queue.h revision 42382
1/* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)queue.h 8.5 (Berkeley) 8/20/94 34 * $Id: queue.h,v 1.23 1999/01/06 20:03:11 n_hibma Exp $ 35 */ 36 37#ifndef _SYS_QUEUE_H_ 38#define _SYS_QUEUE_H_ 39 40/* 41 * This file defines five types of data structures: singly-linked lists, 42 * slingly-linked tail queues, lists, tail queues, and circular queues. 43 * 44 * A singly-linked list is headed by a single forward pointer. The elements 45 * are singly linked for minimum space and pointer manipulation overhead at 46 * the expense of O(n) removal for arbitrary elements. New elements can be 47 * added to the list after an existing element or at the head of the list. 48 * Elements being removed from the head of the list should use the explicit 49 * macro for this purpose for optimum efficiency. A singly-linked list may 50 * only be traversed in the forward direction. Singly-linked lists are ideal 51 * for applications with large datasets and few or no removals or for 52 * implementing a LIFO queue. 53 * 54 * A singly-linked tail queue is headed by a pair of pointers, one to the 55 * head of the list and the other to the tail of the list. The elements are 56 * singly linked for minimum space and pointer manipulation overhead at the 57 * expense of O(n) removal for arbitrary elements. New elements can be added 58 * to the list after an existing element, at the head of the list, or at the 59 * end of the list. Elements being removed from the head of the tail queue 60 * should use the explicit macro for this purpose for optimum efficiency. 61 * A singly-linked tail queue may only be traversed in the forward direction. 62 * Singly-linked tail queues are ideal for applications with large datasets 63 * and few or no removals or for implementing a FIFO queue. 64 * 65 * A list is headed by a single forward pointer (or an array of forward 66 * pointers for a hash table header). The elements are doubly linked 67 * so that an arbitrary element can be removed without a need to 68 * traverse the list. New elements can be added to the list before 69 * or after an existing element or at the head of the list. A list 70 * may only be traversed in the forward direction. 71 * 72 * A tail queue is headed by a pair of pointers, one to the head of the 73 * list and the other to the tail of the list. The elements are doubly 74 * linked so that an arbitrary element can be removed without a need to 75 * traverse the list. New elements can be added to the list before or 76 * after an existing element, at the head of the list, or at the end of 77 * the list. A tail queue may only be traversed in the forward direction. 78 * 79 * A circle queue is headed by a pair of pointers, one to the head of the 80 * list and the other to the tail of the list. The elements are doubly 81 * linked so that an arbitrary element can be removed without a need to 82 * traverse the list. New elements can be added to the list before or after 83 * an existing element, at the head of the list, or at the end of the list. 84 * A circle queue may be traversed in either direction, but has a more 85 * complex end of list detection. 86 * 87 * For details on the use of these macros, see the queue(3) manual page. 88 * 89 * 90 * SLIST LIST STAILQ TAILQ CIRCLEQ 91 * _HEAD + + + + + 92 * _ENTRY + + + + + 93 * _INIT + + + + + 94 * _EMPTY + + + + + 95 * _FIRST + + + + + 96 * _NEXT + + + + + 97 * _PREV - - - + + 98 * _LAST - - + + + 99 * _FOREACH + + - + + 100 * _INSERT_HEAD + + + + + 101 * _INSERT_BEFORE - + - + + 102 * _INSERT_AFTER + + + + + 103 * _INSERT_TAIL - - + + + 104 * _REMOVE_HEAD + - + - - 105 * _REMOVE + + + + + 106 * 107 */ 108 109/* 110 * Singly-linked List definitions. 111 */ 112#define SLIST_HEAD(name, type) \ 113struct name { \ 114 struct type *slh_first; /* first element */ \ 115} 116 117#define SLIST_ENTRY(type) \ 118struct { \ 119 struct type *sle_next; /* next element */ \ 120} 121 122/* 123 * Singly-linked List functions. 124 */ 125#define SLIST_EMPTY(head) ((head)->slh_first == NULL) 126 127#define SLIST_FIRST(head) ((head)->slh_first) 128 129#define SLIST_FOREACH(var, head, field) \ 130 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 131 132#define SLIST_INIT(head) { \ 133 (head)->slh_first = NULL; \ 134} 135 136#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 137 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 138 (slistelm)->field.sle_next = (elm); \ 139} while (0) 140 141#define SLIST_INSERT_HEAD(head, elm, field) do { \ 142 (elm)->field.sle_next = (head)->slh_first; \ 143 (head)->slh_first = (elm); \ 144} while (0) 145 146#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 147 148#define SLIST_REMOVE_HEAD(head, field) do { \ 149 (head)->slh_first = (head)->slh_first->field.sle_next; \ 150} while (0) 151 152#define SLIST_REMOVE(head, elm, type, field) do { \ 153 if ((head)->slh_first == (elm)) { \ 154 SLIST_REMOVE_HEAD((head), field); \ 155 } \ 156 else { \ 157 struct type *curelm = (head)->slh_first; \ 158 while( curelm->field.sle_next != (elm) ) \ 159 curelm = curelm->field.sle_next; \ 160 curelm->field.sle_next = \ 161 curelm->field.sle_next->field.sle_next; \ 162 } \ 163} while (0) 164 165/* 166 * Singly-linked Tail queue definitions. 167 */ 168#define STAILQ_HEAD(name, type) \ 169struct name { \ 170 struct type *stqh_first;/* first element */ \ 171 struct type **stqh_last;/* addr of last next element */ \ 172} 173 174#define STAILQ_HEAD_INITIALIZER(head) \ 175 { NULL, &(head).stqh_first } 176 177#define STAILQ_ENTRY(type) \ 178struct { \ 179 struct type *stqe_next; /* next element */ \ 180} 181 182/* 183 * Singly-linked Tail queue functions. 184 */ 185#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 186 187#define STAILQ_INIT(head) do { \ 188 (head)->stqh_first = NULL; \ 189 (head)->stqh_last = &(head)->stqh_first; \ 190} while (0) 191 192#define STAILQ_FIRST(head) ((head)->stqh_first) 193#define STAILQ_LAST(head) (*(head)->stqh_last) 194 195#define STAILQ_INSERT_HEAD(head, elm, field) do { \ 196 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 197 (head)->stqh_last = &(elm)->field.stqe_next; \ 198 (head)->stqh_first = (elm); \ 199} while (0) 200 201#define STAILQ_INSERT_TAIL(head, elm, field) do { \ 202 (elm)->field.stqe_next = NULL; \ 203 *(head)->stqh_last = (elm); \ 204 (head)->stqh_last = &(elm)->field.stqe_next; \ 205} while (0) 206 207#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 208 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\ 209 (head)->stqh_last = &(elm)->field.stqe_next; \ 210 (tqelm)->field.stqe_next = (elm); \ 211} while (0) 212 213#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 214 215#define STAILQ_REMOVE_HEAD(head, field) do { \ 216 if (((head)->stqh_first = \ 217 (head)->stqh_first->field.stqe_next) == NULL) \ 218 (head)->stqh_last = &(head)->stqh_first; \ 219} while (0) 220 221#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 222 if (((head)->stqh_first = (elm)->field.stqe_next) == NULL) \ 223 (head)->stqh_last = &(head)->stqh_first; \ 224} while (0) 225 226 227#define STAILQ_REMOVE(head, elm, type, field) do { \ 228 if ((head)->stqh_first == (elm)) { \ 229 STAILQ_REMOVE_HEAD(head, field); \ 230 } \ 231 else { \ 232 struct type *curelm = (head)->stqh_first; \ 233 while( curelm->field.stqe_next != (elm) ) \ 234 curelm = curelm->field.stqe_next; \ 235 if((curelm->field.stqe_next = \ 236 curelm->field.stqe_next->field.stqe_next) == NULL) \ 237 (head)->stqh_last = &(curelm)->field.stqe_next; \ 238 } \ 239} while (0) 240 241/* 242 * List definitions. 243 */ 244#define LIST_HEAD(name, type) \ 245struct name { \ 246 struct type *lh_first; /* first element */ \ 247} 248 249#define LIST_HEAD_INITIALIZER(head) \ 250 { NULL } 251 252#define LIST_ENTRY(type) \ 253struct { \ 254 struct type *le_next; /* next element */ \ 255 struct type **le_prev; /* address of previous next element */ \ 256} 257 258/* 259 * List functions. 260 */ 261 262#define LIST_EMPTY(head) ((head)->lh_first == NULL) 263 264#define LIST_FIRST(head) ((head)->lh_first) 265 266#define LIST_FOREACH(var, head, field) \ 267 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next) 268 269#define LIST_INIT(head) do { \ 270 (head)->lh_first = NULL; \ 271} while (0) 272 273#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 274 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 275 (listelm)->field.le_next->field.le_prev = \ 276 &(elm)->field.le_next; \ 277 (listelm)->field.le_next = (elm); \ 278 (elm)->field.le_prev = &(listelm)->field.le_next; \ 279} while (0) 280 281#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 282 (elm)->field.le_prev = (listelm)->field.le_prev; \ 283 (elm)->field.le_next = (listelm); \ 284 *(listelm)->field.le_prev = (elm); \ 285 (listelm)->field.le_prev = &(elm)->field.le_next; \ 286} while (0) 287 288#define LIST_INSERT_HEAD(head, elm, field) do { \ 289 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 290 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 291 (head)->lh_first = (elm); \ 292 (elm)->field.le_prev = &(head)->lh_first; \ 293} while (0) 294 295#define LIST_NEXT(elm, field) ((elm)->field.le_next) 296 297#define LIST_REMOVE(elm, field) do { \ 298 if ((elm)->field.le_next != NULL) \ 299 (elm)->field.le_next->field.le_prev = \ 300 (elm)->field.le_prev; \ 301 *(elm)->field.le_prev = (elm)->field.le_next; \ 302} while (0) 303 304/* 305 * Tail queue definitions. 306 */ 307#define TAILQ_HEAD(name, type) \ 308struct name { \ 309 struct type *tqh_first; /* first element */ \ 310 struct type **tqh_last; /* addr of last next element */ \ 311} 312 313#define TAILQ_HEAD_INITIALIZER(head) \ 314 { NULL, &(head).tqh_first } 315 316#define TAILQ_ENTRY(type) \ 317struct { \ 318 struct type *tqe_next; /* next element */ \ 319 struct type **tqe_prev; /* address of previous next element */ \ 320} 321 322/* 323 * Tail queue functions. 324 */ 325#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 326 327#define TAILQ_FOREACH(var, head, field) \ 328 for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field)) 329 330#define TAILQ_FIRST(head) ((head)->tqh_first) 331 332#define TAILQ_LAST(head, headname) \ 333 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 334 335#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 336 337#define TAILQ_PREV(elm, headname, field) \ 338 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 339 340#define TAILQ_INIT(head) do { \ 341 (head)->tqh_first = NULL; \ 342 (head)->tqh_last = &(head)->tqh_first; \ 343} while (0) 344 345#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 346 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 347 (head)->tqh_first->field.tqe_prev = \ 348 &(elm)->field.tqe_next; \ 349 else \ 350 (head)->tqh_last = &(elm)->field.tqe_next; \ 351 (head)->tqh_first = (elm); \ 352 (elm)->field.tqe_prev = &(head)->tqh_first; \ 353} while (0) 354 355#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 356 (elm)->field.tqe_next = NULL; \ 357 (elm)->field.tqe_prev = (head)->tqh_last; \ 358 *(head)->tqh_last = (elm); \ 359 (head)->tqh_last = &(elm)->field.tqe_next; \ 360} while (0) 361 362#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 363 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 364 (elm)->field.tqe_next->field.tqe_prev = \ 365 &(elm)->field.tqe_next; \ 366 else \ 367 (head)->tqh_last = &(elm)->field.tqe_next; \ 368 (listelm)->field.tqe_next = (elm); \ 369 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 370} while (0) 371 372#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 373 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 374 (elm)->field.tqe_next = (listelm); \ 375 *(listelm)->field.tqe_prev = (elm); \ 376 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 377} while (0) 378 379#define TAILQ_REMOVE(head, elm, field) do { \ 380 if (((elm)->field.tqe_next) != NULL) \ 381 (elm)->field.tqe_next->field.tqe_prev = \ 382 (elm)->field.tqe_prev; \ 383 else \ 384 (head)->tqh_last = (elm)->field.tqe_prev; \ 385 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 386} while (0) 387 388/* 389 * Circular queue definitions. 390 */ 391#define CIRCLEQ_HEAD(name, type) \ 392struct name { \ 393 struct type *cqh_first; /* first element */ \ 394 struct type *cqh_last; /* last element */ \ 395} 396 397#define CIRCLEQ_ENTRY(type) \ 398struct { \ 399 struct type *cqe_next; /* next element */ \ 400 struct type *cqe_prev; /* previous element */ \ 401} 402 403/* 404 * Circular queue functions. 405 */ 406#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 407 408#define CIRCLEQ_FIRST(head) ((head)->cqh_first) 409 410#define CIRCLEQ_FOREACH(var, head, field) \ 411 for((var) = (head)->cqh_first; \ 412 (var) != (void *)(head); \ 413 (var) = (var)->field.cqe_next) 414 415#define CIRCLEQ_INIT(head) do { \ 416 (head)->cqh_first = (void *)(head); \ 417 (head)->cqh_last = (void *)(head); \ 418} while (0) 419 420#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 421 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 422 (elm)->field.cqe_prev = (listelm); \ 423 if ((listelm)->field.cqe_next == (void *)(head)) \ 424 (head)->cqh_last = (elm); \ 425 else \ 426 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 427 (listelm)->field.cqe_next = (elm); \ 428} while (0) 429 430#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 431 (elm)->field.cqe_next = (listelm); \ 432 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 433 if ((listelm)->field.cqe_prev == (void *)(head)) \ 434 (head)->cqh_first = (elm); \ 435 else \ 436 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 437 (listelm)->field.cqe_prev = (elm); \ 438} while (0) 439 440#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 441 (elm)->field.cqe_next = (head)->cqh_first; \ 442 (elm)->field.cqe_prev = (void *)(head); \ 443 if ((head)->cqh_last == (void *)(head)) \ 444 (head)->cqh_last = (elm); \ 445 else \ 446 (head)->cqh_first->field.cqe_prev = (elm); \ 447 (head)->cqh_first = (elm); \ 448} while (0) 449 450#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 451 (elm)->field.cqe_next = (void *)(head); \ 452 (elm)->field.cqe_prev = (head)->cqh_last; \ 453 if ((head)->cqh_first == (void *)(head)) \ 454 (head)->cqh_first = (elm); \ 455 else \ 456 (head)->cqh_last->field.cqe_next = (elm); \ 457 (head)->cqh_last = (elm); \ 458} while (0) 459 460#define CIRCLEQ_LAST(head) ((head)->cqh_last) 461 462#define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) 463 464#define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) 465 466#define CIRCLEQ_REMOVE(head, elm, field) do { \ 467 if ((elm)->field.cqe_next == (void *)(head)) \ 468 (head)->cqh_last = (elm)->field.cqe_prev; \ 469 else \ 470 (elm)->field.cqe_next->field.cqe_prev = \ 471 (elm)->field.cqe_prev; \ 472 if ((elm)->field.cqe_prev == (void *)(head)) \ 473 (head)->cqh_first = (elm)->field.cqe_next; \ 474 else \ 475 (elm)->field.cqe_prev->field.cqe_next = \ 476 (elm)->field.cqe_next; \ 477} while (0) 478 479#ifdef KERNEL 480 481/* 482 * XXX insque() and remque() are an old way of handling certain queues. 483 * They bogusly assumes that all queue heads look alike. 484 */ 485 486struct quehead { 487 struct quehead *qh_link; 488 struct quehead *qh_rlink; 489}; 490 491#ifdef __GNUC__ 492 493static __inline void 494insque(void *a, void *b) 495{ 496 struct quehead *element = a, *head = b; 497 498 element->qh_link = head->qh_link; 499 element->qh_rlink = head; 500 head->qh_link = element; 501 element->qh_link->qh_rlink = element; 502} 503 504static __inline void 505remque(void *a) 506{ 507 struct quehead *element = a; 508 509 element->qh_link->qh_rlink = element->qh_rlink; 510 element->qh_rlink->qh_link = element->qh_link; 511 element->qh_rlink = 0; 512} 513 514#else /* !__GNUC__ */ 515 516void insque __P((void *a, void *b)); 517void remque __P((void *a)); 518 519#endif /* __GNUC__ */ 520 521#endif /* KERNEL */ 522 523#endif /* !_SYS_QUEUE_H_ */ 524