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/*

 * Copyright (C) 2005 Sergey Bondari

 * 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.

 */

#include <mm/slab.h>

#include <memstr.h>

#include <sort.h>

#include <panic.h>

#define EBUFSIZE    32

void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot);

void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot);

/** Quicksort wrapper

 *

 * This is only a wrapper that takes care of memory allocations for storing

 * the pivot and temporary elements for generic quicksort algorithm.

 *

 * This function _can_ sleep

 *

 * @param data Pointer to data to be sorted.

 * @param n Number of elements to be sorted.

 * @param e_size Size of one element.

 * @param cmp Comparator function.

 *

 */

void qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))

{

    __u8 buf_tmp[EBUFSIZE];

    __u8 buf_pivot[EBUFSIZE];

    void * tmp = buf_tmp;

    void * pivot = buf_pivot;

    if (e_size > EBUFSIZE) {

        pivot = (void *) malloc(e_size, 0);

        tmp = (void *) malloc(e_size, 0);

    }

    _qsort(data, n, e_size, cmp, tmp, pivot);

    if (e_size > EBUFSIZE) {

        free(tmp);

        free(pivot);

    }

}

/** Quicksort

 *

 * Apply generic quicksort algorithm on supplied data, using pre-allocated buffers.

 *

 * @param data Pointer to data to be sorted.

 * @param n Number of elements to be sorted.

 * @param e_size Size of one element.

 * @param cmp Comparator function.

 * @param tmp Pointer to scratch memory buffer e_size bytes long.

 * @param pivot Pointer to scratch memory buffer e_size bytes long.

 *

 */

void _qsort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *tmp, void *pivot)

{

    if (n > 4) {

        int i = 0, j = n - 1;

        memcpy(pivot, data, e_size);

        while (1) {

            while ((cmp(data + i * e_size, pivot) < 0) && i < n) i++;

            while ((cmp(data + j * e_size, pivot) >=0) && j > 0) j--;

            if (i<j) {

                memcpy(tmp, data + i * e_size, e_size);

                memcpy(data + i * e_size, data + j * e_size, e_size);

                memcpy(data + j * e_size, tmp, e_size);

            } else {

                break;

            }

        }

        _qsort(data, j + 1, e_size, cmp, tmp, pivot);

        _qsort(data + (j + 1) * e_size, n - j - 1, e_size, cmp, tmp, pivot);

    } else {

        _bubblesort(data, n, e_size, cmp, tmp);

    }

}

/** Bubblesort wrapper

 *

 * This is only a wrapper that takes care of memory allocation for storing

 * the slot element for generic bubblesort algorithm.

 *

 * @param data Pointer to data to be sorted.

 * @param n Number of elements to be sorted.

 * @param e_size Size of one element.

 * @param cmp Comparator function.

 *

 */

void bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b))

{

    __u8 buf_slot[EBUFSIZE];

    void * slot = buf_slot;

    if (e_size > EBUFSIZE) {

        slot = (void *) malloc(e_size, 0);

    }

    _bubblesort(data, n, e_size, cmp, slot);

    if (e_size > EBUFSIZE) {

        free(slot);

    }

}

/** Bubblesort

 *

 * Apply generic bubblesort algorithm on supplied data, using pre-allocated buffer.

 *

 * @param data Pointer to data to be sorted.

 * @param n Number of elements to be sorted.

 * @param e_size Size of one element.

 * @param cmp Comparator function.

 * @param slot Pointer to scratch memory buffer e_size bytes long.

 *

 */

void _bubblesort(void * data, count_t n, size_t e_size, int (* cmp) (void * a, void * b), void *slot)

{

    bool done = false;

    void * p;

    while (!done) {

        done = true;

        for (p = data; p < data + e_size * (n - 1); p = p + e_size) {

            if (cmp(p, p + e_size) == 1) {

                memcpy(slot, p, e_size);

                memcpy(p, p + e_size, e_size);

                memcpy(p + e_size, slot, e_size);

                done = false;

            }

        }

    }

}

/*

 * Comparator returns 1 if a > b, 0 if a == b, -1 if a < b

 */

int int_cmp(void * a, void * b)

{

    return (* (int *) a > * (int*)b) ? 1 : (*(int *)a < * (int *)b) ? -1 : 0;

}

int __u8_cmp(void * a, void * b)

{

    return (* (__u8 *) a > * (__u8 *)b) ? 1 : (*(__u8 *)a < * (__u8 *)b) ? -1 : 0;

}

int __u16_cmp(void * a, void * b)

{

    return (* (__u16 *) a > * (__u16 *)b) ? 1 : (*(__u16 *)a < * (__u16 *)b) ? -1 : 0;

}

int __u32_cmp(void * a, void * b)

{

    return (* (__u32 *) a > * (__u32 *)b) ? 1 : (*(__u32 *)a < * (__u32 *)b) ? -1 : 0;

}