queue.h revision 21673
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: head/sys/sys/queue.h 21673 1997-01-14 07:20:47Z jkh $ 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_INIT(head) { \ 221 (head)->lh_first = NULL; \ 222} 223 224#define LIST_INSERT_AFTER(listelm, elm, field) { \ 225 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 226 (listelm)->field.le_next->field.le_prev = \ 227 &(elm)->field.le_next; \ 228 (listelm)->field.le_next = (elm); \ 229 (elm)->field.le_prev = &(listelm)->field.le_next; \ 230} 231 232#define LIST_INSERT_BEFORE(listelm, elm, field) { \ 233 (elm)->field.le_prev = (listelm)->field.le_prev; \ 234 (elm)->field.le_next = (listelm); \ 235 *(listelm)->field.le_prev = (elm); \ 236 (listelm)->field.le_prev = &(elm)->field.le_next; \ 237} 238 239#define LIST_INSERT_HEAD(head, elm, field) { \ 240 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 241 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 242 (head)->lh_first = (elm); \ 243 (elm)->field.le_prev = &(head)->lh_first; \ 244} 245 246#define LIST_REMOVE(elm, field) { \ 247 if ((elm)->field.le_next != NULL) \ 248 (elm)->field.le_next->field.le_prev = \ 249 (elm)->field.le_prev; \ 250 *(elm)->field.le_prev = (elm)->field.le_next; \ 251} 252 253/* 254 * Tail queue definitions. 255 */ 256#define TAILQ_HEAD(name, type) \ 257struct name { \ 258 struct type *tqh_first; /* first element */ \ 259 struct type **tqh_last; /* addr of last next element */ \ 260} 261 262#define TAILQ_ENTRY(type) \ 263struct { \ 264 struct type *tqe_next; /* next element */ \ 265 struct type **tqe_prev; /* address of previous next element */ \ 266} 267 268/* 269 * Tail queue functions. 270 */ 271#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 272 273#define TAILQ_FIRST(head) ((head)->tqh_first) 274 275#define TAILQ_LAST(head) ((head)->tqh_last) 276 277#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 278 279#define TAILQ_PREV(elm, field) ((elm)->field.tqe_prev) 280 281#define TAILQ_INIT(head) { \ 282 (head)->tqh_first = NULL; \ 283 (head)->tqh_last = &(head)->tqh_first; \ 284} 285 286#define TAILQ_INSERT_HEAD(head, elm, field) { \ 287 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 288 (head)->tqh_first->field.tqe_prev = \ 289 &(elm)->field.tqe_next; \ 290 else \ 291 (head)->tqh_last = &(elm)->field.tqe_next; \ 292 (head)->tqh_first = (elm); \ 293 (elm)->field.tqe_prev = &(head)->tqh_first; \ 294} 295 296#define TAILQ_INSERT_TAIL(head, elm, field) { \ 297 (elm)->field.tqe_next = NULL; \ 298 (elm)->field.tqe_prev = (head)->tqh_last; \ 299 *(head)->tqh_last = (elm); \ 300 (head)->tqh_last = &(elm)->field.tqe_next; \ 301} 302 303#define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ 304 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 305 (elm)->field.tqe_next->field.tqe_prev = \ 306 &(elm)->field.tqe_next; \ 307 else \ 308 (head)->tqh_last = &(elm)->field.tqe_next; \ 309 (listelm)->field.tqe_next = (elm); \ 310 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 311} 312 313#define TAILQ_INSERT_BEFORE(listelm, elm, field) { \ 314 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 315 (elm)->field.tqe_next = (listelm); \ 316 *(listelm)->field.tqe_prev = (elm); \ 317 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 318} 319 320#define TAILQ_REMOVE(head, elm, field) { \ 321 if (((elm)->field.tqe_next) != NULL) \ 322 (elm)->field.tqe_next->field.tqe_prev = \ 323 (elm)->field.tqe_prev; \ 324 else \ 325 (head)->tqh_last = (elm)->field.tqe_prev; \ 326 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 327} 328 329/* 330 * Circular queue definitions. 331 */ 332#define CIRCLEQ_HEAD(name, type) \ 333struct name { \ 334 struct type *cqh_first; /* first element */ \ 335 struct type *cqh_last; /* last element */ \ 336} 337 338#define CIRCLEQ_ENTRY(type) \ 339struct { \ 340 struct type *cqe_next; /* next element */ \ 341 struct type *cqe_prev; /* previous element */ \ 342} 343 344/* 345 * Circular queue functions. 346 */ 347#define CIRCLEQ_INIT(head) { \ 348 (head)->cqh_first = (void *)(head); \ 349 (head)->cqh_last = (void *)(head); \ 350} 351 352#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ 353 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 354 (elm)->field.cqe_prev = (listelm); \ 355 if ((listelm)->field.cqe_next == (void *)(head)) \ 356 (head)->cqh_last = (elm); \ 357 else \ 358 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 359 (listelm)->field.cqe_next = (elm); \ 360} 361 362#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ 363 (elm)->field.cqe_next = (listelm); \ 364 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 365 if ((listelm)->field.cqe_prev == (void *)(head)) \ 366 (head)->cqh_first = (elm); \ 367 else \ 368 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 369 (listelm)->field.cqe_prev = (elm); \ 370} 371 372#define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ 373 (elm)->field.cqe_next = (head)->cqh_first; \ 374 (elm)->field.cqe_prev = (void *)(head); \ 375 if ((head)->cqh_last == (void *)(head)) \ 376 (head)->cqh_last = (elm); \ 377 else \ 378 (head)->cqh_first->field.cqe_prev = (elm); \ 379 (head)->cqh_first = (elm); \ 380} 381 382#define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ 383 (elm)->field.cqe_next = (void *)(head); \ 384 (elm)->field.cqe_prev = (head)->cqh_last; \ 385 if ((head)->cqh_first == (void *)(head)) \ 386 (head)->cqh_first = (elm); \ 387 else \ 388 (head)->cqh_last->field.cqe_next = (elm); \ 389 (head)->cqh_last = (elm); \ 390} 391 392#define CIRCLEQ_REMOVE(head, elm, field) { \ 393 if ((elm)->field.cqe_next == (void *)(head)) \ 394 (head)->cqh_last = (elm)->field.cqe_prev; \ 395 else \ 396 (elm)->field.cqe_next->field.cqe_prev = \ 397 (elm)->field.cqe_prev; \ 398 if ((elm)->field.cqe_prev == (void *)(head)) \ 399 (head)->cqh_first = (elm)->field.cqe_next; \ 400 else \ 401 (elm)->field.cqe_prev->field.cqe_next = \ 402 (elm)->field.cqe_next; \ 403} 404 405#ifdef KERNEL 406 407/* 408 * XXX insque() and remque() are an old way of handling certain queues. 409 * They bogusly assumes that all queue heads look alike. 410 */ 411 412struct quehead { 413 struct quehead *qh_link; 414 struct quehead *qh_rlink; 415}; 416 417#ifdef __GNUC__ 418 419static __inline void 420insque(void *a, void *b) 421{ 422 struct quehead *element = a, *head = b; 423 424 element->qh_link = head->qh_link; 425 element->qh_rlink = head; 426 head->qh_link = element; 427 element->qh_link->qh_rlink = element; 428} 429 430static __inline void 431remque(void *a) 432{ 433 struct quehead *element = a; 434 435 element->qh_link->qh_rlink = element->qh_rlink; 436 element->qh_rlink->qh_link = element->qh_link; 437 element->qh_rlink = 0; 438} 439 440#else /* !__GNUC__ */ 441 442void insque __P((void *a, void *b)); 443void remque __P((void *a)); 444 445#endif /* __GNUC__ */ 446 447#endif /* KERNEL */ 448 449#endif /* !_SYS_QUEUE_H_ */ 450