queue.h (35044 bytes)
1 /* $OpenBSD: queue.h,v 1.38 2013/07/03 15:05:21 fgsch Exp $ */ 2 /* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */ 3 4 /* 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)queue.h 8.5 (Berkeley) 8/20/94 33 */ 34 35 #ifndef _SYS_QUEUE_H_ 36 #define _SYS_QUEUE_H_ 37 38 /* 39 * This file defines five types of data structures: singly-linked lists, 40 * lists, simple queues, tail queues, and circular queues. 41 * 42 * 43 * A singly-linked list is headed by a single forward pointer. The elements 44 * are singly linked for minimum space and pointer manipulation overhead at 45 * the expense of O(n) removal for arbitrary elements. New elements can be 46 * added to the list after an existing element or at the head of the list. 47 * Elements being removed from the head of the list should use the explicit 48 * macro for this purpose for optimum efficiency. A singly-linked list may 49 * only be traversed in the forward direction. Singly-linked lists are ideal 50 * for applications with large datasets and few or no removals or for 51 * implementing a LIFO queue. 52 * 53 * A list is headed by a single forward pointer (or an array of forward 54 * pointers for a hash table header). The elements are doubly linked 55 * so that an arbitrary element can be removed without a need to 56 * traverse the list. New elements can be added to the list before 57 * or after an existing element or at the head of the list. A list 58 * may only be traversed in the forward direction. 59 * 60 * A simple queue is headed by a pair of pointers, one the head of the 61 * list and the other to the tail of the list. The elements are singly 62 * linked to save space, so elements can only be removed from the 63 * head of the list. New elements can be added to the list before or after 64 * an existing element, at the head of the list, or at the end of the 65 * list. A simple queue may only be traversed in the forward direction. 66 * 67 * A tail queue is headed by a pair of pointers, one to the head of the 68 * list and the other to the tail of the list. The elements are doubly 69 * linked 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 or 71 * after an existing element, at the head of the list, or at the end of 72 * the list. A tail queue may be traversed in either direction. 73 * 74 * A circle 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 after 78 * an existing element, at the head of the list, or at the end of the list. 79 * A circle queue may be traversed in either direction, but has a more 80 * complex end of list detection. 81 * 82 * For details on the use of these macros, see the queue(3) manual page. 83 */ 84 85 #if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC)) 86 #define _Q_INVALIDATE(a) (a) = ((void *)-1) 87 #else 88 #define _Q_INVALIDATE(a) 89 #endif 90 91 /* 92 * Singly-linked List definitions. 93 */ 94 #define SLIST_HEAD(name, type) \ 95 struct name { \ 96 struct type *slh_first; /* first element */ \ 97 } 98 99 #define SLIST_HEAD_INITIALIZER(head) \ 100 { NULL } 101 102 #define SLIST_ENTRY(type) \ 103 struct { \ 104 struct type *sle_next; /* next element */ \ 105 } 106 107 /* 108 * Singly-linked List access methods. 109 */ 110 #define SLIST_FIRST(head) ((head)->slh_first) 111 #define SLIST_END(head) NULL 112 #define SLIST_EMPTY(head) (SLIST_FIRST(head) == SLIST_END(head)) 113 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 114 115 #define SLIST_FOREACH(var, head, field) \ 116 for ((var) = SLIST_FIRST(head); (var) != SLIST_END(head); \ 117 (var) = SLIST_NEXT(var, field)) 118 119 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 120 for ((var) = SLIST_FIRST(head); \ 121 (var) && ((tvar) = SLIST_NEXT(var, field), 1); (var) = (tvar)) 122 123 /* 124 * Singly-linked List functions. 125 */ 126 #define SLIST_INIT(head) \ 127 { SLIST_FIRST(head) = SLIST_END(head); } 128 129 #define SLIST_INSERT_AFTER(slistelm, elm, field) \ 130 do { \ 131 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 132 (slistelm)->field.sle_next = (elm); \ 133 } while (0) 134 135 #define SLIST_INSERT_HEAD(head, elm, field) \ 136 do { \ 137 (elm)->field.sle_next = (head)->slh_first; \ 138 (head)->slh_first = (elm); \ 139 } while (0) 140 141 #define SLIST_REMOVE_AFTER(elm, field) \ 142 do { \ 143 (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next; \ 144 } while (0) 145 146 #define SLIST_REMOVE_HEAD(head, field) \ 147 do { \ 148 (head)->slh_first = (head)->slh_first->field.sle_next; \ 149 } while (0) 150 151 #define SLIST_REMOVE(head, elm, type, field) \ 152 do { \ 153 if ((head)->slh_first == (elm)) { \ 154 SLIST_REMOVE_HEAD((head), field); \ 155 } else { \ 156 struct type *curelm = (head)->slh_first; \ 157 \ 158 while (curelm->field.sle_next != (elm)) \ 159 curelm = curelm->field.sle_next; \ 160 curelm->field.sle_next = curelm->field.sle_next->field.sle_next; \ 161 _Q_INVALIDATE((elm)->field.sle_next); \ 162 } \ 163 } while (0) 164 165 /* 166 * List definitions. 167 */ 168 #define LIST_HEAD(name, type) \ 169 struct name { \ 170 struct type *lh_first; /* first element */ \ 171 } 172 173 #define LIST_HEAD_INITIALIZER(head) \ 174 { NULL } 175 176 #define LIST_ENTRY(type) \ 177 struct { \ 178 struct type *le_next; /* next element */ \ 179 struct type **le_prev; /* address of previous next element */ \ 180 } 181 182 /* 183 * List access methods 184 */ 185 #define LIST_FIRST(head) ((head)->lh_first) 186 #define LIST_END(head) NULL 187 #define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head)) 188 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 189 190 #define LIST_FOREACH(var, head, field) \ 191 for ((var) = LIST_FIRST(head); (var) != LIST_END(head); \ 192 (var) = LIST_NEXT(var, field)) 193 194 #define LIST_FOREACH_SAFE(var, head, field, tvar) \ 195 for ((var) = LIST_FIRST(head); (var) && ((tvar) = LIST_NEXT(var, field), 1); \ 196 (var) = (tvar)) 197 198 /* 199 * List functions. 200 */ 201 #define LIST_INIT(head) \ 202 do { \ 203 LIST_FIRST(head) = LIST_END(head); \ 204 } while (0) 205 206 #define LIST_INSERT_AFTER(listelm, elm, field) \ 207 do { \ 208 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 209 (listelm)->field.le_next->field.le_prev = &(elm)->field.le_next; \ 210 (listelm)->field.le_next = (elm); \ 211 (elm)->field.le_prev = &(listelm)->field.le_next; \ 212 } while (0) 213 214 #define LIST_INSERT_BEFORE(listelm, elm, field) \ 215 do { \ 216 (elm)->field.le_prev = (listelm)->field.le_prev; \ 217 (elm)->field.le_next = (listelm); \ 218 *(listelm)->field.le_prev = (elm); \ 219 (listelm)->field.le_prev = &(elm)->field.le_next; \ 220 } while (0) 221 222 #define LIST_INSERT_HEAD(head, elm, field) \ 223 do { \ 224 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 225 (head)->lh_first->field.le_prev = &(elm)->field.le_next; \ 226 (head)->lh_first = (elm); \ 227 (elm)->field.le_prev = &(head)->lh_first; \ 228 } while (0) 229 230 #define LIST_REMOVE(elm, field) \ 231 do { \ 232 if ((elm)->field.le_next != NULL) \ 233 (elm)->field.le_next->field.le_prev = (elm)->field.le_prev; \ 234 *(elm)->field.le_prev = (elm)->field.le_next; \ 235 _Q_INVALIDATE((elm)->field.le_prev); \ 236 _Q_INVALIDATE((elm)->field.le_next); \ 237 } while (0) 238 239 #define LIST_REPLACE(elm, elm2, field) \ 240 do { \ 241 if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \ 242 (elm2)->field.le_next->field.le_prev = &(elm2)->field.le_next; \ 243 (elm2)->field.le_prev = (elm)->field.le_prev; \ 244 *(elm2)->field.le_prev = (elm2); \ 245 _Q_INVALIDATE((elm)->field.le_prev); \ 246 _Q_INVALIDATE((elm)->field.le_next); \ 247 } while (0) 248 249 /* 250 * Simple queue definitions. 251 */ 252 #define SIMPLEQ_HEAD(name, type) \ 253 struct name { \ 254 struct type *sqh_first; /* first element */ \ 255 struct type **sqh_last; /* addr of last next element */ \ 256 } 257 258 #define SIMPLEQ_HEAD_INITIALIZER(head) \ 259 { NULL, &(head).sqh_first } 260 261 #define SIMPLEQ_ENTRY(type) \ 262 struct { \ 263 struct type *sqe_next; /* next element */ \ 264 } 265 266 /* 267 * Simple queue access methods. 268 */ 269 #define SIMPLEQ_FIRST(head) ((head)->sqh_first) 270 #define SIMPLEQ_END(head) NULL 271 #define SIMPLEQ_EMPTY(head) (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head)) 272 #define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 273 274 #define SIMPLEQ_FOREACH(var, head, field) \ 275 for ((var) = SIMPLEQ_FIRST(head); (var) != SIMPLEQ_END(head); \ 276 (var) = SIMPLEQ_NEXT(var, field)) 277 278 #define SIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \ 279 for ((var) = SIMPLEQ_FIRST(head); \ 280 (var) && ((tvar) = SIMPLEQ_NEXT(var, field), 1); (var) = (tvar)) 281 282 /* 283 * Simple queue functions. 284 */ 285 #define SIMPLEQ_INIT(head) \ 286 do { \ 287 (head)->sqh_first = NULL; \ 288 (head)->sqh_last = &(head)->sqh_first; \ 289 } while (0) 290 291 #define SIMPLEQ_INSERT_HEAD(head, elm, field) \ 292 do { \ 293 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 294 (head)->sqh_last = &(elm)->field.sqe_next; \ 295 (head)->sqh_first = (elm); \ 296 } while (0) 297 298 #define SIMPLEQ_INSERT_TAIL(head, elm, field) \ 299 do { \ 300 (elm)->field.sqe_next = NULL; \ 301 *(head)->sqh_last = (elm); \ 302 (head)->sqh_last = &(elm)->field.sqe_next; \ 303 } while (0) 304 305 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) \ 306 do { \ 307 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 308 (head)->sqh_last = &(elm)->field.sqe_next; \ 309 (listelm)->field.sqe_next = (elm); \ 310 } while (0) 311 312 #define SIMPLEQ_REMOVE_HEAD(head, field) \ 313 do { \ 314 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \ 315 (head)->sqh_last = &(head)->sqh_first; \ 316 } while (0) 317 318 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) \ 319 do { \ 320 if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) == \ 321 NULL) \ 322 (head)->sqh_last = &(elm)->field.sqe_next; \ 323 } while (0) 324 325 /* 326 * XOR Simple queue definitions. 327 */ 328 #define XSIMPLEQ_HEAD(name, type) \ 329 struct name { \ 330 struct type *sqx_first; /* first element */ \ 331 struct type **sqx_last; /* addr of last next element */ \ 332 unsigned long sqx_cookie; \ 333 } 334 335 #define XSIMPLEQ_ENTRY(type) \ 336 struct { \ 337 struct type *sqx_next; /* next element */ \ 338 } 339 340 /* 341 * XOR Simple queue access methods. 342 */ 343 #define XSIMPLEQ_XOR(head, ptr) \ 344 ((__typeof(ptr))((head)->sqx_cookie ^ (unsigned long)(ptr))) 345 #define XSIMPLEQ_FIRST(head) XSIMPLEQ_XOR(head, ((head)->sqx_first)) 346 #define XSIMPLEQ_END(head) NULL 347 #define XSIMPLEQ_EMPTY(head) (XSIMPLEQ_FIRST(head) == XSIMPLEQ_END(head)) 348 #define XSIMPLEQ_NEXT(head, elm, field) \ 349 XSIMPLEQ_XOR(head, ((elm)->field.sqx_next)) 350 351 #define XSIMPLEQ_FOREACH(var, head, field) \ 352 for ((var) = XSIMPLEQ_FIRST(head); (var) != XSIMPLEQ_END(head); \ 353 (var) = XSIMPLEQ_NEXT(head, var, field)) 354 355 #define XSIMPLEQ_FOREACH_SAFE(var, head, field, tvar) \ 356 for ((var) = XSIMPLEQ_FIRST(head); \ 357 (var) && ((tvar) = XSIMPLEQ_NEXT(head, var, field), 1); (var) = (tvar)) 358 359 /* 360 * XOR Simple queue functions. 361 */ 362 #define XSIMPLEQ_INIT(head) \ 363 do { \ 364 arc4random_buf(&(head)->sqx_cookie, sizeof((head)->sqx_cookie)); \ 365 (head)->sqx_first = XSIMPLEQ_XOR(head, NULL); \ 366 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \ 367 } while (0) 368 369 #define XSIMPLEQ_INSERT_HEAD(head, elm, field) \ 370 do { \ 371 if (((elm)->field.sqx_next = (head)->sqx_first) == \ 372 XSIMPLEQ_XOR(head, NULL)) \ 373 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 374 (head)->sqx_first = XSIMPLEQ_XOR(head, (elm)); \ 375 } while (0) 376 377 #define XSIMPLEQ_INSERT_TAIL(head, elm, field) \ 378 do { \ 379 (elm)->field.sqx_next = XSIMPLEQ_XOR(head, NULL); \ 380 *(XSIMPLEQ_XOR(head, (head)->sqx_last)) = XSIMPLEQ_XOR(head, (elm)); \ 381 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 382 } while (0) 383 384 #define XSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) \ 385 do { \ 386 if (((elm)->field.sqx_next = (listelm)->field.sqx_next) == \ 387 XSIMPLEQ_XOR(head, NULL)) \ 388 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 389 (listelm)->field.sqx_next = XSIMPLEQ_XOR(head, (elm)); \ 390 } while (0) 391 392 #define XSIMPLEQ_REMOVE_HEAD(head, field) \ 393 do { \ 394 if (((head)->sqx_first = \ 395 XSIMPLEQ_XOR(head, (head)->sqx_first)->field.sqx_next) == \ 396 XSIMPLEQ_XOR(head, NULL)) \ 397 (head)->sqx_last = XSIMPLEQ_XOR(head, &(head)->sqx_first); \ 398 } while (0) 399 400 #define XSIMPLEQ_REMOVE_AFTER(head, elm, field) \ 401 do { \ 402 if (((elm)->field.sqx_next = \ 403 XSIMPLEQ_XOR(head, (elm)->field.sqx_next)->field.sqx_next) == \ 404 XSIMPLEQ_XOR(head, NULL)) \ 405 (head)->sqx_last = XSIMPLEQ_XOR(head, &(elm)->field.sqx_next); \ 406 } while (0) 407 408 /* 409 * Tail queue definitions. 410 */ 411 #define TAILQ_HEAD(name, type) \ 412 struct name { \ 413 struct type *tqh_first; /* first element */ \ 414 struct type **tqh_last; /* addr of last next element */ \ 415 } 416 417 #define TAILQ_HEAD_INITIALIZER(head) \ 418 { NULL, &(head).tqh_first } 419 420 #define TAILQ_ENTRY(type) \ 421 struct { \ 422 struct type *tqe_next; /* next element */ \ 423 struct type **tqe_prev; /* address of previous next element */ \ 424 } 425 426 /* 427 * tail queue access methods 428 */ 429 #define TAILQ_FIRST(head) ((head)->tqh_first) 430 #define TAILQ_END(head) NULL 431 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 432 #define TAILQ_LAST(head, headname) \ 433 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 434 /* XXX */ 435 #define TAILQ_PREV(elm, headname, field) \ 436 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 437 #define TAILQ_EMPTY(head) (TAILQ_FIRST(head) == TAILQ_END(head)) 438 439 #define TAILQ_FOREACH(var, head, field) \ 440 for ((var) = TAILQ_FIRST(head); (var) != TAILQ_END(head); \ 441 (var) = TAILQ_NEXT(var, field)) 442 443 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 444 for ((var) = TAILQ_FIRST(head); \ 445 (var) != TAILQ_END(head) && ((tvar) = TAILQ_NEXT(var, field), 1); \ 446 (var) = (tvar)) 447 448 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 449 for ((var) = TAILQ_LAST(head, headname); (var) != TAILQ_END(head); \ 450 (var) = TAILQ_PREV(var, headname, field)) 451 452 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 453 for ((var) = TAILQ_LAST(head, headname); \ 454 (var) != TAILQ_END(head) && \ 455 ((tvar) = TAILQ_PREV(var, headname, field), 1); \ 456 (var) = (tvar)) 457 458 /* 459 * Tail queue functions. 460 */ 461 #define TAILQ_INIT(head) \ 462 do { \ 463 (head)->tqh_first = NULL; \ 464 (head)->tqh_last = &(head)->tqh_first; \ 465 } while (0) 466 467 #define TAILQ_INSERT_HEAD(head, elm, field) \ 468 do { \ 469 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 470 (head)->tqh_first->field.tqe_prev = &(elm)->field.tqe_next; \ 471 else \ 472 (head)->tqh_last = &(elm)->field.tqe_next; \ 473 (head)->tqh_first = (elm); \ 474 (elm)->field.tqe_prev = &(head)->tqh_first; \ 475 } while (0) 476 477 #define TAILQ_INSERT_TAIL(head, elm, field) \ 478 do { \ 479 (elm)->field.tqe_next = NULL; \ 480 (elm)->field.tqe_prev = (head)->tqh_last; \ 481 *(head)->tqh_last = (elm); \ 482 (head)->tqh_last = &(elm)->field.tqe_next; \ 483 } while (0) 484 485 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) \ 486 do { \ 487 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL) \ 488 (elm)->field.tqe_next->field.tqe_prev = &(elm)->field.tqe_next; \ 489 else \ 490 (head)->tqh_last = &(elm)->field.tqe_next; \ 491 (listelm)->field.tqe_next = (elm); \ 492 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 493 } while (0) 494 495 #define TAILQ_INSERT_BEFORE(listelm, elm, field) \ 496 do { \ 497 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 498 (elm)->field.tqe_next = (listelm); \ 499 *(listelm)->field.tqe_prev = (elm); \ 500 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 501 } while (0) 502 503 #define TAILQ_REMOVE(head, elm, field) \ 504 do { \ 505 if (((elm)->field.tqe_next) != NULL) \ 506 (elm)->field.tqe_next->field.tqe_prev = (elm)->field.tqe_prev; \ 507 else \ 508 (head)->tqh_last = (elm)->field.tqe_prev; \ 509 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 510 _Q_INVALIDATE((elm)->field.tqe_prev); \ 511 _Q_INVALIDATE((elm)->field.tqe_next); \ 512 } while (0) 513 514 #define TAILQ_REPLACE(head, elm, elm2, field) \ 515 do { \ 516 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 517 (elm2)->field.tqe_next->field.tqe_prev = &(elm2)->field.tqe_next; \ 518 else \ 519 (head)->tqh_last = &(elm2)->field.tqe_next; \ 520 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 521 *(elm2)->field.tqe_prev = (elm2); \ 522 _Q_INVALIDATE((elm)->field.tqe_prev); \ 523 _Q_INVALIDATE((elm)->field.tqe_next); \ 524 } while (0) 525 526 /* 527 * Circular queue definitions. 528 */ 529 #define CIRCLEQ_HEAD(name, type) \ 530 struct name { \ 531 struct type *cqh_first; /* first element */ \ 532 struct type *cqh_last; /* last element */ \ 533 } 534 535 #define CIRCLEQ_HEAD_INITIALIZER(head) \ 536 { CIRCLEQ_END(&head), CIRCLEQ_END(&head) } 537 538 #define CIRCLEQ_ENTRY(type) \ 539 struct { \ 540 struct type *cqe_next; /* next element */ \ 541 struct type *cqe_prev; /* previous element */ \ 542 } 543 544 /* 545 * Circular queue access methods 546 */ 547 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 548 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 549 #define CIRCLEQ_END(head) ((void *)(head)) 550 #define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 551 #define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 552 #define CIRCLEQ_EMPTY(head) (CIRCLEQ_FIRST(head) == CIRCLEQ_END(head)) 553 554 #define CIRCLEQ_FOREACH(var, head, field) \ 555 for ((var) = CIRCLEQ_FIRST(head); (var) != CIRCLEQ_END(head); \ 556 (var) = CIRCLEQ_NEXT(var, field)) 557 558 #define CIRCLEQ_FOREACH_SAFE(var, head, field, tvar) \ 559 for ((var) = CIRCLEQ_FIRST(head); \ 560 (var) != CIRCLEQ_END(head) && ((tvar) = CIRCLEQ_NEXT(var, field), 1); \ 561 (var) = (tvar)) 562 563 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 564 for ((var) = CIRCLEQ_LAST(head); (var) != CIRCLEQ_END(head); \ 565 (var) = CIRCLEQ_PREV(var, field)) 566 567 #define CIRCLEQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 568 for ((var) = CIRCLEQ_LAST(head, headname); \ 569 (var) != CIRCLEQ_END(head) && \ 570 ((tvar) = CIRCLEQ_PREV(var, headname, field), 1); \ 571 (var) = (tvar)) 572 573 /* 574 * Circular queue functions. 575 */ 576 #define CIRCLEQ_INIT(head) \ 577 do { \ 578 (head)->cqh_first = CIRCLEQ_END(head); \ 579 (head)->cqh_last = CIRCLEQ_END(head); \ 580 } while (0) 581 582 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) \ 583 do { \ 584 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 585 (elm)->field.cqe_prev = (listelm); \ 586 if ((listelm)->field.cqe_next == CIRCLEQ_END(head)) \ 587 (head)->cqh_last = (elm); \ 588 else \ 589 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 590 (listelm)->field.cqe_next = (elm); \ 591 } while (0) 592 593 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) \ 594 do { \ 595 (elm)->field.cqe_next = (listelm); \ 596 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 597 if ((listelm)->field.cqe_prev == CIRCLEQ_END(head)) \ 598 (head)->cqh_first = (elm); \ 599 else \ 600 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 601 (listelm)->field.cqe_prev = (elm); \ 602 } while (0) 603 604 #define CIRCLEQ_INSERT_HEAD(head, elm, field) \ 605 do { \ 606 (elm)->field.cqe_next = (head)->cqh_first; \ 607 (elm)->field.cqe_prev = CIRCLEQ_END(head); \ 608 if ((head)->cqh_last == CIRCLEQ_END(head)) \ 609 (head)->cqh_last = (elm); \ 610 else \ 611 (head)->cqh_first->field.cqe_prev = (elm); \ 612 (head)->cqh_first = (elm); \ 613 } while (0) 614 615 #define CIRCLEQ_INSERT_TAIL(head, elm, field) \ 616 do { \ 617 (elm)->field.cqe_next = CIRCLEQ_END(head); \ 618 (elm)->field.cqe_prev = (head)->cqh_last; \ 619 if ((head)->cqh_first == CIRCLEQ_END(head)) \ 620 (head)->cqh_first = (elm); \ 621 else \ 622 (head)->cqh_last->field.cqe_next = (elm); \ 623 (head)->cqh_last = (elm); \ 624 } while (0) 625 626 #define CIRCLEQ_REMOVE(head, elm, field) \ 627 do { \ 628 if ((elm)->field.cqe_next == CIRCLEQ_END(head)) \ 629 (head)->cqh_last = (elm)->field.cqe_prev; \ 630 else \ 631 (elm)->field.cqe_next->field.cqe_prev = (elm)->field.cqe_prev; \ 632 if ((elm)->field.cqe_prev == CIRCLEQ_END(head)) \ 633 (head)->cqh_first = (elm)->field.cqe_next; \ 634 else \ 635 (elm)->field.cqe_prev->field.cqe_next = (elm)->field.cqe_next; \ 636 _Q_INVALIDATE((elm)->field.cqe_prev); \ 637 _Q_INVALIDATE((elm)->field.cqe_next); \ 638 } while (0) 639 640 #define CIRCLEQ_REPLACE(head, elm, elm2, field) \ 641 do { \ 642 if (((elm2)->field.cqe_next = (elm)->field.cqe_next) == CIRCLEQ_END(head)) \ 643 (head)->cqh_last = (elm2); \ 644 else \ 645 (elm2)->field.cqe_next->field.cqe_prev = (elm2); \ 646 if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) == CIRCLEQ_END(head)) \ 647 (head)->cqh_first = (elm2); \ 648 else \ 649 (elm2)->field.cqe_prev->field.cqe_next = (elm2); \ 650 _Q_INVALIDATE((elm)->field.cqe_prev); \ 651 _Q_INVALIDATE((elm)->field.cqe_next); \ 652 } while (0) 653 654 #endif /* !_SYS_QUEUE_H_ */