1 /* $OpenBSD: queue.h,v 1.32 2007/04/30 18:42:34 pedro 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 #if defined(__clang_analyzer__) || defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC)) 86 #define _Q_INVALIDATE(a) ((a) = ((void *)-1)) 87 #else 88 #define _Q_INVALIDATE(a) 89 #endif 90 91 #if defined(__clang_analyzer__) 92 #define _Q_ASSERT(a) assert((a)) 93 #else 94 #define _Q_ASSERT(a) 95 #endif 96 97 /* 98 * Singly-linked List definitions. 99 */ 100 101 /* 102 * The following macros are not used and are in conflict with Win32 API 103 */ 104 105 #if 0 106 107 #define SLIST_HEAD(name, type) \ 108 struct name { \ 109 struct type *slh_first; /* first element */ \ 110 } 111 112 #define SLIST_HEAD_INITIALIZER(head) \ 113 { NULL } 114 115 #define SLIST_ENTRY(type) \ 116 struct { \ 117 struct type *sle_next; /* next element */ \ 118 } 119 120 /* 121 * Singly-linked List access methods. 122 */ 123 #define SLIST_FIRST(head) ((head)->slh_first) 124 #define SLIST_END(head) NULL 125 #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) 126 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 127 128 #define SLIST_FOREACH(var, head, field) \ 129 for((var) = SLIST_FIRST(head); \ 130 (var) != SLIST_END(head); \ 131 (var) = SLIST_NEXT(var, field)) 132 133 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \ 134 for ((varp) = &SLIST_FIRST((head)); \ 135 ((var) = *(varp)) != SLIST_END(head); \ 136 (varp) = &SLIST_NEXT((var), field)) 137 138 /* 139 * Singly-linked List functions. 140 */ 141 #define SLIST_INIT(head) { \ 142 SLIST_FIRST(head) = SLIST_END(head); \ 143 } 144 145 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 146 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 147 (slistelm)->field.sle_next = (elm); \ 148 } while (0) 149 150 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 151 (elm)->field.sle_next = (head)->slh_first; \ 152 (head)->slh_first = (elm); \ 153 } while (0) 154 155 #define SLIST_REMOVE_NEXT(head, elm, field) do { \ 156 (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \ 157 } while (0) 158 159 #define SLIST_REMOVE_HEAD(head, field) do { \ 160 (head)->slh_first = (head)->slh_first->field.sle_next; \ 161 } while (0) 162 163 #define SLIST_REMOVE(head, elm, type, field) do { \ 164 if ((head)->slh_first == (elm)) { \ 165 SLIST_REMOVE_HEAD((head), field); \ 166 } else { \ 167 struct type *curelm = (head)->slh_first; \ 168 \ 169 while (curelm->field.sle_next != (elm)) \ 170 curelm = curelm->field.sle_next; \ 171 curelm->field.sle_next = \ 172 curelm->field.sle_next->field.sle_next; \ 173 _Q_INVALIDATE((elm)->field.sle_next); \ 174 } \ 175 } while (0) 176 177 #endif /* 0 */ 178 179 /* 180 * List definitions. 181 */ 182 #define LIST_HEAD(name, type) \ 183 struct name { \ 184 struct type *lh_first; /* first element */ \ 185 } 186 187 #define LIST_HEAD_INITIALIZER(head) \ 188 { NULL } 189 190 #define LIST_ENTRY(type) \ 191 struct { \ 192 struct type *le_next; /* next element */ \ 193 struct type **le_prev; /* address of previous next element */ \ 194 } 195 196 /* 197 * List access methods 198 */ 199 #define LIST_FIRST(head) ((head)->lh_first) 200 #define LIST_END(head) NULL 201 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 202 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 203 204 #define LIST_FOREACH(var, head, field) \ 205 for((var) = LIST_FIRST(head); \ 206 (var)!= LIST_END(head); \ 207 (var) = LIST_NEXT(var, field)) 208 209 /* 210 * List functions. 211 */ 212 #define LIST_INIT(head) do { \ 213 LIST_FIRST(head) = LIST_END(head); \ 214 } while (0) 215 216 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 217 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 218 (listelm)->field.le_next->field.le_prev = \ 219 &(elm)->field.le_next; \ 220 (listelm)->field.le_next = (elm); \ 221 (elm)->field.le_prev = &(listelm)->field.le_next; \ 222 } while (0) 223 224 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 225 (elm)->field.le_prev = (listelm)->field.le_prev; \ 226 (elm)->field.le_next = (listelm); \ 227 *(listelm)->field.le_prev = (elm); \ 228 (listelm)->field.le_prev = &(elm)->field.le_next; \ 229 } while (0) 230 231 #define LIST_INSERT_HEAD(head, elm, field) do { \ 232 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 233 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 234 (head)->lh_first = (elm); \ 235 (elm)->field.le_prev = &(head)->lh_first; \ 236 } while (0) 237 238 #define LIST_REMOVE(elm, field) do { \ 239 if ((elm)->field.le_next != NULL) \ 240 (elm)->field.le_next->field.le_prev = \ 241 (elm)->field.le_prev; \ 242 *(elm)->field.le_prev = (elm)->field.le_next; \ 243 _Q_INVALIDATE((elm)->field.le_prev); \ 244 _Q_INVALIDATE((elm)->field.le_next); \ 245 } while (0) 246 247 #define LIST_REPLACE(elm, elm2, field) do { \ 248 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 249 (elm2)->field.le_next->field.le_prev = \ 250 &(elm2)->field.le_next; \ 251 (elm2)->field.le_prev = (elm)->field.le_prev; \ 252 *(elm2)->field.le_prev = (elm2); \ 253 _Q_INVALIDATE((elm)->field.le_prev); \ 254 _Q_INVALIDATE((elm)->field.le_next); \ 255 } while (0) 256 257 /* 258 * Simple queue definitions. 259 */ 260 #define SIMPLEQ_HEAD(name, type) \ 261 struct name { \ 262 struct type *sqh_first; /* first element */ \ 263 struct type **sqh_last; /* addr of last next element */ \ 264 } 265 266 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 267 { NULL, &(head).sqh_first } 268 269 #define SIMPLEQ_ENTRY(type) \ 270 struct { \ 271 struct type *sqe_next; /* next element */ \ 272 } 273 274 /* 275 * Simple queue access methods. 276 */ 277 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 278 #define SIMPLEQ_END(head) NULL 279 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 280 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 281 282 #define SIMPLEQ_FOREACH(var, head, field) \ 283 for((var) = SIMPLEQ_FIRST(head); \ 284 (var) != SIMPLEQ_END(head); \ 285 (var) = SIMPLEQ_NEXT(var, field)) 286 287 /* 288 * Simple queue functions. 289 */ 290 #define SIMPLEQ_INIT(head) do { \ 291 (head)->sqh_first = NULL; \ 292 (head)->sqh_last = &(head)->sqh_first; \ 293 } while (0) 294 295 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 296 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 297 (head)->sqh_last = &(elm)->field.sqe_next; \ 298 (head)->sqh_first = (elm); \ 299 } while (0) 300 301 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 302 (elm)->field.sqe_next = NULL; \ 303 *(head)->sqh_last = (elm); \ 304 (head)->sqh_last = &(elm)->field.sqe_next; \ 305 } while (0) 306 307 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 308 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 309 (head)->sqh_last = &(elm)->field.sqe_next; \ 310 (listelm)->field.sqe_next = (elm); \ 311 } while (0) 312 313 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \ 314 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 315 (head)->sqh_last = &(head)->sqh_first; \ 316 } while (0) 317 318 /* 319 * Tail queue definitions. 320 */ 321 #define TAILQ_HEAD(name, type) \ 322 struct name { \ 323 struct type *tqh_first; /* first element */ \ 324 struct type **tqh_last; /* addr of last next element */ \ 325 } 326 327 #define TAILQ_HEAD_INITIALIZER(head) \ 328 { NULL, &(head).tqh_first } 329 330 #define TAILQ_ENTRY(type) \ 331 struct { \ 332 struct type *tqe_next; /* next element */ \ 333 struct type **tqe_prev; /* address of previous next element */ \ 334 } 335 336 /* 337 * tail queue access methods 338 */ 339 #define TAILQ_FIRST(head) ((head)->tqh_first) 340 #define TAILQ_END(head) NULL 341 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 342 #define TAILQ_LAST(head, headname) \ 343 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 344 /* XXX */ 345 #define TAILQ_PREV(elm, headname, field) \ 346 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 347 #define TAILQ_EMPTY(head) \ 348 (TAILQ_FIRST(head) == TAILQ_END(head)) 349 350 #define TAILQ_FOREACH(var, head, field) \ 351 for((var) = TAILQ_FIRST(head); \ 352 (var) != TAILQ_END(head); \ 353 (var) = TAILQ_NEXT(var, field)) 354 355 /* removal safe iterator using a temprary element has last param */ 356 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 357 for((var) = TAILQ_FIRST(head), \ 358 (tvar) = TAILQ_FIRST(head) ? TAILQ_NEXT(TAILQ_FIRST(head), field): NULL ; \ 359 (var) != TAILQ_END(head); \ 360 (var = tvar), (tvar) = var ? TAILQ_NEXT(var, field): NULL) 361 362 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 363 for((var) = TAILQ_LAST(head, headname); \ 364 (var) != TAILQ_END(head); \ 365 (var) = TAILQ_PREV(var, headname, field)) 366 367 /* 368 * Tail queue functions. 369 */ 370 #define TAILQ_INIT(head) do { \ 371 (head)->tqh_first = NULL; \ 372 (head)->tqh_last = &(head)->tqh_first; \ 373 } while (0) 374 375 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 376 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 377 (head)->tqh_first->field.tqe_prev = \ 378 &(elm)->field.tqe_next; \ 379 else \ 380 (head)->tqh_last = &(elm)->field.tqe_next; \ 381 (head)->tqh_first = (elm); \ 382 (elm)->field.tqe_prev = &(head)->tqh_first; \ 383 } while (0) 384 385 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 386 _Q_ASSERT((elm)); \ 387 _Q_ASSERT((head)); \ 388 (elm)->field.tqe_next = NULL; \ 389 (elm)->field.tqe_prev = (head)->tqh_last; \ 390 *(head)->tqh_last = (elm); \ 391 _Q_ASSERT(*(head)->tqh_last); \ 392 (head)->tqh_last = &(elm)->field.tqe_next; \ 393 } while (0) 394 395 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 396 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 397 (elm)->field.tqe_next->field.tqe_prev = \ 398 &(elm)->field.tqe_next; \ 399 else \ 400 (head)->tqh_last = &(elm)->field.tqe_next; \ 401 (listelm)->field.tqe_next = (elm); \ 402 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 403 } while (0) 404 405 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 406 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 407 (elm)->field.tqe_next = (listelm); \ 408 *(listelm)->field.tqe_prev = (elm); \ 409 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 410 } while (0) 411 412 #define TAILQ_REMOVE(head, elm, field) do { \ 413 if (((elm)->field.tqe_next) != NULL) \ 414 (elm)->field.tqe_next->field.tqe_prev = \ 415 (elm)->field.tqe_prev; \ 416 else \ 417 (head)->tqh_last = (elm)->field.tqe_prev; \ 418 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 419 _Q_ASSERT((head)->tqh_first != (elm)); \ 420 _Q_INVALIDATE((elm)->field.tqe_prev); \ 421 _Q_INVALIDATE((elm)->field.tqe_next); \ 422 } while (0) 423 424 #define TAILQ_REPLACE(head, elm, elm2, field) do { \ 425 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 426 (elm2)->field.tqe_next->field.tqe_prev = \ 427 &(elm2)->field.tqe_next; \ 428 else \ 429 (head)->tqh_last = &(elm2)->field.tqe_next; \ 430 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 431 *(elm2)->field.tqe_prev = (elm2); \ 432 _Q_INVALIDATE((elm)->field.tqe_prev); \ 433 _Q_INVALIDATE((elm)->field.tqe_next); \ 434 } while (0) 435 436 /* 437 * Circular queue definitions. 438 */ 439 #define CIRCLEQ_HEAD(name, type) \ 440 struct name { \ 441 struct type *cqh_first; /* first element */ \ 442 struct type *cqh_last; /* last element */ \ 443 } 444 445 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 446 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 447 448 #define CIRCLEQ_ENTRY(type) \ 449 struct { \ 450 struct type *cqe_next; /* next element */ \ 451 struct type *cqe_prev; /* previous element */ \ 452 } 453 454 /* 455 * Circular queue access methods 456 */ 457 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 458 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 459 #define CIRCLEQ_END(head) ((void *)(head)) 460 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 461 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 462 #define CIRCLEQ_EMPTY(head) \ 463 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 464 465 #define CIRCLEQ_FOREACH(var, head, field) \ 466 for((var) = CIRCLEQ_FIRST(head); \ 467 (var) != CIRCLEQ_END(head); \ 468 (var) = CIRCLEQ_NEXT(var, field)) 469 470 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 471 for((var) = CIRCLEQ_LAST(head); \ 472 (var) != CIRCLEQ_END(head); \ 473 (var) = CIRCLEQ_PREV(var, field)) 474 475 /* 476 * Circular queue functions. 477 */ 478 #define CIRCLEQ_INIT(head) do { \ 479 (head)->cqh_first = CIRCLEQ_END(head); \ 480 (head)->cqh_last = CIRCLEQ_END(head); \ 481 } while (0) 482 483 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 484 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 485 (elm)->field.cqe_prev = (listelm); \ 486 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 487 (head)->cqh_last = (elm); \ 488 else \ 489 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 490 (listelm)->field.cqe_next = (elm); \ 491 } while (0) 492 493 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 494 (elm)->field.cqe_next = (listelm); \ 495 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 496 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 497 (head)->cqh_first = (elm); \ 498 else \ 499 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 500 (listelm)->field.cqe_prev = (elm); \ 501 } while (0) 502 503 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 504 (elm)->field.cqe_next = (head)->cqh_first; \ 505 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 506 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 507 (head)->cqh_last = (elm); \ 508 else \ 509 (head)->cqh_first->field.cqe_prev = (elm); \ 510 (head)->cqh_first = (elm); \ 511 } while (0) 512 513 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 514 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 515 (elm)->field.cqe_prev = (head)->cqh_last; \ 516 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 517 (head)->cqh_first = (elm); \ 518 else \ 519 (head)->cqh_last->field.cqe_next = (elm); \ 520 (head)->cqh_last = (elm); \ 521 } while (0) 522 523 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 524 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 525 (head)->cqh_last = (elm)->field.cqe_prev; \ 526 else \ 527 (elm)->field.cqe_next->field.cqe_prev = \ 528 (elm)->field.cqe_prev; \ 529 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 530 (head)->cqh_first = (elm)->field.cqe_next; \ 531 else \ 532 (elm)->field.cqe_prev->field.cqe_next = \ 533 (elm)->field.cqe_next; \ 534 _Q_INVALIDATE((elm)->field.cqe_prev); \ 535 _Q_INVALIDATE((elm)->field.cqe_next); \ 536 } while (0) 537 538 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ 539 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ 540 CIRCLEQ_END(head)) \ 541 (head).cqh_last = (elm2); \ 542 else \ 543 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 544 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ 545 CIRCLEQ_END(head)) \ 546 (head).cqh_first = (elm2); \ 547 else \ 548 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 549 _Q_INVALIDATE((elm)->field.cqe_prev); \ 550 _Q_INVALIDATE((elm)->field.cqe_next); \ 551 } while (0) 552 553 #define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar) \ 554 for ((var) = CIRCLEQ_FIRST(head); \ 555 (var) != CIRCLEQ_END(head) && \ 556 ((tvar) = CIRCLEQ_NEXT(var, field), 1); \ 557 (var) = (tvar)) 558 559 #define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 560 for ((var) = CIRCLEQ_LAST(head, headname); \ 561 (var) != CIRCLEQ_END(head) && \ 562 ((tvar) = CIRCLEQ_PREV(var, headname, field), 1); \ 563 (var) = (tvar)) 564 565 #endif /* !_SYS_QUEUE_H_ */ 566