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_ */