/* ----------------------------------------------------------------------------
 *         SAM Software Package License
 * ----------------------------------------------------------------------------
 * Copyright (c) 2015, Atmel Corporation
 *
 * 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 disclaimer below.
 *
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
 * ----------------------------------------------------------------------------
 */

/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/

#include "board.h"
#include "chip.h"

#include "crc.h"

/*------------------------------------------------------------------------------
 *         Local variables
 *----------------------------------------------------------------------------*/

uint8_t Crc8;

//------------------------------------------------------------------------------
///        Local functions
//------------------------------------------------------------------------------

//------------------------------------------------------------------------------
// Calculate the CRC8 of the byte value provided with the current
// global 'crc8' value.
// Returns current global crc8 value
//------------------------------------------------------------------------------

static const uint8_t dscrc_table[] =
{
	0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65,
	157,195, 33,127,252,162, 64, 30, 95,  1,227,189, 62, 96,130,220,
	35,125,159,193, 66, 28,254,160,225,191, 93,  3,128,222, 60, 98,
	190,224,  2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255,
	70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89,  7,
	219,133,103, 57,186,228,  6, 88, 25, 71,165,251,120, 38,196,154,
	101, 59,217,135,  4, 90,184,230,167,249, 27, 69,198,152,122, 36,
	248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91,  5,231,185,
	140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205,
	17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80,
	175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238,
	50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115,
	202,148,118, 40,171,245, 23, 73,  8, 86,180,234,105, 55,213,139,
	87,  9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22,
	233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168,
	116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53};

static uint8_t _do_crc8 (uint8_t value)
{
	return dscrc_table[Crc8 ^ value];
}

//------------------------------------------------------------------------------
//------------------------------------------------------------------------------

uint8_t compute_crc8 (uint8_t* pData, uint8_t Length)
{
	Crc8 = 0x00;
	while (Length)
	{
		Crc8 = _do_crc8( *pData);
		pData ++;
		Length--;
	}
	return Crc8;
}