queue.h revision 50477
1139969Simp/* 21556Srgrimes * Copyright (c) 1991, 1993 31556Srgrimes * The Regents of the University of California. All rights reserved. 41556Srgrimes * 51556Srgrimes * Redistribution and use in source and binary forms, with or without 61556Srgrimes * modification, are permitted provided that the following conditions 71556Srgrimes * are met: 81556Srgrimes * 1. Redistributions of source code must retain the above copyright 91556Srgrimes * notice, this list of conditions and the following disclaimer. 101556Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111556Srgrimes * notice, this list of conditions and the following disclaimer in the 121556Srgrimes * documentation and/or other materials provided with the distribution. 131556Srgrimes * 3. All advertising materials mentioning features or use of this software 141556Srgrimes * must display the following acknowledgement: 151556Srgrimes * This product includes software developed by the University of 161556Srgrimes * California, Berkeley and its contributors. 171556Srgrimes * 4. Neither the name of the University nor the names of its contributors 181556Srgrimes * may be used to endorse or promote products derived from this software 191556Srgrimes * without specific prior written permission. 201556Srgrimes * 211556Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221556Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231556Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241556Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251556Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261556Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271556Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281556Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291556Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30114433Sobrien * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311556Srgrimes * SUCH DAMAGE. 3220415Ssteve * 331556Srgrimes * @(#)queue.h 8.5 (Berkeley) 8/20/94 341556Srgrimes * $FreeBSD: head/sys/sys/queue.h 50477 1999-08-28 01:08:13Z peter $ 351556Srgrimes */ 361556Srgrimes 371556Srgrimes#ifndef _SYS_QUEUE_H_ 3836012Scharnier#define _SYS_QUEUE_H_ 39114433Sobrien 4036012Scharnier/* 4199109Sobrien * This file defines five types of data structures: singly-linked lists, 4299109Sobrien * slingly-linked tail queues, lists, tail queues, and circular queues. 431556Srgrimes * 441556Srgrimes * A singly-linked list is headed by a single forward pointer. The elements 451556Srgrimes * are singly linked for minimum space and pointer manipulation overhead at 461556Srgrimes * the expense of O(n) removal for arbitrary elements. New elements can be 471556Srgrimes * added to the list after an existing element or at the head of the list. 481556Srgrimes * Elements being removed from the head of the list should use the explicit 491556Srgrimes * macro for this purpose for optimum efficiency. A singly-linked list may 501556Srgrimes * only be traversed in the forward direction. Singly-linked lists are ideal 511556Srgrimes * for applications with large datasets and few or no removals or for 52250037Seadler * implementing a LIFO queue. 5320415Ssteve * 541556Srgrimes * A singly-linked tail queue is headed by a pair of pointers, one to the 5590110Simp * head of the list and the other to the tail of the list. The elements are 561556Srgrimes * singly linked for minimum space and pointer manipulation overhead at the 571556Srgrimes * expense of O(n) removal for arbitrary elements. New elements can be added 581556Srgrimes * to the list after an existing element, at the head of the list, or at the 591556Srgrimes * end of the list. Elements being removed from the head of the tail queue 601556Srgrimes * should use the explicit macro for this purpose for optimum efficiency. 61165006Skientzle * A singly-linked tail queue may only be traversed in the forward direction. 621556Srgrimes * Singly-linked tail queues are ideal for applications with large datasets 63165004Skientzle * and few or no removals or for implementing a FIFO queue. 64165006Skientzle * 65165006Skientzle * A list is headed by a single forward pointer (or an array of forward 66165006Skientzle * pointers for a hash table header). The elements are doubly linked 67165006Skientzle * so that an arbitrary element can be removed without a need to 68165006Skientzle * traverse the list. New elements can be added to the list before 69165004Skientzle * or after an existing element or at the head of the list. A list 701556Srgrimes * may only be traversed in the forward direction. 711556Srgrimes * 721556Srgrimes * A tail queue is headed by a pair of pointers, one to the head of the 731556Srgrimes * list and the other to the tail of the list. The elements are doubly 741556Srgrimes * linked so that an arbitrary element can be removed without a need to 7520415Ssteve * traverse the list. New elements can be added to the list before or 761556Srgrimes * after an existing element, at the head of the list, or at the end of 771556Srgrimes * the list. A tail queue may only be traversed in the forward direction. 781556Srgrimes * 791556Srgrimes * A circle queue is headed by a pair of pointers, one to the head of the 8020415Ssteve * list and the other to the tail of the list. The elements are doubly 8120415Ssteve * linked so that an arbitrary element can be removed without a need to 8220415Ssteve * traverse the list. New elements can be added to the list before or after 831556Srgrimes * an existing element, at the head of the list, or at the end of the list. 8476877Skris * A circle queue may be traversed in either direction, but has a more 851556Srgrimes * complex end of list detection. 861556Srgrimes * 8776877Skris * For details on the use of these macros, see the queue(3) manual page. 881556Srgrimes * 8991084Smarkm * 9091084Smarkm * SLIST LIST STAILQ TAILQ CIRCLEQ 9191084Smarkm * _HEAD + + + + + 9291084Smarkm * _ENTRY + + + + + 9391084Smarkm * _INIT + + + + + 941556Srgrimes * _EMPTY + + + + + 951556Srgrimes * _FIRST + + + + + 961556Srgrimes * _NEXT + + + + + 971556Srgrimes * _PREV - - - + + 9820415Ssteve * _LAST - - + + + 99194795Sdelphij * _FOREACH + + - + + 10090110Simp * _INSERT_HEAD + + + + + 10120415Ssteve * _INSERT_BEFORE - + - + + 10220415Ssteve * _INSERT_AFTER + + + + + 103165006Skientzle * _INSERT_TAIL - - + + + 10420415Ssteve * _REMOVE_HEAD + - + - - 10520415Ssteve * _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(head) \ 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