/*

 * Copyright 2005-2020 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include "ssl_local.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(void)

{

    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(piterator *item)

{

    pitem *ret;

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

        return NULL;

    /* *item != NULL */

    ret = *item;

    *item = (*item)->next;

    return ret;

}

size_t pqueue_size(pqueue *pq)

{

    pitem *item = pq->items;

    size_t count = 0;

    while (item != NULL) {

        count++;

        item = item->next;

    }

    return count;

}