1 /* $OpenBSD: queue.h,v 1.15 2000/04/15 00:20:13 deraadt 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 /* 140 * List definitions. 141 */ 142 #define LIST_HEAD(name, type) \ 143 struct name { \ 144 struct type *lh_first; /* first element */ \ 145 } 146 147 #define LIST_HEAD_INITIALIZER(head) \ 148 { NULL } 149 150 #define LIST_ENTRY(type) \ 151 struct { \ 152 struct type *le_next; /* next element */ \ 153 struct type **le_prev; /* address of previous next element */ \ 154 } 155 156 /* 157 * List access methods 158 */ 159 #define LIST_FIRST(head) ((head)->lh_first) 160 #define LIST_END(head) NULL 161 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 162 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 163 164 #define LIST_FOREACH(var, head, field) \ 165 for((var) = LIST_FIRST(head); \ 166 (var)!= LIST_END(head); \ 167 (var) = LIST_NEXT(var, field)) 168 169 /* 170 * List functions. 171 */ 172 #define LIST_INIT(head) do { \ 173 LIST_FIRST(head) = LIST_END(head); \ 174 } while (0) 175 176 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 177 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 178 (listelm)->field.le_next->field.le_prev = \ 179 &(elm)->field.le_next; \ 180 (listelm)->field.le_next = (elm); \ 181 (elm)->field.le_prev = &(listelm)->field.le_next; \ 182 } while (0) 183 184 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 185 (elm)->field.le_prev = (listelm)->field.le_prev; \ 186 (elm)->field.le_next = (listelm); \ 187 *(listelm)->field.le_prev = (elm); \ 188 (listelm)->field.le_prev = &(elm)->field.le_next; \ 189 } while (0) 190 191 #define LIST_INSERT_HEAD(head, elm, field) do { \ 192 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 193 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 194 (head)->lh_first = (elm); \ 195 (elm)->field.le_prev = &(head)->lh_first; \ 196 } while (0) 197 198 #define LIST_REMOVE(elm, field) do { \ 199 if ((elm)->field.le_next != NULL) \ 200 (elm)->field.le_next->field.le_prev = \ 201 (elm)->field.le_prev; \ 202 *(elm)->field.le_prev = (elm)->field.le_next; \ 203 } while (0) 204 205 #define LIST_REPLACE(elm, elm2, field) do { \ 206 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 207 (elm2)->field.le_next->field.le_prev = \ 208 &(elm2)->field.le_next; \ 209 (elm2)->field.le_prev = (elm)->field.le_prev; \ 210 *(elm2)->field.le_prev = (elm2); \ 211 } while (0) 212 213 /* 214 * Simple queue definitions. 215 */ 216 #define SIMPLEQ_HEAD(name, type) \ 217 struct name { \ 218 struct type *sqh_first; /* first element */ \ 219 struct type **sqh_last; /* addr of last next element */ \ 220 } 221 222 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 223 { NULL, &(head).sqh_first } 224 225 #define SIMPLEQ_ENTRY(type) \ 226 struct { \ 227 struct type *sqe_next; /* next element */ \ 228 } 229 230 /* 231 * Simple queue access methods. 232 */ 233 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 234 #define SIMPLEQ_END(head) NULL 235 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 236 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 237 238 #define SIMPLEQ_FOREACH(var, head, field) \ 239 for((var) = SIMPLEQ_FIRST(head); \ 240 (var) != SIMPLEQ_END(head); \ 241 (var) = SIMPLEQ_NEXT(var, field)) 242 243 /* 244 * Simple queue functions. 245 */ 246 #define SIMPLEQ_INIT(head) do { \ 247 (head)->sqh_first = NULL; \ 248 (head)->sqh_last = &(head)->sqh_first; \ 249 } while (0) 250 251 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 252 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 253 (head)->sqh_last = &(elm)->field.sqe_next; \ 254 (head)->sqh_first = (elm); \ 255 } while (0) 256 257 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 258 (elm)->field.sqe_next = NULL; \ 259 *(head)->sqh_last = (elm); \ 260 (head)->sqh_last = &(elm)->field.sqe_next; \ 261 } while (0) 262 263 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 264 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\ 265 (head)->sqh_last = &(elm)->field.sqe_next; \ 266 (listelm)->field.sqe_next = (elm); \ 267 } while (0) 268 269 #define SIMPLEQ_REMOVE_HEAD(head, elm, field) do { \ 270 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) \ 271 (head)->sqh_last = &(head)->sqh_first; \ 272 } while (0) 273 274 /* 275 * Tail queue definitions. 276 */ 277 #define TAILQ_HEAD(name, type) \ 278 struct name { \ 279 struct type *tqh_first; /* first element */ \ 280 struct type **tqh_last; /* addr of last next element */ \ 281 } 282 283 #define TAILQ_HEAD_INITIALIZER(head) \ 284 { NULL, &(head).tqh_first } 285 286 #define TAILQ_ENTRY(type) \ 287 struct { \ 288 struct type *tqe_next; /* next element */ \ 289 struct type **tqe_prev; /* address of previous next element */ \ 290 } 291 292 /* 293 * tail queue access methods 294 */ 295 #define TAILQ_FIRST(head) ((head)->tqh_first) 296 #define TAILQ_END(head) NULL 297 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 298 #define TAILQ_LAST(head, headname) \ 299 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 300 /* XXX */ 301 #define TAILQ_PREV(elm, headname, field) \ 302 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 303 #define TAILQ_EMPTY(head) \ 304 (TAILQ_FIRST(head) == TAILQ_END(head)) 305 306 #define TAILQ_FOREACH(var, head, field) \ 307 for((var) = TAILQ_FIRST(head); \ 308 (var) != TAILQ_END(head); \ 309 (var) = TAILQ_NEXT(var, field)) 310 311 #define TAILQ_FOREACH_REVERSE(var, head, field) \ 312 for((var) = TAILQ_LAST(head); \ 313 (var) != TAILQ_END(head); \ 314 (var) = TAILQ_PREV(var, field)) 315 316 /* 317 * Tail queue functions. 318 */ 319 #define TAILQ_INIT(head) do { \ 320 (head)->tqh_first = NULL; \ 321 (head)->tqh_last = &(head)->tqh_first; \ 322 } while (0) 323 324 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 325 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 326 (head)->tqh_first->field.tqe_prev = \ 327 &(elm)->field.tqe_next; \ 328 else \ 329 (head)->tqh_last = &(elm)->field.tqe_next; \ 330 (head)->tqh_first = (elm); \ 331 (elm)->field.tqe_prev = &(head)->tqh_first; \ 332 } while (0) 333 334 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 335 (elm)->field.tqe_next = NULL; \ 336 (elm)->field.tqe_prev = (head)->tqh_last; \ 337 *(head)->tqh_last = (elm); \ 338 (head)->tqh_last = &(elm)->field.tqe_next; \ 339 } while (0) 340 341 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 342 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 343 (elm)->field.tqe_next->field.tqe_prev = \ 344 &(elm)->field.tqe_next; \ 345 else \ 346 (head)->tqh_last = &(elm)->field.tqe_next; \ 347 (listelm)->field.tqe_next = (elm); \ 348 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 349 } while (0) 350 351 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 352 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 353 (elm)->field.tqe_next = (listelm); \ 354 *(listelm)->field.tqe_prev = (elm); \ 355 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 356 } while (0) 357 358 #define TAILQ_REMOVE(head, elm, field) do { \ 359 if (((elm)->field.tqe_next) != NULL) \ 360 (elm)->field.tqe_next->field.tqe_prev = \ 361 (elm)->field.tqe_prev; \ 362 else \ 363 (head)->tqh_last = (elm)->field.tqe_prev; \ 364 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 365 } while (0) 366 367 #define TAILQ_REPLACE(head, elm, elm2, field) do { \ 368 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 369 (elm2)->field.tqe_next->field.tqe_prev = \ 370 &(elm2)->field.tqe_next; \ 371 else \ 372 (head)->tqh_last = &(elm2)->field.tqe_next; \ 373 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 374 *(elm2)->field.tqe_prev = (elm2); \ 375 } while (0) 376 377 /* 378 * Circular queue definitions. 379 */ 380 #define CIRCLEQ_HEAD(name, type) \ 381 struct name { \ 382 struct type *cqh_first; /* first element */ \ 383 struct type *cqh_last; /* last element */ \ 384 } 385 386 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 387 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 388 389 #define CIRCLEQ_ENTRY(type) \ 390 struct { \ 391 struct type *cqe_next; /* next element */ \ 392 struct type *cqe_prev; /* previous element */ \ 393 } 394 395 /* 396 * Circular queue access methods 397 */ 398 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 399 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 400 #define CIRCLEQ_END(head) ((void *)(head)) 401 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 402 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 403 #define CIRCLEQ_EMPTY(head) \ 404 (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 405 406 #define CIRCLEQ_FOREACH(var, head, field) \ 407 for((var) = CIRCLEQ_FIRST(head); \ 408 (var) != CIRCLEQ_END(head); \ 409 (var) = CIRCLEQ_NEXT(var, field)) 410 411 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 412 for((var) = CIRCLEQ_LAST(head); \ 413 (var) != CIRCLEQ_END(head); \ 414 (var) = CIRCLEQ_PREV(var, field)) 415 416 /* 417 * Circular queue functions. 418 */ 419 #define CIRCLEQ_INIT(head) do { \ 420 (head)->cqh_first = CIRCLEQ_END(head); \ 421 (head)->cqh_last = CIRCLEQ_END(head); \ 422 } while (0) 423 424 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 425 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 426 (elm)->field.cqe_prev = (listelm); \ 427 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 428 (head)->cqh_last = (elm); \ 429 else \ 430 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 431 (listelm)->field.cqe_next = (elm); \ 432 } while (0) 433 434 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 435 (elm)->field.cqe_next = (listelm); \ 436 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 437 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 438 (head)->cqh_first = (elm); \ 439 else \ 440 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 441 (listelm)->field.cqe_prev = (elm); \ 442 } while (0) 443 444 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 445 (elm)->field.cqe_next = (head)->cqh_first; \ 446 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 447 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 448 (head)->cqh_last = (elm); \ 449 else \ 450 (head)->cqh_first->field.cqe_prev = (elm); \ 451 (head)->cqh_first = (elm); \ 452 } while (0) 453 454 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 455 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 456 (elm)->field.cqe_prev = (head)->cqh_last; \ 457 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 458 (head)->cqh_first = (elm); \ 459 else \ 460 (head)->cqh_last->field.cqe_next = (elm); \ 461 (head)->cqh_last = (elm); \ 462 } while (0) 463 464 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 465 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 466 (head)->cqh_last = (elm)->field.cqe_prev; \ 467 else \ 468 (elm)->field.cqe_next->field.cqe_prev = \ 469 (elm)->field.cqe_prev; \ 470 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 471 (head)->cqh_first = (elm)->field.cqe_next; \ 472 else \ 473 (elm)->field.cqe_prev->field.cqe_next = \ 474 (elm)->field.cqe_next; \ 475 } while (0) 476 477 #define CIRCLEQ_REPLACE(head, elm, elm2, field) do { \ 478 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == \ 479 CIRCLEQ_END(head)) \ 480 (head).cqh_last = (elm2); \ 481 else \ 482 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 483 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == \ 484 CIRCLEQ_END(head)) \ 485 (head).cqh_first = (elm2); \ 486 else \ 487 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 488 } while (0) 489 490 #endif /* !_SYS_QUEUE_H_ */ 491