pqueue.c

/*
 * DTLS implementation written by Nagendra Modadugu
 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
 */
/* ====================================================================
 * Copyright (c) 1999-2005 The OpenSSL Project.  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 acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include "ssl_locl.h"
#include <openssl/bn.h>

struct pqueue_st {
    pitem *items;
    int count;
};

pitem *pitem_new(unsigned char *prio64be, void *data)
{
    pitem *item = OPENSSL_malloc(sizeof(*item));
    if (item == NULL)
        return NULL;

    memcpy(item->priority, prio64be, sizeof(item->priority));

    item->data = data;
    item->next = NULL;

    return item;
}

void pitem_free(pitem *item)
{
    OPENSSL_free(item);
}

pqueue *pqueue_new()
{
    pqueue *pq = OPENSSL_zalloc(sizeof(*pq));

    return pq;
}

void pqueue_free(pqueue *pq)
{
    OPENSSL_free(pq);
}

pitem *pqueue_insert(pqueue *pq, pitem *item)
{
    pitem *curr, *next;

    if (pq->items == NULL) {
        pq->items = item;
        return item;
    }

    for (curr = NULL, next = pq->items;
         next != NULL; curr = next, next = next->next) {
        /*
         * we can compare 64-bit value in big-endian encoding with memcmp:-)
         */
        int cmp = memcmp(next->priority, item->priority, 8);
        if (cmp > 0) {          /* next > item */
            item->next = next;

            if (curr == NULL)
                pq->items = item;
            else
                curr->next = item;

            return item;
        }

        else if (cmp == 0)      /* duplicates not allowed */
            return NULL;
    }

    item->next = NULL;
    curr->next = item;

    return item;
}

pitem *pqueue_peek(pqueue *pq)
{
    return pq->items;
}

pitem *pqueue_pop(pqueue *pq)
{
    pitem *item = pq->items;

    if (pq->items != NULL)
        pq->items = pq->items->next;

    return item;
}

pitem *pqueue_find(pqueue *pq, unsigned char *prio64be)
{
    pitem *next;
    pitem *found = NULL;

    if (pq->items == NULL)
        return NULL;

    for (next = pq->items; next->next != NULL; next = next->next) {
        if (memcmp(next->priority, prio64be, 8) == 0) {
            found = next;
            break;
        }
    }

    /* check the one last node */
    if (memcmp(next->priority, prio64be, 8) == 0)
        found = next;

    if (!found)
        return NULL;

    return found;
}

pitem *pqueue_iterator(pqueue *pq)
{
    return pqueue_peek(pq);
}

pitem *pqueue_next(pitem **item)
{
    pitem *ret;

    if (item == NULL || *item == NULL)
        return NULL;

    /* *item != NULL */
    ret = *item;
    *item = (*item)->next;

    return ret;
}

int pqueue_size(pqueue *pq)
{
    pitem *item = pq->items;
    int count = 0;

    while (item != NULL) {
        count++;
        item = item->next;
    }
    return count;
}