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: src/sys/sys/queue.h,v 1.32.2.7 2002/04/17 14:21:02 des Exp $ 35 * $DragonFly: src/sys/sys/queue.h,v 1.8 2007/01/08 12:15:27 swildner Exp $ 36 */ 37 38 #ifndef _SYS_QUEUE_H_ 39 #define _SYS_QUEUE_H_ 40 41 #ifndef _MACHINE_STDINT_H_ 42 #include <machine/stdint.h> /* for __offsetof */ 43 #endif 44 45 /* 46 * This file defines five types of data structures: singly-linked lists, 47 * singly-linked tail queues, lists, tail queues, and circular queues. 48 * 49 * A singly-linked list is headed by a single forward pointer. The elements 50 * are singly linked for minimum space and pointer manipulation overhead at 51 * the expense of O(n) removal for arbitrary elements. New elements can be 52 * added to the list after an existing element or at the head of the list. 53 * Elements being removed from the head of the list should use the explicit 54 * macro for this purpose for optimum efficiency. A singly-linked list may 55 * only be traversed in the forward direction. Singly-linked lists are ideal 56 * for applications with large datasets and few or no removals or for 57 * implementing a LIFO queue. 58 * 59 * A singly-linked tail queue is headed by a pair of pointers, one to the 60 * head of the list and the other to the tail of the list. The elements are 61 * singly linked for minimum space and pointer manipulation overhead at the 62 * expense of O(n) removal for arbitrary elements. New elements can be added 63 * to the list after an existing element, at the head of the list, or at the 64 * end of the list. Elements being removed from the head of the tail queue 65 * should use the explicit macro for this purpose for optimum efficiency. 66 * A singly-linked tail queue may only be traversed in the forward direction. 67 * Singly-linked tail queues are ideal for applications with large datasets 68 * and few or no removals or for implementing a FIFO queue. 69 * 70 * A list is headed by a single forward pointer (or an array of forward 71 * pointers for a hash table header). The elements are doubly linked 72 * 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 74 * or after an existing element or at the head of the list. A list 75 * may only be traversed in the forward direction. 76 * 77 * A tail queue is headed by a pair of pointers, one to the head of the 78 * list and the other to the tail of the list. The elements are doubly 79 * linked so that an arbitrary element can be removed without a need to 80 * traverse the list. New elements can be added to the list before or 81 * after an existing element, at the head of the list, or at the end of 82 * the list. A tail queue may be traversed in either direction. 83 * 84 * A circle queue is headed by a pair of pointers, one to the head of the 85 * list and the other to the tail of the list. The elements are doubly 86 * linked so that an arbitrary element can be removed without a need to 87 * traverse the list. New elements can be added to the list before or after 88 * an existing element, at the head of the list, or at the end of the list. 89 * A circle queue may be traversed in either direction, but has a more 90 * complex end of list detection. 91 * 92 * For details on the use of these macros, see the queue(3) manual page. 93 * 94 * 95 * SLIST LIST STAILQ TAILQ CIRCLEQ 96 * _HEAD + + + + + 97 * _HEAD_INITIALIZER + + + + + 98 * _ENTRY + + + + + 99 * _INIT + + + + + 100 * _EMPTY + + + + + 101 * _FIRST + + + + + 102 * _NEXT + + + + + 103 * _PREV - - - + + 104 * _LAST - - + + + 105 * _FOREACH + + + + + 106 * _FOREACH_MUTABLE - + - + - 107 * _FOREACH_REVERSE - - - + + 108 * _INSERT_HEAD + + + + + 109 * _INSERT_BEFORE - + - + + 110 * _INSERT_AFTER + + + + + 111 * _INSERT_TAIL - - + + + 112 * _CONCAT - - + + - 113 * _REMOVE_HEAD + - + - - 114 * _REMOVE + + + + + 115 * 116 */ 117 118 /* 119 * Singly-linked List declarations. 120 */ 121 #define SLIST_HEAD(name, type) \ 122 struct name { \ 123 struct type *slh_first; /* first element */ \ 124 } 125 126 #define SLIST_HEAD_INITIALIZER(head) \ 127 { NULL } 128 129 #define SLIST_ENTRY(type) \ 130 struct { \ 131 struct type *sle_next; /* next element */ \ 132 } 133 134 #define SLIST_ENTRY_INITIALIZER { NULL } 135 136 /* 137 * Singly-linked List functions. 138 */ 139 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 140 141 #define SLIST_FIRST(head) ((head)->slh_first) 142 143 #define SLIST_FOREACH(var, head, field) \ 144 for ((var) = SLIST_FIRST((head)); \ 145 (var); \ 146 (var) = SLIST_NEXT((var), field)) 147 148 #define SLIST_INIT(head) do { \ 149 SLIST_FIRST((head)) = NULL; \ 150 } while (0) 151 152 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 153 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 154 SLIST_NEXT((slistelm), field) = (elm); \ 155 } while (0) 156 157 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 158 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 159 SLIST_FIRST((head)) = (elm); \ 160 } while (0) 161 162 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 163 164 #define SLIST_REMOVE(head, elm, type, field) do { \ 165 if (SLIST_FIRST((head)) == (elm)) { \ 166 SLIST_REMOVE_HEAD((head), field); \ 167 } \ 168 else { \ 169 struct type *curelm = SLIST_FIRST((head)); \ 170 while (SLIST_NEXT(curelm, field) != (elm)) \ 171 curelm = SLIST_NEXT(curelm, field); \ 172 SLIST_NEXT(curelm, field) = \ 173 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \ 174 } \ 175 } while (0) 176 177 #define SLIST_REMOVE_HEAD(head, field) do { \ 178 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 179 } while (0) 180 181 /* 182 * Singly-linked Tail queue declarations. 183 */ 184 #define STAILQ_HEAD(name, type) \ 185 struct name { \ 186 struct type *stqh_first;/* first element */ \ 187 struct type **stqh_last;/* addr of last next element */ \ 188 } 189 190 #define STAILQ_HEAD_INITIALIZER(head) \ 191 { NULL, &(head).stqh_first } 192 193 #define STAILQ_ENTRY(type) \ 194 struct { \ 195 struct type *stqe_next; /* next element */ \ 196 } 197 198 /* 199 * Singly-linked Tail queue functions. 200 */ 201 #define STAILQ_CONCAT(head1, head2) do { \ 202 if (!STAILQ_EMPTY((head2))) { \ 203 *(head1)->stqh_last = (head2)->stqh_first; \ 204 (head1)->stqh_last = (head2)->stqh_last; \ 205 STAILQ_INIT((head2)); \ 206 } \ 207 } while (0) 208 209 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 210 211 #define STAILQ_FIRST(head) ((head)->stqh_first) 212 213 #define STAILQ_FOREACH(var, head, field) \ 214 for((var) = STAILQ_FIRST((head)); \ 215 (var); \ 216 (var) = STAILQ_NEXT((var), field)) 217 218 #define STAILQ_INIT(head) do { \ 219 STAILQ_FIRST((head)) = NULL; \ 220 (head)->stqh_last = &STAILQ_FIRST((head)); \ 221 } while (0) 222 223 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 224 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 225 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 226 STAILQ_NEXT((tqelm), field) = (elm); \ 227 } while (0) 228 229 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 230 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 231 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 232 STAILQ_FIRST((head)) = (elm); \ 233 } while (0) 234 235 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 236 STAILQ_NEXT((elm), field) = NULL; \ 237 *(head)->stqh_last = (elm); \ 238 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 239 } while (0) 240 241 #define STAILQ_LAST(head, type, field) \ 242 (STAILQ_EMPTY(head) ? \ 243 NULL : \ 244 ((struct type *) \ 245 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 246 247 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 248 249 #define STAILQ_REMOVE(head, elm, type, field) do { \ 250 if (STAILQ_FIRST((head)) == (elm)) { \ 251 STAILQ_REMOVE_HEAD(head, field); \ 252 } \ 253 else { \ 254 struct type *curelm = STAILQ_FIRST((head)); \ 255 while (STAILQ_NEXT(curelm, field) != (elm)) \ 256 curelm = STAILQ_NEXT(curelm, field); \ 257 if ((STAILQ_NEXT(curelm, field) = \ 258 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\ 259 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\ 260 } \ 261 } while (0) 262 263 #define STAILQ_REMOVE_HEAD(head, field) do { \ 264 if ((STAILQ_FIRST((head)) = \ 265 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 266 (head)->stqh_last = &STAILQ_FIRST((head)); \ 267 } while (0) 268 269 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 270 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \ 271 (head)->stqh_last = &STAILQ_FIRST((head)); \ 272 } while (0) 273 274 /* 275 * List declarations. 276 */ 277 #define LIST_HEAD(name, type) \ 278 struct name { \ 279 struct type *lh_first; /* first element */ \ 280 } 281 282 #define LIST_HEAD_INITIALIZER(head) \ 283 { NULL } 284 285 #define LIST_ENTRY(type) \ 286 struct { \ 287 struct type *le_next; /* next element */ \ 288 struct type **le_prev; /* address of previous next element */ \ 289 } 290 291 /* 292 * List functions. 293 */ 294 295 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 296 297 #define LIST_FIRST(head) ((head)->lh_first) 298 299 #define LIST_FOREACH(var, head, field) \ 300 for ((var) = LIST_FIRST((head)); \ 301 (var); \ 302 (var) = LIST_NEXT((var), field)) 303 304 #define LIST_FOREACH_MUTABLE(var, head, field, nvar) \ 305 for ((var) = LIST_FIRST((head)); \ 306 (var) && ((nvar) = LIST_NEXT((var), field), (var)); \ 307 (var) = (nvar)) 308 309 #define LIST_INIT(head) do { \ 310 LIST_FIRST((head)) = NULL; \ 311 } while (0) 312 313 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 314 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 315 LIST_NEXT((listelm), field)->field.le_prev = \ 316 &LIST_NEXT((elm), field); \ 317 LIST_NEXT((listelm), field) = (elm); \ 318 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 319 } while (0) 320 321 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 322 (elm)->field.le_prev = (listelm)->field.le_prev; \ 323 LIST_NEXT((elm), field) = (listelm); \ 324 *(listelm)->field.le_prev = (elm); \ 325 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 326 } while (0) 327 328 #define LIST_INSERT_HEAD(head, elm, field) do { \ 329 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 330 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 331 LIST_FIRST((head)) = (elm); \ 332 (elm)->field.le_prev = &LIST_FIRST((head)); \ 333 } while (0) 334 335 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 336 337 #define LIST_REMOVE(elm, field) do { \ 338 if (LIST_NEXT((elm), field) != NULL) \ 339 LIST_NEXT((elm), field)->field.le_prev = \ 340 (elm)->field.le_prev; \ 341 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 342 } while (0) 343 344 /* 345 * Tail queue declarations. 346 */ 347 #define TAILQ_HEAD(name, type) \ 348 struct name { \ 349 struct type *tqh_first; /* first element */ \ 350 struct type **tqh_last; /* addr of last next element */ \ 351 } 352 353 #define TAILQ_HEAD_INITIALIZER(head) \ 354 { NULL, &(head).tqh_first } 355 356 #define TAILQ_ENTRY(type) \ 357 struct { \ 358 struct type *tqe_next; /* next element */ \ 359 struct type **tqe_prev; /* address of previous next element */ \ 360 } 361 362 /* 363 * Tail queue functions. 364 */ 365 #define TAILQ_CONCAT(head1, head2, field) do { \ 366 if (!TAILQ_EMPTY(head2)) { \ 367 *(head1)->tqh_last = (head2)->tqh_first; \ 368 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 369 (head1)->tqh_last = (head2)->tqh_last; \ 370 TAILQ_INIT((head2)); \ 371 } \ 372 } while (0) 373 374 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 375 376 #define TAILQ_FIRST(head) ((head)->tqh_first) 377 378 #define TAILQ_FOREACH(var, head, field) \ 379 for ((var) = TAILQ_FIRST((head)); \ 380 (var); \ 381 (var) = TAILQ_NEXT((var), field)) 382 383 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 384 for ((var) = TAILQ_LAST((head), headname); \ 385 (var); \ 386 (var) = TAILQ_PREV((var), headname, field)) 387 388 #define TAILQ_FOREACH_MUTABLE(var, head, field, nvar) \ 389 for ((var) = TAILQ_FIRST((head)); \ 390 (var) && ((nvar) = TAILQ_NEXT((var), field), (var)); \ 391 (var) = (nvar)) 392 393 #define TAILQ_INIT(head) do { \ 394 TAILQ_FIRST((head)) = NULL; \ 395 (head)->tqh_last = &TAILQ_FIRST((head)); \ 396 } while (0) 397 398 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 399 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 400 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 401 &TAILQ_NEXT((elm), field); \ 402 else \ 403 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 404 TAILQ_NEXT((listelm), field) = (elm); \ 405 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 406 } while (0) 407 408 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 409 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 410 TAILQ_NEXT((elm), field) = (listelm); \ 411 *(listelm)->field.tqe_prev = (elm); \ 412 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 413 } while (0) 414 415 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 416 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 417 TAILQ_FIRST((head))->field.tqe_prev = \ 418 &TAILQ_NEXT((elm), field); \ 419 else \ 420 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 421 TAILQ_FIRST((head)) = (elm); \ 422 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 423 } while (0) 424 425 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 426 TAILQ_NEXT((elm), field) = NULL; \ 427 (elm)->field.tqe_prev = (head)->tqh_last; \ 428 *(head)->tqh_last = (elm); \ 429 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 430 } while (0) 431 432 #define TAILQ_LAST(head, headname) \ 433 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 434 435 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 436 437 #define TAILQ_PREV(elm, headname, field) \ 438 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 439 440 #define TAILQ_REMOVE(head, elm, field) do { \ 441 if ((TAILQ_NEXT((elm), field)) != NULL) \ 442 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 443 (elm)->field.tqe_prev; \ 444 else \ 445 (head)->tqh_last = (elm)->field.tqe_prev; \ 446 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 447 } while (0) 448 449 /* 450 * Circular queue declarations. 451 */ 452 #define CIRCLEQ_HEAD(name, type) \ 453 struct name { \ 454 struct type *cqh_first; /* first element */ \ 455 struct type *cqh_last; /* last element */ \ 456 } 457 458 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 459 { (void *)&(head), (void *)&(head) } 460 461 #define CIRCLEQ_ENTRY(type) \ 462 struct { \ 463 struct type *cqe_next; /* next element */ \ 464 struct type *cqe_prev; /* previous element */ \ 465 } 466 467 /* 468 * Circular queue functions. 469 */ 470 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 471 472 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 473 474 #define CIRCLEQ_FOREACH(var, head, field) \ 475 for ((var) = CIRCLEQ_FIRST((head)); \ 476 (var) != (void *)(head) || ((var) = NULL); \ 477 (var) = CIRCLEQ_NEXT((var), field)) 478 479 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 480 for ((var) = CIRCLEQ_LAST((head)); \ 481 (var) != (void *)(head) || ((var) = NULL); \ 482 (var) = CIRCLEQ_PREV((var), field)) 483 484 #define CIRCLEQ_INIT(head) do { \ 485 CIRCLEQ_FIRST((head)) = (void *)(head); \ 486 CIRCLEQ_LAST((head)) = (void *)(head); \ 487 } while (0) 488 489 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 490 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \ 491 CIRCLEQ_PREV((elm), field) = (listelm); \ 492 if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \ 493 CIRCLEQ_LAST((head)) = (elm); \ 494 else \ 495 CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\ 496 CIRCLEQ_NEXT((listelm), field) = (elm); \ 497 } while (0) 498 499 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 500 CIRCLEQ_NEXT((elm), field) = (listelm); \ 501 CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \ 502 if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \ 503 CIRCLEQ_FIRST((head)) = (elm); \ 504 else \ 505 CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\ 506 CIRCLEQ_PREV((listelm), field) = (elm); \ 507 } while (0) 508 509 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 510 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \ 511 CIRCLEQ_PREV((elm), field) = (void *)(head); \ 512 if (CIRCLEQ_LAST((head)) == (void *)(head)) \ 513 CIRCLEQ_LAST((head)) = (elm); \ 514 else \ 515 CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \ 516 CIRCLEQ_FIRST((head)) = (elm); \ 517 } while (0) 518 519 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 520 CIRCLEQ_NEXT((elm), field) = (void *)(head); \ 521 CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \ 522 if (CIRCLEQ_FIRST((head)) == (void *)(head)) \ 523 CIRCLEQ_FIRST((head)) = (elm); \ 524 else \ 525 CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \ 526 CIRCLEQ_LAST((head)) = (elm); \ 527 } while (0) 528 529 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 530 531 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) 532 533 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) 534 535 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 536 if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \ 537 CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \ 538 else \ 539 CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \ 540 CIRCLEQ_PREV((elm), field); \ 541 if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \ 542 CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \ 543 else \ 544 CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \ 545 CIRCLEQ_NEXT((elm), field); \ 546 } while (0) 547 548 #ifdef _KERNEL 549 550 /* 551 * XXX insque() and remque() are an old way of handling certain queues. 552 * They bogusly assumes that all queue heads look alike. 553 */ 554 555 struct quehead { 556 struct quehead *qh_link; 557 struct quehead *qh_rlink; 558 }; 559 560 #ifdef __GNUC__ 561 562 static __inline void 563 insque(void *a, void *b) 564 { 565 struct quehead *element = (struct quehead *)a, 566 *head = (struct quehead *)b; 567 568 element->qh_link = head->qh_link; 569 element->qh_rlink = head; 570 head->qh_link = element; 571 element->qh_link->qh_rlink = element; 572 } 573 574 static __inline void 575 remque(void *a) 576 { 577 struct quehead *element = (struct quehead *)a; 578 579 element->qh_link->qh_rlink = element->qh_rlink; 580 element->qh_rlink->qh_link = element->qh_link; 581 element->qh_rlink = 0; 582 } 583 584 #else /* !__GNUC__ */ 585 586 void insque (void *a, void *b); 587 void remque (void *a); 588 589 #endif /* __GNUC__ */ 590 591 #endif /* _KERNEL */ 592 593 #endif /* !_SYS_QUEUE_H_ */ 594