acr122.py 文件源码

def ccid_xfr_block(self, data, timeout=0.1):
        """Encapsulate host command *data* into an PC/SC Escape command to
        send to the device and extract the chip response if received
        within *timeout* seconds.

        """
        frame = struct.pack("<BI5B", 0x6F, len(data), 0, 0, 0, 0, 0) + data
        self.transport.write(bytearray(frame))
        frame = self.transport.read(int(timeout * 1000))
        if not frame or len(frame) < 10:
            log.error("insufficient data for decoding ccid response")
            raise IOError(errno.EIO, os.strerror(errno.EIO))
        if frame[0] != 0x80:
            log.error("expected a RDR_to_PC_DataBlock")
            raise IOError(errno.EIO, os.strerror(errno.EIO))
        if len(frame) != 10 + struct.unpack("<I", buffer(frame, 1, 4))[0]:
            log.error("RDR_to_PC_DataBlock length mismatch")
            raise IOError(errno.EIO, os.strerror(errno.EIO))
        return frame[10:]