source: mainline/kernel/generic/src/adt/list.c@ 174156fd

/*
 * Copyright (c) 2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup kernel_generic_adt
 * @{
 */

/**
 * @file
 * @brief       Functions completing doubly linked circular list implementation.
 *
 * This file contains some of the functions implementing doubly linked circular lists.
 * However, this ADT is mostly implemented in @ref list.h.
 */

#include <adt/list.h>

/** Check for membership
 *
 * Check whether link is contained in a list.
 * Membership is defined as pointer equivalence.
 *
 * @param link  Item to look for.
 * @param list  List to look in.
 *
 * @return true if link is contained in list, false otherwise.
 *
 */
bool list_member(const link_t *link, const list_t *list)
{
        bool found = false;
        link_t *hlp = list->head.next;

        while (hlp != &list->head) {
                if (hlp == link) {
                        found = true;
                        break;
                }
                hlp = hlp->next;
        }

        return found;
}

/** Moves items of one list into another after the specified item.
 *
 * Inserts all items of @a list after item at @a pos in another list.
 * Both lists may be empty.
 *
 * @param list Source list to move after pos. Empty afterwards.
 * @param pos Source items will be placed after this item.
 */
void list_splice(list_t *list, link_t *pos)
{
        if (list_empty(list))
                return;

        /* Attach list to destination. */
        list->head.next->prev = pos;
        list->head.prev->next = pos->next;

        /* Link destination list to the added list. */
        pos->next->prev = list->head.prev;
        pos->next = list->head.next;

        list_initialize(list);
}

/** Count list items
 *
 * Return the number of items in the list.
 *
 * @param list          List to count.
 * @return              Number of items in the list.
 */
unsigned long list_count(const list_t *list)
{
        unsigned long count = 0;

        link_t *link = list_first(list);
        while (link != NULL) {
                count++;
                link = list_next(link, list);
        }

        return count;
}

/** @}
 */