circ-queue.h

Go to the documentation of this file.

/*
 * Copyright (c) 1991, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *  @(#)queue.h 8.5 (Berkeley) 8/20/94
 * $FreeBSD: ports/misc/44bsd-more/files/queue.h,v 1.1 2001/01/06 03:41:36 hoek Exp $
 */
 
/*
 * Circular queue definitions.
 */
#define CIRCLEQ_HEAD(name, type)                    \
struct name {                               \
    struct type *cqh_first;     /* first element */     \
    struct type *cqh_last;      /* last element */      \
}
 
#define CIRCLEQ_ENTRY(type)                     \
struct {                                \
    struct type *cqe_next;      /* next element */      \
    struct type *cqe_prev;      /* previous element */      \
}
 
/*
 * Circular queue functions.
 */
#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
 
#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
 
#define CIRCLEQ_FOREACH(var, head, field)               \
    for((var) = (head)->cqh_first;                  \
        (var) != (void *)(head);                    \
        (var) = (var)->field.cqe_next)
 
#define CIRCLEQ_FOREACH_REVERSE(var, head, field)           \
    for((var) = (head)->cqh_last;                   \
        (var) != (void *)(head);                    \
        (var) = (var)->field.cqe_prev)
 
#define CIRCLEQ_INIT(head) do {                     \
    (head)->cqh_first = (void *)(head);             \
    (head)->cqh_last = (void *)(head);              \
} while (0)
 
#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {        \
    (elm)->field.cqe_next = (listelm)->field.cqe_next;      \
    (elm)->field.cqe_prev = (listelm);              \
    if ((listelm)->field.cqe_next == (void *)(head))        \
        (head)->cqh_last = (elm);               \
    else                                \
        (listelm)->field.cqe_next->field.cqe_prev = (elm);  \
    (listelm)->field.cqe_next = (elm);              \
} while (0)
 
#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {       \
    (elm)->field.cqe_next = (listelm);              \
    (elm)->field.cqe_prev = (listelm)->field.cqe_prev;      \
    if ((listelm)->field.cqe_prev == (void *)(head))        \
        (head)->cqh_first = (elm);              \
    else                                \
        (listelm)->field.cqe_prev->field.cqe_next = (elm);  \
    (listelm)->field.cqe_prev = (elm);              \
} while (0)
 
#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {          \
    (elm)->field.cqe_next = (head)->cqh_first;          \
    (elm)->field.cqe_prev = (void *)(head);             \
    if ((head)->cqh_last == (void *)(head))             \
        (head)->cqh_last = (elm);               \
    else                                \
        (head)->cqh_first->field.cqe_prev = (elm);      \
    (head)->cqh_first = (elm);                  \
} while (0)
 
#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {          \
    (elm)->field.cqe_next = (void *)(head);             \
    (elm)->field.cqe_prev = (head)->cqh_last;           \
    if ((head)->cqh_first == (void *)(head))            \
        (head)->cqh_first = (elm);              \
    else                                \
        (head)->cqh_last->field.cqe_next = (elm);       \
    (head)->cqh_last = (elm);                   \
} while (0)
 
#define CIRCLEQ_LAST(head) ((head)->cqh_last)
 
#define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
 
#define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
 
#define CIRCLEQ_REMOVE(head, elm, field) do {               \
    if ((elm)->field.cqe_next == (void *)(head))            \
        (head)->cqh_last = (elm)->field.cqe_prev;       \
    else                                \
        (elm)->field.cqe_next->field.cqe_prev =         \
            (elm)->field.cqe_prev;              \
    if ((elm)->field.cqe_prev == (void *)(head))            \
        (head)->cqh_first = (elm)->field.cqe_next;      \
    else                                \
        (elm)->field.cqe_prev->field.cqe_next =         \
            (elm)->field.cqe_next;              \
} while (0)