Return to queue.c CVS log

Up to [local] / prex / dev / lib

Annotation of prex/dev/lib/queue.c, Revision 1.1

1.1     ! nbrk        1: /*-
        !             2:  * Copyright (c) 2005, Kohsuke Ohtani
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms, with or without
        !             6:  * modification, are permitted provided that the following conditions
        !             7:  * are met:
        !             8:  * 1. Redistributions of source code must retain the above copyright
        !             9:  *    notice, this list of conditions and the following disclaimer.
        !            10:  * 2. Redistributions in binary form must reproduce the above copyright
        !            11:  *    notice, this list of conditions and the following disclaimer in the
        !            12:  *    documentation and/or other materials provided with the distribution.
        !            13:  * 3. Neither the name of the author nor the names of any co-contributors
        !            14:  *    may be used to endorse or promote products derived from this software
        !            15:  *    without specific prior written permission.
        !            16:  *
        !            17:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
        !            18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
        !            21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            27:  * SUCH DAMAGE.
        !            28:  */
        !            29:
        !            30: /*
        !            31:  * queue.c - generic queue management library
        !            32:  */
        !            33: #include <queue.h>
        !            34:
        !            35: /*
        !            36:  * Insert element at tail of queue
        !            37:  */
        !            38: void
        !            39: enqueue(queue_t head, queue_t item)
        !            40: {
        !            41:        item->next = head;
        !            42:        item->prev = head->prev;
        !            43:        item->prev->next = item;
        !            44:        head->prev = item;
        !            45: }
        !            46:
        !            47: /*
        !            48:  * Remove and return element of head of queue
        !            49:  */
        !            50: queue_t
        !            51: dequeue(queue_t head)
        !            52: {
        !            53:        queue_t item;
        !            54:
        !            55:        if (head->next == head)
        !            56:                return ((queue_t)0);
        !            57:        item = head->next;
        !            58:        item->next->prev = head;
        !            59:        head->next = item->next;
        !            60:        return item;
        !            61: }
        !            62:
        !            63: /*
        !            64:  * Insert element after specified element
        !            65:  */
        !            66: void
        !            67: queue_insert(queue_t prev, queue_t item)
        !            68: {
        !            69:        item->prev = prev;
        !            70:        item->next = prev->next;
        !            71:        prev->next->prev = item;
        !            72:        prev->next = item;
        !            73: }
        !            74:
        !            75: /*
        !            76:  * Remove specified element from queue
        !            77:  */
        !            78: void
        !            79: queue_remove(queue_t item)
        !            80: {
        !            81:        item->prev->next = item->next;
        !            82:        item->next->prev = item->prev;
        !            83: }