1 /* $NetBSD: queue.h,v 1.42 2005/07/13 15:08:24 wiz 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 * 3. 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 */ 33 /* 34 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 35 * Use is subject to license terms. 36 */ 37 38 #ifndef _SYS_QUEUE_H 39 #define _SYS_QUEUE_H 40 41 #include <sys/note.h> 42 43 #ifdef __cplusplus 44 extern "C" { 45 #endif 46 47 /* 48 * This file defines five types of data structures: singly-linked lists, 49 * lists, simple queues, tail queues, and circular queues. 50 * 51 * A singly-linked list is headed by a single forward pointer. The 52 * elements are singly linked for minimum space and pointer manipulation 53 * overhead at the expense of O(n) removal for arbitrary elements. New 54 * elements can be added to the list after an existing element or at the 55 * head of the list. Elements being removed from the head of the list 56 * should use the explicit macro for this purpose for optimum 57 * efficiency. A singly-linked list may only be traversed in the forward 58 * direction. Singly-linked lists are ideal for applications with large 59 * datasets and few or no removals or for implementing a LIFO queue. 60 * 61 * A list is headed by a single forward pointer (or an array of forward 62 * pointers for a hash table header). The elements are doubly linked 63 * so that an arbitrary element can be removed without a need to 64 * traverse the list. New elements can be added to the list before 65 * or after an existing element or at the head of the list. A list 66 * may only be traversed in the forward direction. 67 * 68 * A simple queue is headed by a pair of pointers, one the head of the 69 * list and the other to the tail of the list. The elements are singly 70 * linked to save space, so elements can only be removed from the 71 * head of the list. New elements can be added to the list after 72 * an existing element, at the head of the list, or at the end of the 73 * list. A simple queue 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 * A circle queue is headed by a pair of pointers, one to the head of the 83 * list and the other to the tail of the list. The elements are doubly 84 * linked so that an arbitrary element can be removed without a need to 85 * traverse the list. New elements can be added to the list before or after 86 * an existing element, at the head of the list, or at the end of the list. 87 * A circle queue may be traversed in either direction, but has a more 88 * complex end of list detection. 89 * 90 * For details on the use of these macros, see the queue(3) manual page. 91 */ 92 93 /* 94 * List definitions. 95 */ 96 #define LIST_HEAD(name, type) \ 97 struct name { \ 98 struct type *lh_first; /* first element */ \ 99 } 100 101 #define LIST_HEAD_INITIALIZER(head) \ 102 { NULL } 103 104 #define LIST_ENTRY(type) \ 105 struct { \ 106 struct type *le_next; /* next element */ \ 107 struct type **le_prev; /* address of previous next element */ \ 108 } 109 110 /* 111 * List functions. 112 */ 113 #if defined(_KERNEL) && defined(QUEUEDEBUG) 114 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) \ 115 if ((head)->lh_first && \ 116 (head)->lh_first->field.le_prev != &(head)->lh_first) \ 117 panic("LIST_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__); 118 #define QUEUEDEBUG_LIST_OP(elm, field) \ 119 if ((elm)->field.le_next && \ 120 (elm)->field.le_next->field.le_prev != \ 121 &(elm)->field.le_next) \ 122 panic("LIST_* forw %p %s:%d", (elm), __FILE__, __LINE__);\ 123 if (*(elm)->field.le_prev != (elm)) \ 124 panic("LIST_* back %p %s:%d", (elm), __FILE__, __LINE__); 125 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) \ 126 (elm)->field.le_next = (void *)1L; \ 127 (elm)->field.le_prev = (void *)1L; 128 #else 129 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) 130 #define QUEUEDEBUG_LIST_OP(elm, field) 131 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) 132 #endif 133 134 #define LIST_INIT(head) do { \ 135 (head)->lh_first = NULL; \ 136 _NOTE(CONSTCOND) \ 137 } while (0) 138 139 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 140 QUEUEDEBUG_LIST_OP((listelm), field) \ 141 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 142 (listelm)->field.le_next->field.le_prev = \ 143 &(elm)->field.le_next; \ 144 (listelm)->field.le_next = (elm); \ 145 (elm)->field.le_prev = &(listelm)->field.le_next; \ 146 _NOTE(CONSTCOND) \ 147 } while (0) 148 149 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 150 QUEUEDEBUG_LIST_OP((listelm), field) \ 151 (elm)->field.le_prev = (listelm)->field.le_prev; \ 152 (elm)->field.le_next = (listelm); \ 153 *(listelm)->field.le_prev = (elm); \ 154 (listelm)->field.le_prev = &(elm)->field.le_next; \ 155 _NOTE(CONSTCOND) \ 156 } while (0) 157 158 #define LIST_INSERT_HEAD(head, elm, field) do { \ 159 QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field) \ 160 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 161 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 162 (head)->lh_first = (elm); \ 163 (elm)->field.le_prev = &(head)->lh_first; \ 164 _NOTE(CONSTCOND) \ 165 } while (0) 166 167 #define LIST_REMOVE(elm, field) do { \ 168 QUEUEDEBUG_LIST_OP((elm), field) \ 169 if ((elm)->field.le_next != NULL) \ 170 (elm)->field.le_next->field.le_prev = \ 171 (elm)->field.le_prev; \ 172 *(elm)->field.le_prev = (elm)->field.le_next; \ 173 QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \ 174 _NOTE(CONSTCOND) \ 175 } while (0) 176 177 #define LIST_FOREACH(var, head, field) \ 178 for ((var) = ((head)->lh_first); \ 179 (var); \ 180 (var) = ((var)->field.le_next)) 181 182 /* 183 * List access methods. 184 */ 185 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 186 #define LIST_FIRST(head) ((head)->lh_first) 187 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 188 189 190 /* 191 * Singly-linked List definitions. 192 */ 193 #define SLIST_HEAD(name, type) \ 194 struct name { \ 195 struct type *slh_first; /* first element */ \ 196 } 197 198 #define SLIST_HEAD_INITIALIZER(head) \ 199 { NULL } 200 201 #define SLIST_ENTRY(type) \ 202 struct { \ 203 struct type *sle_next; /* next element */ \ 204 } 205 206 /* 207 * Singly-linked List functions. 208 */ 209 #define SLIST_INIT(head) do { \ 210 (head)->slh_first = NULL; \ 211 _NOTE(CONSTCOND) \ 212 } while (0) 213 214 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 215 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 216 (slistelm)->field.sle_next = (elm); \ 217 _NOTE(CONSTCOND) \ 218 } while (0) 219 220 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 221 (elm)->field.sle_next = (head)->slh_first; \ 222 (head)->slh_first = (elm); \ 223 _NOTE(CONSTCOND) \ 224 } while (0) 225 226 #define SLIST_REMOVE_HEAD(head, field) do { \ 227 (head)->slh_first = (head)->slh_first->field.sle_next; \ 228 _NOTE(CONSTCOND) \ 229 } while (0) 230 231 #define SLIST_REMOVE(head, elm, type, field) do { \ 232 if ((head)->slh_first == (elm)) { \ 233 SLIST_REMOVE_HEAD((head), field); \ 234 } \ 235 else { \ 236 struct type *curelm = (head)->slh_first; \ 237 while (curelm->field.sle_next != (elm)) \ 238 curelm = curelm->field.sle_next; \ 239 curelm->field.sle_next = \ 240 curelm->field.sle_next->field.sle_next; \ 241 } \ 242 _NOTE(CONSTCOND) \ 243 } while (0) 244 245 #define SLIST_FOREACH(var, head, field) \ 246 for ((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 247 248 /* 249 * Singly-linked List access methods. 250 */ 251 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 252 #define SLIST_FIRST(head) ((head)->slh_first) 253 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 254 255 256 /* 257 * Singly-linked Tail queue declarations. 258 */ 259 #define STAILQ_HEAD(name, type) \ 260 struct name { \ 261 struct type *stqh_first; /* first element */ \ 262 struct type **stqh_last; /* addr of last next element */ \ 263 } 264 265 #define STAILQ_HEAD_INITIALIZER(head) \ 266 { NULL, &(head).stqh_first } 267 268 #define STAILQ_ENTRY(type) \ 269 struct { \ 270 struct type *stqe_next; /* next element */ \ 271 } 272 273 /* 274 * Singly-linked Tail queue functions. 275 */ 276 #define STAILQ_INIT(head) do { \ 277 (head)->stqh_first = NULL; \ 278 (head)->stqh_last = &(head)->stqh_first; \ 279 _NOTE(CONSTCOND) \ 280 } while (0) 281 282 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 283 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 284 (head)->stqh_last = &(elm)->field.stqe_next; \ 285 (head)->stqh_first = (elm); \ 286 _NOTE(CONSTCOND) \ 287 } while (0) 288 289 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 290 (elm)->field.stqe_next = NULL; \ 291 *(head)->stqh_last = (elm); \ 292 (head)->stqh_last = &(elm)->field.stqe_next; \ 293 _NOTE(CONSTCOND) \ 294 } while (0) 295 296 #define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 297 if (((elm)->field.stqe_next = (listelm)->field.stqe_next) \ 298 == NULL) \ 299 (head)->stqh_last = &(elm)->field.stqe_next; \ 300 (listelm)->field.stqe_next = (elm); \ 301 _NOTE(CONSTCOND) \ 302 } while (0) 303 304 #define STAILQ_REMOVE_HEAD(head, field) do { \ 305 if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) \ 306 == NULL) \ 307 (head)->stqh_last = &(head)->stqh_first; \ 308 _NOTE(CONSTCOND) \ 309 } while (0) 310 311 #define STAILQ_REMOVE(head, elm, type, field) do { \ 312 if ((head)->stqh_first == (elm)) { \ 313 STAILQ_REMOVE_HEAD((head), field); \ 314 } else { \ 315 struct type *curelm = (head)->stqh_first; \ 316 while (curelm->field.stqe_next != (elm)) \ 317 curelm = curelm->field.stqe_next; \ 318 if ((curelm->field.stqe_next = \ 319 curelm->field.stqe_next->field.stqe_next) == NULL) \ 320 (head)->stqh_last = &(curelm)->field.stqe_next; \ 321 } \ 322 _NOTE(CONSTCOND) \ 323 } while (0) 324 325 #define STAILQ_FOREACH(var, head, field) \ 326 for ((var) = ((head)->stqh_first); \ 327 (var); \ 328 (var) = ((var)->field.stqe_next)) 329 330 /* 331 * Singly-linked Tail queue access methods. 332 */ 333 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 334 #define STAILQ_FIRST(head) ((head)->stqh_first) 335 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 336 337 338 /* 339 * Simple queue definitions. 340 */ 341 #define SIMPLEQ_HEAD(name, type) \ 342 struct name { \ 343 struct type *sqh_first; /* first element */ \ 344 struct type **sqh_last; /* addr of last next element */ \ 345 } 346 347 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 348 { NULL, &(head).sqh_first } 349 350 #define SIMPLEQ_ENTRY(type) \ 351 struct { \ 352 struct type *sqe_next; /* next element */ \ 353 } 354 355 /* 356 * Simple queue functions. 357 */ 358 #define SIMPLEQ_INIT(head) do { \ 359 (head)->sqh_first = NULL; \ 360 (head)->sqh_last = &(head)->sqh_first; \ 361 _NOTE(CONSTCOND) \ 362 } while (0) 363 364 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 365 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 366 (head)->sqh_last = &(elm)->field.sqe_next; \ 367 (head)->sqh_first = (elm); \ 368 _NOTE(CONSTCOND) \ 369 } while (0) 370 371 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 372 (elm)->field.sqe_next = NULL; \ 373 *(head)->sqh_last = (elm); \ 374 (head)->sqh_last = &(elm)->field.sqe_next; \ 375 _NOTE(CONSTCOND) \ 376 } while (0) 377 378 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 379 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 380 (head)->sqh_last = &(elm)->field.sqe_next; \ 381 (listelm)->field.sqe_next = (elm); \ 382 _NOTE(CONSTCOND) \ 383 } while (0) 384 385 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \ 386 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 387 (head)->sqh_last = &(head)->sqh_first; \ 388 _NOTE(CONSTCOND) \ 389 } while (0) 390 391 #define SIMPLEQ_REMOVE(head, elm, type, field) do { \ 392 if ((head)->sqh_first == (elm)) { \ 393 SIMPLEQ_REMOVE_HEAD((head), field); \ 394 } else { \ 395 struct type *curelm = (head)->sqh_first; \ 396 while (curelm->field.sqe_next != (elm)) \ 397 curelm = curelm->field.sqe_next; \ 398 if ((curelm->field.sqe_next = \ 399 curelm->field.sqe_next->field.sqe_next) == NULL) \ 400 (head)->sqh_last = &(curelm)->field.sqe_next; \ 401 } \ 402 _NOTE(CONSTCOND) \ 403 } while (0) 404 405 #define SIMPLEQ_FOREACH(var, head, field) \ 406 for ((var) = ((head)->sqh_first); \ 407 (var); \ 408 (var) = ((var)->field.sqe_next)) 409 410 /* 411 * Simple queue access methods. 412 */ 413 #define SIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 414 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 415 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 416 417 418 /* 419 * Tail queue definitions. 420 */ 421 #define _TAILQ_HEAD(name, type) \ 422 struct name { \ 423 type *tqh_first; /* first element */ \ 424 type **tqh_last; /* addr of last next element */ \ 425 } 426 #define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type) 427 428 #define TAILQ_HEAD_INITIALIZER(head) \ 429 { NULL, &(head).tqh_first } 430 431 #define _TAILQ_ENTRY(type) \ 432 struct { \ 433 type *tqe_next; /* next element */ \ 434 type **tqe_prev; /* address of previous next element */\ 435 } 436 #define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type) 437 438 /* 439 * Tail queue functions. 440 */ 441 #if defined(_KERNEL) && defined(QUEUEDEBUG) 442 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) \ 443 if ((head)->tqh_first && \ 444 (head)->tqh_first->field.tqe_prev != &(head)->tqh_first) \ 445 panic("TAILQ_INSERT_HEAD %p %s:%d", (void *)(head), \ 446 __FILE__, __LINE__); 447 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) \ 448 if (*(head)->tqh_last != NULL) \ 449 panic("TAILQ_INSERT_TAIL %p %s:%d", (void *)(head), \ 450 __FILE__, __LINE__); 451 #define QUEUEDEBUG_TAILQ_OP(elm, field) \ 452 if ((elm)->field.tqe_next && \ 453 (elm)->field.tqe_next->field.tqe_prev != \ 454 &(elm)->field.tqe_next) \ 455 panic("TAILQ_* forw %p %s:%d", (void *)(elm), \ 456 __FILE__, __LINE__);\ 457 if (*(elm)->field.tqe_prev != (elm)) \ 458 panic("TAILQ_* back %p %s:%d", (void *)(elm), \ 459 __FILE__, __LINE__); 460 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) \ 461 if ((elm)->field.tqe_next == NULL && \ 462 (head)->tqh_last != &(elm)->field.tqe_next) \ 463 panic("TAILQ_PREREMOVE head %p elm %p %s:%d", \ 464 (void *)(head), (void *)(elm), __FILE__, __LINE__); 465 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) \ 466 (elm)->field.tqe_next = (void *)1L; \ 467 (elm)->field.tqe_prev = (void *)1L; 468 #else 469 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) 470 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) 471 #define QUEUEDEBUG_TAILQ_OP(elm, field) 472 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) 473 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) 474 #endif 475 476 #define TAILQ_INIT(head) do { \ 477 (head)->tqh_first = NULL; \ 478 (head)->tqh_last = &(head)->tqh_first; \ 479 _NOTE(CONSTCOND) \ 480 } while (0) 481 482 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 483 QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field) \ 484 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 485 (head)->tqh_first->field.tqe_prev = \ 486 &(elm)->field.tqe_next; \ 487 else \ 488 (head)->tqh_last = &(elm)->field.tqe_next; \ 489 (head)->tqh_first = (elm); \ 490 (elm)->field.tqe_prev = &(head)->tqh_first; \ 491 _NOTE(CONSTCOND) \ 492 } while (0) 493 494 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 495 QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field) \ 496 (elm)->field.tqe_next = NULL; \ 497 (elm)->field.tqe_prev = (head)->tqh_last; \ 498 *(head)->tqh_last = (elm); \ 499 (head)->tqh_last = &(elm)->field.tqe_next; \ 500 _NOTE(CONSTCOND) \ 501 } while (0) 502 503 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 504 QUEUEDEBUG_TAILQ_OP((listelm), field) \ 505 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 506 (elm)->field.tqe_next->field.tqe_prev = \ 507 &(elm)->field.tqe_next; \ 508 else \ 509 (head)->tqh_last = &(elm)->field.tqe_next; \ 510 (listelm)->field.tqe_next = (elm); \ 511 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 512 _NOTE(CONSTCOND) \ 513 } while (0) 514 515 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 516 QUEUEDEBUG_TAILQ_OP((listelm), field) \ 517 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 518 (elm)->field.tqe_next = (listelm); \ 519 *(listelm)->field.tqe_prev = (elm); \ 520 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 521 _NOTE(CONSTCOND) \ 522 } while (0) 523 524 #define TAILQ_REMOVE(head, elm, field) do { \ 525 QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field) \ 526 QUEUEDEBUG_TAILQ_OP((elm), field) \ 527 if (((elm)->field.tqe_next) != NULL) \ 528 (elm)->field.tqe_next->field.tqe_prev = \ 529 (elm)->field.tqe_prev; \ 530 else \ 531 (head)->tqh_last = (elm)->field.tqe_prev; \ 532 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 533 QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \ 534 _NOTE(CONSTCOND) \ 535 } while (0) 536 537 #define TAILQ_FOREACH(var, head, field) \ 538 for ((var) = ((head)->tqh_first); \ 539 (var); \ 540 (var) = ((var)->field.tqe_next)) 541 542 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 543 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));\ 544 (var); \ 545 (var) = \ 546 (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 547 548 /* 549 * Tail queue access methods. 550 */ 551 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 552 #define TAILQ_FIRST(head) ((head)->tqh_first) 553 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 554 555 #define TAILQ_LAST(head, headname) \ 556 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 557 #define TAILQ_PREV(elm, headname, field) \ 558 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 559 560 561 /* 562 * Circular queue definitions. 563 */ 564 #define CIRCLEQ_HEAD(name, type) \ 565 struct name { \ 566 struct type *cqh_first; /* first element */ \ 567 struct type *cqh_last; /* last element */ \ 568 } 569 570 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 571 { (void *)&head, (void *)&head } 572 573 #define CIRCLEQ_ENTRY(type) \ 574 struct { \ 575 struct type *cqe_next; /* next element */ \ 576 struct type *cqe_prev; /* previous element */ \ 577 } 578 579 /* 580 * Circular queue functions. 581 */ 582 #define CIRCLEQ_INIT(head) do { \ 583 (head)->cqh_first = (void *)(head); \ 584 (head)->cqh_last = (void *)(head); \ 585 _NOTE(CONSTCOND) \ 586 } while (0) 587 588 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 589 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 590 (elm)->field.cqe_prev = (listelm); \ 591 if ((listelm)->field.cqe_next == (void *)(head)) \ 592 (head)->cqh_last = (elm); \ 593 else \ 594 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 595 (listelm)->field.cqe_next = (elm); \ 596 _NOTE(CONSTCOND) \ 597 } while (0) 598 599 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 600 (elm)->field.cqe_next = (listelm); \ 601 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 602 if ((listelm)->field.cqe_prev == (void *)(head)) \ 603 (head)->cqh_first = (elm); \ 604 else \ 605 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 606 (listelm)->field.cqe_prev = (elm); \ 607 _NOTE(CONSTCOND) \ 608 } while (0) 609 610 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 611 (elm)->field.cqe_next = (head)->cqh_first; \ 612 (elm)->field.cqe_prev = (void *)(head); \ 613 if ((head)->cqh_last == (void *)(head)) \ 614 (head)->cqh_last = (elm); \ 615 else \ 616 (head)->cqh_first->field.cqe_prev = (elm); \ 617 (head)->cqh_first = (elm); \ 618 _NOTE(CONSTCOND) \ 619 } while (0) 620 621 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 622 (elm)->field.cqe_next = (void *)(head); \ 623 (elm)->field.cqe_prev = (head)->cqh_last; \ 624 if ((head)->cqh_first == (void *)(head)) \ 625 (head)->cqh_first = (elm); \ 626 else \ 627 (head)->cqh_last->field.cqe_next = (elm); \ 628 (head)->cqh_last = (elm); \ 629 _NOTE(CONSTCOND) \ 630 } while (0) 631 632 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 633 if ((elm)->field.cqe_next == (void *)(head)) \ 634 (head)->cqh_last = (elm)->field.cqe_prev; \ 635 else \ 636 (elm)->field.cqe_next->field.cqe_prev = \ 637 (elm)->field.cqe_prev; \ 638 if ((elm)->field.cqe_prev == (void *)(head)) \ 639 (head)->cqh_first = (elm)->field.cqe_next; \ 640 else \ 641 (elm)->field.cqe_prev->field.cqe_next = \ 642 (elm)->field.cqe_next; \ 643 _NOTE(CONSTCOND) \ 644 } while (0) 645 646 #define CIRCLEQ_FOREACH(var, head, field) \ 647 for ((var) = ((head)->cqh_first); \ 648 (var) != (void *)(head); \ 649 (var) = ((var)->field.cqe_next)) 650 651 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 652 for ((var) = ((head)->cqh_last); \ 653 (var) != (void *)(head); \ 654 (var) = ((var)->field.cqe_prev)) 655 656 /* 657 * Circular queue access methods. 658 */ 659 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 660 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 661 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 662 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 663 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 664 665 #ifdef __cplusplus 666 } 667 #endif 668 669 #endif /* !_SYS_QUEUE_H */ 670