355 (head)->sqh_first = (elm); \ 356} while (0) 357 358#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 359 (elm)->field.sqe_next = NULL; \ 360 *(head)->sqh_last = (elm); \ 361 (head)->sqh_last = &(elm)->field.sqe_next; \ 362} while (0) 363 364#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 365 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 366 (head)->sqh_last = &(elm)->field.sqe_next; \ 367 (listelm)->field.sqe_next = (elm); \ 368} while (0) 369 370#define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \ 371 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \ 372 (head)->sqh_last = &(head)->sqh_first; \ 373} while (0) 374 375/* 376 * Tail queue definitions. 377 */ 378#define TAILQ_HEAD(name, type) \ 379struct name { \ 380 struct type *tqh_first; /* first element */ \ 381 struct type **tqh_last; /* addr of last next element */ \ 382} 383 384#define TAILQ_HEAD_INITIALIZER(head) \ 385 { NULL, &(head).tqh_first } 386 387#define TAILQ_ENTRY(type) \ 388struct { \ 389 struct type *tqe_next; /* next element */ \ 390 struct type **tqe_prev; /* address of previous next element */ \ 391} 392 393/* 394 * tail queue access methods 395 */ 396#define TAILQ_FIRST(head) ((head)->tqh_first) 397#define TAILQ_END(head) NULL 398#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 399#define TAILQ_LAST(head, headname) \ 400 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 401/* XXX */ 402#define TAILQ_PREV(elm, headname, field) \ 403 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 404#define TAILQ_EMPTY(head) \ 405 (TAILQ_FIRST(head) == TAILQ_END(head)) 406 407#define TAILQ_FOREACH(var, head, field) \ 408 for((var) = TAILQ_FIRST(head); \ 409 (var) != TAILQ_END(head); \ 410 (var) = TAILQ_NEXT(var, field)) 411 412#define TAILQ_FOREACH_REVERSE(var, head, field, headname) \ 413 for((var) = TAILQ_LAST(head, headname); \ 414 (var) != TAILQ_END(head); \ 415 (var) = TAILQ_PREV(var, headname, field)) 416 417/* 418 * Tail queue functions. 419 */ 420#define TAILQ_INIT(head) do { \ 421 (head)->tqh_first = NULL; \ 422 (head)->tqh_last = &(head)->tqh_first; \ 423} while (0) 424 425#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 426 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 427 (head)->tqh_first->field.tqe_prev = \ 428 &(elm)->field.tqe_next; \ 429 else \ 430 (head)->tqh_last = &(elm)->field.tqe_next; \ 431 (head)->tqh_first = (elm); \ 432 (elm)->field.tqe_prev = &(head)->tqh_first; \ 433} while (0) 434 435#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 436 (elm)->field.tqe_next = NULL; \ 437 (elm)->field.tqe_prev = (head)->tqh_last; \ 438 *(head)->tqh_last = (elm); \ 439 (head)->tqh_last = &(elm)->field.tqe_next; \ 440} while (0) 441 442#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 443 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 444 (elm)->field.tqe_next->field.tqe_prev = \ 445 &(elm)->field.tqe_next; \ 446 else \ 447 (head)->tqh_last = &(elm)->field.tqe_next; \ 448 (listelm)->field.tqe_next = (elm); \ 449 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 450} while (0) 451 452#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 453 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 454 (elm)->field.tqe_next = (listelm); \ 455 *(listelm)->field.tqe_prev = (elm); \ 456 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 457} while (0) 458 459#define TAILQ_REMOVE(head, elm, field) do { \ 460 if (((elm)->field.tqe_next) != NULL) \ 461 (elm)->field.tqe_next->field.tqe_prev = \ 462 (elm)->field.tqe_prev; \ 463 else \ 464 (head)->tqh_last = (elm)->field.tqe_prev; \ 465 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 466} while (0) 467 468#define TAILQ_REPLACE(head, elm, elm2, field) do { \ 469 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 470 (elm2)->field.tqe_next->field.tqe_prev = \ 471 &(elm2)->field.tqe_next; \ 472 else \ 473 (head)->tqh_last = &(elm2)->field.tqe_next; \ 474 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 475 *(elm2)->field.tqe_prev = (elm2); \ 476} while (0) 477 478/* 479 * Circular queue definitions. 480 */ 481#define CIRCLEQ_HEAD(name, type) \ 482struct name { \ 483 struct type *cqh_first; /* first element */ \ 484 struct type *cqh_last; /* last element */ \ 485} 486 487#define CIRCLEQ_HEAD_INITIALIZER(head) \ 488 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 489 490#define CIRCLEQ_ENTRY(type) \ 491struct { \ 492 struct type *cqe_next; /* next element */ \ 493 struct type *cqe_prev; /* previous element */ \ 494} 495 496/* 497 * Circular queue access methods 498 */ 499#define CIRCLEQ_FIRST(head) ((head)->cqh_first) 500#define CIRCLEQ_LAST(head) ((head)->cqh_last) 501#define CIRCLEQ_END(head) ((void *)(head)) 502#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 503#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 504#define CIRCLEQ_EMPTY(head) \ 505 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 506 507#define CIRCLEQ_FOREACH(var, head, field) \ 508 for((var) = CIRCLEQ_FIRST(head); \ 509 (var) != CIRCLEQ_END(head); \ 510 (var) = CIRCLEQ_NEXT(var, field)) 511 512#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 513 for((var) = CIRCLEQ_LAST(head); \ 514 (var) != CIRCLEQ_END(head); \ 515 (var) = CIRCLEQ_PREV(var, field)) 516 517/* 518 * Circular queue functions. 519 */ 520#define CIRCLEQ_INIT(head) do { \ 521 (head)->cqh_first = CIRCLEQ_END(head); \ 522 (head)->cqh_last = CIRCLEQ_END(head); \ 523} while (0) 524 525#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 526 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 527 (elm)->field.cqe_prev = (listelm); \ 528 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 529 (head)->cqh_last = (elm); \ 530 else \ 531 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 532 (listelm)->field.cqe_next = (elm); \ 533} while (0) 534 535#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 536 (elm)->field.cqe_next = (listelm); \ 537 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 538 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 539 (head)->cqh_first = (elm); \ 540 else \ 541 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 542 (listelm)->field.cqe_prev = (elm); \ 543} while (0) 544 545#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 546 (elm)->field.cqe_next = (head)->cqh_first; \ 547 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 548 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 549 (head)->cqh_last = (elm); \ 550 else \ 551 (head)->cqh_first->field.cqe_prev = (elm); \ 552 (head)->cqh_first = (elm); \ 553} while (0) 554 555#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 556 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 557 (elm)->field.cqe_prev = (head)->cqh_last; \ 558 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 559 (head)->cqh_first = (elm); \ 560 else \ 561 (head)->cqh_last->field.cqe_next = (elm); \ 562 (head)->cqh_last = (elm); \ 563} while (0) 564 565#define CIRCLEQ_REMOVE(head, elm, field) do { \ 566 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 567 (head)->cqh_last = (elm)->field.cqe_prev; \ 568 else \ 569 (elm)->field.cqe_next->field.cqe_prev = \ 570 (elm)->field.cqe_prev; \ 571 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 572 (head)->cqh_first = (elm)->field.cqe_next; \ 573 else \ 574 (elm)->field.cqe_prev->field.cqe_next = \ 575 (elm)->field.cqe_next; \ 576} while (0) 577 578#define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ 579 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ 580 CIRCLEQ_END(head)) \ 581 (head).cqh_last = (elm2); \ 582 else \ 583 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 584 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ 585 CIRCLEQ_END(head)) \ 586 (head).cqh_first = (elm2); \ 587 else \ 588 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 589} while (0) 590 591#ifdef __cplusplus 592} 593#endif 594 595#endif /* _SYS_QUEUE_H */ 596