1 /* $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */ 2 3 /* 4 * Qemu version: Copy from netbsd, removed debug code, removed some of 5 * the implementations. Left in lists, simple queues, tail queues and 6 * circular queues. 7 */ 8 9 /* 10 * Copyright (c) 1991, 1993 11 * The Regents of the University of California. All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)queue.h 8.5 (Berkeley) 8/20/94 38 */ 39 40 #ifndef QEMU_SYS_QUEUE_H_ 41 #define QEMU_SYS_QUEUE_H_ 42 43 /* 44 * This file defines four types of data structures: 45 * lists, simple queues, tail queues, and circular queues. 46 * 47 * A list is headed by a single forward pointer (or an array of forward 48 * pointers for a hash table header). The elements are doubly linked 49 * so that an arbitrary element can be removed without a need to 50 * traverse the list. New elements can be added to the list before 51 * or after an existing element or at the head of the list. A list 52 * may only be traversed in the forward direction. 53 * 54 * A simple queue is headed by a pair of pointers, one the head of the 55 * list and the other to the tail of the list. The elements are singly 56 * linked to save space, so elements can only be removed from the 57 * head of the list. New elements can be added to the list after 58 * an existing element, at the head of the list, or at the end of the 59 * list. A simple queue may only be traversed in the forward direction. 60 * 61 * A tail queue is headed by a pair of pointers, one to the head of the 62 * list and the other to the tail of the list. The elements are doubly 63 * linked so that an arbitrary element can be removed without a need to 64 * traverse the list. New elements can be added to the list before or 65 * after an existing element, at the head of the list, or at the end of 66 * the list. A tail queue may be traversed in either direction. 67 * 68 * A circle queue is headed by a pair of pointers, one to the head of the 69 * list and the other to the tail of the list. The elements are doubly 70 * linked so that an arbitrary element can be removed without a need to 71 * traverse the list. New elements can be added to the list before or after 72 * an existing element, at the head of the list, or at the end of the list. 73 * A circle queue may be traversed in either direction, but has a more 74 * complex end of list detection. 75 * 76 * For details on the use of these macros, see the queue(3) manual page. 77 */ 78 79 /* 80 * List definitions. 81 */ 82 #define QLIST_HEAD(name, type) \ 83 struct name { \ 84 struct type *lh_first; /* first element */ \ 85 } 86 87 #define QLIST_HEAD_INITIALIZER(head) \ 88 { NULL } 89 90 #define QLIST_ENTRY(type) \ 91 struct { \ 92 struct type *le_next; /* next element */ \ 93 struct type **le_prev; /* address of previous next element */ \ 94 } 95 96 /* 97 * List functions. 98 */ 99 #define QLIST_INIT(head) do { \ 100 (head)->lh_first = NULL; \ 101 } while (/*CONSTCOND*/0) 102 103 #define QLIST_INSERT_AFTER(listelm, elm, field) do { \ 104 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 105 (listelm)->field.le_next->field.le_prev = \ 106 &(elm)->field.le_next; \ 107 (listelm)->field.le_next = (elm); \ 108 (elm)->field.le_prev = &(listelm)->field.le_next; \ 109 } while (/*CONSTCOND*/0) 110 111 #define QLIST_INSERT_BEFORE(listelm, elm, field) do { \ 112 (elm)->field.le_prev = (listelm)->field.le_prev; \ 113 (elm)->field.le_next = (listelm); \ 114 *(listelm)->field.le_prev = (elm); \ 115 (listelm)->field.le_prev = &(elm)->field.le_next; \ 116 } while (/*CONSTCOND*/0) 117 118 #define QLIST_INSERT_HEAD(head, elm, field) do { \ 119 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 120 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 121 (head)->lh_first = (elm); \ 122 (elm)->field.le_prev = &(head)->lh_first; \ 123 } while (/*CONSTCOND*/0) 124 125 #define QLIST_REMOVE(elm, field) do { \ 126 if ((elm)->field.le_next != NULL) \ 127 (elm)->field.le_next->field.le_prev = \ 128 (elm)->field.le_prev; \ 129 *(elm)->field.le_prev = (elm)->field.le_next; \ 130 } while (/*CONSTCOND*/0) 131 132 #define QLIST_FOREACH(var, head, field) \ 133 for ((var) = ((head)->lh_first); \ 134 (var); \ 135 (var) = ((var)->field.le_next)) 136 137 #define QLIST_FOREACH_SAFE(var, head, field, next_var) \ 138 for ((var) = ((head)->lh_first); \ 139 (var) && ((next_var) = ((var)->field.le_next), 1); \ 140 (var) = (next_var)) 141 142 /* 143 * List access methods. 144 */ 145 #define QLIST_EMPTY(head) ((head)->lh_first == NULL) 146 #define QLIST_FIRST(head) ((head)->lh_first) 147 #define QLIST_NEXT(elm, field) ((elm)->field.le_next) 148 149 150 /* 151 * Simple queue definitions. 152 */ 153 #define QSIMPLEQ_HEAD(name, type) \ 154 struct name { \ 155 struct type *sqh_first; /* first element */ \ 156 struct type **sqh_last; /* addr of last next element */ \ 157 } 158 159 #define QSIMPLEQ_HEAD_INITIALIZER(head) \ 160 { NULL, &(head).sqh_first } 161 162 #define QSIMPLEQ_ENTRY(type) \ 163 struct { \ 164 struct type *sqe_next; /* next element */ \ 165 } 166 167 /* 168 * Simple queue functions. 169 */ 170 #define QSIMPLEQ_INIT(head) do { \ 171 (head)->sqh_first = NULL; \ 172 (head)->sqh_last = &(head)->sqh_first; \ 173 } while (/*CONSTCOND*/0) 174 175 #define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 176 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 177 (head)->sqh_last = &(elm)->field.sqe_next; \ 178 (head)->sqh_first = (elm); \ 179 } while (/*CONSTCOND*/0) 180 181 #define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 182 (elm)->field.sqe_next = NULL; \ 183 *(head)->sqh_last = (elm); \ 184 (head)->sqh_last = &(elm)->field.sqe_next; \ 185 } while (/*CONSTCOND*/0) 186 187 #define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 188 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 189 (head)->sqh_last = &(elm)->field.sqe_next; \ 190 (listelm)->field.sqe_next = (elm); \ 191 } while (/*CONSTCOND*/0) 192 193 #define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ 194 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ 195 (head)->sqh_last = &(head)->sqh_first; \ 196 } while (/*CONSTCOND*/0) 197 198 #define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ 199 if ((head)->sqh_first == (elm)) { \ 200 QSIMPLEQ_REMOVE_HEAD((head), field); \ 201 } else { \ 202 struct type *curelm = (head)->sqh_first; \ 203 while (curelm->field.sqe_next != (elm)) \ 204 curelm = curelm->field.sqe_next; \ 205 if ((curelm->field.sqe_next = \ 206 curelm->field.sqe_next->field.sqe_next) == NULL) \ 207 (head)->sqh_last = &(curelm)->field.sqe_next; \ 208 } \ 209 } while (/*CONSTCOND*/0) 210 211 #define QSIMPLEQ_FOREACH(var, head, field) \ 212 for ((var) = ((head)->sqh_first); \ 213 (var); \ 214 (var) = ((var)->field.sqe_next)) 215 216 #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 217 for ((var) = ((head)->sqh_first); \ 218 (var) && ((next = ((var)->field.sqe_next)), 1); \ 219 (var) = (next)) 220 221 #define QSIMPLEQ_CONCAT(head1, head2) do { \ 222 if (!QSIMPLEQ_EMPTY((head2))) { \ 223 *(head1)->sqh_last = (head2)->sqh_first; \ 224 (head1)->sqh_last = (head2)->sqh_last; \ 225 QSIMPLEQ_INIT((head2)); \ 226 } \ 227 } while (/*CONSTCOND*/0) 228 229 #define QSIMPLEQ_LAST(head, type, field) \ 230 (QSIMPLEQ_EMPTY((head)) ? \ 231 NULL : \ 232 ((struct type *)(void *) \ 233 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 234 235 /* 236 * Simple queue access methods. 237 */ 238 #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 239 #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 240 #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 241 242 243 /* 244 * Tail queue definitions. 245 */ 246 #define Q_TAILQ_HEAD(name, type, qual) \ 247 struct name { \ 248 qual type *tqh_first; /* first element */ \ 249 qual type *qual *tqh_last; /* addr of last next element */ \ 250 } 251 #define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,) 252 253 #define QTAILQ_HEAD_INITIALIZER(head) \ 254 { NULL, &(head).tqh_first } 255 256 #define Q_TAILQ_ENTRY(type, qual) \ 257 struct { \ 258 qual type *tqe_next; /* next element */ \ 259 qual type *qual *tqe_prev; /* address of previous next element */\ 260 } 261 #define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,) 262 263 /* 264 * Tail queue functions. 265 */ 266 #define QTAILQ_INIT(head) do { \ 267 (head)->tqh_first = NULL; \ 268 (head)->tqh_last = &(head)->tqh_first; \ 269 } while (/*CONSTCOND*/0) 270 271 #define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 272 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 273 (head)->tqh_first->field.tqe_prev = \ 274 &(elm)->field.tqe_next; \ 275 else \ 276 (head)->tqh_last = &(elm)->field.tqe_next; \ 277 (head)->tqh_first = (elm); \ 278 (elm)->field.tqe_prev = &(head)->tqh_first; \ 279 } while (/*CONSTCOND*/0) 280 281 #define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 282 (elm)->field.tqe_next = NULL; \ 283 (elm)->field.tqe_prev = (head)->tqh_last; \ 284 *(head)->tqh_last = (elm); \ 285 (head)->tqh_last = &(elm)->field.tqe_next; \ 286 } while (/*CONSTCOND*/0) 287 288 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 289 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 290 (elm)->field.tqe_next->field.tqe_prev = \ 291 &(elm)->field.tqe_next; \ 292 else \ 293 (head)->tqh_last = &(elm)->field.tqe_next; \ 294 (listelm)->field.tqe_next = (elm); \ 295 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 296 } while (/*CONSTCOND*/0) 297 298 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 299 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 300 (elm)->field.tqe_next = (listelm); \ 301 *(listelm)->field.tqe_prev = (elm); \ 302 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 303 } while (/*CONSTCOND*/0) 304 305 #define QTAILQ_REMOVE(head, elm, field) do { \ 306 if (((elm)->field.tqe_next) != NULL) \ 307 (elm)->field.tqe_next->field.tqe_prev = \ 308 (elm)->field.tqe_prev; \ 309 else \ 310 (head)->tqh_last = (elm)->field.tqe_prev; \ 311 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 312 } while (/*CONSTCOND*/0) 313 314 #define QTAILQ_FOREACH(var, head, field) \ 315 for ((var) = ((head)->tqh_first); \ 316 (var); \ 317 (var) = ((var)->field.tqe_next)) 318 319 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 320 for ((var) = ((head)->tqh_first); \ 321 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 322 (var) = (next_var)) 323 324 #define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \ 325 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 326 (var); \ 327 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 328 329 /* 330 * Tail queue access methods. 331 */ 332 #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 333 #define QTAILQ_FIRST(head) ((head)->tqh_first) 334 #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 335 336 #define QTAILQ_LAST(head, headname) \ 337 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 338 #define QTAILQ_PREV(elm, headname, field) \ 339 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 340 341 342 /* 343 * Circular queue definitions. 344 */ 345 #define QCIRCLEQ_HEAD(name, type) \ 346 struct name { \ 347 struct type *cqh_first; /* first element */ \ 348 struct type *cqh_last; /* last element */ \ 349 } 350 351 #define QCIRCLEQ_HEAD_INITIALIZER(head) \ 352 { (void *)&head, (void *)&head } 353 354 #define QCIRCLEQ_ENTRY(type) \ 355 struct { \ 356 struct type *cqe_next; /* next element */ \ 357 struct type *cqe_prev; /* previous element */ \ 358 } 359 360 /* 361 * Circular queue functions. 362 */ 363 #define QCIRCLEQ_INIT(head) do { \ 364 (head)->cqh_first = (void *)(head); \ 365 (head)->cqh_last = (void *)(head); \ 366 } while (/*CONSTCOND*/0) 367 368 #define QCIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 369 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 370 (elm)->field.cqe_prev = (listelm); \ 371 if ((listelm)->field.cqe_next == (void *)(head)) \ 372 (head)->cqh_last = (elm); \ 373 else \ 374 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 375 (listelm)->field.cqe_next = (elm); \ 376 } while (/*CONSTCOND*/0) 377 378 #define QCIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \ 379 (elm)->field.cqe_next = (listelm); \ 380 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 381 if ((listelm)->field.cqe_prev == (void *)(head)) \ 382 (head)->cqh_first = (elm); \ 383 else \ 384 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 385 (listelm)->field.cqe_prev = (elm); \ 386 } while (/*CONSTCOND*/0) 387 388 #define QCIRCLEQ_INSERT_HEAD(head, elm, field) do { \ 389 (elm)->field.cqe_next = (head)->cqh_first; \ 390 (elm)->field.cqe_prev = (void *)(head); \ 391 if ((head)->cqh_last == (void *)(head)) \ 392 (head)->cqh_last = (elm); \ 393 else \ 394 (head)->cqh_first->field.cqe_prev = (elm); \ 395 (head)->cqh_first = (elm); \ 396 } while (/*CONSTCOND*/0) 397 398 #define QCIRCLEQ_INSERT_TAIL(head, elm, field) do { \ 399 (elm)->field.cqe_next = (void *)(head); \ 400 (elm)->field.cqe_prev = (head)->cqh_last; \ 401 if ((head)->cqh_first == (void *)(head)) \ 402 (head)->cqh_first = (elm); \ 403 else \ 404 (head)->cqh_last->field.cqe_next = (elm); \ 405 (head)->cqh_last = (elm); \ 406 } while (/*CONSTCOND*/0) 407 408 #define QCIRCLEQ_REMOVE(head, elm, field) do { \ 409 if ((elm)->field.cqe_next == (void *)(head)) \ 410 (head)->cqh_last = (elm)->field.cqe_prev; \ 411 else \ 412 (elm)->field.cqe_next->field.cqe_prev = \ 413 (elm)->field.cqe_prev; \ 414 if ((elm)->field.cqe_prev == (void *)(head)) \ 415 (head)->cqh_first = (elm)->field.cqe_next; \ 416 else \ 417 (elm)->field.cqe_prev->field.cqe_next = \ 418 (elm)->field.cqe_next; \ 419 } while (/*CONSTCOND*/0) 420 421 #define QCIRCLEQ_FOREACH(var, head, field) \ 422 for ((var) = ((head)->cqh_first); \ 423 (var) != (const void *)(head); \ 424 (var) = ((var)->field.cqe_next)) 425 426 #define QCIRCLEQ_FOREACH_REVERSE(var, head, field) \ 427 for ((var) = ((head)->cqh_last); \ 428 (var) != (const void *)(head); \ 429 (var) = ((var)->field.cqe_prev)) 430 431 /* 432 * Circular queue access methods. 433 */ 434 #define QCIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head)) 435 #define QCIRCLEQ_FIRST(head) ((head)->cqh_first) 436 #define QCIRCLEQ_LAST(head) ((head)->cqh_last) 437 #define QCIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next) 438 #define QCIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev) 439 440 #define QCIRCLEQ_LOOP_NEXT(head, elm, field) \ 441 (((elm)->field.cqe_next == (void *)(head)) \ 442 ? ((head)->cqh_first) \ 443 : (elm->field.cqe_next)) 444 #define QCIRCLEQ_LOOP_PREV(head, elm, field) \ 445 (((elm)->field.cqe_prev == (void *)(head)) \ 446 ? ((head)->cqh_last) \ 447 : (elm->field.cqe_prev)) 448 449 #endif /* !QEMU_SYS_QUEUE_H_ */ 450