1/* $OpenBSD: queue.h,v 1.16 2000/09/07 19:47:59 art 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/* 86 * Singly-linked List definitions. 87 */ 88#define SLIST_HEAD(name, type) \ 89struct name { \ 90 struct type *slh_first; /* first element */ \ 91} 92 93#define SLIST_HEAD_INITIALIZER(head) \ 94 { NULL } 95 96#ifndef WIN32 97#define SLIST_ENTRY(type) \ 98struct { \ 99 struct type *sle_next; /* next element */ \ 100} 101#endif 102 103/* 104 * Singly-linked List access methods. 105 */ 106#define SLIST_FIRST(head) ((head)->slh_first) 107#define SLIST_END(head) NULL 108#define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) 109#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 110 111#define SLIST_FOREACH(var, head, field) \ 112 for((var) = SLIST_FIRST(head); \ 113 (var) != SLIST_END(head); \ 114 (var) = SLIST_NEXT(var, field)) 115 116/* 117 * Singly-linked List functions. 118 */ 119#define SLIST_INIT(head) { \ 120 SLIST_FIRST(head) = SLIST_END(head); \ 121} 122 123#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 124 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 125 (slistelm)->field.sle_next = (elm); \ 126} while (0) 127 128#define SLIST_INSERT_HEAD(head, elm, field) do { \ 129 (elm)->field.sle_next = (head)->slh_first; \ 130 (head)->slh_first = (elm); \ 131} while (0) 132 133#define SLIST_REMOVE_HEAD(head, field) do { \ 134 (head)->slh_first = (head)->slh_first->field.sle_next; \ 135} while (0) 136 137/* 138 * List definitions. 139 */ 140#define LIST_HEAD(name, type) \ 141struct name { \ 142 struct type *lh_first; /* first element */ \ 143} 144 145#define LIST_HEAD_INITIALIZER(head) \ 146 { NULL } 147 148#define LIST_ENTRY(type) \ 149struct { \ 150 struct type *le_next; /* next element */ \ 151 struct type **le_prev; /* address of previous next element */ \ 152} 153 154/* 155 * List access methods 156 */ 157#define LIST_FIRST(head) ((head)->lh_first) 158#define LIST_END(head) NULL 159#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 160#define LIST_NEXT(elm, field) ((elm)->field.le_next) 161 162#define LIST_FOREACH(var, head, field) \ 163 for((var) = LIST_FIRST(head); \ 164 (var)!= LIST_END(head); \ 165 (var) = LIST_NEXT(var, field)) 166 167/* 168 * List functions. 169 */ 170#define LIST_INIT(head) do { \ 171 LIST_FIRST(head) = LIST_END(head); \ 172} while (0) 173 174#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 175 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 176 (listelm)->field.le_next->field.le_prev = \ 177 &(elm)->field.le_next; \ 178 (listelm)->field.le_next = (elm); \ 179 (elm)->field.le_prev = &(listelm)->field.le_next; \ 180} while (0) 181 182#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 183 (elm)->field.le_prev = (listelm)->field.le_prev; \ 184 (elm)->field.le_next = (listelm); \ 185 *(listelm)->field.le_prev = (elm); \ 186 (listelm)->field.le_prev = &(elm)->field.le_next; \ 187} while (0) 188 189#define LIST_INSERT_HEAD(head, elm, field) do { \ 190 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 191 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 192 (head)->lh_first = (elm); \ 193 (elm)->field.le_prev = &(head)->lh_first; \ 194} while (0) 195 196#define LIST_REMOVE(elm, field) do { \ 197 if ((elm)->field.le_next != NULL) \ 198 (elm)->field.le_next->field.le_prev = \ 199 (elm)->field.le_prev; \ 200 *(elm)->field.le_prev = (elm)->field.le_next; \ 201} while (0) 202 203#define LIST_REPLACE(elm, elm2, field) do { \ 204 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 205 (elm2)->field.le_next->field.le_prev = \ 206 &(elm2)->field.le_next; \ 207 (elm2)->field.le_prev = (elm)->field.le_prev; \ 208 *(elm2)->field.le_prev = (elm2); \ 209} while (0) 210 211/* 212 * Simple queue definitions. 213 */ 214#define SIMPLEQ_HEAD(name, type) \ 215struct name { \ 216 struct type *sqh_first; /* first element */ \ 217 struct type **sqh_last; /* addr of last next element */ \ 218} 219 220#define SIMPLEQ_HEAD_INITIALIZER(head) \ 221 { NULL, &(head).sqh_first } 222 223#define SIMPLEQ_ENTRY(type) \ 224struct { \ 225 struct type *sqe_next; /* next element */ \ 226} 227 228/* 229 * Simple queue access methods. 230 */ 231#define SIMPLEQ_FIRST(head) ((head)->sqh_first) 232#define SIMPLEQ_END(head) NULL 233#define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 234#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 235 236#define SIMPLEQ_FOREACH(var, head, field) \ 237 for((var) = SIMPLEQ_FIRST(head); \ 238 (var) != SIMPLEQ_END(head); \ 239 (var) = SIMPLEQ_NEXT(var, field)) 240 241/* 242 * Simple queue functions. 243 */ 244#define SIMPLEQ_INIT(head) do { \ 245 (head)->sqh_first = NULL; \ 246 (head)->sqh_last = &(head)->sqh_first; \ 247} while (0) 248 249#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 250 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 251 (head)->sqh_last = &(elm)->field.sqe_next; \ 252 (head)->sqh_first = (elm); \ 253} while (0) 254 255#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 256 (elm)->field.sqe_next = NULL; \ 257 *(head)->sqh_last = (elm); \ 258 (head)->sqh_last = &(elm)->field.sqe_next; \ 259} while (0) 260 261#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 262 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 263 (head)->sqh_last = &(elm)->field.sqe_next; \ 264 (listelm)->field.sqe_next = (elm); \ 265} while (0) 266 267#define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \ 268 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \ 269 (head)->sqh_last = &(head)->sqh_first; \ 270} while (0) 271 272/* 273 * Tail queue definitions. 274 */ 275#define TAILQ_HEAD(name, type) \ 276struct name { \ 277 struct type *tqh_first; /* first element */ \ 278 struct type **tqh_last; /* addr of last next element */ \ 279} 280 281#define TAILQ_HEAD_INITIALIZER(head) \ 282 { NULL, &(head).tqh_first } 283 284#define TAILQ_ENTRY(type) \ 285struct { \ 286 struct type *tqe_next; /* next element */ \ 287 struct type **tqe_prev; /* address of previous next element */ \ 288} 289 290/* 291 * tail queue access methods 292 */ 293#define TAILQ_FIRST(head) ((head)->tqh_first) 294#define TAILQ_END(head) NULL 295#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 296#define TAILQ_LAST(head, headname) \ 297 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 298/* XXX */ 299#define TAILQ_PREV(elm, headname, field) \ 300 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 301#define TAILQ_EMPTY(head) \ 302 (TAILQ_FIRST(head) == TAILQ_END(head)) 303 304#define TAILQ_FOREACH(var, head, field) \ 305 for((var) = TAILQ_FIRST(head); \ 306 (var) != TAILQ_END(head); \ 307 (var) = TAILQ_NEXT(var, field)) 308 309#define TAILQ_FOREACH_REVERSE(var, head, field, headname) \ 310 for((var) = TAILQ_LAST(head, headname); \ 311 (var) != TAILQ_END(head); \ 312 (var) = TAILQ_PREV(var, headname, field)) 313 314/* 315 * Tail queue functions. 316 */ 317#define TAILQ_INIT(head) do { \ 318 (head)->tqh_first = NULL; \ 319 (head)->tqh_last = &(head)->tqh_first; \ 320} while (0) 321 322#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 323 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 324 (head)->tqh_first->field.tqe_prev = \ 325 &(elm)->field.tqe_next; \ 326 else \ 327 (head)->tqh_last = &(elm)->field.tqe_next; \ 328 (head)->tqh_first = (elm); \ 329 (elm)->field.tqe_prev = &(head)->tqh_first; \ 330} while (0) 331 332#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 333 (elm)->field.tqe_next = NULL; \ 334 (elm)->field.tqe_prev = (head)->tqh_last; \ 335 *(head)->tqh_last = (elm); \ 336 (head)->tqh_last = &(elm)->field.tqe_next; \ 337} while (0) 338 339#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 340 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 341 (elm)->field.tqe_next->field.tqe_prev = \ 342 &(elm)->field.tqe_next; \ 343 else \ 344 (head)->tqh_last = &(elm)->field.tqe_next; \ 345 (listelm)->field.tqe_next = (elm); \ 346 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 347} while (0) 348 349#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 350 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 351 (elm)->field.tqe_next = (listelm); \ 352 *(listelm)->field.tqe_prev = (elm); \ 353 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 354} while (0) 355 356#define TAILQ_REMOVE(head, elm, field) do { \ 357 if (((elm)->field.tqe_next) != NULL) \ 358 (elm)->field.tqe_next->field.tqe_prev = \ 359 (elm)->field.tqe_prev; \ 360 else \ 361 (head)->tqh_last = (elm)->field.tqe_prev; \ 362 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 363} while (0) 364 365#define TAILQ_REPLACE(head, elm, elm2, field) do { \ 366 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 367 (elm2)->field.tqe_next->field.tqe_prev = \ 368 &(elm2)->field.tqe_next; \ 369 else \ 370 (head)->tqh_last = &(elm2)->field.tqe_next; \ 371 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 372 *(elm2)->field.tqe_prev = (elm2); \ 373} while (0) 374 375/* 376 * Circular queue definitions. 377 */ 378#define CIRCLEQ_HEAD(name, type) \ 379struct name { \ 380 struct type *cqh_first; /* first element */ \ 381 struct type *cqh_last; /* last element */ \ 382} 383 384#define CIRCLEQ_HEAD_INITIALIZER(head) \ 385 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 386 387#define CIRCLEQ_ENTRY(type) \ 388struct { \ 389 struct type *cqe_next; /* next element */ \ 390 struct type *cqe_prev; /* previous element */ \ 391} 392 393/* 394 * Circular queue access methods 395 */ 396#define CIRCLEQ_FIRST(head) ((head)->cqh_first) 397#define CIRCLEQ_LAST(head) ((head)->cqh_last) 398#define CIRCLEQ_END(head) ((void *)(head)) 399#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 400#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 401#define CIRCLEQ_EMPTY(head) \ 402 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 403 404#define CIRCLEQ_FOREACH(var, head, field) \ 405 for((var) = CIRCLEQ_FIRST(head); \ 406 (var) != CIRCLEQ_END(head); \ 407 (var) = CIRCLEQ_NEXT(var, field)) 408 409#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 410 for((var) = CIRCLEQ_LAST(head); \ 411 (var) != CIRCLEQ_END(head); \ 412 (var) = CIRCLEQ_PREV(var, field)) 413 414/* 415 * Circular queue functions. 416 */ 417#define CIRCLEQ_INIT(head) do { \ 418 (head)->cqh_first = CIRCLEQ_END(head); \ 419 (head)->cqh_last = CIRCLEQ_END(head); \ 420} while (0) 421 422#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 423 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 424 (elm)->field.cqe_prev = (listelm); \ 425 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 426 (head)->cqh_last = (elm); \ 427 else \ 428 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 429 (listelm)->field.cqe_next = (elm); \ 430} while (0) 431 432#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 433 (elm)->field.cqe_next = (listelm); \ 434 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 435 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 436 (head)->cqh_first = (elm); \ 437 else \ 438 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 439 (listelm)->field.cqe_prev = (elm); \ 440} while (0) 441 442#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 443 (elm)->field.cqe_next = (head)->cqh_first; \ 444 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 445 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 446 (head)->cqh_last = (elm); \ 447 else \ 448 (head)->cqh_first->field.cqe_prev = (elm); \ 449 (head)->cqh_first = (elm); \ 450} while (0) 451 452#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 453 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 454 (elm)->field.cqe_prev = (head)->cqh_last; \ 455 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 456 (head)->cqh_first = (elm); \ 457 else \ 458 (head)->cqh_last->field.cqe_next = (elm); \ 459 (head)->cqh_last = (elm); \ 460} while (0) 461 462#define CIRCLEQ_REMOVE(head, elm, field) do { \ 463 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 464 (head)->cqh_last = (elm)->field.cqe_prev; \ 465 else \ 466 (elm)->field.cqe_next->field.cqe_prev = \ 467 (elm)->field.cqe_prev; \ 468 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 469 (head)->cqh_first = (elm)->field.cqe_next; \ 470 else \ 471 (elm)->field.cqe_prev->field.cqe_next = \ 472 (elm)->field.cqe_next; \ 473} while (0) 474 475#define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ 476 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ 477 CIRCLEQ_END(head)) \ 478 (head).cqh_last = (elm2); \ 479 else \ 480 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 481 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ 482 CIRCLEQ_END(head)) \ 483 (head).cqh_first = (elm2); \ 484 else \ 485 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 486} while (0) 487 488#endif /* !_SYS_QUEUE_H_ */ 489