qemu-queue.h

   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_ */