1/* $OpenBSD: queue.h,v 1.46 2020/12/30 13:33:12 millert 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#include <sys/_null.h> 39 40/* 41 * This file defines five types of data structures: singly-linked lists, 42 * lists, simple queues, tail queues and XOR simple queues. 43 * 44 * 45 * A singly-linked list is headed by a single forward pointer. The elements 46 * are singly linked for minimum space and pointer manipulation overhead at 47 * the expense of O(n) removal for arbitrary elements. New elements can be 48 * added to the list after an existing element or at the head of the list. 49 * Elements being removed from the head of the list should use the explicit 50 * macro for this purpose for optimum efficiency. A singly-linked list may 51 * only be traversed in the forward direction. Singly-linked lists are ideal 52 * for applications with large datasets and few or no removals or for 53 * implementing a LIFO queue. 54 * 55 * A list is headed by a single forward pointer (or an array of forward 56 * pointers for a hash table header). The elements are doubly linked 57 * so that an arbitrary element can be removed without a need to 58 * traverse the list. New elements can be added to the list before 59 * or after an existing element or at the head of the list. A list 60 * may only be traversed in the forward direction. 61 * 62 * A simple queue is headed by a pair of pointers, one to the head of the 63 * list and the other to the tail of the list. The elements are singly 64 * linked to save space, so elements can only be removed from the 65 * head of the list. New elements can be added to the list before or after 66 * an existing element, at the head of the list, or at the end of the 67 * list. A simple queue may only be traversed in the forward direction. 68 * 69 * A tail queue is headed by a pair of pointers, one to the head of the 70 * list and the other to the tail of the list. The elements are doubly 71 * linked so that an arbitrary element can be removed without a need to 72 * traverse the list. New elements can be added to the list before or 73 * after an existing element, at the head of the list, or at the end of 74 * the list. A tail queue may be traversed in either direction. 75 * 76 * An XOR simple queue is used in the same way as a regular simple queue. 77 * The difference is that the head structure also includes a "cookie" that 78 * is XOR'd with the queue pointer (first, last or next) to generate the 79 * real pointer value. 80 * 81 * For details on the use of these macros, see the queue(3) manual page. 82 */ 83 84#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC)) 85#define _Q_INVALID ((void *)-1) 86#define _Q_INVALIDATE(a) (a) = _Q_INVALID 87#else 88#define _Q_INVALIDATE(a) 89#endif 90 91/* 92 * Singly-linked List definitions. 93 */ 94#define SLIST_HEAD(name, type) \ 95struct name { \ 96 struct type *slh_first; /* first element */ \ 97} 98 99#define SLIST_HEAD_INITIALIZER(head) \ 100 { NULL } 101 102#define SLIST_ENTRY(type) \ 103struct { \ 104 struct type *sle_next; /* next element */ \ 105} 106 107/* 108 * Singly-linked List access methods. 109 */ 110#define SLIST_FIRST(head) ((head)->slh_first) 111#define SLIST_END(head) NULL 112#define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) 113#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 114 115#define SLIST_FOREACH(var, head, field) \ 116 for((var) = SLIST_FIRST(head); \ 117 (var) != SLIST_END(head); \ 118 (var) = SLIST_NEXT(var, field)) 119 120#define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 121 for ((var) = SLIST_FIRST(head); \ 122 (var) && ((tvar) = SLIST_NEXT(var, field), 1); \ 123 (var) = (tvar)) 124 125/* 126 * Singly-linked List functions. 127 */ 128#define SLIST_INIT(head) { \ 129 SLIST_FIRST(head) = SLIST_END(head); \ 130} 131 132#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 133 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 134 (slistelm)->field.sle_next = (elm); \ 135} while (0) 136 137#define SLIST_INSERT_HEAD(head, elm, field) do { \ 138 (elm)->field.sle_next = (head)->slh_first; \ 139 (head)->slh_first = (elm); \ 140} while (0) 141 142#define SLIST_REMOVE_AFTER(elm, field) do { \ 143 (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \ 144} while (0) 145 146#define SLIST_REMOVE_HEAD(head, field) do { \ 147 (head)->slh_first = (head)->slh_first->field.sle_next; \ 148} while (0) 149 150#define SLIST_REMOVE(head, elm, type, field) do { \ 151 if ((head)->slh_first == (elm)) { \ 152 SLIST_REMOVE_HEAD((head), field); \ 153 } else { \ 154 struct type *curelm = (head)->slh_first; \ 155 \ 156 while (curelm->field.sle_next != (elm)) \ 157 curelm = curelm->field.sle_next; \ 158 curelm->field.sle_next = \ 159 curelm->field.sle_next->field.sle_next; \ 160 } \ 161 _Q_INVALIDATE((elm)->field.sle_next); \ 162} while (0) 163 164/* 165 * List definitions. 166 */ 167#define LIST_HEAD(name, type) \ 168struct name { \ 169 struct type *lh_first; /* first element */ \ 170} 171 172#define LIST_HEAD_INITIALIZER(head) \ 173 { NULL } 174 175#define LIST_ENTRY(type) \ 176struct { \ 177 struct type *le_next; /* next element */ \ 178 struct type **le_prev; /* address of previous next element */ \ 179} 180 181/* 182 * List access methods. 183 */ 184#define LIST_FIRST(head) ((head)->lh_first) 185#define LIST_END(head) NULL 186#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 187#define LIST_NEXT(elm, field) ((elm)->field.le_next) 188 189#define LIST_FOREACH(var, head, field) \ 190 for((var) = LIST_FIRST(head); \ 191 (var)!= LIST_END(head); \ 192 (var) = LIST_NEXT(var, field)) 193 194#define LIST_FOREACH_SAFE(var, head, field, tvar) \ 195 for ((var) = LIST_FIRST(head); \ 196 (var) && ((tvar) = LIST_NEXT(var, field), 1); \ 197 (var) = (tvar)) 198 199/* 200 * List functions. 201 */ 202#define LIST_INIT(head) do { \ 203 LIST_FIRST(head) = LIST_END(head); \ 204} while (0) 205 206#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 207 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 208 (listelm)->field.le_next->field.le_prev = \ 209 &(elm)->field.le_next; \ 210 (listelm)->field.le_next = (elm); \ 211 (elm)->field.le_prev = &(listelm)->field.le_next; \ 212} while (0) 213 214#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 215 (elm)->field.le_prev = (listelm)->field.le_prev; \ 216 (elm)->field.le_next = (listelm); \ 217 *(listelm)->field.le_prev = (elm); \ 218 (listelm)->field.le_prev = &(elm)->field.le_next; \ 219} while (0) 220 221#define LIST_INSERT_HEAD(head, elm, field) do { \ 222 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 223 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 224 (head)->lh_first = (elm); \ 225 (elm)->field.le_prev = &(head)->lh_first; \ 226} while (0) 227 228#define LIST_REMOVE(elm, field) do { \ 229 if ((elm)->field.le_next != NULL) \ 230 (elm)->field.le_next->field.le_prev = \ 231 (elm)->field.le_prev; \ 232 *(elm)->field.le_prev = (elm)->field.le_next; \ 233 _Q_INVALIDATE((elm)->field.le_prev); \ 234 _Q_INVALIDATE((elm)->field.le_next); \ 235} while (0) 236 237#define LIST_REPLACE(elm, elm2, field) do { \ 238 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 239 (elm2)->field.le_next->field.le_prev = \ 240 &(elm2)->field.le_next; \ 241 (elm2)->field.le_prev = (elm)->field.le_prev; \ 242 *(elm2)->field.le_prev = (elm2); \ 243 _Q_INVALIDATE((elm)->field.le_prev); \ 244 _Q_INVALIDATE((elm)->field.le_next); \ 245} while (0) 246 247/* 248 * Simple queue definitions. 249 */ 250#define SIMPLEQ_HEAD(name, type) \ 251struct name { \ 252 struct type *sqh_first; /* first element */ \ 253 struct type **sqh_last; /* addr of last next element */ \ 254} 255 256#define SIMPLEQ_HEAD_INITIALIZER(head) \ 257 { NULL, &(head).sqh_first } 258 259#define SIMPLEQ_ENTRY(type) \ 260struct { \ 261 struct type *sqe_next; /* next element */ \ 262} 263 264/* 265 * Simple queue access methods. 266 */ 267#define SIMPLEQ_FIRST(head) ((head)->sqh_first) 268#define SIMPLEQ_END(head) NULL 269#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 270#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 271 272#define SIMPLEQ_FOREACH(var, head, field) \ 273 for((var) = SIMPLEQ_FIRST(head); \ 274 (var) != SIMPLEQ_END(head); \ 275 (var) = SIMPLEQ_NEXT(var, field)) 276 277#define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \ 278 for ((var) = SIMPLEQ_FIRST(head); \ 279 (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1); \ 280 (var) = (tvar)) 281 282/* 283 * Simple queue functions. 284 */ 285#define SIMPLEQ_INIT(head) do { \ 286 (head)->sqh_first = NULL; \ 287 (head)->sqh_last = &(head)->sqh_first; \ 288} while (0) 289 290#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 291 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 292 (head)->sqh_last = &(elm)->field.sqe_next; \ 293 (head)->sqh_first = (elm); \ 294} while (0) 295 296#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 297 (elm)->field.sqe_next = NULL; \ 298 *(head)->sqh_last = (elm); \ 299 (head)->sqh_last = &(elm)->field.sqe_next; \ 300} while (0) 301 302#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 303 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 304 (head)->sqh_last = &(elm)->field.sqe_next; \ 305 (listelm)->field.sqe_next = (elm); \ 306} while (0) 307 308#define SIMPLEQ_REMOVE_HEAD(head, field) do { \ 309 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 310 (head)->sqh_last = &(head)->sqh_first; \ 311} while (0) 312 313#define SIMPLEQ_REMOVE_AFTER(head, elm, field) do { \ 314 if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \ 315 == NULL) \ 316 (head)->sqh_last = &(elm)->field.sqe_next; \ 317} while (0) 318 319#define SIMPLEQ_CONCAT(head1, head2) do { \ 320 if (!SIMPLEQ_EMPTY((head2))) { \ 321 *(head1)->sqh_last = (head2)->sqh_first; \ 322 (head1)->sqh_last = (head2)->sqh_last; \ 323 SIMPLEQ_INIT((head2)); \ 324 } \ 325} while (0) 326 327/* 328 * XOR Simple queue definitions. 329 */ 330#define XSIMPLEQ_HEAD(name, type) \ 331struct name { \ 332 struct type *sqx_first; /* first element */ \ 333 struct type **sqx_last; /* addr of last next element */ \ 334 unsigned long sqx_cookie; \ 335} 336 337#define XSIMPLEQ_ENTRY(type) \ 338struct { \ 339 struct type *sqx_next; /* next element */ \ 340} 341 342/* 343 * XOR Simple queue access methods. 344 */ 345#define XSIMPLEQ_XOR(head, ptr) ((__typeof(ptr))((head)->sqx_cookie ^ \ 346 (unsigned long)(ptr))) 347#define XSIMPLEQ_FIRST(head) XSIMPLEQ_XOR(head, ((head)->sqx_first)) 348#define XSIMPLEQ_END(head) NULL 349#define XSIMPLEQ_EMPTY(head) (XSIMPLEQ_FIRST(head) == XSIMPLEQ_END(head)) 350#define XSIMPLEQ_NEXT(head, elm, field) XSIMPLEQ_XOR(head, ((elm)->field.sqx_next)) 351 352 353#define XSIMPLEQ_FOREACH(var, head, field) \ 354 for ((var) = XSIMPLEQ_FIRST(head); \ 355 (var) != XSIMPLEQ_END(head); \ 356 (var) = XSIMPLEQ_NEXT(head, var, field)) 357 358#define XSIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \ 359 for ((var) = XSIMPLEQ_FIRST(head); \ 360 (var) && ((tvar) = XSIMPLEQ_NEXT(head, var, field), 1); \ 361 (var) = (tvar)) 362 363/* 364 * XOR Simple queue functions. 365 */ 366#define XSIMPLEQ_INIT(head) do { \ 367 arc4random_buf(&(head)->sqx_cookie, sizeof((head)->sqx_cookie)); \ 368 (head)->sqx_first = XSIMPLEQ_XOR(head, NULL); \ 369 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \ 370} while (0) 371 372#define XSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 373 if (((elm)->field.sqx_next = (head)->sqx_first) == \ 374 XSIMPLEQ_XOR(head, NULL)) \ 375 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 376 (head)->sqx_first = XSIMPLEQ_XOR(head, (elm)); \ 377} while (0) 378 379#define XSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 380 (elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL); \ 381 *(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \ 382 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 383} while (0) 384 385#define XSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 386 if (((elm)->field.sqx_next = (listelm)->field.sqx_next) == \ 387 XSIMPLEQ_XOR(head, NULL)) \ 388 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 389 (listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm)); \ 390} while (0) 391 392#define XSIMPLEQ_REMOVE_HEAD(head, field) do { \ 393 if (((head)->sqx_first = XSIMPLEQ_XOR(head, \ 394 (head)->sqx_first)->field.sqx_next) == XSIMPLEQ_XOR(head, NULL)) \ 395 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \ 396} while (0) 397 398#define XSIMPLEQ_REMOVE_AFTER(head, elm, field) do { \ 399 if (((elm)->field.sqx_next = XSIMPLEQ_XOR(head, \ 400 (elm)->field.sqx_next)->field.sqx_next) \ 401 == XSIMPLEQ_XOR(head, NULL)) \ 402 (head)->sqx_last = \ 403 XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 404} while (0) 405 406 407/* 408 * Tail queue definitions. 409 */ 410#define TAILQ_HEAD(name, type) \ 411struct name { \ 412 struct type *tqh_first; /* first element */ \ 413 struct type **tqh_last; /* addr of last next element */ \ 414} 415 416#define TAILQ_HEAD_INITIALIZER(head) \ 417 { NULL, &(head).tqh_first } 418 419#define TAILQ_ENTRY(type) \ 420struct { \ 421 struct type *tqe_next; /* next element */ \ 422 struct type **tqe_prev; /* address of previous next element */ \ 423} 424 425/* 426 * Tail queue access methods. 427 */ 428#define TAILQ_FIRST(head) ((head)->tqh_first) 429#define TAILQ_END(head) NULL 430#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 431#define TAILQ_LAST(head, headname) \ 432 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 433/* XXX */ 434#define TAILQ_PREV(elm, headname, field) \ 435 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 436#define TAILQ_EMPTY(head) \ 437 (TAILQ_FIRST(head) == TAILQ_END(head)) 438 439#define TAILQ_FOREACH(var, head, field) \ 440 for((var) = TAILQ_FIRST(head); \ 441 (var) != TAILQ_END(head); \ 442 (var) = TAILQ_NEXT(var, field)) 443 444#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 445 for ((var) = TAILQ_FIRST(head); \ 446 (var) != TAILQ_END(head) && \ 447 ((tvar) = TAILQ_NEXT(var, field), 1); \ 448 (var) = (tvar)) 449 450 451#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 452 for((var) = TAILQ_LAST(head, headname); \ 453 (var) != TAILQ_END(head); \ 454 (var) = TAILQ_PREV(var, headname, field)) 455 456#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 457 for ((var) = TAILQ_LAST(head, headname); \ 458 (var) != TAILQ_END(head) && \ 459 ((tvar) = TAILQ_PREV(var, headname, field), 1); \ 460 (var) = (tvar)) 461 462/* 463 * Tail queue functions. 464 */ 465#define TAILQ_INIT(head) do { \ 466 (head)->tqh_first = NULL; \ 467 (head)->tqh_last = &(head)->tqh_first; \ 468} while (0) 469 470#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 471 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 472 (head)->tqh_first->field.tqe_prev = \ 473 &(elm)->field.tqe_next; \ 474 else \ 475 (head)->tqh_last = &(elm)->field.tqe_next; \ 476 (head)->tqh_first = (elm); \ 477 (elm)->field.tqe_prev = &(head)->tqh_first; \ 478} while (0) 479 480#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 481 (elm)->field.tqe_next = NULL; \ 482 (elm)->field.tqe_prev = (head)->tqh_last; \ 483 *(head)->tqh_last = (elm); \ 484 (head)->tqh_last = &(elm)->field.tqe_next; \ 485} while (0) 486 487#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 488 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 489 (elm)->field.tqe_next->field.tqe_prev = \ 490 &(elm)->field.tqe_next; \ 491 else \ 492 (head)->tqh_last = &(elm)->field.tqe_next; \ 493 (listelm)->field.tqe_next = (elm); \ 494 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 495} while (0) 496 497#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 498 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 499 (elm)->field.tqe_next = (listelm); \ 500 *(listelm)->field.tqe_prev = (elm); \ 501 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 502} while (0) 503 504#define TAILQ_REMOVE(head, elm, field) do { \ 505 if (((elm)->field.tqe_next) != NULL) \ 506 (elm)->field.tqe_next->field.tqe_prev = \ 507 (elm)->field.tqe_prev; \ 508 else \ 509 (head)->tqh_last = (elm)->field.tqe_prev; \ 510 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 511 _Q_INVALIDATE((elm)->field.tqe_prev); \ 512 _Q_INVALIDATE((elm)->field.tqe_next); \ 513} while (0) 514 515#define TAILQ_REPLACE(head, elm, elm2, field) do { \ 516 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 517 (elm2)->field.tqe_next->field.tqe_prev = \ 518 &(elm2)->field.tqe_next; \ 519 else \ 520 (head)->tqh_last = &(elm2)->field.tqe_next; \ 521 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 522 *(elm2)->field.tqe_prev = (elm2); \ 523 _Q_INVALIDATE((elm)->field.tqe_prev); \ 524 _Q_INVALIDATE((elm)->field.tqe_next); \ 525} while (0) 526 527#define TAILQ_CONCAT(head1, head2, field) do { \ 528 if (!TAILQ_EMPTY(head2)) { \ 529 *(head1)->tqh_last = (head2)->tqh_first; \ 530 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 531 (head1)->tqh_last = (head2)->tqh_last; \ 532 TAILQ_INIT((head2)); \ 533 } \ 534} while (0) 535 536/* 537 * Singly-linked Tail queue declarations. 538 */ 539#define STAILQ_HEAD(name, type) \ 540struct name { \ 541 struct type *stqh_first; /* first element */ \ 542 struct type **stqh_last; /* addr of last next element */ \ 543} 544 545#define STAILQ_HEAD_INITIALIZER(head) \ 546 { NULL, &(head).stqh_first } 547 548#define STAILQ_ENTRY(type) \ 549struct { \ 550 struct type *stqe_next; /* next element */ \ 551} 552 553/* 554 * Singly-linked Tail queue access methods. 555 */ 556#define STAILQ_FIRST(head) ((head)->stqh_first) 557#define STAILQ_END(head) NULL 558#define STAILQ_EMPTY(head) (STAILQ_FIRST(head) == STAILQ_END(head)) 559#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 560 561#define STAILQ_FOREACH(var, head, field) \ 562 for ((var) = STAILQ_FIRST(head); \ 563 (var) != STAILQ_END(head); \ 564 (var) = STAILQ_NEXT(var, field)) 565 566#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \ 567 for ((var) = STAILQ_FIRST(head); \ 568 (var) && ((tvar) = STAILQ_NEXT(var, field), 1); \ 569 (var) = (tvar)) 570 571/* 572 * Singly-linked Tail queue functions. 573 */ 574#define STAILQ_INIT(head) do { \ 575 STAILQ_FIRST((head)) = NULL; \ 576 (head)->stqh_last = &STAILQ_FIRST((head)); \ 577} while (0) 578 579#define STAILQ_INSERT_HEAD(head, elm, field) do { \ 580 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 581 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 582 STAILQ_FIRST((head)) = (elm); \ 583} while (0) 584 585#define STAILQ_INSERT_TAIL(head, elm, field) do { \ 586 STAILQ_NEXT((elm), field) = NULL; \ 587 *(head)->stqh_last = (elm); \ 588 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 589} while (0) 590 591#define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 592 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((elm), field)) == NULL)\ 593 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 594 STAILQ_NEXT((elm), field) = (elm); \ 595} while (0) 596 597#define STAILQ_REMOVE_HEAD(head, field) do { \ 598 if ((STAILQ_FIRST((head)) = \ 599 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 600 (head)->stqh_last = &STAILQ_FIRST((head)); \ 601} while (0) 602 603#define STAILQ_REMOVE_AFTER(head, elm, field) do { \ 604 if ((STAILQ_NEXT(elm, field) = \ 605 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \ 606 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 607} while (0) 608 609#define STAILQ_REMOVE(head, elm, type, field) do { \ 610 if (STAILQ_FIRST((head)) == (elm)) { \ 611 STAILQ_REMOVE_HEAD((head), field); \ 612 } else { \ 613 struct type *curelm = (head)->stqh_first; \ 614 while (STAILQ_NEXT(curelm, field) != (elm)) \ 615 curelm = STAILQ_NEXT(curelm, field); \ 616 STAILQ_REMOVE_AFTER(head, curelm, field); \ 617 } \ 618} while (0) 619 620#define STAILQ_CONCAT(head1, head2) do { \ 621 if (!STAILQ_EMPTY((head2))) { \ 622 *(head1)->stqh_last = (head2)->stqh_first; \ 623 (head1)->stqh_last = (head2)->stqh_last; \ 624 STAILQ_INIT((head2)); \ 625 } \ 626} while (0) 627 628#define STAILQ_LAST(head, type, field) \ 629 (STAILQ_EMPTY((head)) ? NULL : \ 630 ((struct type *)(void *) \ 631 ((char *)((head)->stqh_last) - offsetof(struct type, field)))) 632 633#endif /* !_SYS_QUEUE_H_ */ 634