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 1.32.2.4 2001/03/31 03:33:39 hsu Exp $ 35 */ 36 37 #ifndef _LFT_QUEUE_H_ 38 #define _LFT_QUEUE_H_ 39 40 #define __offsetof(type, field) ((size_t)(&((type *)0)->field)) 41 42 /* 43 * This file defines five types of data structures: singly-linked lists, 44 * singly-linked tail queues, lists, tail queues, and circular 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 * A circle queue is headed by a pair of pointers, one to the head of the 82 * list and the other to the tail of the list. The elements are doubly 83 * linked so that an arbitrary element can be removed without a need to 84 * traverse the list. New elements can be added to the list before or after 85 * an existing element, at the head of the list, or at the end of the list. 86 * A circle queue may be traversed in either direction, but has a more 87 * complex end of list detection. 88 * 89 * For details on the use of these macros, see the queue(3) manual page. 90 * 91 * 92 * SLIST LIST STAILQ TAILQ CIRCLEQ 93 * _HEAD + + + + + 94 * _ENTRY + + + + + 95 * _INIT + + + + + 96 * _EMPTY + + + + + 97 * _FIRST + + + + + 98 * _NEXT + + + + + 99 * _PREV - - - + + 100 * _LAST - - + + + 101 * _FOREACH + + + + + 102 * _FOREACH_REVERSE - - - + + 103 * _INSERT_HEAD + + + + + 104 * _INSERT_BEFORE - + - + + 105 * _INSERT_AFTER + + + + + 106 * _INSERT_TAIL - - + + + 107 * _REMOVE_HEAD + - + - - 108 * _REMOVE + + + + + 109 * 110 */ 111 112 /* 113 * Singly-linked List definitions. 114 */ 115 #define SLIST_HEAD(name, type) \ 116 struct name { \ 117 struct type *slh_first; /* first element */ \ 118 } 119 120 #define SLIST_HEAD_INITIALIZER(head) \ 121 { NULL } 122 123 #undef SLIST_ENTRY 124 #define SLIST_ENTRY(type) \ 125 struct { \ 126 struct type *sle_next; /* next element */ \ 127 } 128 129 /* 130 * Singly-linked List functions. 131 */ 132 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 133 134 #define SLIST_FIRST(head) ((head)->slh_first) 135 136 #define SLIST_FOREACH(var, head, field) \ 137 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 138 139 #define SLIST_INIT(head) { \ 140 (head)->slh_first = NULL; \ 141 } 142 143 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 144 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 145 (slistelm)->field.sle_next = (elm); \ 146 } while (0) 147 148 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 149 (elm)->field.sle_next = (head)->slh_first; \ 150 (head)->slh_first = (elm); \ 151 } while (0) 152 153 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 154 155 #define SLIST_REMOVE_HEAD(head, field) do { \ 156 (head)->slh_first = (head)->slh_first->field.sle_next; \ 157 } while (0) 158 159 #define SLIST_REMOVE(head, elm, type, field) do { \ 160 if ((head)->slh_first == (elm)) { \ 161 SLIST_REMOVE_HEAD((head), field); \ 162 } \ 163 else { \ 164 struct type *curelm = (head)->slh_first; \ 165 while( curelm->field.sle_next != (elm) ) \ 166 curelm = curelm->field.sle_next; \ 167 curelm->field.sle_next = \ 168 curelm->field.sle_next->field.sle_next; \ 169 } \ 170 } while (0) 171 172 /* 173 * Singly-linked Tail queue definitions. 174 */ 175 #define STAILQ_HEAD(name, type) \ 176 struct name { \ 177 struct type *stqh_first;/* first element */ \ 178 struct type **stqh_last;/* addr of last next element */ \ 179 } 180 181 #define STAILQ_HEAD_INITIALIZER(head) \ 182 { NULL, &(head).stqh_first } 183 184 #define STAILQ_ENTRY(type) \ 185 struct { \ 186 struct type *stqe_next; /* next element */ \ 187 } 188 189 /* 190 * Singly-linked Tail queue functions. 191 */ 192 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 193 194 #define STAILQ_INIT(head) do { \ 195 (head)->stqh_first = NULL; \ 196 (head)->stqh_last = &(head)->stqh_first; \ 197 } while (0) 198 199 #define STAILQ_FIRST(head) ((head)->stqh_first) 200 201 #ifndef STAILQ_LAST 202 #define STAILQ_LAST(head, type, field) \ 203 (STAILQ_EMPTY(head) ? \ 204 NULL : \ 205 ((struct type *) \ 206 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 207 #endif 208 209 #define STAILQ_FOREACH(var, head, field) \ 210 for((var) = (head)->stqh_first; (var); (var) = (var)->field.stqe_next) 211 212 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 213 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 214 (head)->stqh_last = &(elm)->field.stqe_next; \ 215 (head)->stqh_first = (elm); \ 216 } while (0) 217 218 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 219 (elm)->field.stqe_next = NULL; \ 220 *(head)->stqh_last = (elm); \ 221 (head)->stqh_last = &(elm)->field.stqe_next; \ 222 } while (0) 223 224 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 225 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\ 226 (head)->stqh_last = &(elm)->field.stqe_next; \ 227 (tqelm)->field.stqe_next = (elm); \ 228 } while (0) 229 230 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 231 232 #define STAILQ_REMOVE_HEAD(head, field) do { \ 233 if (((head)->stqh_first = \ 234 (head)->stqh_first->field.stqe_next) == NULL) \ 235 (head)->stqh_last = &(head)->stqh_first; \ 236 } while (0) 237 238 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \ 239 if (((head)->stqh_first = (elm)->field.stqe_next) == NULL) \ 240 (head)->stqh_last = &(head)->stqh_first; \ 241 } while (0) 242 243 #define STAILQ_REMOVE(head, elm, type, field) do { \ 244 if ((head)->stqh_first == (elm)) { \ 245 STAILQ_REMOVE_HEAD(head, field); \ 246 } \ 247 else { \ 248 struct type *curelm = (head)->stqh_first; \ 249 while( curelm->field.stqe_next != (elm) ) \ 250 curelm = curelm->field.stqe_next; \ 251 if((curelm->field.stqe_next = \ 252 curelm->field.stqe_next->field.stqe_next) == NULL) \ 253 (head)->stqh_last = &(curelm)->field.stqe_next; \ 254 } \ 255 } while (0) 256 257 /* 258 * List definitions. 259 */ 260 #define LIST_HEAD(name, type) \ 261 struct name { \ 262 struct type *lh_first; /* first element */ \ 263 } 264 265 #define LIST_HEAD_INITIALIZER(head) \ 266 { NULL } 267 268 #define LIST_ENTRY(type) \ 269 struct { \ 270 struct type *le_next; /* next element */ \ 271 struct type **le_prev; /* address of previous next element */ \ 272 } 273 274 /* 275 * List functions. 276 */ 277 278 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 279 280 #define LIST_FIRST(head) ((head)->lh_first) 281 282 #define LIST_FOREACH(var, head, field) \ 283 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next) 284 285 #define LIST_INIT(head) do { \ 286 (head)->lh_first = NULL; \ 287 } while (0) 288 289 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 290 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 291 (listelm)->field.le_next->field.le_prev = \ 292 &(elm)->field.le_next; \ 293 (listelm)->field.le_next = (elm); \ 294 (elm)->field.le_prev = &(listelm)->field.le_next; \ 295 } while (0) 296 297 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 298 (elm)->field.le_prev = (listelm)->field.le_prev; \ 299 (elm)->field.le_next = (listelm); \ 300 *(listelm)->field.le_prev = (elm); \ 301 (listelm)->field.le_prev = &(elm)->field.le_next; \ 302 } while (0) 303 304 #define LIST_INSERT_HEAD(head, elm, field) do { \ 305 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 306 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 307 (head)->lh_first = (elm); \ 308 (elm)->field.le_prev = &(head)->lh_first; \ 309 } while (0) 310 311 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 312 313 #define LIST_REMOVE(elm, field) do { \ 314 if ((elm)->field.le_next != NULL) \ 315 (elm)->field.le_next->field.le_prev = \ 316 (elm)->field.le_prev; \ 317 *(elm)->field.le_prev = (elm)->field.le_next; \ 318 } while (0) 319 320 /* 321 * Tail queue definitions. 322 */ 323 #define TAILQ_HEAD(name, type) \ 324 struct name { \ 325 struct type *tqh_first; /* first element */ \ 326 struct type **tqh_last; /* addr of last next element */ \ 327 } 328 329 #define TAILQ_HEAD_INITIALIZER(head) \ 330 { NULL, &(head).tqh_first } 331 332 #define TAILQ_ENTRY(type) \ 333 struct { \ 334 struct type *tqe_next; /* next element */ \ 335 struct type **tqe_prev; /* address of previous next element */ \ 336 } 337 338 /* 339 * Tail queue functions. 340 */ 341 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 342 343 #define TAILQ_FOREACH(var, head, field) \ 344 for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field)) 345 346 #ifndef TAILQ_FOREACH_REVERSE 347 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 348 for ((var) = TAILQ_LAST((head), headname); \ 349 (var); \ 350 (var) = TAILQ_PREV((var), headname, field)) 351 #endif 352 353 #define TAILQ_FIRST(head) ((head)->tqh_first) 354 355 #define TAILQ_LAST(head, headname) \ 356 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 357 358 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 359 360 #define TAILQ_PREV(elm, headname, field) \ 361 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 362 363 #define TAILQ_INIT(head) do { \ 364 (head)->tqh_first = NULL; \ 365 (head)->tqh_last = &(head)->tqh_first; \ 366 } while (0) 367 368 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 369 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 370 (head)->tqh_first->field.tqe_prev = \ 371 &(elm)->field.tqe_next; \ 372 else \ 373 (head)->tqh_last = &(elm)->field.tqe_next; \ 374 (head)->tqh_first = (elm); \ 375 (elm)->field.tqe_prev = &(head)->tqh_first; \ 376 } while (0) 377 378 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 379 (elm)->field.tqe_next = NULL; \ 380 (elm)->field.tqe_prev = (head)->tqh_last; \ 381 *(head)->tqh_last = (elm); \ 382 (head)->tqh_last = &(elm)->field.tqe_next; \ 383 } while (0) 384 385 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 386 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 387 (elm)->field.tqe_next->field.tqe_prev = \ 388 &(elm)->field.tqe_next; \ 389 else \ 390 (head)->tqh_last = &(elm)->field.tqe_next; \ 391 (listelm)->field.tqe_next = (elm); \ 392 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 393 } while (0) 394 395 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 396 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 397 (elm)->field.tqe_next = (listelm); \ 398 *(listelm)->field.tqe_prev = (elm); \ 399 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 400 } while (0) 401 402 #define TAILQ_REMOVE(head, elm, field) do { \ 403 if (((elm)->field.tqe_next) != NULL) \ 404 (elm)->field.tqe_next->field.tqe_prev = \ 405 (elm)->field.tqe_prev; \ 406 else \ 407 (head)->tqh_last = (elm)->field.tqe_prev; \ 408 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 409 } while (0) 410 411 /* 412 * Circular queue definitions. 413 */ 414 #define CIRCLEQ_HEAD(name, type) \ 415 struct name { \ 416 struct type *cqh_first; /* first element */ \ 417 struct type *cqh_last; /* last element */ \ 418 } 419 420 #define CIRCLEQ_ENTRY(type) \ 421 struct { \ 422 struct type *cqe_next; /* next element */ \ 423 struct type *cqe_prev; /* previous element */ \ 424 } 425 426 /* 427 * Circular queue functions. 428 */ 429 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 430 431 #define CIRCLEQ_FIRST(head) ((head)->cqh_first) 432 433 #define CIRCLEQ_FOREACH(var, head, field) \ 434 for((var) = (head)->cqh_first; \ 435 (var) != (void *)(head); \ 436 (var) = (var)->field.cqe_next) 437 438 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \ 439 for((var) = (head)->cqh_last; \ 440 (var) != (void *)(head); \ 441 (var) = (var)->field.cqe_prev) 442 443 #define CIRCLEQ_INIT(head) do { \ 444 (head)->cqh_first = (void *)(head); \ 445 (head)->cqh_last = (void *)(head); \ 446 } while (0) 447 448 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 449 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 450 (elm)->field.cqe_prev = (listelm); \ 451 if ((listelm)->field.cqe_next == (void *)(head)) \ 452 (head)->cqh_last = (elm); \ 453 else \ 454 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 455 (listelm)->field.cqe_next = (elm); \ 456 } while (0) 457 458 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 459 (elm)->field.cqe_next = (listelm); \ 460 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 461 if ((listelm)->field.cqe_prev == (void *)(head)) \ 462 (head)->cqh_first = (elm); \ 463 else \ 464 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 465 (listelm)->field.cqe_prev = (elm); \ 466 } while (0) 467 468 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 469 (elm)->field.cqe_next = (head)->cqh_first; \ 470 (elm)->field.cqe_prev = (void *)(head); \ 471 if ((head)->cqh_last == (void *)(head)) \ 472 (head)->cqh_last = (elm); \ 473 else \ 474 (head)->cqh_first->field.cqe_prev = (elm); \ 475 (head)->cqh_first = (elm); \ 476 } while (0) 477 478 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 479 (elm)->field.cqe_next = (void *)(head); \ 480 (elm)->field.cqe_prev = (head)->cqh_last; \ 481 if ((head)->cqh_first == (void *)(head)) \ 482 (head)->cqh_first = (elm); \ 483 else \ 484 (head)->cqh_last->field.cqe_next = (elm); \ 485 (head)->cqh_last = (elm); \ 486 } while (0) 487 488 #define CIRCLEQ_LAST(head) ((head)->cqh_last) 489 490 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next) 491 492 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev) 493 494 #define CIRCLEQ_REMOVE(head, elm, field) do { \ 495 if ((elm)->field.cqe_next == (void *)(head)) \ 496 (head)->cqh_last = (elm)->field.cqe_prev; \ 497 else \ 498 (elm)->field.cqe_next->field.cqe_prev = \ 499 (elm)->field.cqe_prev; \ 500 if ((elm)->field.cqe_prev == (void *)(head)) \ 501 (head)->cqh_first = (elm)->field.cqe_next; \ 502 else \ 503 (elm)->field.cqe_prev->field.cqe_next = \ 504 (elm)->field.cqe_next; \ 505 } while (0) 506 507 #endif /* !_LFT_QUEUE_H_ */ 508