lib/libpthread/pthread_queue.h

   1 /*      $NetBSD: pthread_queue.h,v 1.4 2008/04/28 20:23:01 martin Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Nathan J. Williams.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #ifndef _LIB_PTHREAD_QUEUE_H
  33 #define _LIB_PTHREAD_QUEUE_H
  34
  35 /*
  36  * Definition of a queue interface for the pthread library.
  37  * Style modeled on the sys/queue.h macros; implementation taken from
  38  * the tail queue, with the added property of static initializability
  39  * (and a corresponding extra cost in the _INSERT_TAIL() function.
  40 */
  41
  42 /*
  43  * Queue definitions.
  44  */
  45
  46 #define PTQ_HEAD(name, type)                                            \
  47 struct name {                                                           \
  48         struct type *ptqh_first;/* first element */                     \
  49         struct type **ptqh_last;/* addr of last next element */         \
  50 }
  51
  52 #define PTQ_HEAD_INITIALIZER { NULL, NULL }
  53
  54 #define PTQ_ENTRY(type)                                                 \
  55 struct {                                                                \
  56         struct type *ptqe_next; /* next element */                      \
  57         struct type **ptqe_prev;/* address of previous next element */  \
  58 }
  59
  60 /*
  61  * Queue functions.
  62  */
  63
  64 #define PTQ_INIT(head) do {                                             \
  65         (head)->ptqh_first = NULL;                                      \
  66         (head)->ptqh_last = &(head)->ptqh_first;                        \
  67 } while (/*CONSTCOND*/0)
  68
  69 #define PTQ_INSERT_HEAD(head, elm, field) do {                          \
  70         if (((elm)->field.ptqe_next = (head)->ptqh_first) != NULL)      \
  71                 (head)->ptqh_first->field.ptqe_prev =                   \
  72                     &(elm)->field.ptqe_next;                            \
  73         else                                                            \
  74                 (head)->ptqh_last = &(elm)->field.ptqe_next;            \
  75         (head)->ptqh_first = (elm);                                     \
  76         (elm)->field.ptqe_prev = &(head)->ptqh_first;                   \
  77 } while (/*CONSTCOND*/0)
  78
  79 #define PTQ_INSERT_TAIL(head, elm, field) do {                          \
  80         (elm)->field.ptqe_next = NULL;                                  \
  81         if ((head)->ptqh_last == NULL)                                  \
  82                 (head)->ptqh_last = &(head)->ptqh_first;                \
  83         (elm)->field.ptqe_prev = (head)->ptqh_last;                     \
  84         *(head)->ptqh_last = (elm);                                     \
  85         (head)->ptqh_last = &(elm)->field.ptqe_next;                    \
  86 } while (/*CONSTCOND*/0)
  87
  88 #define PTQ_INSERT_AFTER(head, listelm, elm, field) do {                \
  89         if (((elm)->field.ptqe_next = (listelm)->field.ptqe_next) != NULL)\
  90                 (elm)->field.ptqe_next->field.ptqe_prev =               \
  91                     &(elm)->field.ptqe_next;                            \
  92         else                                                            \
  93                 (head)->ptqh_last = &(elm)->field.ptqe_next;            \
  94         (listelm)->field.ptqe_next = (elm);                             \
  95         (elm)->field.ptqe_prev = &(listelm)->field.ptqe_next;           \
  96 } while (/*CONSTCOND*/0)
  97
  98 #define PTQ_INSERT_BEFORE(listelm, elm, field) do {                     \
  99         (elm)->field.ptqe_prev = (listelm)->field.ptqe_prev;            \
 100         (elm)->field.ptqe_next = (listelm);                             \
 101         *(listelm)->field.ptqe_prev = (elm);                            \
 102         (listelm)->field.ptqe_prev = &(elm)->field.ptqe_next;           \
 103 } while (/*CONSTCOND*/0)
 104
 105 #define PTQ_REMOVE(head, elm, field) do {                               \
 106         if (((elm)->field.ptqe_next) != NULL)                           \
 107                 (elm)->field.ptqe_next->field.ptqe_prev =               \
 108                     (elm)->field.ptqe_prev;                             \
 109         else                                                            \
 110                 (head)->ptqh_last = (elm)->field.ptqe_prev;             \
 111         *(elm)->field.ptqe_prev = (elm)->field.ptqe_next;               \
 112 } while (/*CONSTCOND*/0)
 113
 114 /*
 115  * Queue access methods.
 116  */
 117
 118 #define PTQ_EMPTY(head)                 ((head)->ptqh_first == NULL)
 119 #define PTQ_FIRST(head)                 ((head)->ptqh_first)
 120 #define PTQ_NEXT(elm, field)            ((elm)->field.ptqe_next)
 121
 122 #define PTQ_LAST(head, headname)                                        \
 123         (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last))
 124 #define PTQ_PREV(elm, headname, field)                                  \
 125         (*(((struct headname *)(void *)((elm)->field.ptqe_prev))->ptqh_last))
 126
 127 #define PTQ_FOREACH(var, head, field)                                   \
 128         for ((var) = ((head)->ptqh_first);                              \
 129                 (var);                                                  \
 130                 (var) = ((var)->field.ptqe_next))
 131
 132 #define PTQ_FOREACH_REVERSE(var, head, headname, field)                 \
 133         for ((var) = (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last));  \
 134                 (var);                                                  \
 135                 (var) = (*(((struct headname *)(void *)((var)->field.ptqe_prev))->ptqh_last)))
 136
 137 #endif /* _LIB_PTHREAD_QUEUE_H */