1 /* $OpenBSD: queue.h,v 1.22 2001/06/23 04:39:35 angelos 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)queue.h 8.5 (Berkeley) 8/20/94 37 */ 38 39 #ifndef _SYS_QUEUE_H_ 40 #define _SYS_QUEUE_H_ 41 42 /* 43 * This file defines five types of data structures: singly-linked lists, 44 * lists, simple queues, tail queues, and circular queues. 45 * 46 * 47 * A singly-linked list is headed by a single forward pointer. The elements 48 * are singly linked for minimum space and pointer manipulation overhead at 49 * the expense of O(n) removal for arbitrary elements. New elements can be 50 * added to the list after an existing element or at the head of the list. 51 * Elements being removed from the head of the list should use the explicit 52 * macro for this purpose for optimum efficiency. A singly-linked list may 53 * only be traversed in the forward direction. Singly-linked lists are ideal 54 * for applications with large datasets and few or no removals or for 55 * implementing a LIFO queue. 56 * 57 * A list is headed by a single forward pointer (or an array of forward 58 * pointers for a hash table header). The elements are doubly linked 59 * so that an arbitrary element can be removed without a need to 60 * traverse the list. New elements can be added to the list before 61 * or after an existing element or at the head of the list. A list 62 * may only be traversed in the forward direction. 63 * 64 * A simple queue is headed by a pair of pointers, one the head of the 65 * list and the other to the tail of the list. The elements are singly 66 * linked to save space, so elements can only be removed from the 67 * head of the list. New elements can be added to the list before or after 68 * an existing element, at the head of the list, or at the end of the 69 * list. A simple queue may only be traversed in the forward direction. 70 * 71 * A tail queue is headed by a pair of pointers, one to the head of the 72 * list and the other to the tail of the list. The elements are doubly 73 * linked so that an arbitrary element can be removed without a need to 74 * traverse the list. New elements can be added to the list before or 75 * after an existing element, at the head of the list, or at the end of 76 * the list. A tail queue may be traversed in either direction. 77 * 78 * A circle queue is headed by a pair of pointers, one to the head of the 79 * list and the other to the tail of the list. The elements are doubly 80 * linked so that an arbitrary element can be removed without a need to 81 * traverse the list. New elements can be added to the list before or after 82 * an existing element, at the head of the list, or at the end of the list. 83 * A circle queue may be traversed in either direction, but has a more 84 * complex end of list detection. 85 * 86 * For details on the use of these macros, see the queue(3) manual page. 87 */ 88 89 /* 90 * Singly-linked List definitions. 91 */ 92 #define SLIST_HEAD(name, type) \ 93 struct name { \ 94 struct type *slh_first; /* first element */ \ 95 } 96 97 #define SLIST_HEAD_INITIALIZER(head) \ 98 { NULL } 99 100 #define SLIST_ENTRY(type) \ 101 struct { \ 102 struct type *sle_next; /* next element */ \ 103 } 104 105 /* 106 * Singly-linked List access methods. 107 */ 108 #define SLIST_FIRST(head) ((head)->slh_first) 109 #define SLIST_END(head) NULL 110 #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) 111 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 112 113 #define SLIST_FOREACH(var, head, field) \ 114 for((var) = SLIST_FIRST(head); \ 115 (var) != SLIST_END(head); \ 116 (var) = SLIST_NEXT(var, field)) 117 118 /* 119 * Singly-linked List functions. 120 */ 121 #define SLIST_INIT(head) { \ 122 SLIST_FIRST(head) = SLIST_END(head); \ 123 } 124 125 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 126 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 127 (slistelm)->field.sle_next = (elm); \ 128 } while (0) 129 130 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 131 (elm)->field.sle_next = (head)->slh_first; \ 132 (head)->slh_first = (elm); \ 133 } while (0) 134 135 #define SLIST_REMOVE_HEAD(head, field) do { \ 136 (head)->slh_first = (head)->slh_first->field.sle_next; \ 137 } while (0) 138 139 #define SLIST_REMOVE(head, elm, type, field) do { \ 140 if ((head)->slh_first == (elm)) { \ 141 SLIST_REMOVE_HEAD((head), field); \ 142 } \ 143 else { \ 144 struct type *curelm = (head)->slh_first; \ 145 while( curelm->field.sle_next != (elm) ) \ 146 curelm = curelm->field.sle_next; \ 147 curelm->field.sle_next = \ 148 curelm->field.sle_next->field.sle_next; \ 149 } \ 150 } while (0) 151 152 /* 153 * List definitions. 154 */ 155 #define LIST_HEAD(name, type) \ 156 struct name { \ 157 struct type *lh_first; /* first element */ \ 158 } 159 160 #define LIST_HEAD_INITIALIZER(head) \ 161 { NULL } 162 163 #define LIST_ENTRY(type) \ 164 struct { \ 165 struct type *le_next; /* next element */ \ 166 struct type **le_prev; /* address of previous next element */ \ 167 } 168 169 /* 170 * List access methods 171 */ 172 #define LIST_FIRST(head) ((head)->lh_first) 173 #define LIST_END(head) NULL 174 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 175 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 176 177 #define LIST_FOREACH(var, head, field) \ 178 for((var) = LIST_FIRST(head); \ 179 (var)!= LIST_END(head); \ 180 (var) = LIST_NEXT(var, field)) 181 182 /* 183 * List functions. 184 */ 185 #define LIST_INIT(head) do { \ 186 LIST_FIRST(head) = LIST_END(head); \ 187 } while (0) 188 189 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 190 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 191 (listelm)->field.le_next->field.le_prev = \ 192 &(elm)->field.le_next; \ 193 (listelm)->field.le_next = (elm); \ 194 (elm)->field.le_prev = &(listelm)->field.le_next; \ 195 } while (0) 196 197 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 198 (elm)->field.le_prev = (listelm)->field.le_prev; \ 199 (elm)->field.le_next = (listelm); \ 200 *(listelm)->field.le_prev = (elm); \ 201 (listelm)->field.le_prev = &(elm)->field.le_next; \ 202 } while (0) 203 204 #define LIST_INSERT_HEAD(head, elm, field) do { \ 205 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 206 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 207 (head)->lh_first = (elm); \ 208 (elm)->field.le_prev = &(head)->lh_first; \ 209 } while (0) 210 211 #define LIST_REMOVE(elm, field) do { \ 212 if ((elm)->field.le_next != NULL) \ 213 (elm)->field.le_next->field.le_prev = \ 214 (elm)->field.le_prev; \ 215 *(elm)->field.le_prev = (elm)->field.le_next; \ 216 } while (0) 217 218 #define LIST_REPLACE(elm, elm2, field) do { \ 219 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 220 (elm2)->field.le_next->field.le_prev = \ 221 &(elm2)->field.le_next; \ 222 (elm2)->field.le_prev = (elm)->field.le_prev; \ 223 *(elm2)->field.le_prev = (elm2); \ 224 } while (0) 225 226 /* 227 * Simple queue definitions. 228 */ 229 #define SIMPLEQ_HEAD(name, type) \ 230 struct name { \ 231 struct type *sqh_first; /* first element */ \ 232 struct type **sqh_last; /* addr of last next element */ \ 233 } 234 235 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 236 { NULL, &(head).sqh_first } 237 238 #define SIMPLEQ_ENTRY(type) \ 239 struct { \ 240 struct type *sqe_next; /* next element */ \ 241 } 242 243 /* 244 * Simple queue access methods. 245 */ 246 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 247 #define SIMPLEQ_END(head) NULL 248 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 249 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 250 251 #define SIMPLEQ_FOREACH(var, head, field) \ 252 for((var) = SIMPLEQ_FIRST(head); \ 253 (var) != SIMPLEQ_END(head); \ 254 (var) = SIMPLEQ_NEXT(var, field)) 255 256 /* 257 * Simple queue functions. 258 */ 259 #define SIMPLEQ_INIT(head) do { \ 260 (head)->sqh_first = NULL; \ 261 (head)->sqh_last = &(head)->sqh_first; \ 262 } while (0) 263 264 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 265 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 266 (head)->sqh_last = &(elm)->field.sqe_next; \ 267 (head)->sqh_first = (elm); \ 268 } while (0) 269 270 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 271 (elm)->field.sqe_next = NULL; \ 272 *(head)->sqh_last = (elm); \ 273 (head)->sqh_last = &(elm)->field.sqe_next; \ 274 } while (0) 275 276 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 277 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 278 (head)->sqh_last = &(elm)->field.sqe_next; \ 279 (listelm)->field.sqe_next = (elm); \ 280 } while (0) 281 282 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \ 283 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \ 284 (head)->sqh_last = &(head)->sqh_first; \ 285 } while (0) 286 287 /* 288 * Tail queue definitions. 289 */ 290 #define TAILQ_HEAD(name, type) \ 291 struct name { \ 292 struct type *tqh_first; /* first element */ \ 293 struct type **tqh_last; /* addr of last next element */ \ 294 } 295 296 #define TAILQ_HEAD_INITIALIZER(head) \ 297 { NULL, &(head).tqh_first } 298 299 #define TAILQ_ENTRY(type) \ 300 struct { \ 301 struct type *tqe_next; /* next element */ \ 302 struct type **tqe_prev; /* address of previous next element */ \ 303 } 304 305 /* 306 * tail queue access methods 307 */ 308 #define TAILQ_FIRST(head) ((head)->tqh_first) 309 #define TAILQ_END(head) NULL 310 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 311 #define TAILQ_LAST(head, headname) \ 312 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 313 /* XXX */ 314 #define TAILQ_PREV(elm, headname, field) \ 315 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 316 #define TAILQ_EMPTY(head) \ 317 (TAILQ_FIRST(head) == TAILQ_END(head)) 318 319 #define TAILQ_FOREACH(var, head, field) \ 320 for((var) = TAILQ_FIRST(head); \ 321 (var) != TAILQ_END(head); \ 322 (var) = TAILQ_NEXT(var, field)) 323 324 #define TAILQ_FOREACH_REVERSE(var, head, field, headname) \ 325 for((var) = TAILQ_LAST(head, headname); \ 326 (var) != TAILQ_END(head); \ 327 (var) = TAILQ_PREV(var, headname, field)) 328 329 /* 330 * Tail queue functions. 331 */ 332 #define TAILQ_INIT(head) do { \ 333 (head)->tqh_first = NULL; \ 334 (head)->tqh_last = &(head)->tqh_first; \ 335 } while (0) 336 337 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 338 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 339 (head)->tqh_first->field.tqe_prev = \ 340 &(elm)->field.tqe_next; \ 341 else \ 342 (head)->tqh_last = &(elm)->field.tqe_next; \ 343 (head)->tqh_first = (elm); \ 344 (elm)->field.tqe_prev = &(head)->tqh_first; \ 345 } while (0) 346 347 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 348 (elm)->field.tqe_next = NULL; \ 349 (elm)->field.tqe_prev = (head)->tqh_last; \ 350 *(head)->tqh_last = (elm); \ 351 (head)->tqh_last = &(elm)->field.tqe_next; \ 352 } while (0) 353 354 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 355 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 356 (elm)->field.tqe_next->field.tqe_prev = \ 357 &(elm)->field.tqe_next; \ 358 else \ 359 (head)->tqh_last = &(elm)->field.tqe_next; \ 360 (listelm)->field.tqe_next = (elm); \ 361 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 362 } while (0) 363 364 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 365 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 366 (elm)->field.tqe_next = (listelm); \ 367 *(listelm)->field.tqe_prev = (elm); \ 368 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 369 } while (0) 370 371 #define TAILQ_REMOVE(head, elm, field) do { \ 372 if (((elm)->field.tqe_next) != NULL) \ 373 (elm)->field.tqe_next->field.tqe_prev = \ 374 (elm)->field.tqe_prev; \ 375 else \ 376 (head)->tqh_last = (elm)->field.tqe_prev; \ 377 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 378 } while (0) 379 380 #define TAILQ_REPLACE(head, elm, elm2, field) do { \ 381 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 382 (elm2)->field.tqe_next->field.tqe_prev = \ 383 &(elm2)->field.tqe_next; \ 384 else \ 385 (head)->tqh_last = &(elm2)->field.tqe_next; \ 386 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 387 *(elm2)->field.tqe_prev = (elm2); \ 388 } while (0) 389 390 /* 391 * Circular queue definitions. 392 */ 393 #define CIRCLEQ_HEAD(name, type) \ 394 struct name { \ 395 struct type *cqh_first; /* first element */ \ 396 struct type *cqh_last; /* last element */ \ 397 } 398 399 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 400 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 401 402 #define CIRCLEQ_ENTRY(type) \ 403 struct { \ 404 struct type *cqe_next; /* next element */ \ 405 struct type *cqe_prev; /* previous element */ \ 406 } 407 408 /* 409 * Circular queue access methods 410 */ 411 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 412 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 413 #define CIRCLEQ_END(head) ((void *)(head)) 414 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 415 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 416 #define CIRCLEQ_EMPTY(head) \ 417 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 418 419 #define CIRCLEQ_FOREACH(var, head, field) \ 420 for((var) = CIRCLEQ_FIRST(head); \ 421 (var) != CIRCLEQ_END(head); \ 422 (var) = CIRCLEQ_NEXT(var, field)) 423 424 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 425 for((var) = CIRCLEQ_LAST(head); \ 426 (var) != CIRCLEQ_END(head); \ 427 (var) = CIRCLEQ_PREV(var, field)) 428 429 /* 430 * Circular queue functions. 431 */ 432 #define CIRCLEQ_INIT(head) do { \ 433 (head)->cqh_first = CIRCLEQ_END(head); \ 434 (head)->cqh_last = CIRCLEQ_END(head); \ 435 } while (0) 436 437 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 438 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 439 (elm)->field.cqe_prev = (listelm); \ 440 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 441 (head)->cqh_last = (elm); \ 442 else \ 443 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 444 (listelm)->field.cqe_next = (elm); \ 445 } while (0) 446 447 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 448 (elm)->field.cqe_next = (listelm); \ 449 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 450 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 451 (head)->cqh_first = (elm); \ 452 else \ 453 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 454 (listelm)->field.cqe_prev = (elm); \ 455 } while (0) 456 457 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 458 (elm)->field.cqe_next = (head)->cqh_first; \ 459 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 460 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 461 (head)->cqh_last = (elm); \ 462 else \ 463 (head)->cqh_first->field.cqe_prev = (elm); \ 464 (head)->cqh_first = (elm); \ 465 } while (0) 466 467 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 468 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 469 (elm)->field.cqe_prev = (head)->cqh_last; \ 470 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 471 (head)->cqh_first = (elm); \ 472 else \ 473 (head)->cqh_last->field.cqe_next = (elm); \ 474 (head)->cqh_last = (elm); \ 475 } while (0) 476 477 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 478 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 479 (head)->cqh_last = (elm)->field.cqe_prev; \ 480 else \ 481 (elm)->field.cqe_next->field.cqe_prev = \ 482 (elm)->field.cqe_prev; \ 483 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 484 (head)->cqh_first = (elm)->field.cqe_next; \ 485 else \ 486 (elm)->field.cqe_prev->field.cqe_next = \ 487 (elm)->field.cqe_next; \ 488 } while (0) 489 490 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ 491 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ 492 CIRCLEQ_END(head)) \ 493 (head).cqh_last = (elm2); \ 494 else \ 495 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 496 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ 497 CIRCLEQ_END(head)) \ 498 (head).cqh_first = (elm2); \ 499 else \ 500 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 501 } while (0) 502 503 #endif /* !_SYS_QUEUE_H_ */ 504