/*
 *  Copyright (c) 2009-2020, Peter Haag
 *  Copyright (c) 2004-2008, SWITCH - Teleinformatikdienste fuer Lehre und Forschung
 *  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.
 *   * Neither the name of the author nor the names of its contributors may be
 *     used to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR 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.
 *
 */

typedef void (*siftElement_t)(SortElement_t *SortElement, uint32_t numbersSize, uint32_t node);

static void heapSort(SortElement_t *SortElement, uint32_t array_size, int topN, int direction);

static inline void siftDown(SortElement_t *SortElement, uint32_t root, uint32_t bottom);

static inline void siftUp(SortElement_t *SortElement, uint32_t numbersSize, uint32_t node);

static void heapSort(SortElement_t *SortElement, uint32_t array_size, int topN, int direction) {
    int32_t i, maxindex;

    siftElement_t siftElement = direction == DESCENDING ? siftDown : siftUp;

    for (i = array_size - 1; i >= 0; i--) siftElement(SortElement, array_size, i);

    /*
     * we are only interested in the first top N => skip sorting the rest
     * For topN == 0 -> all flows gets sorted
     */
    if ((topN >= (array_size - 1)) || topN == 0) {
        maxindex = 0;
    } else {
        maxindex = array_size - 1 - topN;
    }

    for (i = array_size - 1; i > maxindex; i--) {
        SortElement_t temp = SortElement[0];
        SortElement[0] = SortElement[i];
        SortElement[i] = temp;
        siftElement(SortElement, i, 0);
    }

}  // End of heapSort

static inline void siftDown(SortElement_t *SortElement, uint32_t numbersSize, uint32_t node) {
    uint32_t i, parent, child;

    parent = node;
    i = parent + 1;
    while (i != parent) {
        i = parent;

        // Compare with left child node
        child = 2 * i + 1;
        if ((child) < numbersSize && SortElement[child].count > SortElement[parent].count) parent = child;

        // Compare with right child node
        child = 2 * i + 2;
        if ((child) < numbersSize && SortElement[child].count > SortElement[parent].count) parent = child;

        if (i != parent) {
            SortElement_t temp = SortElement[i];
            SortElement[i] = SortElement[parent];
            SortElement[parent] = temp;
        }
    }
}  // End of siftDown

static inline void siftUp(SortElement_t *SortElement, uint32_t numbersSize, uint32_t node) {
    uint32_t i, parent, child;

    parent = node;
    i = parent + 1;
    while (i != parent) {
        i = parent;

        // Compare with left child node
        child = 2 * i + 1;
        if ((child) < numbersSize && SortElement[child].count < SortElement[parent].count) parent = child;

        // Compare with right child node
        child = 2 * i + 2;
        if ((child) < numbersSize && SortElement[child].count < SortElement[parent].count) parent = child;

        if (i != parent) {
            SortElement_t temp = SortElement[i];
            SortElement[i] = SortElement[parent];
            SortElement[parent] = temp;
        }
    }
}  // End of siftUp
