audio/sys-queue.h

   1 /*
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)queue.h     8.3 (Berkeley) 12/13/93
  30  */
  31
  32 #ifndef _SYS_QUEUE_H
  33 #define _SYS_QUEUE_H 1
  34
  35 /*
  36  * This file defines three types of data structures: lists, tail queues,
  37  * and circular queues.
  38  *
  39  * A list is headed by a single forward pointer (or an array of forward
  40  * pointers for a hash table header). The elements are doubly linked
  41  * so that an arbitrary element can be removed without a need to
  42  * traverse the list. New elements can be added to the list after
  43  * an existing element or at the head of the list. A list may only be
  44  * traversed in the forward direction.
  45  *
  46  * A tail queue is headed by a pair of pointers, one to the head of the
  47  * list and the other to the tail of the list. The elements are doubly
  48  * linked so that an arbitrary element can be removed without a need to
  49  * traverse the list. New elements can be added to the list after
  50  * an existing element, at the head of the list, or at the end of the
  51  * list. A tail queue may only be traversed in the forward direction.
  52  *
  53  * A circle 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 after
  57  * an existing element, at the head of the list, or at the end of the list.
  58  * A circle queue may be traversed in either direction, but has a more
  59  * complex end of list detection.
  60  *
  61  * For details on the use of these macros, see the queue(3) manual page.
  62  */
  63
  64 /*
  65  * List definitions.
  66  */
  67 #define LIST_HEAD(name, type)                                           \
  68 struct name {                                                           \
  69         struct type *lh_first;  /* first element */                     \
  70 }
  71
  72 #define LIST_ENTRY(type)                                                \
  73 struct {                                                                \
  74         struct type *le_next;   /* next element */                      \
  75         struct type **le_prev;  /* address of previous next element */  \
  76 }
  77
  78 /*
  79  * List functions.
  80  */
  81 #define LIST_INIT(head) {                                               \
  82         (head)->lh_first = NULL;                                        \
  83 }
  84
  85 #define LIST_INSERT_AFTER(listelm, elm, field) {                        \
  86         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
  87                 (listelm)->field.le_next->field.le_prev =               \
  88                     &(elm)->field.le_next;                              \
  89         (listelm)->field.le_next = (elm);                               \
  90         (elm)->field.le_prev = &(listelm)->field.le_next;               \
  91 }
  92
  93 #define LIST_INSERT_HEAD(head, elm, field) {                            \
  94         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
  95                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
  96         (head)->lh_first = (elm);                                       \
  97         (elm)->field.le_prev = &(head)->lh_first;                       \
  98 }
  99
 100 #define LIST_REMOVE(elm, field) {                                       \
 101         if ((elm)->field.le_next != NULL)                               \
 102                 (elm)->field.le_next->field.le_prev =                   \
 103                     (elm)->field.le_prev;                               \
 104         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 105 }
 106
 107 /*
 108  * Tail queue definitions.
 109  */
 110 #define TAILQ_HEAD(name, type)                                          \
 111 struct name {                                                           \
 112         struct type *tqh_first; /* first element */                     \
 113         struct type **tqh_last; /* addr of last next element */         \
 114 }
 115
 116 #define TAILQ_ENTRY(type)                                               \
 117 struct {                                                                \
 118         struct type *tqe_next;  /* next element */                      \
 119         struct type **tqe_prev; /* address of previous next element */  \
 120 }
 121
 122 /*
 123  * Tail queue functions.
 124  */
 125 #define TAILQ_INIT(head) {                                              \
 126         (head)->tqh_first = NULL;                                       \
 127         (head)->tqh_last = &(head)->tqh_first;                          \
 128 }
 129
 130 #define TAILQ_INSERT_HEAD(head, elm, field) {                           \
 131         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 132                 (elm)->field.tqe_next->field.tqe_prev =                 \
 133                     &(elm)->field.tqe_next;                             \
 134         else                                                            \
 135                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 136         (head)->tqh_first = (elm);                                      \
 137         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 138 }
 139
 140 #define TAILQ_INSERT_TAIL(head, elm, field) {                           \
 141         (elm)->field.tqe_next = NULL;                                   \
 142         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 143         *(head)->tqh_last = (elm);                                      \
 144         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 145 }
 146
 147 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) {                 \
 148         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 149                 (elm)->field.tqe_next->field.tqe_prev =                 \
 150                     &(elm)->field.tqe_next;                             \
 151         else                                                            \
 152                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 153         (listelm)->field.tqe_next = (elm);                              \
 154         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 155 }
 156
 157 #define TAILQ_REMOVE(head, elm, field) {                                \
 158         if (((elm)->field.tqe_next) != NULL)                            \
 159                 (elm)->field.tqe_next->field.tqe_prev =                 \
 160                     (elm)->field.tqe_prev;                              \
 161         else                                                            \
 162                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 163         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 164 }
 165
 166 /*
 167  * Circular queue definitions.
 168  */
 169 #define CIRCLEQ_HEAD(name, type)                                        \
 170 struct name {                                                           \
 171         struct type *cqh_first;         /* first element */             \
 172         struct type *cqh_last;          /* last element */              \
 173 }
 174
 175 #define CIRCLEQ_ENTRY(type)                                             \
 176 struct {                                                                \
 177         struct type *cqe_next;          /* next element */              \
 178         struct type *cqe_prev;          /* previous element */          \
 179 }
 180
 181 /*
 182  * Circular queue functions.
 183  */
 184 #define CIRCLEQ_INIT(head) {                                            \
 185         (head)->cqh_first = (void *)(head);                             \
 186         (head)->cqh_last = (void *)(head);                              \
 187 }
 188
 189 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) {               \
 190         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 191         (elm)->field.cqe_prev = (listelm);                              \
 192         if ((listelm)->field.cqe_next == (void *)(head))                \
 193                 (head)->cqh_last = (elm);                               \
 194         else                                                            \
 195                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 196         (listelm)->field.cqe_next = (elm);                              \
 197 }
 198
 199 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) {              \
 200         (elm)->field.cqe_next = (listelm);                              \
 201         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 202         if ((listelm)->field.cqe_prev == (void *)(head))                \
 203                 (head)->cqh_first = (elm);                              \
 204         else                                                            \
 205                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 206         (listelm)->field.cqe_prev = (elm);                              \
 207 }
 208
 209 #define CIRCLEQ_INSERT_HEAD(head, elm, field) {                         \
 210         (elm)->field.cqe_next = (head)->cqh_first;                      \
 211         (elm)->field.cqe_prev = (void *)(head);                         \
 212         if ((head)->cqh_last == (void *)(head))                         \
 213                 (head)->cqh_last = (elm);                               \
 214         else                                                            \
 215                 (head)->cqh_first->field.cqe_prev = (elm);              \
 216         (head)->cqh_first = (elm);                                      \
 217 }
 218
 219 #define CIRCLEQ_INSERT_TAIL(head, elm, field) {                         \
 220         (elm)->field.cqe_next = (void *)(head);                         \
 221         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 222         if ((head)->cqh_first == (void *)(head))                        \
 223                 (head)->cqh_first = (elm);                              \
 224         else                                                            \
 225                 (head)->cqh_last->field.cqe_next = (elm);               \
 226         (head)->cqh_last = (elm);                                       \
 227 }
 228
 229 #define CIRCLEQ_REMOVE(head, elm, field) {                              \
 230         if ((elm)->field.cqe_next == (void *)(head))                    \
 231                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 232         else                                                            \
 233                 (elm)->field.cqe_next->field.cqe_prev =                 \
 234                     (elm)->field.cqe_prev;                              \
 235         if ((elm)->field.cqe_prev == (void *)(head))                    \
 236                 (head)->cqh_first = (elm)->field.cqe_next;              \
 237         else                                                            \
 238                 (elm)->field.cqe_prev->field.cqe_next =                 \
 239                     (elm)->field.cqe_next;                              \
 240 }
 241 #endif  /* sys/queue.h */