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(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 /* 92 * Singly-linked List definitions. 93 */ 94 #define SLIST_HEAD(name, type) \ 95 struct name { \ 96 struct type *slh_first; /* first element */ \ 97 } 98 99 #define SLIST_HEAD_INITIALIZER(head) \ 100 { NULL } 101 102 #define SLIST_ENTRY(type) \ 103 struct { \ 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_PREVPTR(var, varp, head, field) \ 121 for ((varp) = &SLIST_FIRST((head)); \ 122 ((var) = *(varp)) != SLIST_END(head); \ 123 (varp) = &SLIST_NEXT((var), field)) 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_NEXT(head, 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 _Q_INVALIDATE((elm)->field.sle_next); \ 161 } \ 162 } while (0) 163 164 /* 165 * List definitions. 166 */ 167 #define LIST_HEAD(name, type) \ 168 struct name { \ 169 struct type *lh_first; /* first element */ \ 170 } 171 172 #define LIST_HEAD_INITIALIZER(head) \ 173 { NULL } 174 175 #define LIST_ENTRY(type) \ 176 struct { \ 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 /* 195 * List functions. 196 */ 197 #define LIST_INIT(head) do { \ 198 LIST_FIRST(head) = LIST_END(head); \ 199 } while (0) 200 201 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 202 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 203 (listelm)->field.le_next->field.le_prev = \ 204 &(elm)->field.le_next; \ 205 (listelm)->field.le_next = (elm); \ 206 (elm)->field.le_prev = &(listelm)->field.le_next; \ 207 } while (0) 208 209 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 210 (elm)->field.le_prev = (listelm)->field.le_prev; \ 211 (elm)->field.le_next = (listelm); \ 212 *(listelm)->field.le_prev = (elm); \ 213 (listelm)->field.le_prev = &(elm)->field.le_next; \ 214 } while (0) 215 216 #define LIST_INSERT_HEAD(head, elm, field) do { \ 217 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 218 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 219 (head)->lh_first = (elm); \ 220 (elm)->field.le_prev = &(head)->lh_first; \ 221 } while (0) 222 223 #define LIST_REMOVE(elm, field) do { \ 224 if ((elm)->field.le_next != NULL) \ 225 (elm)->field.le_next->field.le_prev = \ 226 (elm)->field.le_prev; \ 227 *(elm)->field.le_prev = (elm)->field.le_next; \ 228 _Q_INVALIDATE((elm)->field.le_prev); \ 229 _Q_INVALIDATE((elm)->field.le_next); \ 230 } while (0) 231 232 #define LIST_REPLACE(elm, elm2, field) do { \ 233 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 234 (elm2)->field.le_next->field.le_prev = \ 235 &(elm2)->field.le_next; \ 236 (elm2)->field.le_prev = (elm)->field.le_prev; \ 237 *(elm2)->field.le_prev = (elm2); \ 238 _Q_INVALIDATE((elm)->field.le_prev); \ 239 _Q_INVALIDATE((elm)->field.le_next); \ 240 } while (0) 241 242 /* 243 * Simple queue definitions. 244 */ 245 #define SIMPLEQ_HEAD(name, type) \ 246 struct name { \ 247 struct type *sqh_first; /* first element */ \ 248 struct type **sqh_last; /* addr of last next element */ \ 249 } 250 251 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 252 { NULL, &(head).sqh_first } 253 254 #define SIMPLEQ_ENTRY(type) \ 255 struct { \ 256 struct type *sqe_next; /* next element */ \ 257 } 258 259 /* 260 * Simple queue access methods. 261 */ 262 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 263 #define SIMPLEQ_END(head) NULL 264 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 265 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 266 267 #define SIMPLEQ_FOREACH(var, head, field) \ 268 for((var) = SIMPLEQ_FIRST(head); \ 269 (var) != SIMPLEQ_END(head); \ 270 (var) = SIMPLEQ_NEXT(var, field)) 271 272 /* 273 * Simple queue functions. 274 */ 275 #define SIMPLEQ_INIT(head) do { \ 276 (head)->sqh_first = NULL; \ 277 (head)->sqh_last = &(head)->sqh_first; \ 278 } while (0) 279 280 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 281 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 282 (head)->sqh_last = &(elm)->field.sqe_next; \ 283 (head)->sqh_first = (elm); \ 284 } while (0) 285 286 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 287 (elm)->field.sqe_next = NULL; \ 288 *(head)->sqh_last = (elm); \ 289 (head)->sqh_last = &(elm)->field.sqe_next; \ 290 } while (0) 291 292 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 293 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 294 (head)->sqh_last = &(elm)->field.sqe_next; \ 295 (listelm)->field.sqe_next = (elm); \ 296 } while (0) 297 298 #define SIMPLEQ_REMOVE_HEAD(head, field) do { \ 299 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 300 (head)->sqh_last = &(head)->sqh_first; \ 301 } while (0) 302 303 /* 304 * Tail queue definitions. 305 */ 306 #define TAILQ_HEAD(name, type) \ 307 struct name { \ 308 struct type *tqh_first; /* first element */ \ 309 struct type **tqh_last; /* addr of last next element */ \ 310 } 311 312 #define TAILQ_HEAD_INITIALIZER(head) \ 313 { NULL, &(head).tqh_first } 314 315 #define TAILQ_ENTRY(type) \ 316 struct { \ 317 struct type *tqe_next; /* next element */ \ 318 struct type **tqe_prev; /* address of previous next element */ \ 319 } 320 321 /* 322 * tail queue access methods 323 */ 324 #define TAILQ_FIRST(head) ((head)->tqh_first) 325 #define TAILQ_END(head) NULL 326 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 327 #define TAILQ_LAST(head, headname) \ 328 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 329 /* XXX */ 330 #define TAILQ_PREV(elm, headname, field) \ 331 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 332 #define TAILQ_EMPTY(head) \ 333 (TAILQ_FIRST(head) == TAILQ_END(head)) 334 335 #define TAILQ_FOREACH(var, head, field) \ 336 for((var) = TAILQ_FIRST(head); \ 337 (var) != TAILQ_END(head); \ 338 (var) = TAILQ_NEXT(var, field)) 339 340 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 341 for((var) = TAILQ_LAST(head, headname); \ 342 (var) != TAILQ_END(head); \ 343 (var) = TAILQ_PREV(var, headname, field)) 344 345 /* 346 * Tail queue functions. 347 */ 348 #define TAILQ_INIT(head) do { \ 349 (head)->tqh_first = NULL; \ 350 (head)->tqh_last = &(head)->tqh_first; \ 351 } while (0) 352 353 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 354 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 355 (head)->tqh_first->field.tqe_prev = \ 356 &(elm)->field.tqe_next; \ 357 else \ 358 (head)->tqh_last = &(elm)->field.tqe_next; \ 359 (head)->tqh_first = (elm); \ 360 (elm)->field.tqe_prev = &(head)->tqh_first; \ 361 } while (0) 362 363 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 364 (elm)->field.tqe_next = NULL; \ 365 (elm)->field.tqe_prev = (head)->tqh_last; \ 366 *(head)->tqh_last = (elm); \ 367 (head)->tqh_last = &(elm)->field.tqe_next; \ 368 } while (0) 369 370 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 371 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 372 (elm)->field.tqe_next->field.tqe_prev = \ 373 &(elm)->field.tqe_next; \ 374 else \ 375 (head)->tqh_last = &(elm)->field.tqe_next; \ 376 (listelm)->field.tqe_next = (elm); \ 377 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 378 } while (0) 379 380 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 381 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 382 (elm)->field.tqe_next = (listelm); \ 383 *(listelm)->field.tqe_prev = (elm); \ 384 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 385 } while (0) 386 387 #define TAILQ_REMOVE(head, elm, field) do { \ 388 if (((elm)->field.tqe_next) != NULL) \ 389 (elm)->field.tqe_next->field.tqe_prev = \ 390 (elm)->field.tqe_prev; \ 391 else \ 392 (head)->tqh_last = (elm)->field.tqe_prev; \ 393 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 394 _Q_INVALIDATE((elm)->field.tqe_prev); \ 395 _Q_INVALIDATE((elm)->field.tqe_next); \ 396 } while (0) 397 398 #define TAILQ_REPLACE(head, elm, elm2, field) do { \ 399 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 400 (elm2)->field.tqe_next->field.tqe_prev = \ 401 &(elm2)->field.tqe_next; \ 402 else \ 403 (head)->tqh_last = &(elm2)->field.tqe_next; \ 404 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 405 *(elm2)->field.tqe_prev = (elm2); \ 406 _Q_INVALIDATE((elm)->field.tqe_prev); \ 407 _Q_INVALIDATE((elm)->field.tqe_next); \ 408 } while (0) 409 410 /* 411 * Circular queue definitions. 412 */ 413 #define CIRCLEQ_HEAD(name, type) \ 414 struct name { \ 415 struct type *cqh_first; /* first element */ \ 416 struct type *cqh_last; /* last element */ \ 417 } 418 419 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 420 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 421 422 #define CIRCLEQ_ENTRY(type) \ 423 struct { \ 424 struct type *cqe_next; /* next element */ \ 425 struct type *cqe_prev; /* previous element */ \ 426 } 427 428 /* 429 * Circular queue access methods 430 */ 431 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 432 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 433 #define CIRCLEQ_END(head) ((void *)(head)) 434 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 435 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 436 #define CIRCLEQ_EMPTY(head) \ 437 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 438 439 #define CIRCLEQ_FOREACH(var, head, field) \ 440 for((var) = CIRCLEQ_FIRST(head); \ 441 (var) != CIRCLEQ_END(head); \ 442 (var) = CIRCLEQ_NEXT(var, field)) 443 444 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 445 for((var) = CIRCLEQ_LAST(head); \ 446 (var) != CIRCLEQ_END(head); \ 447 (var) = CIRCLEQ_PREV(var, field)) 448 449 /* 450 * Circular queue functions. 451 */ 452 #define CIRCLEQ_INIT(head) do { \ 453 (head)->cqh_first = CIRCLEQ_END(head); \ 454 (head)->cqh_last = CIRCLEQ_END(head); \ 455 } while (0) 456 457 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 458 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 459 (elm)->field.cqe_prev = (listelm); \ 460 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 461 (head)->cqh_last = (elm); \ 462 else \ 463 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 464 (listelm)->field.cqe_next = (elm); \ 465 } while (0) 466 467 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 468 (elm)->field.cqe_next = (listelm); \ 469 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 470 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 471 (head)->cqh_first = (elm); \ 472 else \ 473 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 474 (listelm)->field.cqe_prev = (elm); \ 475 } while (0) 476 477 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 478 (elm)->field.cqe_next = (head)->cqh_first; \ 479 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 480 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 481 (head)->cqh_last = (elm); \ 482 else \ 483 (head)->cqh_first->field.cqe_prev = (elm); \ 484 (head)->cqh_first = (elm); \ 485 } while (0) 486 487 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 488 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 489 (elm)->field.cqe_prev = (head)->cqh_last; \ 490 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 491 (head)->cqh_first = (elm); \ 492 else \ 493 (head)->cqh_last->field.cqe_next = (elm); \ 494 (head)->cqh_last = (elm); \ 495 } while (0) 496 497 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 498 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 499 (head)->cqh_last = (elm)->field.cqe_prev; \ 500 else \ 501 (elm)->field.cqe_next->field.cqe_prev = \ 502 (elm)->field.cqe_prev; \ 503 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 504 (head)->cqh_first = (elm)->field.cqe_next; \ 505 else \ 506 (elm)->field.cqe_prev->field.cqe_next = \ 507 (elm)->field.cqe_next; \ 508 _Q_INVALIDATE((elm)->field.cqe_prev); \ 509 _Q_INVALIDATE((elm)->field.cqe_next); \ 510 } while (0) 511 512 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ 513 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ 514 CIRCLEQ_END(head)) \ 515 (head).cqh_last = (elm2); \ 516 else \ 517 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 518 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ 519 CIRCLEQ_END(head)) \ 520 (head).cqh_first = (elm2); \ 521 else \ 522 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 523 _Q_INVALIDATE((elm)->field.cqe_prev); \ 524 _Q_INVALIDATE((elm)->field.cqe_next); \ 525 } while (0) 526 527 #endif /* !_SYS_QUEUE_H_ */ 528 529 530