queue.h revision 50604
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 * $FreeBSD: head/sys/sys/queue.h 50604 1999-08-30 01:01:19Z jdp $ 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_FOREACH(var, head, field) \ 196 for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next) 197 198#define STAILQ_INSERT_HEAD(head, elm, field) do { \ 199 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 200 (head)->stqh_last = &(elm)->field.stqe_next; \ 201 (head)->stqh_first = (elm); \ 202} while (0) 203 204#define STAILQ_INSERT_TAIL(head, elm, field) do { \ 205 (elm)->field.stqe_next = NULL; \ 206 *(head)->stqh_last = (elm); \ 207 (head)->stqh_last = &(elm)->field.stqe_next; \ 208} while (0) 209 210#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 211 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\ 212 (head)->stqh_last = &(elm)->field.stqe_next; \ 213 (tqelm)->field.stqe_next = (elm); \ 214} while (0) 215 216#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 217 218#define STAILQ_REMOVE_HEAD(head, field) do { \ 219 if (((head)->stqh_first = \ 220 (head)->stqh_first->field.stqe_next) == NULL) \ 221 (head)->stqh_last = &(head)->stqh_first; \ 222} while (0) 223 224 225#define STAILQ_REMOVE(head, elm, type, field) do { \ 226 if ((head)->stqh_first == (elm)) { \ 227 STAILQ_REMOVE_HEAD(head, field); \ 228 } \ 229 else { \ 230 struct type *curelm = (head)->stqh_first; \ 231 while( curelm->field.stqe_next != (elm) ) \ 232 curelm = curelm->field.stqe_next; \ 233 if((curelm->field.stqe_next = \ 234 curelm->field.stqe_next->field.stqe_next) == NULL) \ 235 (head)->stqh_last = &(curelm)->field.stqe_next; \ 236 } \ 237} while (0) 238 239/* 240 * List definitions. 241 */ 242#define LIST_HEAD(name, type) \ 243struct name { \ 244 struct type *lh_first; /* first element */ \ 245} 246 247#define LIST_HEAD_INITIALIZER(head) \ 248 { NULL } 249 250#define LIST_ENTRY(type) \ 251struct { \ 252 struct type *le_next; /* next element */ \ 253 struct type **le_prev; /* address of previous next element */ \ 254} 255 256/* 257 * List functions. 258 */ 259 260#define LIST_EMPTY(head) ((head)->lh_first == NULL) 261 262#define LIST_FIRST(head) ((head)->lh_first) 263 264#define LIST_FOREACH(var, head, field) \ 265 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next) 266 267#define LIST_INIT(head) do { \ 268 (head)->lh_first = NULL; \ 269} while (0) 270 271#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 272 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 273 (listelm)->field.le_next->field.le_prev = \ 274 &(elm)->field.le_next; \ 275 (listelm)->field.le_next = (elm); \ 276 (elm)->field.le_prev = &(listelm)->field.le_next; \ 277} while (0) 278 279#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 280 (elm)->field.le_prev = (listelm)->field.le_prev; \ 281 (elm)->field.le_next = (listelm); \ 282 *(listelm)->field.le_prev = (elm); \ 283 (listelm)->field.le_prev = &(elm)->field.le_next; \ 284} while (0) 285 286#define LIST_INSERT_HEAD(head, elm, field) do { \ 287 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 288 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 289 (head)->lh_first = (elm); \ 290 (elm)->field.le_prev = &(head)->lh_first; \ 291} while (0) 292 293#define LIST_NEXT(elm, field) ((elm)->field.le_next) 294 295#define LIST_REMOVE(elm, field) do { \ 296 if ((elm)->field.le_next != NULL) \ 297 (elm)->field.le_next->field.le_prev = \ 298 (elm)->field.le_prev; \ 299 *(elm)->field.le_prev = (elm)->field.le_next; \ 300} while (0) 301 302/* 303 * Tail queue definitions. 304 */ 305#define TAILQ_HEAD(name, type) \ 306struct name { \ 307 struct type *tqh_first; /* first element */ \ 308 struct type **tqh_last; /* addr of last next element */ \ 309} 310 311#define TAILQ_HEAD_INITIALIZER(head) \ 312 { NULL, &(head).tqh_first } 313 314#define TAILQ_ENTRY(type) \ 315struct { \ 316 struct type *tqe_next; /* next element */ \ 317 struct type **tqe_prev; /* address of previous next element */ \ 318} 319 320/* 321 * Tail queue functions. 322 */ 323#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 324 325#define TAILQ_FOREACH(var, head, field) \ 326 for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field)) 327 328#define TAILQ_FIRST(head) ((head)->tqh_first) 329 330#define TAILQ_LAST(head, headname) \ 331 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 332 333#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 334 335#define TAILQ_PREV(elm, headname, field) \ 336 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 337 338#define TAILQ_INIT(head) do { \ 339 (head)->tqh_first = NULL; \ 340 (head)->tqh_last = &(head)->tqh_first; \ 341} while (0) 342 343#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 344 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 345 (head)->tqh_first->field.tqe_prev = \ 346 &(elm)->field.tqe_next; \ 347 else \ 348 (head)->tqh_last = &(elm)->field.tqe_next; \ 349 (head)->tqh_first = (elm); \ 350 (elm)->field.tqe_prev = &(head)->tqh_first; \ 351} while (0) 352 353#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 354 (elm)->field.tqe_next = NULL; \ 355 (elm)->field.tqe_prev = (head)->tqh_last; \ 356 *(head)->tqh_last = (elm); \ 357 (head)->tqh_last = &(elm)->field.tqe_next; \ 358} while (0) 359 360#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 361 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 362 (elm)->field.tqe_next->field.tqe_prev = \ 363 &(elm)->field.tqe_next; \ 364 else \ 365 (head)->tqh_last = &(elm)->field.tqe_next; \ 366 (listelm)->field.tqe_next = (elm); \ 367 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 368} while (0) 369 370#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 371 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 372 (elm)->field.tqe_next = (listelm); \ 373 *(listelm)->field.tqe_prev = (elm); \ 374 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 375} while (0) 376 377#define TAILQ_REMOVE(head, elm, field) do { \ 378 if (((elm)->field.tqe_next) != NULL) \ 379 (elm)->field.tqe_next->field.tqe_prev = \ 380 (elm)->field.tqe_prev; \ 381 else \ 382 (head)->tqh_last = (elm)->field.tqe_prev; \ 383 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 384} while (0) 385 386/* 387 * Circular queue definitions. 388 */ 389#define CIRCLEQ_HEAD(name, type) \ 390struct name { \ 391 struct type *cqh_first; /* first element */ \ 392 struct type *cqh_last; /* last element */ \ 393} 394 395#define CIRCLEQ_ENTRY(type) \ 396struct { \ 397 struct type *cqe_next; /* next element */ \ 398 struct type *cqe_prev; /* previous element */ \ 399} 400 401/* 402 * Circular queue functions. 403 */ 404#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 405 406#define CIRCLEQ_FIRST(head) ((head)->cqh_first) 407 408#define CIRCLEQ_FOREACH(var, head, field) \ 409 for((var) = (head)->cqh_first; \ 410 (var) != (void *)(head); \ 411 (var) = (var)->field.cqe_next) 412 413#define CIRCLEQ_INIT(head) do { \ 414 (head)->cqh_first = (void *)(head); \ 415 (head)->cqh_last = (void *)(head); \ 416} while (0) 417 418#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 419 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 420 (elm)->field.cqe_prev = (listelm); \ 421 if ((listelm)->field.cqe_next == (void *)(head)) \ 422 (head)->cqh_last = (elm); \ 423 else \ 424 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 425 (listelm)->field.cqe_next = (elm); \ 426} while (0) 427 428#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 429 (elm)->field.cqe_next = (listelm); \ 430 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 431 if ((listelm)->field.cqe_prev == (void *)(head)) \ 432 (head)->cqh_first = (elm); \ 433 else \ 434 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 435 (listelm)->field.cqe_prev = (elm); \ 436} while (0) 437 438#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 439 (elm)->field.cqe_next = (head)->cqh_first; \ 440 (elm)->field.cqe_prev = (void *)(head); \ 441 if ((head)->cqh_last == (void *)(head)) \ 442 (head)->cqh_last = (elm); \ 443 else \ 444 (head)->cqh_first->field.cqe_prev = (elm); \ 445 (head)->cqh_first = (elm); \ 446} while (0) 447 448#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 449 (elm)->field.cqe_next = (void *)(head); \ 450 (elm)->field.cqe_prev = (head)->cqh_last; \ 451 if ((head)->cqh_first == (void *)(head)) \ 452 (head)->cqh_first = (elm); \ 453 else \ 454 (head)->cqh_last->field.cqe_next = (elm); \ 455 (head)->cqh_last = (elm); \ 456} while (0) 457 458#define CIRCLEQ_LAST(head) ((head)->cqh_last) 459 460#define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) 461 462#define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) 463 464#define CIRCLEQ_REMOVE(head, elm, field) do { \ 465 if ((elm)->field.cqe_next == (void *)(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 == (void *)(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#ifdef KERNEL 478 479/* 480 * XXX insque() and remque() are an old way of handling certain queues. 481 * They bogusly assumes that all queue heads look alike. 482 */ 483 484struct quehead { 485 struct quehead *qh_link; 486 struct quehead *qh_rlink; 487}; 488 489#ifdef __GNUC__ 490 491static __inline void 492insque(void *a, void *b) 493{ 494 struct quehead *element = a, *head = b; 495 496 element->qh_link = head->qh_link; 497 element->qh_rlink = head; 498 head->qh_link = element; 499 element->qh_link->qh_rlink = element; 500} 501 502static __inline void 503remque(void *a) 504{ 505 struct quehead *element = a; 506 507 element->qh_link->qh_rlink = element->qh_rlink; 508 element->qh_rlink->qh_link = element->qh_link; 509 element->qh_rlink = 0; 510} 511 512#else /* !__GNUC__ */ 513 514void insque __P((void *a, void *b)); 515void remque __P((void *a)); 516 517#endif /* __GNUC__ */ 518 519#endif /* KERNEL */ 520 521#endif /* !_SYS_QUEUE_H_ */ 522