/*      $NetBSD: pthread_queue.h,v 1.7 2022/04/19 20:32:17 rillig Exp $ */

/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Nathan J. Williams.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef _LIB_PTHREAD_QUEUE_H
#define _LIB_PTHREAD_QUEUE_H

/*
* Definition of a queue interface for the pthread library.
* Style modeled on the sys/queue.h macros; implementation taken from
* the tail queue, with the added property of static initializability
* (and a corresponding extra cost in the _INSERT_TAIL() function.
*/

/*
* Queue definitions.
*/

#define PTQ_HEAD(name, type)                                            \
struct name {                                                           \
       struct type *ptqh_first;/* first element */                     \
       struct type **ptqh_last;/* addr of last next element */         \
}

#define PTQ_HEAD_INITIALIZER { NULL, NULL }

#define PTQ_ENTRY(type)                                                 \
struct {                                                                \
       struct type *ptqe_next; /* next element */                      \
       struct type **ptqe_prev;/* address of previous next element */  \
}

/*
* Queue functions.
*/

#define PTQ_INIT(head) do {                                             \
       (head)->ptqh_first = NULL;                                      \
       (head)->ptqh_last = &(head)->ptqh_first;                        \
} while (0)

#define PTQ_INSERT_HEAD(head, elm, field) do {                          \
       if (((elm)->field.ptqe_next = (head)->ptqh_first) != NULL)      \
               (head)->ptqh_first->field.ptqe_prev =                   \
                   &(elm)->field.ptqe_next;                            \
       else                                                            \
               (head)->ptqh_last = &(elm)->field.ptqe_next;            \
       (head)->ptqh_first = (elm);                                     \
       (elm)->field.ptqe_prev = &(head)->ptqh_first;                   \
} while (0)

#define PTQ_INSERT_TAIL(head, elm, field) do {                          \
       (elm)->field.ptqe_next = NULL;                                  \
       if ((head)->ptqh_last == NULL)                                  \
               (head)->ptqh_last = &(head)->ptqh_first;                \
       (elm)->field.ptqe_prev = (head)->ptqh_last;                     \
       *(head)->ptqh_last = (elm);                                     \
       (head)->ptqh_last = &(elm)->field.ptqe_next;                    \
} while (0)

#define PTQ_INSERT_AFTER(head, listelm, elm, field) do {                \
       if (((elm)->field.ptqe_next = (listelm)->field.ptqe_next) != NULL)\
               (elm)->field.ptqe_next->field.ptqe_prev =               \
                   &(elm)->field.ptqe_next;                            \
       else                                                            \
               (head)->ptqh_last = &(elm)->field.ptqe_next;            \
       (listelm)->field.ptqe_next = (elm);                             \
       (elm)->field.ptqe_prev = &(listelm)->field.ptqe_next;           \
} while (0)

#define PTQ_INSERT_BEFORE(listelm, elm, field) do {                     \
       (elm)->field.ptqe_prev = (listelm)->field.ptqe_prev;            \
       (elm)->field.ptqe_next = (listelm);                             \
       *(listelm)->field.ptqe_prev = (elm);                            \
       (listelm)->field.ptqe_prev = &(elm)->field.ptqe_next;           \
} while (0)

#define PTQ_REMOVE(head, elm, field) do {                               \
       if (((elm)->field.ptqe_next) != NULL)                           \
               (elm)->field.ptqe_next->field.ptqe_prev =               \
                   (elm)->field.ptqe_prev;                             \
       else                                                            \
               (head)->ptqh_last = (elm)->field.ptqe_prev;             \
       *(elm)->field.ptqe_prev = (elm)->field.ptqe_next;               \
} while (0)

/*
* Queue access methods.
*/

#define PTQ_EMPTY(head)                 ((head)->ptqh_first == NULL)
#define PTQ_FIRST(head)                 ((head)->ptqh_first)
#define PTQ_NEXT(elm, field)            ((elm)->field.ptqe_next)

#define PTQ_LAST(head, headname)                                        \
       (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last))
#define PTQ_PREV(elm, headname, field)                                  \
       (*(((struct headname *)(void *)((elm)->field.ptqe_prev))->ptqh_last))

#define PTQ_FOREACH(var, head, field)                                   \
       for ((var) = ((head)->ptqh_first);                              \
               (var);                                                  \
               (var) = ((var)->field.ptqe_next))

#define PTQ_FOREACH_REVERSE(var, head, headname, field)                 \
       for ((var) = (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last));  \
               (var);                                                  \
               (var) = (*(((struct headname *)(void *)((var)->field.ptqe_prev))->ptqh_last)))

#endif /* _LIB_PTHREAD_QUEUE_H */

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.