queue.h revision 14940
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 1.7 1996/03/11 02:14:38 hsu 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_INIT(head) { \ 107 (head)->slh_first = NULL; \ 108} 109 110#define SLIST_INSERT_AFTER(slistelm, elm, field) { \ 111 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 112 (slistelm)->field.sle_next = (elm); \ 113} 114 115#define SLIST_INSERT_HEAD(head, elm, field) { \ 116 (elm)->field.sle_next = (head)->slh_first; \ 117 (head)->slh_first = (elm); \ 118} 119 120#define SLIST_REMOVE_HEAD(head, field) { \ 121 (head)->slh_first = (head)->slh_first->field.sle_next; \ 122} 123 124#define SLIST_REMOVE(head, elm, type, field) { \ 125 if ((head)->slh_first == (elm)) { \ 126 SLIST_REMOVE_HEAD((head), field); \ 127 } \ 128 else { \ 129 struct type *curelm = (head)->slh_first; \ 130 while( curelm->field.sle_next != (elm) ) \ 131 curelm = curelm->field.sle_next; \ 132 curelm->field.sle_next = \ 133 curelm->field.sle_next->field.sle_next; \ 134 } \ 135} 136 137/* 138 * Singly-linked Tail queue definitions. 139 */ 140#define STAILQ_HEAD(name, type) \ 141struct name { \ 142 struct type *stqh_first;/* first element */ \ 143 struct type **stqh_last;/* addr of last next element */ \ 144} 145 146#define STAILQ_ENTRY(type) \ 147struct { \ 148 struct type *stqe_next; /* next element */ \ 149} 150 151/* 152 * Singly-linked Tail queue functions. 153 */ 154#define STAILQ_INIT(head) { \ 155 (head)->stqh_first = NULL; \ 156 (head)->stqh_last = &(head)->stqh_first; \ 157} 158 159#define STAILQ_INSERT_HEAD(head, elm, field) { \ 160 if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \ 161 (head)->stqh_last = &(elm)->field.stqe_next; \ 162 (head)->stqh_first = (elm); \ 163} 164 165#define STAILQ_INSERT_TAIL(head, elm, field) { \ 166 (elm)->field.stqe_next = NULL; \ 167 *(head)->stqh_last = (elm); \ 168 (head)->stqh_last = &(elm)->field.stqe_next; \ 169} 170 171#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) { \ 172 if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\ 173 (head)->stqh_last = &(elm)->field.stqe_next; \ 174 (tqelm)->field.stqe_next = (elm); \ 175} 176 177#define STAILQ_REMOVE_HEAD(head, field) { \ 178 if (((head)->stqh_first = \ 179 (head)->stqh_first->field.stqe_next) == NULL) \ 180 (head)->stqh_last = &(head)->stqh_first; \ 181} 182 183#define STAILQ_REMOVE(head, elm, type, field) { \ 184 if ((head)->stqh_first == (elm)) { \ 185 STAILQ_REMOVE_HEAD(head, field); \ 186 } \ 187 else { \ 188 struct type *curelm = (head)->stqh_first; \ 189 while( curelm->field.stqe_next != (elm) ) \ 190 curelm = curelm->field.stqe_next; \ 191 if((curelm->field.stqe_next = \ 192 curelm->field.stqe_next->field.stqe_next) == NULL) \ 193 (head)->stqh_last = &(curelm)->field.stqe_next; \ 194 } \ 195} 196 197/* 198 * List definitions. 199 */ 200#define LIST_HEAD(name, type) \ 201struct name { \ 202 struct type *lh_first; /* first element */ \ 203} 204 205#define LIST_ENTRY(type) \ 206struct { \ 207 struct type *le_next; /* next element */ \ 208 struct type **le_prev; /* address of previous next element */ \ 209} 210 211/* 212 * List functions. 213 */ 214#define LIST_INIT(head) { \ 215 (head)->lh_first = NULL; \ 216} 217 218#define LIST_INSERT_AFTER(listelm, elm, field) { \ 219 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 220 (listelm)->field.le_next->field.le_prev = \ 221 &(elm)->field.le_next; \ 222 (listelm)->field.le_next = (elm); \ 223 (elm)->field.le_prev = &(listelm)->field.le_next; \ 224} 225 226#define LIST_INSERT_BEFORE(listelm, elm, field) { \ 227 (elm)->field.le_prev = (listelm)->field.le_prev; \ 228 (elm)->field.le_next = (listelm); \ 229 *(listelm)->field.le_prev = (elm); \ 230 (listelm)->field.le_prev = &(elm)->field.le_next; \ 231} 232 233#define LIST_INSERT_HEAD(head, elm, field) { \ 234 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 235 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 236 (head)->lh_first = (elm); \ 237 (elm)->field.le_prev = &(head)->lh_first; \ 238} 239 240#define LIST_REMOVE(elm, field) { \ 241 if ((elm)->field.le_next != NULL) \ 242 (elm)->field.le_next->field.le_prev = \ 243 (elm)->field.le_prev; \ 244 *(elm)->field.le_prev = (elm)->field.le_next; \ 245} 246 247/* 248 * Tail queue definitions. 249 */ 250#define TAILQ_HEAD(name, type) \ 251struct name { \ 252 struct type *tqh_first; /* first element */ \ 253 struct type **tqh_last; /* addr of last next element */ \ 254} 255 256#define TAILQ_ENTRY(type) \ 257struct { \ 258 struct type *tqe_next; /* next element */ \ 259 struct type **tqe_prev; /* address of previous next element */ \ 260} 261 262/* 263 * Tail queue functions. 264 */ 265#define TAILQ_INIT(head) { \ 266 (head)->tqh_first = NULL; \ 267 (head)->tqh_last = &(head)->tqh_first; \ 268} 269 270#define TAILQ_INSERT_HEAD(head, elm, field) { \ 271 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 272 (head)->tqh_first->field.tqe_prev = \ 273 &(elm)->field.tqe_next; \ 274 else \ 275 (head)->tqh_last = &(elm)->field.tqe_next; \ 276 (head)->tqh_first = (elm); \ 277 (elm)->field.tqe_prev = &(head)->tqh_first; \ 278} 279 280#define TAILQ_INSERT_TAIL(head, elm, field) { \ 281 (elm)->field.tqe_next = NULL; \ 282 (elm)->field.tqe_prev = (head)->tqh_last; \ 283 *(head)->tqh_last = (elm); \ 284 (head)->tqh_last = &(elm)->field.tqe_next; \ 285} 286 287#define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ 288 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 289 (elm)->field.tqe_next->field.tqe_prev = \ 290 &(elm)->field.tqe_next; \ 291 else \ 292 (head)->tqh_last = &(elm)->field.tqe_next; \ 293 (listelm)->field.tqe_next = (elm); \ 294 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 295} 296 297#define TAILQ_INSERT_BEFORE(listelm, elm, field) { \ 298 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 299 (elm)->field.tqe_next = (listelm); \ 300 *(listelm)->field.tqe_prev = (elm); \ 301 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 302} 303 304#define TAILQ_REMOVE(head, elm, field) { \ 305 if (((elm)->field.tqe_next) != NULL) \ 306 (elm)->field.tqe_next->field.tqe_prev = \ 307 (elm)->field.tqe_prev; \ 308 else \ 309 (head)->tqh_last = (elm)->field.tqe_prev; \ 310 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 311} 312 313/* 314 * Circular queue definitions. 315 */ 316#define CIRCLEQ_HEAD(name, type) \ 317struct name { \ 318 struct type *cqh_first; /* first element */ \ 319 struct type *cqh_last; /* last element */ \ 320} 321 322#define CIRCLEQ_ENTRY(type) \ 323struct { \ 324 struct type *cqe_next; /* next element */ \ 325 struct type *cqe_prev; /* previous element */ \ 326} 327 328/* 329 * Circular queue functions. 330 */ 331#define CIRCLEQ_INIT(head) { \ 332 (head)->cqh_first = (void *)(head); \ 333 (head)->cqh_last = (void *)(head); \ 334} 335 336#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ 337 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 338 (elm)->field.cqe_prev = (listelm); \ 339 if ((listelm)->field.cqe_next == (void *)(head)) \ 340 (head)->cqh_last = (elm); \ 341 else \ 342 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 343 (listelm)->field.cqe_next = (elm); \ 344} 345 346#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ 347 (elm)->field.cqe_next = (listelm); \ 348 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 349 if ((listelm)->field.cqe_prev == (void *)(head)) \ 350 (head)->cqh_first = (elm); \ 351 else \ 352 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 353 (listelm)->field.cqe_prev = (elm); \ 354} 355 356#define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ 357 (elm)->field.cqe_next = (head)->cqh_first; \ 358 (elm)->field.cqe_prev = (void *)(head); \ 359 if ((head)->cqh_last == (void *)(head)) \ 360 (head)->cqh_last = (elm); \ 361 else \ 362 (head)->cqh_first->field.cqe_prev = (elm); \ 363 (head)->cqh_first = (elm); \ 364} 365 366#define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ 367 (elm)->field.cqe_next = (void *)(head); \ 368 (elm)->field.cqe_prev = (head)->cqh_last; \ 369 if ((head)->cqh_first == (void *)(head)) \ 370 (head)->cqh_first = (elm); \ 371 else \ 372 (head)->cqh_last->field.cqe_next = (elm); \ 373 (head)->cqh_last = (elm); \ 374} 375 376#define CIRCLEQ_REMOVE(head, elm, field) { \ 377 if ((elm)->field.cqe_next == (void *)(head)) \ 378 (head)->cqh_last = (elm)->field.cqe_prev; \ 379 else \ 380 (elm)->field.cqe_next->field.cqe_prev = \ 381 (elm)->field.cqe_prev; \ 382 if ((elm)->field.cqe_prev == (void *)(head)) \ 383 (head)->cqh_first = (elm)->field.cqe_next; \ 384 else \ 385 (elm)->field.cqe_prev->field.cqe_next = \ 386 (elm)->field.cqe_next; \ 387} 388 389#ifdef KERNEL 390 391/* 392 * XXX insque() and remque() are an old way of handling certain queues. 393 * They bogusly assumes that all queue heads look alike. 394 */ 395 396struct quehead { 397 struct quehead *qh_link; 398 struct quehead *qh_rlink; 399}; 400 401#ifdef __GNUC__ 402 403static __inline void 404insque(void *a, void *b) 405{ 406 struct quehead *element = a, *head = b; 407 408 element->qh_link = head->qh_link; 409 element->qh_rlink = head; 410 head->qh_link = element; 411 element->qh_link->qh_rlink = element; 412} 413 414static __inline void 415remque(void *a) 416{ 417 struct quehead *element = a; 418 419 element->qh_link->qh_rlink = element->qh_rlink; 420 element->qh_rlink->qh_link = element->qh_link; 421 element->qh_rlink = 0; 422} 423 424#else /* !__GNUC__ */ 425 426void insque __P((void *a, void *b)); 427void remque __P((void *a)); 428 429#endif /* __GNUC__ */ 430 431#endif /* KERNEL */ 432 433#endif /* !_SYS_QUEUE_H_ */ 434