include/isc/list.h

	list.h revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright (c) 1998-2001 by Sun Microsystems, Inc.
 * All rights reserved.
 */

/*
 * Copyright (c) 1997,1999 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#ifndef LIST_H
#define LIST_H 1
#include <isc/assertions.h>

#define LIST(type) struct { type *head, *tail; }
#define INIT_LIST(list) \
    do { (list).head = NULL; (list).tail = NULL; } while (0)

#define LINK(type) struct { type *prev, *next; }
#define INIT_LINK_TYPE(elt, link, type) \
    do { \
        (elt)->link.prev = (type *)(-1); \
        (elt)->link.next = (type *)(-1); \
    } while (0)
#define INIT_LINK(elt, link) \
    INIT_LINK_TYPE(elt, link, void)
#define LINKED(elt, link) ((void *)((elt)->link.prev) != (void *)(-1))

#define HEAD(list) ((list).head)
#define TAIL(list) ((list).tail)
#define EMPTY(list) ((list).head == NULL)

#define PREPEND(list, elt, link) \
    do { \
        INSIST(!LINKED(elt, link));\
        if ((list).head != NULL) \
            (list).head->link.prev = (elt); \
        else \
            (list).tail = (elt); \
        (elt)->link.prev = NULL; \
        (elt)->link.next = (list).head; \
        (list).head = (elt); \
    } while (0)

#define APPEND(list, elt, link) \
    do { \
        INSIST(!LINKED(elt, link));\
        if ((list).tail != NULL) \
            (list).tail->link.next = (elt); \
        else \
            (list).head = (elt); \
        (elt)->link.prev = (list).tail; \
        (elt)->link.next = NULL; \
        (list).tail = (elt); \
    } while (0)

#define UNLINK_TYPE(list, elt, link, type) \
    do { \
        INSIST(LINKED(elt, link));\
        if ((elt)->link.next != NULL) \
            (elt)->link.next->link.prev = (elt)->link.prev; \
        else \
            (list).tail = (elt)->link.prev; \
        if ((elt)->link.prev != NULL) \
            (elt)->link.prev->link.next = (elt)->link.next; \
        else \
            (list).head = (elt)->link.next; \
        INIT_LINK_TYPE(elt, link, type); \
    } while (0)
#define UNLINK(list, elt, link) \
    UNLINK_TYPE(list, elt, link, void)

#define PREV(elt, link) ((elt)->link.prev)
#define NEXT(elt, link) ((elt)->link.next)

#define INSERT_BEFORE(list, before, elt, link) \
    do { \
        INSIST(!LINKED(elt, link));\
        if ((before)->link.prev == NULL) \
            PREPEND(list, elt, link); \
        else { \
            (elt)->link.prev = (before)->link.prev; \
            (before)->link.prev = (elt); \
            (elt)->link.prev->link.next = (elt); \
            (elt)->link.next = (before); \
        } \
    } while (0)

#define INSERT_AFTER(list, after, elt, link) \
    do { \
        INSIST(!LINKED(elt, link));\
        if ((after)->link.next == NULL) \
            APPEND(list, elt, link); \
        else { \
            (elt)->link.next = (after)->link.next; \
            (after)->link.next = (elt); \
            (elt)->link.next->link.prev = (elt); \
            (elt)->link.prev = (after); \
        } \
    } while (0)

#define ENQUEUE(list, elt, link) APPEND(list, elt, link)
#define DEQUEUE(list, elt, link) UNLINK(list, elt, link)

#endif /* LIST_H */