sys-queue.h

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