queue.h revision 94938
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 94938 2002-04-17 13:43:31Z tmm $ 35 */ 36 37#ifndef _SYS_QUEUE_H_ 38#define _SYS_QUEUE_H_ 39 40#include <machine/ansi.h> /* for __offsetof */ 41 42/* 43 * This file defines four types of data structures: singly-linked lists, 44 * singly-linked tail queues, lists and tail queues. 45 * 46 * A singly-linked list is headed by a single forward pointer. The elements 47 * are singly linked for minimum space and pointer manipulation overhead at 48 * the expense of O(n) removal for arbitrary elements. New elements can be 49 * added to the list after an existing element or at the head of the list. 50 * Elements being removed from the head of the list should use the explicit 51 * macro for this purpose for optimum efficiency. A singly-linked list may 52 * only be traversed in the forward direction. Singly-linked lists are ideal 53 * for applications with large datasets and few or no removals or for 54 * implementing a LIFO queue. 55 * 56 * A singly-linked tail queue is headed by a pair of pointers, one to the 57 * head of the list and the other to the tail of the list. The elements are 58 * singly linked for minimum space and pointer manipulation overhead at the 59 * expense of O(n) removal for arbitrary elements. New elements can be added 60 * to the list after an existing element, at the head of the list, or at the 61 * end of the list. Elements being removed from the head of the tail queue 62 * should use the explicit macro for this purpose for optimum efficiency. 63 * A singly-linked tail queue may only be traversed in the forward direction. 64 * Singly-linked tail queues are ideal for applications with large datasets 65 * and few or no removals or for implementing a FIFO queue. 66 * 67 * A list is headed by a single forward pointer (or an array of forward 68 * pointers for a hash table header). The elements are doubly linked 69 * so that an arbitrary element can be removed without a need to 70 * traverse the list. New elements can be added to the list before 71 * or after an existing element or at the head of the list. A list 72 * may only be traversed in the forward direction. 73 * 74 * A tail queue is headed by a pair of pointers, one to the head of the 75 * list and the other to the tail of the list. The elements are doubly 76 * linked so that an arbitrary element can be removed without a need to 77 * traverse the list. New elements can be added to the list before or 78 * after an existing element, at the head of the list, or at the end of 79 * the list. A tail queue may be traversed in either direction. 80 * 81 * For details on the use of these macros, see the queue(3) manual page. 82 * 83 * 84 * SLIST LIST STAILQ TAILQ 85 * _HEAD + + + + 86 * _HEAD_INITIALIZER + + + + 87 * _ENTRY + + + + 88 * _INIT + + + + 89 * _EMPTY + + + + 90 * _FIRST + + + + 91 * _NEXT + + + + 92 * _PREV - - - + 93 * _LAST - - + + 94 * _FOREACH + + + + 95 * _FOREACH_REVERSE - - - + 96 * _INSERT_HEAD + + + + 97 * _INSERT_BEFORE - + - + 98 * _INSERT_AFTER + + + + 99 * _INSERT_TAIL - - + + 100 * _CONCAT - - + + 101 * _REMOVE_HEAD + - + - 102 * _REMOVE + + + + 103 * 104 */ 105 106/* 107 * Singly-linked List declarations. 108 */ 109#define SLIST_HEAD(name, type) \ 110struct name { \ 111 struct type *slh_first; /* first element */ \ 112} 113 114#define SLIST_HEAD_INITIALIZER(head) \ 115 { NULL } 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) = SLIST_FIRST((head)); \ 131 (var); \ 132 (var) = SLIST_NEXT((var), field)) 133 134#define SLIST_INIT(head) do { \ 135 SLIST_FIRST((head)) = NULL; \ 136} while (0) 137 138#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 139 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 140 SLIST_NEXT((slistelm), field) = (elm); \ 141} while (0) 142 143#define SLIST_INSERT_HEAD(head, elm, field) do { \ 144 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 145 SLIST_FIRST((head)) = (elm); \ 146} while (0) 147 148#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 149 150#define SLIST_REMOVE(head, elm, type, field) do { \ 151 if (SLIST_FIRST((head)) == (elm)) { \ 152 SLIST_REMOVE_HEAD((head), field); \ 153 } \ 154 else { \ 155 struct type *curelm = SLIST_FIRST((head)); \ 156 while (SLIST_NEXT(curelm, field) != (elm)) \ 157 curelm = SLIST_NEXT(curelm, field); \ 158 SLIST_NEXT(curelm, field) = \ 159 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \ 160 } \ 161} while (0) 162 163#define SLIST_REMOVE_HEAD(head, field) do { \ 164 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 165} while (0) 166 167/* 168 * Singly-linked Tail queue declarations. 169 */ 170#define STAILQ_HEAD(name, type) \ 171struct name { \ 172 struct type *stqh_first;/* first element */ \ 173 struct type **stqh_last;/* addr of last next element */ \ 174} 175 176#define STAILQ_HEAD_INITIALIZER(head) \ 177 { NULL, &(head).stqh_first } 178 179#define STAILQ_ENTRY(type) \ 180struct { \ 181 struct type *stqe_next; /* next element */ \ 182} 183 184/* 185 * Singly-linked Tail queue functions. 186 */ 187#define STAILQ_CONCAT(head1, head2) do { \ 188 if (!STAILQ_EMPTY((head2))) { \ 189 *(head1)->stqh_last = (head2)->stqh_first; \ 190 (head1)->stqh_last = (head2)->stqh_last; \ 191 STAILQ_INIT((head2)); \ 192 } \ 193} while (0) 194 195#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 196 197#define STAILQ_FIRST(head) ((head)->stqh_first) 198 199#define STAILQ_FOREACH(var, head, field) \ 200 for((var) = STAILQ_FIRST((head)); \ 201 (var); \ 202 (var) = STAILQ_NEXT((var), field)) 203 204#define STAILQ_INIT(head) do { \ 205 STAILQ_FIRST((head)) = NULL; \ 206 (head)->stqh_last = &STAILQ_FIRST((head)); \ 207} while (0) 208 209#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 210 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 211 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 212 STAILQ_NEXT((tqelm), field) = (elm); \ 213} while (0) 214 215#define STAILQ_INSERT_HEAD(head, elm, field) do { \ 216 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 217 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 218 STAILQ_FIRST((head)) = (elm); \ 219} while (0) 220 221#define STAILQ_INSERT_TAIL(head, elm, field) do { \ 222 STAILQ_NEXT((elm), field) = NULL; \ 223 *(head)->stqh_last = (elm); \ 224 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 225} while (0) 226 227#define STAILQ_LAST(head, type, field) \ 228 (STAILQ_EMPTY(head) ? \ 229 NULL : \ 230 ((struct type *) \ 231 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 232 233#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 234 235#define STAILQ_REMOVE(head, elm, type, field) do { \ 236 if (STAILQ_FIRST((head)) == (elm)) { \ 237 STAILQ_REMOVE_HEAD(head, field); \ 238 } \ 239 else { \ 240 struct type *curelm = STAILQ_FIRST((head)); \ 241 while (STAILQ_NEXT(curelm, field) != (elm)) \ 242 curelm = STAILQ_NEXT(curelm, field); \ 243 if ((STAILQ_NEXT(curelm, field) = \ 244 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\ 245 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\ 246 } \ 247} while (0) 248 249#define STAILQ_REMOVE_HEAD(head, field) do { \ 250 if ((STAILQ_FIRST((head)) = \ 251 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 252 (head)->stqh_last = &STAILQ_FIRST((head)); \ 253} while (0) 254 255#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 256 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \ 257 (head)->stqh_last = &STAILQ_FIRST((head)); \ 258} while (0) 259 260/* 261 * List declarations. 262 */ 263#define LIST_HEAD(name, type) \ 264struct name { \ 265 struct type *lh_first; /* first element */ \ 266} 267 268#define LIST_HEAD_INITIALIZER(head) \ 269 { NULL } 270 271#define LIST_ENTRY(type) \ 272struct { \ 273 struct type *le_next; /* next element */ \ 274 struct type **le_prev; /* address of previous next element */ \ 275} 276 277/* 278 * List functions. 279 */ 280 281#define LIST_EMPTY(head) ((head)->lh_first == NULL) 282 283#define LIST_FIRST(head) ((head)->lh_first) 284 285#define LIST_FOREACH(var, head, field) \ 286 for ((var) = LIST_FIRST((head)); \ 287 (var); \ 288 (var) = LIST_NEXT((var), field)) 289 290#define LIST_INIT(head) do { \ 291 LIST_FIRST((head)) = NULL; \ 292} while (0) 293 294#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 295 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 296 LIST_NEXT((listelm), field)->field.le_prev = \ 297 &LIST_NEXT((elm), field); \ 298 LIST_NEXT((listelm), field) = (elm); \ 299 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 300} while (0) 301 302#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 303 (elm)->field.le_prev = (listelm)->field.le_prev; \ 304 LIST_NEXT((elm), field) = (listelm); \ 305 *(listelm)->field.le_prev = (elm); \ 306 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 307} while (0) 308 309#define LIST_INSERT_HEAD(head, elm, field) do { \ 310 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 311 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 312 LIST_FIRST((head)) = (elm); \ 313 (elm)->field.le_prev = &LIST_FIRST((head)); \ 314} while (0) 315 316#define LIST_NEXT(elm, field) ((elm)->field.le_next) 317 318#define LIST_REMOVE(elm, field) do { \ 319 if (LIST_NEXT((elm), field) != NULL) \ 320 LIST_NEXT((elm), field)->field.le_prev = \ 321 (elm)->field.le_prev; \ 322 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 323} while (0) 324 325/* 326 * Tail queue declarations. 327 */ 328#define TAILQ_HEAD(name, type) \ 329struct name { \ 330 struct type *tqh_first; /* first element */ \ 331 struct type **tqh_last; /* addr of last next element */ \ 332} 333 334#define TAILQ_HEAD_INITIALIZER(head) \ 335 { NULL, &(head).tqh_first } 336 337#define TAILQ_ENTRY(type) \ 338struct { \ 339 struct type *tqe_next; /* next element */ \ 340 struct type **tqe_prev; /* address of previous next element */ \ 341} 342 343/* 344 * Tail queue functions. 345 */ 346#define TAILQ_CONCAT(head1, head2, field) do { \ 347 if (!TAILQ_EMPTY(head2)) { \ 348 *(head1)->tqh_last = (head2)->tqh_first; \ 349 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 350 (head1)->tqh_last = (head2)->tqh_last; \ 351 TAILQ_INIT((head2)); \ 352 } \ 353} while (0) 354 355#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 356 357#define TAILQ_FIRST(head) ((head)->tqh_first) 358 359#define TAILQ_FOREACH(var, head, field) \ 360 for ((var) = TAILQ_FIRST((head)); \ 361 (var); \ 362 (var) = TAILQ_NEXT((var), field)) 363 364#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 365 for ((var) = TAILQ_LAST((head), headname); \ 366 (var); \ 367 (var) = TAILQ_PREV((var), headname, field)) 368 369#define TAILQ_INIT(head) do { \ 370 TAILQ_FIRST((head)) = NULL; \ 371 (head)->tqh_last = &TAILQ_FIRST((head)); \ 372} while (0) 373 374#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 375 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 376 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 377 &TAILQ_NEXT((elm), field); \ 378 else \ 379 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 380 TAILQ_NEXT((listelm), field) = (elm); \ 381 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 382} while (0) 383 384#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 385 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 386 TAILQ_NEXT((elm), field) = (listelm); \ 387 *(listelm)->field.tqe_prev = (elm); \ 388 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 389} while (0) 390 391#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 392 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 393 TAILQ_FIRST((head))->field.tqe_prev = \ 394 &TAILQ_NEXT((elm), field); \ 395 else \ 396 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 397 TAILQ_FIRST((head)) = (elm); \ 398 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 399} while (0) 400 401#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 402 TAILQ_NEXT((elm), field) = NULL; \ 403 (elm)->field.tqe_prev = (head)->tqh_last; \ 404 *(head)->tqh_last = (elm); \ 405 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 406} while (0) 407 408#define TAILQ_LAST(head, headname) \ 409 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 410 411#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 412 413#define TAILQ_PREV(elm, headname, field) \ 414 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 415 416#define TAILQ_REMOVE(head, elm, field) do { \ 417 if ((TAILQ_NEXT((elm), field)) != NULL) \ 418 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 419 (elm)->field.tqe_prev; \ 420 else \ 421 (head)->tqh_last = (elm)->field.tqe_prev; \ 422 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 423} while (0) 424 425 426#ifdef _KERNEL 427 428/* 429 * XXX insque() and remque() are an old way of handling certain queues. 430 * They bogusly assumes that all queue heads look alike. 431 */ 432 433struct quehead { 434 struct quehead *qh_link; 435 struct quehead *qh_rlink; 436}; 437 438#ifdef __GNUC__ 439 440static __inline void 441insque(void *a, void *b) 442{ 443 struct quehead *element = (struct quehead *)a, 444 *head = (struct quehead *)b; 445 446 element->qh_link = head->qh_link; 447 element->qh_rlink = head; 448 head->qh_link = element; 449 element->qh_link->qh_rlink = element; 450} 451 452static __inline void 453remque(void *a) 454{ 455 struct quehead *element = (struct quehead *)a; 456 457 element->qh_link->qh_rlink = element->qh_rlink; 458 element->qh_rlink->qh_link = element->qh_link; 459 element->qh_rlink = 0; 460} 461 462#else /* !__GNUC__ */ 463 464void insque(void *a, void *b); 465void remque(void *a); 466 467#endif /* __GNUC__ */ 468 469#endif /* _KERNEL */ 470 471#endif /* !_SYS_QUEUE_H_ */ 472