unsigned short update_crc16(unsigned short crc, unsigned char c);
uint16_t crc16(uint8_t const *message, int length, uint16_t remainder, uint16_t polynomial);
uint16_t crc16_ccitt(uint8_t const *message, int length);
uint16_t crc16_ccitt_kermit(uint8_t const *message, int length);
unsigned short update_crc16(unsigned short crc, unsigned char c);
uint16_t crc16(uint8_t const *message, int length, uint16_t remainder, uint16_t polynomial);
uint16_t crc16_ccitt(uint8_t const *message, int length);
uint16_t crc16_ccitt_kermit(uint8_t const *message, int length);