Printer.py 文件源码

def _encode(cls, payload):
        """ Protects a stream of data with escape characters
            The payload should be a bytestring
        """
        out = b''
        for byte in payload:
            if byte >= cls.ESCAPE:
                out += bytearray([cls.ESCAPE])
                byte = ctypes.c_uint8(byte - cls.ESCAPE).value
            out += bytearray([byte])
        return out