/**
 * Calculation of CRC 16 CCITT polynomial.
 *
 * @file        crc16-ccitt.h
 * @ingroup     CO_crc16_ccitt
 * @author      Lammert Bies
 * @author      Janez Paternoster
 * @copyright   2012 - 2013 Janez Paternoster
 *
 * This file is part of CANopenNode, an opensource CANopen Stack.
 * Project home page is <http://canopennode.sourceforge.net>.
 * For more information on CANopen see <http://www.can-cia.org/>.
 *
 * CANopenNode is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */


#ifndef CRC16_CCITT_H
#define CRC16_CCITT_H


/**
 * @defgroup CO_crc16_ccitt CRC 16 CCITT
 * @ingroup CO_CANopen
 * @{
 *
 * Calculation of CRC 16 CCITT polynomial.
 *
 * Equation:
 *
 * `x^16 + x^12 + x^5 + 1`
 */


/**
 * Calculate CRC sum on block of data.
 *
 * @param block Pointer to block of data.
 * @param blockLength Length of data in bytes;
 * @param crc Initial value (zero for xmodem). If block is split into
 * multiple segments, previous CRC is used as initial.
 *
 * @return Calculated CRC.
 */
unsigned short crc16_ccitt(
        const unsigned char     block[],
        unsigned int            blockLength,
        unsigned short          crc);


/** @} */
#endif