1 /* $NetBSD: queue.h,v 1.77 2024/05/12 10:34:56 rillig 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 #ifndef _SYS_QUEUE_H_ 35 #define _SYS_QUEUE_H_ 36 37 /* 38 * This file defines five types of data structures: singly-linked lists, 39 * lists, simple queues, tail queues, and circular queues. 40 * 41 * A singly-linked list is headed by a single forward pointer. The 42 * elements are singly linked for minimum space and pointer manipulation 43 * overhead at the expense of O(n) removal for arbitrary elements. New 44 * elements can be added to the list after an existing element or at the 45 * head of the list. Elements being removed from the head of the list 46 * should use the explicit macro for this purpose for optimum 47 * efficiency. A singly-linked list may only be traversed in the forward 48 * direction. Singly-linked lists are ideal for applications with large 49 * datasets and few or no removals or for implementing a LIFO queue. 50 * 51 * A list is headed by a single forward pointer (or an array of forward 52 * pointers for a hash table header). The elements are doubly linked 53 * so that an arbitrary element can be removed without a need to 54 * traverse the list. New elements can be added to the list before 55 * or after an existing element or at the head of the list. A list 56 * may only be traversed in the forward direction. 57 * 58 * A simple queue is headed by a pair of pointers, one the head of the 59 * list and the other to the tail of the list. The elements are singly 60 * linked to save space, so elements can only be removed from the 61 * head of the list. New elements can be added to the list after 62 * an existing element, at the head of the list, or at the end of the 63 * list. A simple queue may only be traversed in the forward direction. 64 * 65 * A tail queue is headed by a pair of pointers, one to the head of the 66 * list and the other to the tail of the list. The elements are doubly 67 * linked so that an arbitrary element can be removed without a need to 68 * traverse the list. New elements can be added to the list before or 69 * after an existing element, at the head of the list, or at the end of 70 * the list. A tail queue may be traversed in either direction. 71 * 72 * For details on the use of these macros, see the queue(3) manual page. 73 */ 74 75 /* 76 * Include the definition of NULL only on NetBSD because sys/null.h 77 * is not available elsewhere. This conditional makes the header 78 * portable and it can simply be dropped verbatim into any system. 79 * The caveat is that on other systems some other header 80 * must provide NULL before the macros can be used. 81 */ 82 #ifdef __NetBSD__ 83 #include <sys/null.h> 84 #endif 85 86 #if defined(_KERNEL) && defined(DIAGNOSTIC) 87 #define QUEUEDEBUG 1 88 #endif 89 90 #if defined(QUEUEDEBUG) 91 # if defined(_KERNEL) 92 # define QUEUEDEBUG_ABORT(...) panic(__VA_ARGS__) 93 # else 94 # include <err.h> 95 # define QUEUEDEBUG_ABORT(...) err(1, __VA_ARGS__) 96 # endif 97 #endif 98 99 /* 100 * Singly-linked List definitions. 101 */ 102 #define SLIST_HEAD(name, type) \ 103 struct name { \ 104 struct type *slh_first; /* first element */ \ 105 } 106 107 #define SLIST_HEAD_INITIALIZER(head) \ 108 { NULL } 109 110 #define SLIST_ENTRY(type) \ 111 struct { \ 112 struct type *sle_next; /* next element */ \ 113 } 114 115 /* 116 * Singly-linked List access methods. 117 */ 118 #define SLIST_FIRST(head) ((head)->slh_first) 119 #define SLIST_END(head) NULL 120 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 121 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 122 123 #define SLIST_FOREACH(var, head, field) \ 124 for((var) = (head)->slh_first; \ 125 (var) != SLIST_END(head); \ 126 (var) = (var)->field.sle_next) 127 128 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 129 for ((var) = SLIST_FIRST((head)); \ 130 (var) != SLIST_END(head) && \ 131 ((tvar) = SLIST_NEXT((var), field), 1); \ 132 (var) = (tvar)) 133 134 /* 135 * Singly-linked List functions. 136 */ 137 #define SLIST_INIT(head) do { \ 138 (head)->slh_first = SLIST_END(head); \ 139 } while (0) 140 141 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 142 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 143 (slistelm)->field.sle_next = (elm); \ 144 } while (0) 145 146 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 147 (elm)->field.sle_next = (head)->slh_first; \ 148 (head)->slh_first = (elm); \ 149 } while (0) 150 151 #define SLIST_REMOVE_AFTER(slistelm, field) do { \ 152 (slistelm)->field.sle_next = \ 153 SLIST_NEXT(SLIST_NEXT((slistelm), field), field); \ 154 } while (0) 155 156 #define SLIST_REMOVE_HEAD(head, field) do { \ 157 (head)->slh_first = (head)->slh_first->field.sle_next; \ 158 } while (0) 159 160 #define SLIST_REMOVE(head, elm, type, field) do { \ 161 if ((head)->slh_first == (elm)) { \ 162 SLIST_REMOVE_HEAD((head), field); \ 163 } \ 164 else { \ 165 struct type *curelm = (head)->slh_first; \ 166 while(curelm->field.sle_next != (elm)) \ 167 curelm = curelm->field.sle_next; \ 168 curelm->field.sle_next = \ 169 curelm->field.sle_next->field.sle_next; \ 170 } \ 171 } while (0) 172 173 174 /* 175 * List definitions. 176 */ 177 #define LIST_HEAD(name, type) \ 178 struct name { \ 179 struct type *lh_first; /* first element */ \ 180 } 181 182 #define LIST_HEAD_INITIALIZER(head) \ 183 { NULL } 184 185 #define LIST_ENTRY(type) \ 186 struct { \ 187 struct type *le_next; /* next element */ \ 188 struct type **le_prev; /* address of previous next element */ \ 189 } 190 191 /* 192 * List access methods. 193 */ 194 #define LIST_FIRST(head) ((head)->lh_first) 195 #define LIST_END(head) NULL 196 #define LIST_EMPTY(head) ((head)->lh_first == LIST_END(head)) 197 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 198 199 #define LIST_FOREACH(var, head, field) \ 200 for ((var) = ((head)->lh_first); \ 201 (var) != LIST_END(head); \ 202 (var) = ((var)->field.le_next)) 203 204 #define LIST_FOREACH_SAFE(var, head, field, tvar) \ 205 for ((var) = LIST_FIRST((head)); \ 206 (var) != LIST_END(head) && \ 207 ((tvar) = LIST_NEXT((var), field), 1); \ 208 (var) = (tvar)) 209 210 #define LIST_MOVE(head1, head2, field) do { \ 211 LIST_INIT((head2)); \ 212 if (!LIST_EMPTY((head1))) { \ 213 (head2)->lh_first = (head1)->lh_first; \ 214 (head2)->lh_first->field.le_prev = &(head2)->lh_first; \ 215 LIST_INIT((head1)); \ 216 } \ 217 } while (0) 218 219 /* 220 * List functions. 221 */ 222 #if defined(QUEUEDEBUG) 223 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) \ 224 if ((head)->lh_first && \ 225 (head)->lh_first->field.le_prev != &(head)->lh_first) \ 226 QUEUEDEBUG_ABORT("LIST_INSERT_HEAD %p %s:%d", (head), \ 227 __FILE__, __LINE__); 228 #define QUEUEDEBUG_LIST_OP(elm, field) \ 229 if ((elm)->field.le_next && \ 230 (elm)->field.le_next->field.le_prev != \ 231 &(elm)->field.le_next) \ 232 QUEUEDEBUG_ABORT("LIST_* forw %p %s:%d", (elm), \ 233 __FILE__, __LINE__); \ 234 if (*(elm)->field.le_prev != (elm)) \ 235 QUEUEDEBUG_ABORT("LIST_* back %p %s:%d", (elm), \ 236 __FILE__, __LINE__); 237 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) \ 238 (elm)->field.le_next = (void *)1L; \ 239 (elm)->field.le_prev = (void *)1L; 240 #else 241 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) 242 #define QUEUEDEBUG_LIST_OP(elm, field) 243 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) 244 #endif 245 246 #define LIST_INIT(head) do { \ 247 (head)->lh_first = LIST_END(head); \ 248 } while (0) 249 250 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 251 QUEUEDEBUG_LIST_OP((listelm), field) \ 252 if (((elm)->field.le_next = (listelm)->field.le_next) != \ 253 LIST_END(head)) \ 254 (listelm)->field.le_next->field.le_prev = \ 255 &(elm)->field.le_next; \ 256 (listelm)->field.le_next = (elm); \ 257 (elm)->field.le_prev = &(listelm)->field.le_next; \ 258 } while (0) 259 260 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 261 QUEUEDEBUG_LIST_OP((listelm), field) \ 262 (elm)->field.le_prev = (listelm)->field.le_prev; \ 263 (elm)->field.le_next = (listelm); \ 264 *(listelm)->field.le_prev = (elm); \ 265 (listelm)->field.le_prev = &(elm)->field.le_next; \ 266 } while (0) 267 268 #define LIST_INSERT_HEAD(head, elm, field) do { \ 269 QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field) \ 270 if (((elm)->field.le_next = (head)->lh_first) != LIST_END(head))\ 271 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 272 (head)->lh_first = (elm); \ 273 (elm)->field.le_prev = &(head)->lh_first; \ 274 } while (0) 275 276 #define LIST_REMOVE(elm, field) do { \ 277 QUEUEDEBUG_LIST_OP((elm), field) \ 278 if ((elm)->field.le_next != NULL) \ 279 (elm)->field.le_next->field.le_prev = \ 280 (elm)->field.le_prev; \ 281 *(elm)->field.le_prev = (elm)->field.le_next; \ 282 QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \ 283 } while (0) 284 285 #define LIST_REPLACE(elm, elm2, field) do { \ 286 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 287 (elm2)->field.le_next->field.le_prev = \ 288 &(elm2)->field.le_next; \ 289 (elm2)->field.le_prev = (elm)->field.le_prev; \ 290 *(elm2)->field.le_prev = (elm2); \ 291 QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \ 292 } while (0) 293 294 /* 295 * Simple queue definitions. 296 */ 297 #define SIMPLEQ_HEAD(name, type) \ 298 struct name { \ 299 struct type *sqh_first; /* first element */ \ 300 struct type **sqh_last; /* addr of last next element */ \ 301 } 302 303 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 304 { NULL, &(head).sqh_first } 305 306 #define SIMPLEQ_ENTRY(type) \ 307 struct { \ 308 struct type *sqe_next; /* next element */ \ 309 } 310 311 /* 312 * Simple queue access methods. 313 */ 314 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 315 #define SIMPLEQ_END(head) NULL 316 #define SIMPLEQ_EMPTY(head) ((head)->sqh_first == SIMPLEQ_END(head)) 317 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 318 319 #define SIMPLEQ_FOREACH(var, head, field) \ 320 for ((var) = ((head)->sqh_first); \ 321 (var) != SIMPLEQ_END(head); \ 322 (var) = ((var)->field.sqe_next)) 323 324 #define SIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 325 for ((var) = ((head)->sqh_first); \ 326 (var) != SIMPLEQ_END(head) && \ 327 ((next = ((var)->field.sqe_next)), 1); \ 328 (var) = (next)) 329 330 /* 331 * Simple queue functions. 332 */ 333 #define SIMPLEQ_INIT(head) do { \ 334 (head)->sqh_first = NULL; \ 335 (head)->sqh_last = &(head)->sqh_first; \ 336 } while (0) 337 338 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 339 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 340 (head)->sqh_last = &(elm)->field.sqe_next; \ 341 (head)->sqh_first = (elm); \ 342 } while (0) 343 344 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 345 (elm)->field.sqe_next = NULL; \ 346 *(head)->sqh_last = (elm); \ 347 (head)->sqh_last = &(elm)->field.sqe_next; \ 348 } while (0) 349 350 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 351 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 352 (head)->sqh_last = &(elm)->field.sqe_next; \ 353 (listelm)->field.sqe_next = (elm); \ 354 } while (0) 355 356 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \ 357 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 358 (head)->sqh_last = &(head)->sqh_first; \ 359 } while (0) 360 361 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) do { \ 362 if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \ 363 == NULL) \ 364 (head)->sqh_last = &(elm)->field.sqe_next; \ 365 } while (0) 366 367 #define SIMPLEQ_REMOVE(head, elm, type, field) do { \ 368 if ((head)->sqh_first == (elm)) { \ 369 SIMPLEQ_REMOVE_HEAD((head), field); \ 370 } else { \ 371 struct type *curelm = (head)->sqh_first; \ 372 while (curelm->field.sqe_next != (elm)) \ 373 curelm = curelm->field.sqe_next; \ 374 if ((curelm->field.sqe_next = \ 375 curelm->field.sqe_next->field.sqe_next) == NULL) \ 376 (head)->sqh_last = &(curelm)->field.sqe_next; \ 377 } \ 378 } while (0) 379 380 #define SIMPLEQ_CONCAT(head1, head2) do { \ 381 if (!SIMPLEQ_EMPTY((head2))) { \ 382 *(head1)->sqh_last = (head2)->sqh_first; \ 383 (head1)->sqh_last = (head2)->sqh_last; \ 384 SIMPLEQ_INIT((head2)); \ 385 } \ 386 } while (0) 387 388 #define SIMPLEQ_LAST(head, type, field) \ 389 (SIMPLEQ_EMPTY((head)) ? \ 390 NULL : \ 391 ((struct type *)(void *) \ 392 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 393 394 /* 395 * Tail queue definitions. 396 */ 397 #define _TAILQ_HEAD(name, type, qual) \ 398 struct name { \ 399 qual type *tqh_first; /* first element */ \ 400 qual type *qual *tqh_last; /* addr of last next element */ \ 401 } 402 #define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type,) 403 404 #define TAILQ_HEAD_INITIALIZER(head) \ 405 { TAILQ_END(head), &(head).tqh_first } 406 407 #define _TAILQ_ENTRY(type, qual) \ 408 struct { \ 409 qual type *tqe_next; /* next element */ \ 410 qual type *qual *tqe_prev; /* address of previous next element */\ 411 } 412 #define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type,) 413 414 /* 415 * Tail queue access methods. 416 */ 417 #define TAILQ_FIRST(head) ((head)->tqh_first) 418 #define TAILQ_END(head) (NULL) 419 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 420 #define TAILQ_LAST(head, headname) \ 421 (*(((struct headname *)(void *)((head)->tqh_last))->tqh_last)) 422 #define TAILQ_PREV(elm, headname, field) \ 423 (*(((struct headname *)(void *)((elm)->field.tqe_prev))->tqh_last)) 424 #define TAILQ_EMPTY(head) (TAILQ_FIRST(head) == TAILQ_END(head)) 425 426 427 #define TAILQ_FOREACH(var, head, field) \ 428 for ((var) = ((head)->tqh_first); \ 429 (var) != TAILQ_END(head); \ 430 (var) = ((var)->field.tqe_next)) 431 432 #define TAILQ_FOREACH_SAFE(var, head, field, next) \ 433 for ((var) = ((head)->tqh_first); \ 434 (var) != TAILQ_END(head) && \ 435 ((next) = TAILQ_NEXT(var, field), 1); (var) = (next)) 436 437 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 438 for ((var) = TAILQ_LAST((head), headname); \ 439 (var) != TAILQ_END(head); \ 440 (var) = TAILQ_PREV((var), headname, field)) 441 442 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, prev) \ 443 for ((var) = TAILQ_LAST((head), headname); \ 444 (var) != TAILQ_END(head) && \ 445 ((prev) = TAILQ_PREV((var), headname, field), 1); (var) = (prev)) 446 447 /* 448 * Tail queue functions. 449 */ 450 #if defined(QUEUEDEBUG) 451 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) \ 452 if ((head)->tqh_first && \ 453 (head)->tqh_first->field.tqe_prev != &(head)->tqh_first) \ 454 QUEUEDEBUG_ABORT("TAILQ_INSERT_HEAD %p %s:%d", (head), \ 455 __FILE__, __LINE__); 456 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) \ 457 if (*(head)->tqh_last != NULL) \ 458 QUEUEDEBUG_ABORT("TAILQ_INSERT_TAIL %p %s:%d", (head), \ 459 __FILE__, __LINE__); 460 #define QUEUEDEBUG_TAILQ_OP(elm, field) \ 461 if ((elm)->field.tqe_next && \ 462 (elm)->field.tqe_next->field.tqe_prev != \ 463 &(elm)->field.tqe_next) \ 464 QUEUEDEBUG_ABORT("TAILQ_* forw %p %s:%d", (elm), \ 465 __FILE__, __LINE__); \ 466 if (*(elm)->field.tqe_prev != (elm)) \ 467 QUEUEDEBUG_ABORT("TAILQ_* back %p %s:%d", (elm), \ 468 __FILE__, __LINE__); 469 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) \ 470 if ((elm)->field.tqe_next == NULL && \ 471 (head)->tqh_last != &(elm)->field.tqe_next) \ 472 QUEUEDEBUG_ABORT("TAILQ_PREREMOVE head %p elm %p %s:%d",\ 473 (head), (elm), __FILE__, __LINE__); 474 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) \ 475 (elm)->field.tqe_next = (void *)1L; \ 476 (elm)->field.tqe_prev = (void *)1L; 477 #else 478 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) 479 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) 480 #define QUEUEDEBUG_TAILQ_OP(elm, field) 481 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) 482 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) 483 #endif 484 485 #define TAILQ_INIT(head) do { \ 486 (head)->tqh_first = TAILQ_END(head); \ 487 (head)->tqh_last = &(head)->tqh_first; \ 488 } while (0) 489 490 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 491 QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field) \ 492 if (((elm)->field.tqe_next = (head)->tqh_first) != TAILQ_END(head))\ 493 (head)->tqh_first->field.tqe_prev = \ 494 &(elm)->field.tqe_next; \ 495 else \ 496 (head)->tqh_last = &(elm)->field.tqe_next; \ 497 (head)->tqh_first = (elm); \ 498 (elm)->field.tqe_prev = &(head)->tqh_first; \ 499 } while (0) 500 501 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 502 QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field) \ 503 (elm)->field.tqe_next = TAILQ_END(head); \ 504 (elm)->field.tqe_prev = (head)->tqh_last; \ 505 *(head)->tqh_last = (elm); \ 506 (head)->tqh_last = &(elm)->field.tqe_next; \ 507 } while (0) 508 509 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 510 QUEUEDEBUG_TAILQ_OP((listelm), field) \ 511 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != \ 512 TAILQ_END(head)) \ 513 (elm)->field.tqe_next->field.tqe_prev = \ 514 &(elm)->field.tqe_next; \ 515 else \ 516 (head)->tqh_last = &(elm)->field.tqe_next; \ 517 (listelm)->field.tqe_next = (elm); \ 518 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 519 } while (0) 520 521 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 522 QUEUEDEBUG_TAILQ_OP((listelm), field) \ 523 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 524 (elm)->field.tqe_next = (listelm); \ 525 *(listelm)->field.tqe_prev = (elm); \ 526 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 527 } while (0) 528 529 #define TAILQ_REMOVE(head, elm, field) do { \ 530 QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field) \ 531 QUEUEDEBUG_TAILQ_OP((elm), field) \ 532 if (((elm)->field.tqe_next) != TAILQ_END(head)) \ 533 (elm)->field.tqe_next->field.tqe_prev = \ 534 (elm)->field.tqe_prev; \ 535 else \ 536 (head)->tqh_last = (elm)->field.tqe_prev; \ 537 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 538 QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \ 539 } while (0) 540 541 #define TAILQ_REPLACE(head, elm, elm2, field) do { \ 542 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != \ 543 TAILQ_END(head)) \ 544 (elm2)->field.tqe_next->field.tqe_prev = \ 545 &(elm2)->field.tqe_next; \ 546 else \ 547 (head)->tqh_last = &(elm2)->field.tqe_next; \ 548 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 549 *(elm2)->field.tqe_prev = (elm2); \ 550 QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \ 551 } while (0) 552 553 #define TAILQ_CONCAT(head1, head2, field) do { \ 554 if (!TAILQ_EMPTY(head2)) { \ 555 *(head1)->tqh_last = (head2)->tqh_first; \ 556 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 557 (head1)->tqh_last = (head2)->tqh_last; \ 558 TAILQ_INIT((head2)); \ 559 } \ 560 } while (0) 561 562 /* 563 * Singly-linked Tail queue declarations. 564 */ 565 #define STAILQ_HEAD(name, type) \ 566 struct name { \ 567 struct type *stqh_first; /* first element */ \ 568 struct type **stqh_last; /* addr of last next element */ \ 569 } 570 571 #define STAILQ_HEAD_INITIALIZER(head) \ 572 { NULL, &(head).stqh_first } 573 574 #define STAILQ_ENTRY(type) \ 575 struct { \ 576 struct type *stqe_next; /* next element */ \ 577 } 578 579 /* 580 * Singly-linked Tail queue access methods. 581 */ 582 #define STAILQ_FIRST(head) ((head)->stqh_first) 583 #define STAILQ_END(head) NULL 584 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 585 #define STAILQ_EMPTY(head) (STAILQ_FIRST(head) == STAILQ_END(head)) 586 587 /* 588 * Singly-linked Tail queue functions. 589 */ 590 #define STAILQ_INIT(head) do { \ 591 (head)->stqh_first = NULL; \ 592 (head)->stqh_last = &(head)->stqh_first; \ 593 } while (0) 594 595 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 596 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 597 (head)->stqh_last = &(elm)->field.stqe_next; \ 598 (head)->stqh_first = (elm); \ 599 } while (0) 600 601 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 602 (elm)->field.stqe_next = NULL; \ 603 *(head)->stqh_last = (elm); \ 604 (head)->stqh_last = &(elm)->field.stqe_next; \ 605 } while (0) 606 607 #define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 608 if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\ 609 (head)->stqh_last = &(elm)->field.stqe_next; \ 610 (listelm)->field.stqe_next = (elm); \ 611 } while (0) 612 613 #define STAILQ_REMOVE_HEAD(head, field) do { \ 614 if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \ 615 (head)->stqh_last = &(head)->stqh_first; \ 616 } while (0) 617 618 #define STAILQ_REMOVE(head, elm, type, field) do { \ 619 if ((head)->stqh_first == (elm)) { \ 620 STAILQ_REMOVE_HEAD((head), field); \ 621 } else { \ 622 struct type *curelm = (head)->stqh_first; \ 623 while (curelm->field.stqe_next != (elm)) \ 624 curelm = curelm->field.stqe_next; \ 625 if ((curelm->field.stqe_next = \ 626 curelm->field.stqe_next->field.stqe_next) == NULL) \ 627 (head)->stqh_last = &(curelm)->field.stqe_next; \ 628 } \ 629 } while (0) 630 631 #define STAILQ_FOREACH(var, head, field) \ 632 for ((var) = ((head)->stqh_first); \ 633 (var); \ 634 (var) = ((var)->field.stqe_next)) 635 636 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \ 637 for ((var) = STAILQ_FIRST((head)); \ 638 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 639 (var) = (tvar)) 640 641 #define STAILQ_CONCAT(head1, head2) do { \ 642 if (!STAILQ_EMPTY((head2))) { \ 643 *(head1)->stqh_last = (head2)->stqh_first; \ 644 (head1)->stqh_last = (head2)->stqh_last; \ 645 STAILQ_INIT((head2)); \ 646 } \ 647 } while (0) 648 649 #define STAILQ_LAST(head, type, field) \ 650 (STAILQ_EMPTY((head)) ? \ 651 NULL : \ 652 ((struct type *)(void *) \ 653 ((char *)((head)->stqh_last) - offsetof(struct type, field)))) 654 655 #endif /* !_SYS_QUEUE_H_ */ 656