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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)queue.h 8.5 (Berkeley) 8/20/94 30 * $FreeBSD: src/sys/sys/queue.h,v 1.60.2.1 2005/08/16 22:41:39 phk Exp $ 31 */ 32#ifndef _SYS_QUEUE_H_ 33#define _SYS_QUEUE_H_ 34 35#include <sys/cdefs.h> 36 37/* 38 * This file defines four types of data structures: singly-linked lists, 39 * singly-linked tail queues, lists and tail queues. 40 * 41 * A singly-linked list is headed by a single forward pointer. The elements 42 * are singly linked for minimum space and pointer manipulation overhead at 43 * the expense of O(n) removal for arbitrary elements. New elements can be 44 * added to the list after an existing element or at the head of the list. 45 * Elements being removed from the head of the list should use the explicit 46 * macro for this purpose for optimum efficiency. A singly-linked list may 47 * only be traversed in the forward direction. Singly-linked lists are ideal 48 * for applications with large datasets and few or no removals or for 49 * implementing a LIFO queue. 50 * 51 * A singly-linked tail queue is headed by a pair of pointers, one to the 52 * head of the list and the other to the tail of the list. The elements are 53 * singly linked for minimum space and pointer manipulation overhead at the 54 * expense of O(n) removal for arbitrary elements. New elements can be added 55 * to the list after an existing element, at the head of the list, or at the 56 * end of the list. Elements being removed from the head of the tail queue 57 * should use the explicit macro for this purpose for optimum efficiency. 58 * A singly-linked tail queue may only be traversed in the forward direction. 59 * Singly-linked tail queues are ideal for applications with large datasets 60 * and few or no removals or for implementing a FIFO queue. 61 * 62 * A list is headed by a single forward pointer (or an array of forward 63 * pointers for a hash table header). The elements are doubly linked 64 * so that an arbitrary element can be removed without a need to 65 * traverse the list. New elements can be added to the list before 66 * or after an existing element or at the head of the list. A list 67 * may only be traversed in the forward direction. 68 * 69 * A tail queue is headed by a pair of pointers, one to the head of the 70 * list and the other to the tail of the list. The elements are doubly 71 * linked so that an arbitrary element can be removed without a need to 72 * traverse the list. New elements can be added to the list before or 73 * after an existing element, at the head of the list, or at the end of 74 * the list. A tail queue may be traversed in either direction. 75 * 76 * For details on the use of these macros, see the queue(3) manual page. 77 * 78 * 79 * SLIST LIST STAILQ TAILQ 80 * _HEAD + + + + 81 * _HEAD_INITIALIZER + + + + 82 * _ENTRY + + + + 83 * _INIT + + + + 84 * _EMPTY + + + + 85 * _FIRST + + + + 86 * _NEXT + + + + 87 * _PREV - - - + 88 * _LAST - - + + 89 * _FOREACH + + + + 90 * _FOREACH_SAFE + + + + 91 * _FOREACH_REVERSE - - - + 92 * _FOREACH_REVERSE_SAFE - - - + 93 * _INSERT_HEAD + + + + 94 * _INSERT_BEFORE - + - + 95 * _INSERT_AFTER + + + + 96 * _INSERT_TAIL - - + + 97 * _CONCAT - - + + 98 * _REMOVE_HEAD + - + - 99 * _REMOVE + + + + 100 * 101 */ 102#define QUEUE_MACRO_DEBUG 0 103#if QUEUE_MACRO_DEBUG 104/* Store the last 2 places the queue element or head was altered */ 105struct qm_trace { 106 char * lastfile; 107 int lastline; 108 char * prevfile; 109 int prevline; 110}; 111 112#define TRACEBUF struct qm_trace trace; 113#define TRASHIT(x) do {(x) = (void *)-1;} while (0) 114 115#define QMD_TRACE_HEAD(head) do { \ 116 (head)->trace.prevline = (head)->trace.lastline; \ 117 (head)->trace.prevfile = (head)->trace.lastfile; \ 118 (head)->trace.lastline = __LINE__; \ 119 (head)->trace.lastfile = __FILE__; \ 120} while (0) 121 122#define QMD_TRACE_ELEM(elem) do { \ 123 (elem)->trace.prevline = (elem)->trace.lastline; \ 124 (elem)->trace.prevfile = (elem)->trace.lastfile; \ 125 (elem)->trace.lastline = __LINE__; \ 126 (elem)->trace.lastfile = __FILE__; \ 127} while (0) 128 129#else 130#define QMD_TRACE_ELEM(elem) 131#define QMD_TRACE_HEAD(head) 132#define TRACEBUF 133#define TRASHIT(x) 134#endif /* QUEUE_MACRO_DEBUG */ 135 136/* 137 * Singly-linked List declarations. 138 */ 139#define SLIST_HEAD(name, type) \ 140struct name { \ 141 struct type *slh_first; /* first element */ \ 142} 143 144#define SLIST_HEAD_INITIALIZER(head) \ 145 { NULL } 146 147#define SLIST_ENTRY(type) \ 148struct { \ 149 struct type *sle_next; /* next element */ \ 150} 151 152/* 153 * Singly-linked List functions. 154 */ 155#define SLIST_EMPTY(head) ((head)->slh_first == NULL) 156 157#define SLIST_FIRST(head) ((head)->slh_first) 158 159#define SLIST_FOREACH(var, head, field) \ 160 for ((var) = SLIST_FIRST((head)); \ 161 (var); \ 162 (var) = SLIST_NEXT((var), field)) 163 164#define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 165 for ((var) = SLIST_FIRST((head)); \ 166 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 167 (var) = (tvar)) 168 169#define SLIST_FOREACH_PREVPTR(var, varp, head, field) \ 170 for ((varp) = &SLIST_FIRST((head)); \ 171 ((var) = *(varp)) != NULL; \ 172 (varp) = &SLIST_NEXT((var), field)) 173 174#define SLIST_INIT(head) do { \ 175 SLIST_FIRST((head)) = NULL; \ 176} while (0) 177 178#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 179 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 180 SLIST_NEXT((slistelm), field) = (elm); \ 181} while (0) 182 183#define SLIST_INSERT_HEAD(head, elm, field) do { \ 184 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 185 SLIST_FIRST((head)) = (elm); \ 186} while (0) 187 188#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 189 190#define SLIST_REMOVE(head, elm, type, field) do { \ 191 if (SLIST_FIRST((head)) == (elm)) { \ 192 SLIST_REMOVE_HEAD((head), field); \ 193 } \ 194 else { \ 195 struct type *curelm = SLIST_FIRST((head)); \ 196 while (SLIST_NEXT(curelm, field) != (elm)) \ 197 curelm = SLIST_NEXT(curelm, field); \ 198 SLIST_NEXT(curelm, field) = \ 199 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \ 200 } \ 201} while (0) 202 203#define SLIST_REMOVE_HEAD(head, field) do { \ 204 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 205} while (0) 206 207/* 208 * Singly-linked Tail queue declarations. 209 */ 210#define STAILQ_HEAD(name, type) \ 211struct name { \ 212 struct type *stqh_first;/* first element */ \ 213 struct type **stqh_last;/* addr of last next element */ \ 214} 215 216#define STAILQ_HEAD_INITIALIZER(head) \ 217 { NULL, &(head).stqh_first } 218 219#define STAILQ_ENTRY(type) \ 220struct { \ 221 struct type *stqe_next; /* next element */ \ 222} 223 224/* 225 * Singly-linked Tail queue functions. 226 */ 227#define STAILQ_CONCAT(head1, head2) do { \ 228 if (!STAILQ_EMPTY((head2))) { \ 229 *(head1)->stqh_last = (head2)->stqh_first; \ 230 (head1)->stqh_last = (head2)->stqh_last; \ 231 STAILQ_INIT((head2)); \ 232 } \ 233} while (0) 234 235#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 236 237#define STAILQ_FIRST(head) ((head)->stqh_first) 238 239#define STAILQ_FOREACH(var, head, field) \ 240 for((var) = STAILQ_FIRST((head)); \ 241 (var); \ 242 (var) = STAILQ_NEXT((var), field)) 243 244 245#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \ 246 for ((var) = STAILQ_FIRST((head)); \ 247 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 248 (var) = (tvar)) 249 250#define STAILQ_INIT(head) do { \ 251 STAILQ_FIRST((head)) = NULL; \ 252 (head)->stqh_last = &STAILQ_FIRST((head)); \ 253} while (0) 254 255#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 256 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 257 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 258 STAILQ_NEXT((tqelm), field) = (elm); \ 259} while (0) 260 261#define STAILQ_INSERT_HEAD(head, elm, field) do { \ 262 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 263 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 264 STAILQ_FIRST((head)) = (elm); \ 265} while (0) 266 267#define STAILQ_INSERT_TAIL(head, elm, field) do { \ 268 STAILQ_NEXT((elm), field) = NULL; \ 269 *(head)->stqh_last = (elm); \ 270 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 271} while (0) 272 273#define STAILQ_LAST(head, type, field) \ 274 (STAILQ_EMPTY((head)) ? \ 275 NULL : \ 276 ((struct type *) \ 277 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 278 279#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 280 281#define STAILQ_REMOVE(head, elm, type, field) do { \ 282 if (STAILQ_FIRST((head)) == (elm)) { \ 283 STAILQ_REMOVE_HEAD((head), field); \ 284 } \ 285 else { \ 286 struct type *curelm = STAILQ_FIRST((head)); \ 287 while (STAILQ_NEXT(curelm, field) != (elm)) \ 288 curelm = STAILQ_NEXT(curelm, field); \ 289 if ((STAILQ_NEXT(curelm, field) = \ 290 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\ 291 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\ 292 } \ 293} while (0) 294 295#define STAILQ_REMOVE_HEAD(head, field) do { \ 296 if ((STAILQ_FIRST((head)) = \ 297 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 298 (head)->stqh_last = &STAILQ_FIRST((head)); \ 299} while (0) 300 301#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 302 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \ 303 (head)->stqh_last = &STAILQ_FIRST((head)); \ 304} while (0) 305 306/* 307 * List declarations. 308 */ 309#define LIST_HEAD(name, type) \ 310struct name { \ 311 struct type *lh_first; /* first element */ \ 312} 313 314#define LIST_HEAD_INITIALIZER(head) \ 315 { NULL } 316 317#define LIST_ENTRY(type) \ 318struct { \ 319 struct type *le_next; /* next element */ \ 320 struct type **le_prev; /* address of previous next element */ \ 321} 322 323/* 324 * List functions. 325 */ 326 327#define LIST_EMPTY(head) ((head)->lh_first == NULL) 328 329#define LIST_FIRST(head) ((head)->lh_first) 330 331#define LIST_FOREACH(var, head, field) \ 332 for ((var) = LIST_FIRST((head)); \ 333 (var); \ 334 (var) = LIST_NEXT((var), field)) 335 336#define LIST_FOREACH_SAFE(var, head, field, tvar) \ 337 for ((var) = LIST_FIRST((head)); \ 338 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 339 (var) = (tvar)) 340 341#define LIST_INIT(head) do { \ 342 LIST_FIRST((head)) = NULL; \ 343} while (0) 344 345#define LIST_INSERT_AFTER(listelm, elm, field) do { \ 346 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 347 LIST_NEXT((listelm), field)->field.le_prev = \ 348 &LIST_NEXT((elm), field); \ 349 LIST_NEXT((listelm), field) = (elm); \ 350 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 351} while (0) 352 353#define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 354 (elm)->field.le_prev = (listelm)->field.le_prev; \ 355 LIST_NEXT((elm), field) = (listelm); \ 356 *(listelm)->field.le_prev = (elm); \ 357 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 358} while (0) 359 360#define LIST_INSERT_HEAD(head, elm, field) do { \ 361 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 362 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 363 LIST_FIRST((head)) = (elm); \ 364 (elm)->field.le_prev = &LIST_FIRST((head)); \ 365} while (0) 366 367#define LIST_NEXT(elm, field) ((elm)->field.le_next) 368 369#define LIST_REMOVE(elm, field) do { \ 370 if (LIST_NEXT((elm), field) != NULL) \ 371 LIST_NEXT((elm), field)->field.le_prev = \ 372 (elm)->field.le_prev; \ 373 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 374} while (0) 375 376/* 377 * Tail queue declarations. 378 */ 379#define TAILQ_HEAD(name, type) \ 380struct name { \ 381 struct type *tqh_first; /* first element */ \ 382 struct type **tqh_last; /* addr of last next element */ \ 383 TRACEBUF \ 384} 385 386#define TAILQ_HEAD_INITIALIZER(head) \ 387 { NULL, &(head).tqh_first } 388 389#define TAILQ_ENTRY(type) \ 390struct { \ 391 struct type *tqe_next; /* next element */ \ 392 struct type **tqe_prev; /* address of previous next element */ \ 393 TRACEBUF \ 394} 395 396/* 397 * Tail queue functions. 398 */ 399#define TAILQ_CONCAT(head1, head2, field) do { \ 400 if (!TAILQ_EMPTY(head2)) { \ 401 *(head1)->tqh_last = (head2)->tqh_first; \ 402 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 403 (head1)->tqh_last = (head2)->tqh_last; \ 404 TAILQ_INIT((head2)); \ 405 QMD_TRACE_HEAD(head1); \ 406 QMD_TRACE_HEAD(head2); \ 407 } \ 408} while (0) 409 410#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 411 412#define TAILQ_FIRST(head) ((head)->tqh_first) 413 414#define TAILQ_FOREACH(var, head, field) \ 415 for ((var) = TAILQ_FIRST((head)); \ 416 (var); \ 417 (var) = TAILQ_NEXT((var), field)) 418 419#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 420 for ((var) = TAILQ_FIRST((head)); \ 421 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 422 (var) = (tvar)) 423 424#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 425 for ((var) = TAILQ_LAST((head), headname); \ 426 (var); \ 427 (var) = TAILQ_PREV((var), headname, field)) 428 429#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 430 for ((var) = TAILQ_LAST((head), headname); \ 431 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 432 (var) = (tvar)) 433 434#define TAILQ_INIT(head) do { \ 435 TAILQ_FIRST((head)) = NULL; \ 436 (head)->tqh_last = &TAILQ_FIRST((head)); \ 437 QMD_TRACE_HEAD(head); \ 438} while (0) 439 440#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 441 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 442 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 443 &TAILQ_NEXT((elm), field); \ 444 else { \ 445 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 446 QMD_TRACE_HEAD(head); \ 447 } \ 448 TAILQ_NEXT((listelm), field) = (elm); \ 449 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 450 QMD_TRACE_ELEM(&(elm)->field); \ 451 QMD_TRACE_ELEM(&listelm->field); \ 452} while (0) 453 454#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 455 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 456 TAILQ_NEXT((elm), field) = (listelm); \ 457 *(listelm)->field.tqe_prev = (elm); \ 458 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 459 QMD_TRACE_ELEM(&(elm)->field); \ 460 QMD_TRACE_ELEM(&listelm->field); \ 461} while (0) 462 463#define TAILQ_INSERT_HEAD(head, elm, field) do { \ 464 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 465 TAILQ_FIRST((head))->field.tqe_prev = \ 466 &TAILQ_NEXT((elm), field); \ 467 else \ 468 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 469 TAILQ_FIRST((head)) = (elm); \ 470 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 471 QMD_TRACE_HEAD(head); \ 472 QMD_TRACE_ELEM(&(elm)->field); \ 473} while (0) 474 475#define TAILQ_INSERT_TAIL(head, elm, field) do { \ 476 TAILQ_NEXT((elm), field) = NULL; \ 477 (elm)->field.tqe_prev = (head)->tqh_last; \ 478 *(head)->tqh_last = (elm); \ 479 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 480 QMD_TRACE_HEAD(head); \ 481 QMD_TRACE_ELEM(&(elm)->field); \ 482} while (0) 483 484#define TAILQ_LAST(head, headname) \ 485 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 486 487#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 488 489#define TAILQ_PREV(elm, headname, field) \ 490 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 491 492#define TAILQ_REMOVE(head, elm, field) do { \ 493 if ((TAILQ_NEXT((elm), field)) != NULL) \ 494 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 495 (elm)->field.tqe_prev; \ 496 else { \ 497 (head)->tqh_last = (elm)->field.tqe_prev; \ 498 QMD_TRACE_HEAD(head); \ 499 } \ 500 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 501 TRASHIT((elm)->field.tqe_next); \ 502 TRASHIT((elm)->field.tqe_prev); \ 503 QMD_TRACE_ELEM(&(elm)->field); \ 504} while (0) 505 506 507#ifdef _KERNEL 508 509/* 510 * XXX insque() and remque() are an old way of handling certain queues. 511 * They bogusly assumes that all queue heads look alike. 512 */ 513 514struct quehead { 515 struct quehead *qh_link; 516 struct quehead *qh_rlink; 517}; 518 519#ifdef __CC_SUPPORTS___INLINE 520 521static __inline void 522insque(void *a, void *b) 523{ 524 struct quehead *element = (struct quehead *)a, 525 *head = (struct quehead *)b; 526 527 element->qh_link = head->qh_link; 528 element->qh_rlink = head; 529 head->qh_link = element; 530 element->qh_link->qh_rlink = element; 531} 532 533static __inline void 534remque(void *a) 535{ 536 struct quehead *element = (struct quehead *)a; 537 538 element->qh_link->qh_rlink = element->qh_rlink; 539 element->qh_rlink->qh_link = element->qh_link; 540 element->qh_rlink = 0; 541} 542 543#else /* !__CC_SUPPORTS___INLINE */ 544 545void insque(void *a, void *b); 546void remque(void *a); 547 548#endif /* __CC_SUPPORTS___INLINE */ 549 550#endif /* _KERNEL */ 551 552#endif /* !_SYS_QUEUE_H_ */ 553