queue.h revision 48526
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 1.25 1999/04/20 22:37:17 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) 220 221 222#define STAILQ_REMOVE(head, elm, type, field) do { \ 223 if ((head)->stqh_first == (elm)) { \ 224 STAILQ_REMOVE_HEAD(head, field); \ 225 } \ 226 else { \ 227 struct type *curelm = (head)->stqh_first; \ 228 while( curelm->field.stqe_next != (elm) ) \ 229 curelm = curelm->field.stqe_next; \ 230 if((curelm->field.stqe_next = \ 231 curelm->field.stqe_next->field.stqe_next) == NULL) \ 232 (head)->stqh_last = &(curelm)->field.stqe_next; \ 233 } \ 234} while (0) 235 236/* 237 * List definitions. 238 */ 239#define LIST_HEAD(name, type) \ 240struct name { \ 241 struct type *lh_first; /* first element */ \ 242} 243 244#define LIST_HEAD_INITIALIZER \ 245 { NULL } 246 247#define LIST_ENTRY(type) \ 248struct { \ 249 struct type *le_next; /* next element */ \ 250 struct type **le_prev; /* address of previous next element */ \ 251} 252 253/* 254 * List functions. 255 */ 256 257#define LIST_EMPTY(head) ((head)->lh_first == NULL) 258 259#define LIST_FIRST(head) ((head)->lh_first) 260 261#define LIST_FOREACH(var, head, field) \ 262 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next) 263 264#define LIST_INIT(head) do { \ 265 (head)->lh_first = NULL; \ 266} while (0) 267 268#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 269 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 270 (listelm)->field.le_next->field.le_prev = \ 271 &(elm)->field.le_next; \ 272 (listelm)->field.le_next = (elm); \ 273 (elm)->field.le_prev = &(listelm)->field.le_next; \ 274} while (0) 275 276#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 277 (elm)->field.le_prev = (listelm)->field.le_prev; \ 278 (elm)->field.le_next = (listelm); \ 279 *(listelm)->field.le_prev = (elm); \ 280 (listelm)->field.le_prev = &(elm)->field.le_next; \ 281} while (0) 282 283#define LIST_INSERT_HEAD(head, elm, field) do { \ 284 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 285 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 286 (head)->lh_first = (elm); \ 287 (elm)->field.le_prev = &(head)->lh_first; \ 288} while (0) 289 290#define LIST_NEXT(elm, field) ((elm)->field.le_next) 291 292#define LIST_REMOVE(elm, field) do { \ 293 if ((elm)->field.le_next != NULL) \ 294 (elm)->field.le_next->field.le_prev = \ 295 (elm)->field.le_prev; \ 296 *(elm)->field.le_prev = (elm)->field.le_next; \ 297} while (0) 298 299/* 300 * Tail queue definitions. 301 */ 302#define TAILQ_HEAD(name, type) \ 303struct name { \ 304 struct type *tqh_first; /* first element */ \ 305 struct type **tqh_last; /* addr of last next element */ \ 306} 307 308#define TAILQ_HEAD_INITIALIZER(head) \ 309 { NULL, &(head).tqh_first } 310 311#define TAILQ_ENTRY(type) \ 312struct { \ 313 struct type *tqe_next; /* next element */ \ 314 struct type **tqe_prev; /* address of previous next element */ \ 315} 316 317/* 318 * Tail queue functions. 319 */ 320#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 321 322#define TAILQ_FOREACH(var, head, field) \ 323 for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field)) 324 325#define TAILQ_FIRST(head) ((head)->tqh_first) 326 327#define TAILQ_LAST(head, headname) \ 328 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 329 330#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 331 332#define TAILQ_PREV(elm, headname, field) \ 333 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 334 335#define TAILQ_INIT(head) do { \ 336 (head)->tqh_first = NULL; \ 337 (head)->tqh_last = &(head)->tqh_first; \ 338} while (0) 339 340#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 341 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 342 (head)->tqh_first->field.tqe_prev = \ 343 &(elm)->field.tqe_next; \ 344 else \ 345 (head)->tqh_last = &(elm)->field.tqe_next; \ 346 (head)->tqh_first = (elm); \ 347 (elm)->field.tqe_prev = &(head)->tqh_first; \ 348} while (0) 349 350#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 351 (elm)->field.tqe_next = NULL; \ 352 (elm)->field.tqe_prev = (head)->tqh_last; \ 353 *(head)->tqh_last = (elm); \ 354 (head)->tqh_last = &(elm)->field.tqe_next; \ 355} while (0) 356 357#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 358 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 359 (elm)->field.tqe_next->field.tqe_prev = \ 360 &(elm)->field.tqe_next; \ 361 else \ 362 (head)->tqh_last = &(elm)->field.tqe_next; \ 363 (listelm)->field.tqe_next = (elm); \ 364 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 365} while (0) 366 367#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 368 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 369 (elm)->field.tqe_next = (listelm); \ 370 *(listelm)->field.tqe_prev = (elm); \ 371 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 372} while (0) 373 374#define TAILQ_REMOVE(head, elm, field) do { \ 375 if (((elm)->field.tqe_next) != NULL) \ 376 (elm)->field.tqe_next->field.tqe_prev = \ 377 (elm)->field.tqe_prev; \ 378 else \ 379 (head)->tqh_last = (elm)->field.tqe_prev; \ 380 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 381} while (0) 382 383/* 384 * Circular queue definitions. 385 */ 386#define CIRCLEQ_HEAD(name, type) \ 387struct name { \ 388 struct type *cqh_first; /* first element */ \ 389 struct type *cqh_last; /* last element */ \ 390} 391 392#define CIRCLEQ_ENTRY(type) \ 393struct { \ 394 struct type *cqe_next; /* next element */ \ 395 struct type *cqe_prev; /* previous element */ \ 396} 397 398/* 399 * Circular queue functions. 400 */ 401#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 402 403#define CIRCLEQ_FIRST(head) ((head)->cqh_first) 404 405#define CIRCLEQ_FOREACH(var, head, field) \ 406 for((var) = (head)->cqh_first; \ 407 (var) != (void *)(head); \ 408 (var) = (var)->field.cqe_next) 409 410#define CIRCLEQ_INIT(head) do { \ 411 (head)->cqh_first = (void *)(head); \ 412 (head)->cqh_last = (void *)(head); \ 413} while (0) 414 415#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 416 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 417 (elm)->field.cqe_prev = (listelm); \ 418 if ((listelm)->field.cqe_next == (void *)(head)) \ 419 (head)->cqh_last = (elm); \ 420 else \ 421 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 422 (listelm)->field.cqe_next = (elm); \ 423} while (0) 424 425#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 426 (elm)->field.cqe_next = (listelm); \ 427 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 428 if ((listelm)->field.cqe_prev == (void *)(head)) \ 429 (head)->cqh_first = (elm); \ 430 else \ 431 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 432 (listelm)->field.cqe_prev = (elm); \ 433} while (0) 434 435#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 436 (elm)->field.cqe_next = (head)->cqh_first; \ 437 (elm)->field.cqe_prev = (void *)(head); \ 438 if ((head)->cqh_last == (void *)(head)) \ 439 (head)->cqh_last = (elm); \ 440 else \ 441 (head)->cqh_first->field.cqe_prev = (elm); \ 442 (head)->cqh_first = (elm); \ 443} while (0) 444 445#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 446 (elm)->field.cqe_next = (void *)(head); \ 447 (elm)->field.cqe_prev = (head)->cqh_last; \ 448 if ((head)->cqh_first == (void *)(head)) \ 449 (head)->cqh_first = (elm); \ 450 else \ 451 (head)->cqh_last->field.cqe_next = (elm); \ 452 (head)->cqh_last = (elm); \ 453} while (0) 454 455#define CIRCLEQ_LAST(head) ((head)->cqh_last) 456 457#define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) 458 459#define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) 460 461#define CIRCLEQ_REMOVE(head, elm, field) do { \ 462 if ((elm)->field.cqe_next == (void *)(head)) \ 463 (head)->cqh_last = (elm)->field.cqe_prev; \ 464 else \ 465 (elm)->field.cqe_next->field.cqe_prev = \ 466 (elm)->field.cqe_prev; \ 467 if ((elm)->field.cqe_prev == (void *)(head)) \ 468 (head)->cqh_first = (elm)->field.cqe_next; \ 469 else \ 470 (elm)->field.cqe_prev->field.cqe_next = \ 471 (elm)->field.cqe_next; \ 472} while (0) 473 474#ifdef KERNEL 475 476/* 477 * XXX insque() and remque() are an old way of handling certain queues. 478 * They bogusly assumes that all queue heads look alike. 479 */ 480 481struct quehead { 482 struct quehead *qh_link; 483 struct quehead *qh_rlink; 484}; 485 486#ifdef __GNUC__ 487 488static __inline void 489insque(void *a, void *b) 490{ 491 struct quehead *element = a, *head = b; 492 493 element->qh_link = head->qh_link; 494 element->qh_rlink = head; 495 head->qh_link = element; 496 element->qh_link->qh_rlink = element; 497} 498 499static __inline void 500remque(void *a) 501{ 502 struct quehead *element = a; 503 504 element->qh_link->qh_rlink = element->qh_rlink; 505 element->qh_rlink->qh_link = element->qh_link; 506 element->qh_rlink = 0; 507} 508 509#else /* !__GNUC__ */ 510 511void insque __P((void *a, void *b)); 512void remque __P((void *a)); 513 514#endif /* __GNUC__ */ 515 516#endif /* KERNEL */ 517 518#endif /* !_SYS_QUEUE_H_ */ 519