获取bcd码的长度

unsigned int get_bcd_length(const unsigned char* bcd)
{
	unsigned int length = 0;

	while (((*bcd&0xf0) != 0xf0) && ((*bcd&0x0f) != 0x0f))
	{
		length += 2;
		++bcd;
	}

	if (*bcd == 0xff)
	{
		return length;
	}

	return ++length;
}