queue.h revision 24935
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 * $Id: queue.h,v 1.13 1997/02/22 09:45:44 peter Exp $ 35 */ 36 37#ifndef _SYS_QUEUE_H_ 38#define _SYS_QUEUE_H_ 39 40/* 41 * This file defines five types of data structures: singly-linked lists, 42 * slingly-linked tail queues, lists, tail queues, and circular queues. 43 * 44 * A singly-linked list is headed by a single forward pointer. The elements 45 * are singly linked for minimum space and pointer manipulation overhead at 46 * the expense of O(n) removal for arbitrary elements. New elements can be 47 * added to the list after an existing element or at the head of the list. 48 * Elements being removed from the head of the list should use the explicit 49 * macro for this purpose for optimum efficiency. A singly-linked list may 50 * only be traversed in the forward direction. Singly-linked lists are ideal 51 * for applications with large datasets and few or no removals or for 52 * implementing a LIFO queue. 53 * 54 * A singly-linked tail queue is headed by a pair of pointers, one to the 55 * head of the list and the other to the tail of the list. The elements are 56 * singly linked for minimum space and pointer manipulation overhead at the 57 * expense of O(n) removal for arbitrary elements. New elements can be added 58 * to the list after an existing element, at the head of the list, or at the 59 * end of the list. Elements being removed from the head of the tail queue 60 * should use the explicit macro for this purpose for optimum efficiency. 61 * A singly-linked tail queue may only be traversed in the forward direction. 62 * Singly-linked tail queues are ideal for applications with large datasets 63 * and few or no removals or for implementing a FIFO queue. 64 * 65 * A list is headed by a single forward pointer (or an array of forward 66 * pointers for a hash table header). The elements are doubly linked 67 * so that an arbitrary element can be removed without a need to 68 * traverse the list. New elements can be added to the list before 69 * or after an existing element or at the head of the list. A list 70 * may only be traversed in the forward direction. 71 * 72 * A tail queue is headed by a pair of pointers, one to the head of the 73 * list and the other to the tail of the list. The elements are doubly 74 * linked so that an arbitrary element can be removed without a need to 75 * traverse the list. New elements can be added to the list before or 76 * after an existing element, at the head of the list, or at the end of 77 * the list. A tail queue may only be traversed in the forward direction. 78 * 79 * A circle queue is headed by a pair of pointers, one to the head of the 80 * list and the other to the tail of the list. The elements are doubly 81 * linked so that an arbitrary element can be removed without a need to 82 * traverse the list. New elements can be added to the list before or after 83 * an existing element, at the head of the list, or at the end of the list. 84 * A circle queue may be traversed in either direction, but has a more 85 * complex end of list detection. 86 * 87 * For details on the use of these macros, see the queue(3) manual page. 88 */ 89 90/* 91 * Singly-linked List definitions. 92 */ 93#define SLIST_HEAD(name, type) \ 94struct name { \ 95 struct type *slh_first; /* first element */ \ 96} 97 98#define SLIST_ENTRY(type) \ 99struct { \ 100 struct type *sle_next; /* next element */ \ 101} 102 103/* 104 * Singly-linked List functions. 105 */ 106#define SLIST_EMPTY(head) ((head)->slh_first == NULL) 107 108#define SLIST_FIRST(head) ((head)->slh_first) 109 110#define SLIST_INIT(head) { \ 111 (head)->slh_first = NULL; \ 112} 113 114#define SLIST_INSERT_AFTER(slistelm, elm, field) { \ 115 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 116 (slistelm)->field.sle_next = (elm); \ 117} 118 119#define SLIST_INSERT_HEAD(head, elm, field) { \ 120 (elm)->field.sle_next = (head)->slh_first; \ 121 (head)->slh_first = (elm); \ 122} 123 124#define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 125 126#define SLIST_REMOVE_HEAD(head, field) { \ 127 (head)->slh_first = (head)->slh_first->field.sle_next; \ 128} 129 130#define SLIST_REMOVE(head, elm, type, field) { \ 131 if ((head)->slh_first == (elm)) { \ 132 SLIST_REMOVE_HEAD((head), field); \ 133 } \ 134 else { \ 135 struct type *curelm = (head)->slh_first; \ 136 while( curelm->field.sle_next != (elm) ) \ 137 curelm = curelm->field.sle_next; \ 138 curelm->field.sle_next = \ 139 curelm->field.sle_next->field.sle_next; \ 140 } \ 141} 142 143/* 144 * Singly-linked Tail queue definitions. 145 */ 146#define STAILQ_HEAD(name, type) \ 147struct name { \ 148 struct type *stqh_first;/* first element */ \ 149 struct type **stqh_last;/* addr of last next element */ \ 150} 151 152#define STAILQ_ENTRY(type) \ 153struct { \ 154 struct type *stqe_next; /* next element */ \ 155} 156 157/* 158 * Singly-linked Tail queue functions. 159 */ 160#define STAILQ_INIT(head) { \ 161 (head)->stqh_first = NULL; \ 162 (head)->stqh_last = &(head)->stqh_first; \ 163} 164 165#define STAILQ_INSERT_HEAD(head, elm, field) { \ 166 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 167 (head)->stqh_last = &(elm)->field.stqe_next; \ 168 (head)->stqh_first = (elm); \ 169} 170 171#define STAILQ_INSERT_TAIL(head, elm, field) { \ 172 (elm)->field.stqe_next = NULL; \ 173 *(head)->stqh_last = (elm); \ 174 (head)->stqh_last = &(elm)->field.stqe_next; \ 175} 176 177#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) { \ 178 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\ 179 (head)->stqh_last = &(elm)->field.stqe_next; \ 180 (tqelm)->field.stqe_next = (elm); \ 181} 182 183#define STAILQ_REMOVE_HEAD(head, field) { \ 184 if (((head)->stqh_first = \ 185 (head)->stqh_first->field.stqe_next) == NULL) \ 186 (head)->stqh_last = &(head)->stqh_first; \ 187} 188 189#define STAILQ_REMOVE(head, elm, type, field) { \ 190 if ((head)->stqh_first == (elm)) { \ 191 STAILQ_REMOVE_HEAD(head, field); \ 192 } \ 193 else { \ 194 struct type *curelm = (head)->stqh_first; \ 195 while( curelm->field.stqe_next != (elm) ) \ 196 curelm = curelm->field.stqe_next; \ 197 if((curelm->field.stqe_next = \ 198 curelm->field.stqe_next->field.stqe_next) == NULL) \ 199 (head)->stqh_last = &(curelm)->field.stqe_next; \ 200 } \ 201} 202 203/* 204 * List definitions. 205 */ 206#define LIST_HEAD(name, type) \ 207struct name { \ 208 struct type *lh_first; /* first element */ \ 209} 210 211#define LIST_ENTRY(type) \ 212struct { \ 213 struct type *le_next; /* next element */ \ 214 struct type **le_prev; /* address of previous next element */ \ 215} 216 217/* 218 * List functions. 219 */ 220#define LIST_FIRST(head) ((head)->lh_first) 221 222#define LIST_FOREACH(var, head, field) \ 223 for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next) 224 225#define LIST_INIT(head) { \ 226 (head)->lh_first = NULL; \ 227} 228 229#define LIST_INSERT_AFTER(listelm, elm, field) { \ 230 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 231 (listelm)->field.le_next->field.le_prev = \ 232 &(elm)->field.le_next; \ 233 (listelm)->field.le_next = (elm); \ 234 (elm)->field.le_prev = &(listelm)->field.le_next; \ 235} 236 237#define LIST_INSERT_BEFORE(listelm, elm, field) { \ 238 (elm)->field.le_prev = (listelm)->field.le_prev; \ 239 (elm)->field.le_next = (listelm); \ 240 *(listelm)->field.le_prev = (elm); \ 241 (listelm)->field.le_prev = &(elm)->field.le_next; \ 242} 243 244#define LIST_INSERT_HEAD(head, elm, field) { \ 245 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 246 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 247 (head)->lh_first = (elm); \ 248 (elm)->field.le_prev = &(head)->lh_first; \ 249} 250 251#define LIST_NEXT(elm, field) ((elm)->field.le_next) 252 253#define LIST_REMOVE(elm, field) { \ 254 if ((elm)->field.le_next != NULL) \ 255 (elm)->field.le_next->field.le_prev = \ 256 (elm)->field.le_prev; \ 257 *(elm)->field.le_prev = (elm)->field.le_next; \ 258} 259 260/* 261 * Tail queue definitions. 262 */ 263#define TAILQ_HEAD(name, type) \ 264struct name { \ 265 struct type *tqh_first; /* first element */ \ 266 struct type **tqh_last; /* addr of last next element */ \ 267} 268 269#define TAILQ_ENTRY(type) \ 270struct { \ 271 struct type *tqe_next; /* next element */ \ 272 struct type **tqe_prev; /* address of previous next element */ \ 273} 274 275/* 276 * Tail queue functions. 277 */ 278#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 279 280#define TAILQ_FIRST(head) ((head)->tqh_first) 281 282#define TAILQ_LAST(head) ((head)->tqh_last) 283 284#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 285 286#define TAILQ_PREV(elm, field) ((elm)->field.tqe_prev) 287 288#define TAILQ_INIT(head) { \ 289 (head)->tqh_first = NULL; \ 290 (head)->tqh_last = &(head)->tqh_first; \ 291} 292 293#define TAILQ_INSERT_HEAD(head, elm, field) { \ 294 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 295 (head)->tqh_first->field.tqe_prev = \ 296 &(elm)->field.tqe_next; \ 297 else \ 298 (head)->tqh_last = &(elm)->field.tqe_next; \ 299 (head)->tqh_first = (elm); \ 300 (elm)->field.tqe_prev = &(head)->tqh_first; \ 301} 302 303#define TAILQ_INSERT_TAIL(head, elm, field) { \ 304 (elm)->field.tqe_next = NULL; \ 305 (elm)->field.tqe_prev = (head)->tqh_last; \ 306 *(head)->tqh_last = (elm); \ 307 (head)->tqh_last = &(elm)->field.tqe_next; \ 308} 309 310#define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ 311 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 312 (elm)->field.tqe_next->field.tqe_prev = \ 313 &(elm)->field.tqe_next; \ 314 else \ 315 (head)->tqh_last = &(elm)->field.tqe_next; \ 316 (listelm)->field.tqe_next = (elm); \ 317 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 318} 319 320#define TAILQ_INSERT_BEFORE(listelm, elm, field) { \ 321 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 322 (elm)->field.tqe_next = (listelm); \ 323 *(listelm)->field.tqe_prev = (elm); \ 324 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 325} 326 327#define TAILQ_REMOVE(head, elm, field) { \ 328 if (((elm)->field.tqe_next) != NULL) \ 329 (elm)->field.tqe_next->field.tqe_prev = \ 330 (elm)->field.tqe_prev; \ 331 else \ 332 (head)->tqh_last = (elm)->field.tqe_prev; \ 333 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 334} 335 336/* 337 * Circular queue definitions. 338 */ 339#define CIRCLEQ_HEAD(name, type) \ 340struct name { \ 341 struct type *cqh_first; /* first element */ \ 342 struct type *cqh_last; /* last element */ \ 343} 344 345#define CIRCLEQ_ENTRY(type) \ 346struct { \ 347 struct type *cqe_next; /* next element */ \ 348 struct type *cqe_prev; /* previous element */ \ 349} 350 351/* 352 * Circular queue functions. 353 */ 354#define CIRCLEQ_INIT(head) { \ 355 (head)->cqh_first = (void *)(head); \ 356 (head)->cqh_last = (void *)(head); \ 357} 358 359#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ 360 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 361 (elm)->field.cqe_prev = (listelm); \ 362 if ((listelm)->field.cqe_next == (void *)(head)) \ 363 (head)->cqh_last = (elm); \ 364 else \ 365 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 366 (listelm)->field.cqe_next = (elm); \ 367} 368 369#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ 370 (elm)->field.cqe_next = (listelm); \ 371 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 372 if ((listelm)->field.cqe_prev == (void *)(head)) \ 373 (head)->cqh_first = (elm); \ 374 else \ 375 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 376 (listelm)->field.cqe_prev = (elm); \ 377} 378 379#define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ 380 (elm)->field.cqe_next = (head)->cqh_first; \ 381 (elm)->field.cqe_prev = (void *)(head); \ 382 if ((head)->cqh_last == (void *)(head)) \ 383 (head)->cqh_last = (elm); \ 384 else \ 385 (head)->cqh_first->field.cqe_prev = (elm); \ 386 (head)->cqh_first = (elm); \ 387} 388 389#define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ 390 (elm)->field.cqe_next = (void *)(head); \ 391 (elm)->field.cqe_prev = (head)->cqh_last; \ 392 if ((head)->cqh_first == (void *)(head)) \ 393 (head)->cqh_first = (elm); \ 394 else \ 395 (head)->cqh_last->field.cqe_next = (elm); \ 396 (head)->cqh_last = (elm); \ 397} 398 399#define CIRCLEQ_REMOVE(head, elm, field) { \ 400 if ((elm)->field.cqe_next == (void *)(head)) \ 401 (head)->cqh_last = (elm)->field.cqe_prev; \ 402 else \ 403 (elm)->field.cqe_next->field.cqe_prev = \ 404 (elm)->field.cqe_prev; \ 405 if ((elm)->field.cqe_prev == (void *)(head)) \ 406 (head)->cqh_first = (elm)->field.cqe_next; \ 407 else \ 408 (elm)->field.cqe_prev->field.cqe_next = \ 409 (elm)->field.cqe_next; \ 410} 411 412#ifdef KERNEL 413 414/* 415 * XXX insque() and remque() are an old way of handling certain queues. 416 * They bogusly assumes that all queue heads look alike. 417 */ 418 419struct quehead { 420 struct quehead *qh_link; 421 struct quehead *qh_rlink; 422}; 423 424#ifdef __GNUC__ 425 426static __inline void 427insque(void *a, void *b) 428{ 429 struct quehead *element = a, *head = b; 430 431 element->qh_link = head->qh_link; 432 element->qh_rlink = head; 433 head->qh_link = element; 434 element->qh_link->qh_rlink = element; 435} 436 437static __inline void 438remque(void *a) 439{ 440 struct quehead *element = a; 441 442 element->qh_link->qh_rlink = element->qh_rlink; 443 element->qh_rlink->qh_link = element->qh_link; 444 element->qh_rlink = 0; 445} 446 447#else /* !__GNUC__ */ 448 449void insque __P((void *a, void *b)); 450void remque __P((void *a)); 451 452#endif /* __GNUC__ */ 453 454#endif /* KERNEL */ 455 456#endif /* !_SYS_QUEUE_H_ */ 457