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 33 #ifndef _SYS_QUEUE_H_ 34 #define _SYS_QUEUE_H_ 35 36 #include <sys/cdefs.h> 37 38 /* 39 * This file defines four types of data structures: singly-linked lists, 40 * singly-linked tail queues, lists and tail queues. 41 * 42 * A singly-linked list is headed by a single forward pointer. The elements 43 * are singly linked for minimum space and pointer manipulation overhead at 44 * the expense of O(n) removal for arbitrary elements. New elements can be 45 * added to the list after an existing element or at the head of the list. 46 * Elements being removed from the head of the list should use the explicit 47 * macro for this purpose for optimum efficiency. A singly-linked list may 48 * only be traversed in the forward direction. Singly-linked lists are ideal 49 * for applications with large datasets and few or no removals or for 50 * implementing a LIFO queue. 51 * 52 * A singly-linked tail queue is headed by a pair of pointers, one to the 53 * head of the list and the other to the tail of the list. The elements are 54 * singly linked for minimum space and pointer manipulation overhead at the 55 * expense of O(n) removal for arbitrary elements. New elements can be added 56 * to the list after an existing element, at the head of the list, or at the 57 * end of the list. Elements being removed from the head of the tail queue 58 * should use the explicit macro for this purpose for optimum efficiency. 59 * A singly-linked tail queue may only be traversed in the forward direction. 60 * Singly-linked tail queues are ideal for applications with large datasets 61 * and few or no removals or for implementing a FIFO queue. 62 * 63 * A list is headed by a single forward pointer (or an array of forward 64 * pointers for a hash table header). The elements are doubly linked 65 * so that an arbitrary element can be removed without a need to 66 * traverse the list. New elements can be added to the list before 67 * or after an existing element or at the head of the list. A list 68 * may only be traversed in the forward direction. 69 * 70 * A tail queue is headed by a pair of pointers, one to the head of the 71 * list and the other to the tail of the list. The elements are doubly 72 * linked so that an arbitrary element can be removed without a need to 73 * traverse the list. New elements can be added to the list before or 74 * after an existing element, at the head of the list, or at the end of 75 * the list. A tail queue may be traversed in either direction. 76 * 77 * For details on the use of these macros, see the queue(3) manual page. 78 * 79 * 80 * SLIST LIST STAILQ TAILQ 81 * _HEAD + + + + 82 * _HEAD_INITIALIZER + + + + 83 * _ENTRY + + + + 84 * _INIT + + + + 85 * _EMPTY + + + + 86 * _FIRST + + + + 87 * _NEXT + + + + 88 * _PREV - - - + 89 * _LAST - - + + 90 * _FOREACH + + + + 91 * _FOREACH_SAFE + + + + 92 * _FOREACH_REVERSE - - - + 93 * _FOREACH_REVERSE_SAFE - - - + 94 * _INSERT_HEAD + + + + 95 * _INSERT_BEFORE - + - + 96 * _INSERT_AFTER + + + + 97 * _INSERT_TAIL - - + + 98 * _CONCAT - - + + 99 * _REMOVE_HEAD + - + - 100 * _REMOVE + + + + 101 * 102 */ 103 #define QUEUE_MACRO_DEBUG 0 104 #if QUEUE_MACRO_DEBUG 105 /* Store the last 2 places the queue element or head was altered */ 106 struct qm_trace { 107 char * lastfile; 108 int lastline; 109 char * prevfile; 110 int prevline; 111 }; 112 113 #define TRACEBUF struct qm_trace trace; 114 #define TRASHIT(x) do {(x) = (void *)-1;} while (0) 115 116 #define QMD_TRACE_HEAD(head) do { \ 117 (head)->trace.prevline = (head)->trace.lastline; \ 118 (head)->trace.prevfile = (head)->trace.lastfile; \ 119 (head)->trace.lastline = __LINE__; \ 120 (head)->trace.lastfile = __FILE__; \ 121 } while (0) 122 123 #define QMD_TRACE_ELEM(elem) do { \ 124 (elem)->trace.prevline = (elem)->trace.lastline; \ 125 (elem)->trace.prevfile = (elem)->trace.lastfile; \ 126 (elem)->trace.lastline = __LINE__; \ 127 (elem)->trace.lastfile = __FILE__; \ 128 } while (0) 129 130 #else 131 #define QMD_TRACE_ELEM(elem) 132 #define QMD_TRACE_HEAD(head) 133 #define TRACEBUF 134 #define TRASHIT(x) 135 #endif /* QUEUE_MACRO_DEBUG */ 136 137 /* 138 * Singly-linked List declarations. 139 */ 140 #define SLIST_HEAD(name, type) \ 141 struct name { \ 142 struct type *slh_first; /* first element */ \ 143 } 144 145 #define SLIST_HEAD_INITIALIZER(head) \ 146 { NULL } 147 148 #define SLIST_ENTRY(type) \ 149 struct { \ 150 struct type *sle_next; /* next element */ \ 151 } 152 153 /* 154 * Singly-linked List functions. 155 */ 156 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 157 158 #define SLIST_FIRST(head) ((head)->slh_first) 159 160 #define SLIST_FOREACH(var, head, field) \ 161 for ((var) = SLIST_FIRST((head)); \ 162 (var); \ 163 (var) = SLIST_NEXT((var), field)) 164 165 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 166 for ((var) = SLIST_FIRST((head)); \ 167 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 168 (var) = (tvar)) 169 170 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \ 171 for ((varp) = &SLIST_FIRST((head)); \ 172 ((var) = *(varp)) != NULL; \ 173 (varp) = &SLIST_NEXT((var), field)) 174 175 #define SLIST_INIT(head) do { \ 176 SLIST_FIRST((head)) = NULL; \ 177 } while (0) 178 179 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 180 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 181 SLIST_NEXT((slistelm), field) = (elm); \ 182 } while (0) 183 184 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 185 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 186 SLIST_FIRST((head)) = (elm); \ 187 } while (0) 188 189 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 190 191 #define SLIST_REMOVE(head, elm, type, field) do { \ 192 if (SLIST_FIRST((head)) == (elm)) { \ 193 SLIST_REMOVE_HEAD((head), field); \ 194 } \ 195 else { \ 196 struct type *curelm = SLIST_FIRST((head)); \ 197 while (SLIST_NEXT(curelm, field) != (elm)) \ 198 curelm = SLIST_NEXT(curelm, field); \ 199 SLIST_NEXT(curelm, field) = \ 200 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \ 201 } \ 202 } while (0) 203 204 #define SLIST_REMOVE_HEAD(head, field) do { \ 205 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 206 } while (0) 207 208 /* 209 * Singly-linked Tail queue declarations. 210 */ 211 #define STAILQ_HEAD(name, type) \ 212 struct name { \ 213 struct type *stqh_first;/* first element */ \ 214 struct type **stqh_last;/* addr of last next element */ \ 215 } 216 217 #define STAILQ_HEAD_INITIALIZER(head) \ 218 { NULL, &(head).stqh_first } 219 220 #define STAILQ_ENTRY(type) \ 221 struct { \ 222 struct type *stqe_next; /* next element */ \ 223 } 224 225 /* 226 * Singly-linked Tail queue functions. 227 */ 228 #define STAILQ_CONCAT(head1, head2) do { \ 229 if (!STAILQ_EMPTY((head2))) { \ 230 *(head1)->stqh_last = (head2)->stqh_first; \ 231 (head1)->stqh_last = (head2)->stqh_last; \ 232 STAILQ_INIT((head2)); \ 233 } \ 234 } while (0) 235 236 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 237 238 #define STAILQ_FIRST(head) ((head)->stqh_first) 239 240 #define STAILQ_FOREACH(var, head, field) \ 241 for((var) = STAILQ_FIRST((head)); \ 242 (var); \ 243 (var) = STAILQ_NEXT((var), field)) 244 245 246 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \ 247 for ((var) = STAILQ_FIRST((head)); \ 248 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 249 (var) = (tvar)) 250 251 #define STAILQ_INIT(head) do { \ 252 STAILQ_FIRST((head)) = NULL; \ 253 (head)->stqh_last = &STAILQ_FIRST((head)); \ 254 } while (0) 255 256 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 257 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 258 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 259 STAILQ_NEXT((tqelm), field) = (elm); \ 260 } while (0) 261 262 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 263 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 264 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 265 STAILQ_FIRST((head)) = (elm); \ 266 } while (0) 267 268 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 269 STAILQ_NEXT((elm), field) = NULL; \ 270 *(head)->stqh_last = (elm); \ 271 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 272 } while (0) 273 274 #define STAILQ_LAST(head, type, field) \ 275 (STAILQ_EMPTY((head)) ? \ 276 NULL : \ 277 ((struct type *) \ 278 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 279 280 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 281 282 #define STAILQ_REMOVE(head, elm, type, field) do { \ 283 if (STAILQ_FIRST((head)) == (elm)) { \ 284 STAILQ_REMOVE_HEAD((head), field); \ 285 } \ 286 else { \ 287 struct type *curelm = STAILQ_FIRST((head)); \ 288 while (STAILQ_NEXT(curelm, field) != (elm)) \ 289 curelm = STAILQ_NEXT(curelm, field); \ 290 if ((STAILQ_NEXT(curelm, field) = \ 291 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\ 292 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\ 293 } \ 294 } while (0) 295 296 #define STAILQ_REMOVE_HEAD(head, field) do { \ 297 if ((STAILQ_FIRST((head)) = \ 298 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 299 (head)->stqh_last = &STAILQ_FIRST((head)); \ 300 } while (0) 301 302 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 303 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \ 304 (head)->stqh_last = &STAILQ_FIRST((head)); \ 305 } while (0) 306 307 /* 308 * List declarations. 309 */ 310 #define LIST_HEAD(name, type) \ 311 struct name { \ 312 struct type *lh_first; /* first element */ \ 313 } 314 315 #define LIST_HEAD_INITIALIZER(head) \ 316 { NULL } 317 318 #define LIST_ENTRY(type) \ 319 struct { \ 320 struct type *le_next; /* next element */ \ 321 struct type **le_prev; /* address of previous next element */ \ 322 } 323 324 /* 325 * List functions. 326 */ 327 328 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 329 330 #define LIST_FIRST(head) ((head)->lh_first) 331 332 #define LIST_FOREACH(var, head, field) \ 333 for ((var) = LIST_FIRST((head)); \ 334 (var); \ 335 (var) = LIST_NEXT((var), field)) 336 337 #define LIST_FOREACH_SAFE(var, head, field, tvar) \ 338 for ((var) = LIST_FIRST((head)); \ 339 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 340 (var) = (tvar)) 341 342 #define LIST_INIT(head) do { \ 343 LIST_FIRST((head)) = NULL; \ 344 } while (0) 345 346 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 347 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 348 LIST_NEXT((listelm), field)->field.le_prev = \ 349 &LIST_NEXT((elm), field); \ 350 LIST_NEXT((listelm), field) = (elm); \ 351 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 352 } while (0) 353 354 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 355 (elm)->field.le_prev = (listelm)->field.le_prev; \ 356 LIST_NEXT((elm), field) = (listelm); \ 357 *(listelm)->field.le_prev = (elm); \ 358 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 359 } while (0) 360 361 #define LIST_INSERT_HEAD(head, elm, field) do { \ 362 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 363 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 364 LIST_FIRST((head)) = (elm); \ 365 (elm)->field.le_prev = &LIST_FIRST((head)); \ 366 } while (0) 367 368 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 369 370 #define LIST_REMOVE(elm, field) do { \ 371 if (LIST_NEXT((elm), field) != NULL) \ 372 LIST_NEXT((elm), field)->field.le_prev = \ 373 (elm)->field.le_prev; \ 374 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 375 } while (0) 376 377 /* 378 * Tail queue declarations. 379 */ 380 #define TAILQ_HEAD(name, type) \ 381 struct name { \ 382 struct type *tqh_first; /* first element */ \ 383 struct type **tqh_last; /* addr of last next element */ \ 384 TRACEBUF \ 385 } 386 387 #define TAILQ_HEAD_INITIALIZER(head) \ 388 { NULL, &(head).tqh_first } 389 390 #define TAILQ_ENTRY(type) \ 391 struct { \ 392 struct type *tqe_next; /* next element */ \ 393 struct type **tqe_prev; /* address of previous next element */ \ 394 TRACEBUF \ 395 } 396 397 /* 398 * Tail queue functions. 399 */ 400 #define TAILQ_CONCAT(head1, head2, field) do { \ 401 if (!TAILQ_EMPTY(head2)) { \ 402 *(head1)->tqh_last = (head2)->tqh_first; \ 403 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 404 (head1)->tqh_last = (head2)->tqh_last; \ 405 TAILQ_INIT((head2)); \ 406 QMD_TRACE_HEAD(head1); \ 407 QMD_TRACE_HEAD(head2); \ 408 } \ 409 } while (0) 410 411 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 412 413 #define TAILQ_FIRST(head) ((head)->tqh_first) 414 415 #define TAILQ_FOREACH(var, head, field) \ 416 for ((var) = TAILQ_FIRST((head)); \ 417 (var); \ 418 (var) = TAILQ_NEXT((var), field)) 419 420 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 421 for ((var) = TAILQ_FIRST((head)); \ 422 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 423 (var) = (tvar)) 424 425 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 426 for ((var) = TAILQ_LAST((head), headname); \ 427 (var); \ 428 (var) = TAILQ_PREV((var), headname, field)) 429 430 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 431 for ((var) = TAILQ_LAST((head), headname); \ 432 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 433 (var) = (tvar)) 434 435 #define TAILQ_INIT(head) do { \ 436 TAILQ_FIRST((head)) = NULL; \ 437 (head)->tqh_last = &TAILQ_FIRST((head)); \ 438 QMD_TRACE_HEAD(head); \ 439 } while (0) 440 441 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 442 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 443 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 444 &TAILQ_NEXT((elm), field); \ 445 else { \ 446 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 447 QMD_TRACE_HEAD(head); \ 448 } \ 449 TAILQ_NEXT((listelm), field) = (elm); \ 450 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 451 QMD_TRACE_ELEM(&(elm)->field); \ 452 QMD_TRACE_ELEM(&listelm->field); \ 453 } while (0) 454 455 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 456 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 457 TAILQ_NEXT((elm), field) = (listelm); \ 458 *(listelm)->field.tqe_prev = (elm); \ 459 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 460 QMD_TRACE_ELEM(&(elm)->field); \ 461 QMD_TRACE_ELEM(&listelm->field); \ 462 } while (0) 463 464 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 465 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 466 TAILQ_FIRST((head))->field.tqe_prev = \ 467 &TAILQ_NEXT((elm), field); \ 468 else \ 469 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 470 TAILQ_FIRST((head)) = (elm); \ 471 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 472 QMD_TRACE_HEAD(head); \ 473 QMD_TRACE_ELEM(&(elm)->field); \ 474 } while (0) 475 476 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 477 TAILQ_NEXT((elm), field) = NULL; \ 478 (elm)->field.tqe_prev = (head)->tqh_last; \ 479 *(head)->tqh_last = (elm); \ 480 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 481 QMD_TRACE_HEAD(head); \ 482 QMD_TRACE_ELEM(&(elm)->field); \ 483 } while (0) 484 485 #define TAILQ_LAST(head, headname) \ 486 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 487 488 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 489 490 #define TAILQ_PREV(elm, headname, field) \ 491 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 492 493 #define TAILQ_REMOVE(head, elm, field) do { \ 494 if ((TAILQ_NEXT((elm), field)) != NULL) \ 495 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 496 (elm)->field.tqe_prev; \ 497 else { \ 498 (head)->tqh_last = (elm)->field.tqe_prev; \ 499 QMD_TRACE_HEAD(head); \ 500 } \ 501 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 502 TRASHIT((elm)->field.tqe_next); \ 503 TRASHIT((elm)->field.tqe_prev); \ 504 QMD_TRACE_ELEM(&(elm)->field); \ 505 } while (0) 506 507 508 #ifdef _KERNEL 509 510 /* 511 * XXX insque() and remque() are an old way of handling certain queues. 512 * They bogusly assumes that all queue heads look alike. 513 */ 514 515 struct quehead { 516 struct quehead *qh_link; 517 struct quehead *qh_rlink; 518 }; 519 520 #ifdef __CC_SUPPORTS___INLINE 521 522 static __inline void 523 insque(void *a, void *b) 524 { 525 struct quehead *element = (struct quehead *)a, 526 *head = (struct quehead *)b; 527 528 element->qh_link = head->qh_link; 529 element->qh_rlink = head; 530 head->qh_link = element; 531 element->qh_link->qh_rlink = element; 532 } 533 534 static __inline void 535 remque(void *a) 536 { 537 struct quehead *element = (struct quehead *)a; 538 539 element->qh_link->qh_rlink = element->qh_rlink; 540 element->qh_rlink->qh_link = element->qh_link; 541 element->qh_rlink = 0; 542 } 543 544 #else /* !__CC_SUPPORTS___INLINE */ 545 546 void insque(void *a, void *b); 547 void remque(void *a); 548 549 #endif /* __CC_SUPPORTS___INLINE */ 550 551 #endif /* _KERNEL */ 552 553 #endif /* !_SYS_QUEUE_H_ */ 554