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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.

 */

/** @addtogroup generic	

 * @{

 */

/**

 * @file

 * @brief	Sorting functions.

 *

 * This files contains functions implementing several sorting

 * algorithms (e.g. quick sort and bubble sort).

 */

#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))

{

	uint8_t buf_tmp[EBUFSIZE];

	uint8_t 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) {

		unsigned 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))

{

	uint8_t 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 uint8_t_cmp(void * a, void * b)

{

	return (* (uint8_t *) a > * (uint8_t *)b) ? 1 : (*(uint8_t *)a < * (uint8_t *)b) ? -1 : 0;

}

int uint16_t_cmp(void * a, void * b)

{

	return (* (uint16_t *) a > * (uint16_t *)b) ? 1 : (*(uint16_t *)a < * (uint16_t *)b) ? -1 : 0;

}

int uint32_t_cmp(void * a, void * b)

{

	return (* (uint32_t *) a > * (uint32_t *)b) ? 1 : (*(uint32_t *)a < * (uint32_t *)b) ? -1 : 0;

}

/** @}

 */