sys-queue.h

   1 /*      $NetBSD: queue.h,v 1.45.14.1 2007/07/18 20:13:24 liamjfoy Exp $ */
   2
   3 /*
   4  * Qemu version: Copy from netbsd, removed debug code, removed some of
   5  * the implementations.  Left in lists, tail queues and circular queues.
   6  */
   7
   8 /*
   9  * Copyright (c) 1991, 1993
  10  *      The Regents of the University of California.  All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  37  */
  38
  39 #ifndef _SYS_QUEUE_H_
  40 #define _SYS_QUEUE_H_
  41
  42 /*
  43  * This file defines three types of data structures:
  44  * lists, tail queues, and circular queues.
  45  *
  46  * A list is headed by a single forward pointer (or an array of forward
  47  * pointers for a hash table header). The elements are doubly linked
  48  * so that an arbitrary element can be removed without a need to
  49  * traverse the list. New elements can be added to the list before
  50  * or after an existing element or at the head of the list. A list
  51  * may only be traversed in the forward direction.
  52  *
  53  * A tail queue is headed by a pair of pointers, one to the head of the
  54  * list and the other to the tail of the list. The elements are doubly
  55  * linked so that an arbitrary element can be removed without a need to
  56  * traverse the list. New elements can be added to the list before or
  57  * after an existing element, at the head of the list, or at the end of
  58  * the list. A tail queue may be traversed in either direction.
  59  *
  60  * A circle queue is headed by a pair of pointers, one to the head of the
  61  * list and the other to the tail of the list. The elements are doubly
  62  * linked so that an arbitrary element can be removed without a need to
  63  * traverse the list. New elements can be added to the list before or after
  64  * an existing element, at the head of the list, or at the end of the list.
  65  * A circle queue may be traversed in either direction, but has a more
  66  * complex end of list detection.
  67  *
  68  * For details on the use of these macros, see the queue(3) manual page.
  69  */
  70
  71 /*
  72  * List definitions.
  73  */
  74 #define LIST_HEAD(name, type)                                           \
  75 struct name {                                                           \
  76         struct type *lh_first;  /* first element */                     \
  77 }
  78
  79 #define LIST_HEAD_INITIALIZER(head)                                     \
  80         { NULL }
  81
  82 #define LIST_ENTRY(type)                                                \
  83 struct {                                                                \
  84         struct type *le_next;   /* next element */                      \
  85         struct type **le_prev;  /* address of previous next element */  \
  86 }
  87
  88 /*
  89  * List functions.
  90  */
  91 #define LIST_INIT(head) do {                                            \
  92         (head)->lh_first = NULL;                                        \
  93 } while (/*CONSTCOND*/0)
  94
  95 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
  96         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
  97                 (listelm)->field.le_next->field.le_prev =               \
  98                     &(elm)->field.le_next;                              \
  99         (listelm)->field.le_next = (elm);                               \
 100         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 101 } while (/*CONSTCOND*/0)
 102
 103 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 104         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 105         (elm)->field.le_next = (listelm);                               \
 106         *(listelm)->field.le_prev = (elm);                              \
 107         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 108 } while (/*CONSTCOND*/0)
 109
 110 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 111         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 112                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 113         (head)->lh_first = (elm);                                       \
 114         (elm)->field.le_prev = &(head)->lh_first;                       \
 115 } while (/*CONSTCOND*/0)
 116
 117 #define LIST_REMOVE(elm, field) do {                                    \
 118         if ((elm)->field.le_next != NULL)                               \
 119                 (elm)->field.le_next->field.le_prev =                   \
 120                     (elm)->field.le_prev;                               \
 121         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 122 } while (/*CONSTCOND*/0)
 123
 124 #define LIST_FOREACH(var, head, field)                                  \
 125         for ((var) = ((head)->lh_first);                                \
 126                 (var);                                                  \
 127                 (var) = ((var)->field.le_next))
 128
 129 /*
 130  * List access methods.
 131  */
 132 #define LIST_EMPTY(head)                ((head)->lh_first == NULL)
 133 #define LIST_FIRST(head)                ((head)->lh_first)
 134 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 135
 136
 137 /*
 138  * Tail queue definitions.
 139  */
 140 #define _TAILQ_HEAD(name, type, qual)                                   \
 141 struct name {                                                           \
 142         qual type *tqh_first;           /* first element */             \
 143         qual type *qual *tqh_last;      /* addr of last next element */ \
 144 }
 145 #define TAILQ_HEAD(name, type)  _TAILQ_HEAD(name, struct type,)
 146
 147 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 148         { NULL, &(head).tqh_first }
 149
 150 #define _TAILQ_ENTRY(type, qual)                                        \
 151 struct {                                                                \
 152         qual type *tqe_next;            /* next element */              \
 153         qual type *qual *tqe_prev;      /* address of previous next element */\
 154 }
 155 #define TAILQ_ENTRY(type)       _TAILQ_ENTRY(struct type,)
 156
 157 /*
 158  * Tail queue functions.
 159  */
 160 #define TAILQ_INIT(head) do {                                           \
 161         (head)->tqh_first = NULL;                                       \
 162         (head)->tqh_last = &(head)->tqh_first;                          \
 163 } while (/*CONSTCOND*/0)
 164
 165 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 166         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 167                 (head)->tqh_first->field.tqe_prev =                     \
 168                     &(elm)->field.tqe_next;                             \
 169         else                                                            \
 170                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 171         (head)->tqh_first = (elm);                                      \
 172         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 173 } while (/*CONSTCOND*/0)
 174
 175 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 176         (elm)->field.tqe_next = NULL;                                   \
 177         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 178         *(head)->tqh_last = (elm);                                      \
 179         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 180 } while (/*CONSTCOND*/0)
 181
 182 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 183         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 184                 (elm)->field.tqe_next->field.tqe_prev =                 \
 185                     &(elm)->field.tqe_next;                             \
 186         else                                                            \
 187                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 188         (listelm)->field.tqe_next = (elm);                              \
 189         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 190 } while (/*CONSTCOND*/0)
 191
 192 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 193         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 194         (elm)->field.tqe_next = (listelm);                              \
 195         *(listelm)->field.tqe_prev = (elm);                             \
 196         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 197 } while (/*CONSTCOND*/0)
 198
 199 #define TAILQ_REMOVE(head, elm, field) do {                             \
 200         if (((elm)->field.tqe_next) != NULL)                            \
 201                 (elm)->field.tqe_next->field.tqe_prev =                 \
 202                     (elm)->field.tqe_prev;                              \
 203         else                                                            \
 204                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 205         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 206 } while (/*CONSTCOND*/0)
 207
 208 #define TAILQ_FOREACH(var, head, field)                                 \
 209         for ((var) = ((head)->tqh_first);                               \
 210                 (var);                                                  \
 211                 (var) = ((var)->field.tqe_next))
 212
 213 #define TAILQ_FOREACH_SAFE(var, head, field, next_var)                  \
 214         for ((var) = ((head)->tqh_first);                               \
 215                 (var) && ((next_var) = ((var)->field.tqe_next), 1);     \
 216                 (var) = (next_var))
 217
 218 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 219         for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \
 220                 (var);                                                  \
 221                 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
 222
 223 /*
 224  * Tail queue access methods.
 225  */
 226 #define TAILQ_EMPTY(head)               ((head)->tqh_first == NULL)
 227 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 228 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 229
 230 #define TAILQ_LAST(head, headname) \
 231         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 232 #define TAILQ_PREV(elm, headname, field) \
 233         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 234
 235
 236 /*
 237  * Circular queue definitions.
 238  */
 239 #define CIRCLEQ_HEAD(name, type)                                        \
 240 struct name {                                                           \
 241         struct type *cqh_first;         /* first element */             \
 242         struct type *cqh_last;          /* last element */              \
 243 }
 244
 245 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 246         { (void *)&head, (void *)&head }
 247
 248 #define CIRCLEQ_ENTRY(type)                                             \
 249 struct {                                                                \
 250         struct type *cqe_next;          /* next element */              \
 251         struct type *cqe_prev;          /* previous element */          \
 252 }
 253
 254 /*
 255  * Circular queue functions.
 256  */
 257 #define CIRCLEQ_INIT(head) do {                                         \
 258         (head)->cqh_first = (void *)(head);                             \
 259         (head)->cqh_last = (void *)(head);                              \
 260 } while (/*CONSTCOND*/0)
 261
 262 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 263         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 264         (elm)->field.cqe_prev = (listelm);                              \
 265         if ((listelm)->field.cqe_next == (void *)(head))                \
 266                 (head)->cqh_last = (elm);                               \
 267         else                                                            \
 268                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 269         (listelm)->field.cqe_next = (elm);                              \
 270 } while (/*CONSTCOND*/0)
 271
 272 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 273         (elm)->field.cqe_next = (listelm);                              \
 274         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 275         if ((listelm)->field.cqe_prev == (void *)(head))                \
 276                 (head)->cqh_first = (elm);                              \
 277         else                                                            \
 278                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 279         (listelm)->field.cqe_prev = (elm);                              \
 280 } while (/*CONSTCOND*/0)
 281
 282 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 283         (elm)->field.cqe_next = (head)->cqh_first;                      \
 284         (elm)->field.cqe_prev = (void *)(head);                         \
 285         if ((head)->cqh_last == (void *)(head))                         \
 286                 (head)->cqh_last = (elm);                               \
 287         else                                                            \
 288                 (head)->cqh_first->field.cqe_prev = (elm);              \
 289         (head)->cqh_first = (elm);                                      \
 290 } while (/*CONSTCOND*/0)
 291
 292 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 293         (elm)->field.cqe_next = (void *)(head);                         \
 294         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 295         if ((head)->cqh_first == (void *)(head))                        \
 296                 (head)->cqh_first = (elm);                              \
 297         else                                                            \
 298                 (head)->cqh_last->field.cqe_next = (elm);               \
 299         (head)->cqh_last = (elm);                                       \
 300 } while (/*CONSTCOND*/0)
 301
 302 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 303         if ((elm)->field.cqe_next == (void *)(head))                    \
 304                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 305         else                                                            \
 306                 (elm)->field.cqe_next->field.cqe_prev =                 \
 307                     (elm)->field.cqe_prev;                              \
 308         if ((elm)->field.cqe_prev == (void *)(head))                    \
 309                 (head)->cqh_first = (elm)->field.cqe_next;              \
 310         else                                                            \
 311                 (elm)->field.cqe_prev->field.cqe_next =                 \
 312                     (elm)->field.cqe_next;                              \
 313 } while (/*CONSTCOND*/0)
 314
 315 #define CIRCLEQ_FOREACH(var, head, field)                               \
 316         for ((var) = ((head)->cqh_first);                               \
 317                 (var) != (const void *)(head);                          \
 318                 (var) = ((var)->field.cqe_next))
 319
 320 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 321         for ((var) = ((head)->cqh_last);                                \
 322                 (var) != (const void *)(head);                          \
 323                 (var) = ((var)->field.cqe_prev))
 324
 325 /*
 326  * Circular queue access methods.
 327  */
 328 #define CIRCLEQ_EMPTY(head)             ((head)->cqh_first == (void *)(head))
 329 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 330 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 331 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 332 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 333
 334 #define CIRCLEQ_LOOP_NEXT(head, elm, field)                             \
 335         (((elm)->field.cqe_next == (void *)(head))                      \
 336             ? ((head)->cqh_first)                                       \
 337             : (elm->field.cqe_next))
 338 #define CIRCLEQ_LOOP_PREV(head, elm, field)                             \
 339         (((elm)->field.cqe_prev == (void *)(head))                      \
 340             ? ((head)->cqh_last)                                        \
 341             : (elm->field.cqe_prev))
 342
 343 #endif  /* !_SYS_QUEUE_H_ */