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 2006 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 #pragma ident "%Z%%M% %I% %E% SMI" 42 43 #include <sys/note.h> 44 45 #ifdef __cplusplus 46 extern "C" { 47 #endif 48 49 /* 50 * This file defines five types of data structures: singly-linked lists, 51 * lists, simple queues, tail queues, and circular queues. 52 * 53 * A singly-linked list is headed by a single forward pointer. The 54 * elements are singly linked for minimum space and pointer manipulation 55 * overhead at the expense of O(n) removal for arbitrary elements. New 56 * elements can be added to the list after an existing element or at the 57 * head of the list. Elements being removed from the head of the list 58 * should use the explicit macro for this purpose for optimum 59 * efficiency. A singly-linked list may only be traversed in the forward 60 * direction. Singly-linked lists are ideal for applications with large 61 * datasets and few or no removals or for implementing a LIFO queue. 62 * 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 only be traversed in the forward direction. 69 * 70 * A simple queue is headed by a pair of pointers, one the head of the 71 * list and the other to the tail of the list. The elements are singly 72 * linked to save space, so elements can only be removed from the 73 * head of the list. New elements can be added to the list after 74 * an existing element, at the head of the list, or at the end of the 75 * list. A simple queue may only be traversed in the forward direction. 76 * 77 * A tail queue is headed by a pair of pointers, one to the head of the 78 * list and the other to the tail of the list. The elements are doubly 79 * linked so that an arbitrary element can be removed without a need to 80 * traverse the list. New elements can be added to the list before or 81 * after an existing element, at the head of the list, or at the end of 82 * the list. A tail queue may be traversed in either direction. 83 * 84 * A circle queue is headed by a pair of pointers, one to the head of the 85 * list and the other to the tail of the list. The elements are doubly 86 * linked so that an arbitrary element can be removed without a need to 87 * traverse the list. New elements can be added to the list before or after 88 * an existing element, at the head of the list, or at the end of the list. 89 * A circle queue may be traversed in either direction, but has a more 90 * complex end of list detection. 91 * 92 * For details on the use of these macros, see the queue(3) manual page. 93 */ 94 95 /* 96 * List definitions. 97 */ 98 #define LIST_HEAD(name, type) \ 99 struct name { \ 100 struct type *lh_first; /* first element */ \ 101 } 102 103 #define LIST_HEAD_INITIALIZER(head) \ 104 { NULL } 105 106 #define LIST_ENTRY(type) \ 107 struct { \ 108 struct type *le_next; /* next element */ \ 109 struct type **le_prev; /* address of previous next element */ \ 110 } 111 112 /* 113 * List functions. 114 */ 115 #if defined(_KERNEL) && defined(QUEUEDEBUG) 116 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) \ 117 if ((head)->lh_first && \ 118 (head)->lh_first->field.le_prev != &(head)->lh_first) \ 119 panic("LIST_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__); 120 #define QUEUEDEBUG_LIST_OP(elm, field) \ 121 if ((elm)->field.le_next && \ 122 (elm)->field.le_next->field.le_prev != \ 123 &(elm)->field.le_next) \ 124 panic("LIST_* forw %p %s:%d", (elm), __FILE__, __LINE__);\ 125 if (*(elm)->field.le_prev != (elm)) \ 126 panic("LIST_* back %p %s:%d", (elm), __FILE__, __LINE__); 127 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) \ 128 (elm)->field.le_next = (void *)1L; \ 129 (elm)->field.le_prev = (void *)1L; 130 #else 131 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) 132 #define QUEUEDEBUG_LIST_OP(elm, field) 133 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) 134 #endif 135 136 #define LIST_INIT(head) do { \ 137 (head)->lh_first = NULL; \ 138 _NOTE(CONSTCOND) \ 139 } while (0) 140 141 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 142 QUEUEDEBUG_LIST_OP((listelm), field) \ 143 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 144 (listelm)->field.le_next->field.le_prev = \ 145 &(elm)->field.le_next; \ 146 (listelm)->field.le_next = (elm); \ 147 (elm)->field.le_prev = &(listelm)->field.le_next; \ 148 _NOTE(CONSTCOND) \ 149 } while (0) 150 151 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 152 QUEUEDEBUG_LIST_OP((listelm), field) \ 153 (elm)->field.le_prev = (listelm)->field.le_prev; \ 154 (elm)->field.le_next = (listelm); \ 155 *(listelm)->field.le_prev = (elm); \ 156 (listelm)->field.le_prev = &(elm)->field.le_next; \ 157 _NOTE(CONSTCOND) \ 158 } while (0) 159 160 #define LIST_INSERT_HEAD(head, elm, field) do { \ 161 QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field) \ 162 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 163 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 164 (head)->lh_first = (elm); \ 165 (elm)->field.le_prev = &(head)->lh_first; \ 166 _NOTE(CONSTCOND) \ 167 } while (0) 168 169 #define LIST_REMOVE(elm, field) do { \ 170 QUEUEDEBUG_LIST_OP((elm), field) \ 171 if ((elm)->field.le_next != NULL) \ 172 (elm)->field.le_next->field.le_prev = \ 173 (elm)->field.le_prev; \ 174 *(elm)->field.le_prev = (elm)->field.le_next; \ 175 QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \ 176 _NOTE(CONSTCOND) \ 177 } while (0) 178 179 #define LIST_FOREACH(var, head, field) \ 180 for ((var) = ((head)->lh_first); \ 181 (var); \ 182 (var) = ((var)->field.le_next)) 183 184 /* 185 * List access methods. 186 */ 187 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 188 #define LIST_FIRST(head) ((head)->lh_first) 189 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 190 191 192 /* 193 * Singly-linked List definitions. 194 */ 195 #define SLIST_HEAD(name, type) \ 196 struct name { \ 197 struct type *slh_first; /* first element */ \ 198 } 199 200 #define SLIST_HEAD_INITIALIZER(head) \ 201 { NULL } 202 203 #define SLIST_ENTRY(type) \ 204 struct { \ 205 struct type *sle_next; /* next element */ \ 206 } 207 208 /* 209 * Singly-linked List functions. 210 */ 211 #define SLIST_INIT(head) do { \ 212 (head)->slh_first = NULL; \ 213 _NOTE(CONSTCOND) \ 214 } while (0) 215 216 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 217 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 218 (slistelm)->field.sle_next = (elm); \ 219 _NOTE(CONSTCOND) \ 220 } while (0) 221 222 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 223 (elm)->field.sle_next = (head)->slh_first; \ 224 (head)->slh_first = (elm); \ 225 _NOTE(CONSTCOND) \ 226 } while (0) 227 228 #define SLIST_REMOVE_HEAD(head, field) do { \ 229 (head)->slh_first = (head)->slh_first->field.sle_next; \ 230 _NOTE(CONSTCOND) \ 231 } while (0) 232 233 #define SLIST_REMOVE(head, elm, type, field) do { \ 234 if ((head)->slh_first == (elm)) { \ 235 SLIST_REMOVE_HEAD((head), field); \ 236 } \ 237 else { \ 238 struct type *curelm = (head)->slh_first; \ 239 while (curelm->field.sle_next != (elm)) \ 240 curelm = curelm->field.sle_next; \ 241 curelm->field.sle_next = \ 242 curelm->field.sle_next->field.sle_next; \ 243 } \ 244 _NOTE(CONSTCOND) \ 245 } while (0) 246 247 #define SLIST_FOREACH(var, head, field) \ 248 for ((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 249 250 /* 251 * Singly-linked List access methods. 252 */ 253 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 254 #define SLIST_FIRST(head) ((head)->slh_first) 255 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 256 257 258 /* 259 * Singly-linked Tail queue declarations. 260 */ 261 #define STAILQ_HEAD(name, type) \ 262 struct name { \ 263 struct type *stqh_first; /* first element */ \ 264 struct type **stqh_last; /* addr of last next element */ \ 265 } 266 267 #define STAILQ_HEAD_INITIALIZER(head) \ 268 { NULL, &(head).stqh_first } 269 270 #define STAILQ_ENTRY(type) \ 271 struct { \ 272 struct type *stqe_next; /* next element */ \ 273 } 274 275 /* 276 * Singly-linked Tail queue functions. 277 */ 278 #define STAILQ_INIT(head) do { \ 279 (head)->stqh_first = NULL; \ 280 (head)->stqh_last = &(head)->stqh_first; \ 281 _NOTE(CONSTCOND) \ 282 } while (0) 283 284 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 285 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 286 (head)->stqh_last = &(elm)->field.stqe_next; \ 287 (head)->stqh_first = (elm); \ 288 _NOTE(CONSTCOND) \ 289 } while (0) 290 291 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 292 (elm)->field.stqe_next = NULL; \ 293 *(head)->stqh_last = (elm); \ 294 (head)->stqh_last = &(elm)->field.stqe_next; \ 295 _NOTE(CONSTCOND) \ 296 } while (0) 297 298 #define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 299 if (((elm)->field.stqe_next = (listelm)->field.stqe_next) \ 300 == NULL) \ 301 (head)->stqh_last = &(elm)->field.stqe_next; \ 302 (listelm)->field.stqe_next = (elm); \ 303 _NOTE(CONSTCOND) \ 304 } while (0) 305 306 #define STAILQ_REMOVE_HEAD(head, field) do { \ 307 if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) \ 308 == NULL) \ 309 (head)->stqh_last = &(head)->stqh_first; \ 310 _NOTE(CONSTCOND) \ 311 } while (0) 312 313 #define STAILQ_REMOVE(head, elm, type, field) do { \ 314 if ((head)->stqh_first == (elm)) { \ 315 STAILQ_REMOVE_HEAD((head), field); \ 316 } else { \ 317 struct type *curelm = (head)->stqh_first; \ 318 while (curelm->field.stqe_next != (elm)) \ 319 curelm = curelm->field.stqe_next; \ 320 if ((curelm->field.stqe_next = \ 321 curelm->field.stqe_next->field.stqe_next) == NULL) \ 322 (head)->stqh_last = &(curelm)->field.stqe_next; \ 323 } \ 324 _NOTE(CONSTCOND) \ 325 } while (0) 326 327 #define STAILQ_FOREACH(var, head, field) \ 328 for ((var) = ((head)->stqh_first); \ 329 (var); \ 330 (var) = ((var)->field.stqe_next)) 331 332 /* 333 * Singly-linked Tail queue access methods. 334 */ 335 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 336 #define STAILQ_FIRST(head) ((head)->stqh_first) 337 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 338 339 340 /* 341 * Simple queue definitions. 342 */ 343 #define SIMPLEQ_HEAD(name, type) \ 344 struct name { \ 345 struct type *sqh_first; /* first element */ \ 346 struct type **sqh_last; /* addr of last next element */ \ 347 } 348 349 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 350 { NULL, &(head).sqh_first } 351 352 #define SIMPLEQ_ENTRY(type) \ 353 struct { \ 354 struct type *sqe_next; /* next element */ \ 355 } 356 357 /* 358 * Simple queue functions. 359 */ 360 #define SIMPLEQ_INIT(head) do { \ 361 (head)->sqh_first = NULL; \ 362 (head)->sqh_last = &(head)->sqh_first; \ 363 _NOTE(CONSTCOND) \ 364 } while (0) 365 366 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 367 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 368 (head)->sqh_last = &(elm)->field.sqe_next; \ 369 (head)->sqh_first = (elm); \ 370 _NOTE(CONSTCOND) \ 371 } while (0) 372 373 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 374 (elm)->field.sqe_next = NULL; \ 375 *(head)->sqh_last = (elm); \ 376 (head)->sqh_last = &(elm)->field.sqe_next; \ 377 _NOTE(CONSTCOND) \ 378 } while (0) 379 380 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 381 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 382 (head)->sqh_last = &(elm)->field.sqe_next; \ 383 (listelm)->field.sqe_next = (elm); \ 384 _NOTE(CONSTCOND) \ 385 } while (0) 386 387 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \ 388 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 389 (head)->sqh_last = &(head)->sqh_first; \ 390 _NOTE(CONSTCOND) \ 391 } while (0) 392 393 #define SIMPLEQ_REMOVE(head, elm, type, field) do { \ 394 if ((head)->sqh_first == (elm)) { \ 395 SIMPLEQ_REMOVE_HEAD((head), field); \ 396 } else { \ 397 struct type *curelm = (head)->sqh_first; \ 398 while (curelm->field.sqe_next != (elm)) \ 399 curelm = curelm->field.sqe_next; \ 400 if ((curelm->field.sqe_next = \ 401 curelm->field.sqe_next->field.sqe_next) == NULL) \ 402 (head)->sqh_last = &(curelm)->field.sqe_next; \ 403 } \ 404 _NOTE(CONSTCOND) \ 405 } while (0) 406 407 #define SIMPLEQ_FOREACH(var, head, field) \ 408 for ((var) = ((head)->sqh_first); \ 409 (var); \ 410 (var) = ((var)->field.sqe_next)) 411 412 /* 413 * Simple queue access methods. 414 */ 415 #define SIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 416 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 417 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 418 419 420 /* 421 * Tail queue definitions. 422 */ 423 #define _TAILQ_HEAD(name, type) \ 424 struct name { \ 425 type *tqh_first; /* first element */ \ 426 type **tqh_last; /* addr of last next element */ \ 427 } 428 #define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type) 429 430 #define TAILQ_HEAD_INITIALIZER(head) \ 431 { NULL, &(head).tqh_first } 432 433 #define _TAILQ_ENTRY(type) \ 434 struct { \ 435 type *tqe_next; /* next element */ \ 436 type **tqe_prev; /* address of previous next element */\ 437 } 438 #define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type) 439 440 /* 441 * Tail queue functions. 442 */ 443 #if defined(_KERNEL) && defined(QUEUEDEBUG) 444 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) \ 445 if ((head)->tqh_first && \ 446 (head)->tqh_first->field.tqe_prev != &(head)->tqh_first) \ 447 panic("TAILQ_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__); 448 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) \ 449 if (*(head)->tqh_last != NULL) \ 450 panic("TAILQ_INSERT_TAIL %p %s:%d", (head), __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", (elm), __FILE__, __LINE__);\ 456 if (*(elm)->field.tqe_prev != (elm)) \ 457 panic("TAILQ_* back %p %s:%d", (elm), __FILE__, __LINE__); 458 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) \ 459 if ((elm)->field.tqe_next == NULL && \ 460 (head)->tqh_last != &(elm)->field.tqe_next) \ 461 panic("TAILQ_PREREMOVE head %p elm %p %s:%d", \ 462 (head), (elm), __FILE__, __LINE__); 463 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) \ 464 (elm)->field.tqe_next = (void *)1L; \ 465 (elm)->field.tqe_prev = (void *)1L; 466 #else 467 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) 468 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) 469 #define QUEUEDEBUG_TAILQ_OP(elm, field) 470 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) 471 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) 472 #endif 473 474 #define TAILQ_INIT(head) do { \ 475 (head)->tqh_first = NULL; \ 476 (head)->tqh_last = &(head)->tqh_first; \ 477 _NOTE(CONSTCOND) \ 478 } while (0) 479 480 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 481 QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field) \ 482 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 483 (head)->tqh_first->field.tqe_prev = \ 484 &(elm)->field.tqe_next; \ 485 else \ 486 (head)->tqh_last = &(elm)->field.tqe_next; \ 487 (head)->tqh_first = (elm); \ 488 (elm)->field.tqe_prev = &(head)->tqh_first; \ 489 _NOTE(CONSTCOND) \ 490 } while (0) 491 492 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 493 QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field) \ 494 (elm)->field.tqe_next = NULL; \ 495 (elm)->field.tqe_prev = (head)->tqh_last; \ 496 *(head)->tqh_last = (elm); \ 497 (head)->tqh_last = &(elm)->field.tqe_next; \ 498 _NOTE(CONSTCOND) \ 499 } while (0) 500 501 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 502 QUEUEDEBUG_TAILQ_OP((listelm), field) \ 503 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 504 (elm)->field.tqe_next->field.tqe_prev = \ 505 &(elm)->field.tqe_next; \ 506 else \ 507 (head)->tqh_last = &(elm)->field.tqe_next; \ 508 (listelm)->field.tqe_next = (elm); \ 509 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 510 _NOTE(CONSTCOND) \ 511 } while (0) 512 513 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 514 QUEUEDEBUG_TAILQ_OP((listelm), field) \ 515 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 516 (elm)->field.tqe_next = (listelm); \ 517 *(listelm)->field.tqe_prev = (elm); \ 518 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 519 _NOTE(CONSTCOND) \ 520 } while (0) 521 522 #define TAILQ_REMOVE(head, elm, field) do { \ 523 QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field) \ 524 QUEUEDEBUG_TAILQ_OP((elm), field) \ 525 if (((elm)->field.tqe_next) != NULL) \ 526 (elm)->field.tqe_next->field.tqe_prev = \ 527 (elm)->field.tqe_prev; \ 528 else \ 529 (head)->tqh_last = (elm)->field.tqe_prev; \ 530 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 531 QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \ 532 _NOTE(CONSTCOND) \ 533 } while (0) 534 535 #define TAILQ_FOREACH(var, head, field) \ 536 for ((var) = ((head)->tqh_first); \ 537 (var); \ 538 (var) = ((var)->field.tqe_next)) 539 540 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 541 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));\ 542 (var); \ 543 (var) = \ 544 (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 545 546 /* 547 * Tail queue access methods. 548 */ 549 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 550 #define TAILQ_FIRST(head) ((head)->tqh_first) 551 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 552 553 #define TAILQ_LAST(head, headname) \ 554 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 555 #define TAILQ_PREV(elm, headname, field) \ 556 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 557 558 559 /* 560 * Circular queue definitions. 561 */ 562 #define CIRCLEQ_HEAD(name, type) \ 563 struct name { \ 564 struct type *cqh_first; /* first element */ \ 565 struct type *cqh_last; /* last element */ \ 566 } 567 568 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 569 { (void *)&head, (void *)&head } 570 571 #define CIRCLEQ_ENTRY(type) \ 572 struct { \ 573 struct type *cqe_next; /* next element */ \ 574 struct type *cqe_prev; /* previous element */ \ 575 } 576 577 /* 578 * Circular queue functions. 579 */ 580 #define CIRCLEQ_INIT(head) do { \ 581 (head)->cqh_first = (void *)(head); \ 582 (head)->cqh_last = (void *)(head); \ 583 _NOTE(CONSTCOND) \ 584 } while (0) 585 586 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 587 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 588 (elm)->field.cqe_prev = (listelm); \ 589 if ((listelm)->field.cqe_next == (void *)(head)) \ 590 (head)->cqh_last = (elm); \ 591 else \ 592 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 593 (listelm)->field.cqe_next = (elm); \ 594 _NOTE(CONSTCOND) \ 595 } while (0) 596 597 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 598 (elm)->field.cqe_next = (listelm); \ 599 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 600 if ((listelm)->field.cqe_prev == (void *)(head)) \ 601 (head)->cqh_first = (elm); \ 602 else \ 603 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 604 (listelm)->field.cqe_prev = (elm); \ 605 _NOTE(CONSTCOND) \ 606 } while (0) 607 608 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 609 (elm)->field.cqe_next = (head)->cqh_first; \ 610 (elm)->field.cqe_prev = (void *)(head); \ 611 if ((head)->cqh_last == (void *)(head)) \ 612 (head)->cqh_last = (elm); \ 613 else \ 614 (head)->cqh_first->field.cqe_prev = (elm); \ 615 (head)->cqh_first = (elm); \ 616 _NOTE(CONSTCOND) \ 617 } while (0) 618 619 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 620 (elm)->field.cqe_next = (void *)(head); \ 621 (elm)->field.cqe_prev = (head)->cqh_last; \ 622 if ((head)->cqh_first == (void *)(head)) \ 623 (head)->cqh_first = (elm); \ 624 else \ 625 (head)->cqh_last->field.cqe_next = (elm); \ 626 (head)->cqh_last = (elm); \ 627 _NOTE(CONSTCOND) \ 628 } while (0) 629 630 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 631 if ((elm)->field.cqe_next == (void *)(head)) \ 632 (head)->cqh_last = (elm)->field.cqe_prev; \ 633 else \ 634 (elm)->field.cqe_next->field.cqe_prev = \ 635 (elm)->field.cqe_prev; \ 636 if ((elm)->field.cqe_prev == (void *)(head)) \ 637 (head)->cqh_first = (elm)->field.cqe_next; \ 638 else \ 639 (elm)->field.cqe_prev->field.cqe_next = \ 640 (elm)->field.cqe_next; \ 641 _NOTE(CONSTCOND) \ 642 } while (0) 643 644 #define CIRCLEQ_FOREACH(var, head, field) \ 645 for ((var) = ((head)->cqh_first); \ 646 (var) != (void *)(head); \ 647 (var) = ((var)->field.cqe_next)) 648 649 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 650 for ((var) = ((head)->cqh_last); \ 651 (var) != (void *)(head); \ 652 (var) = ((var)->field.cqe_prev)) 653 654 /* 655 * Circular queue access methods. 656 */ 657 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 658 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 659 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 660 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 661 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 662 663 #ifdef __cplusplus 664 } 665 #endif 666 667 #endif /* !_SYS_QUEUE_H */ 668