crc16.h

/*
 *	crc16.h - CRC-16 routine
 *
 * Implements the standard CRC-16:
 *   Width 16
 *   Poly  0x8005 (x^16 + x^15 + x^2 + 1)
 *   Init  0
 *
 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2. See the file COPYING for more details.
 */

#ifndef __CRC16_H
#define __CRC16_H

#include <stdint.h>

extern uint16_t const crc16_table[256];

static inline uint16_t crc16_byte(uint16_t crc, const unsigned char data)
{
	return (crc >> 8) ^ crc16_table[(crc ^ data) & 0xff];
}

/**
 * crc16 - compute the CRC-16 for the data buffer
 * @crc:	previous CRC value
 * @buffer:	data pointer
 * @len:	number of bytes in the buffer
 *
 * Returns the updated CRC value.
 */
static inline uint16_t crc16(uint16_t crc, unsigned char const *buffer,
                             size_t len)
{
	while (len--)
		crc = crc16_byte(crc, *buffer++);
	return crc;
}

#endif /* __CRC16_H */