def get_datetime(self):
response = self._send_message(_READ_RTC_REQUEST, 3)
if response[0:2] != b'\x04\06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 04 06, received %02x %02x' %
(response[0], response[1]))
(timestamp, ) = _STRUCT_TIMESTAMP.unpack(response[2:])
return _convert_timestamp(timestamp)
def _read_parameter(self, parameter_key):
response = self._send_message(_READ_PARAMETER_REQUEST + parameter_key,
4)
if response[0:2] != b'\x03\x06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 03 06, received %02x %02x' %
(response[0], response[1]))
return response[2:]
def _get_reading_count(self):
response = self._send_message(_READ_RECORD_COUNT_REQUEST, 3)
if response[0:2] != b'\x04\06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 04 06, received %02x %02x' %
(response[0], response[1]))
(record_count, ) = _STRUCT_RECORDID.unpack(response[2:])
return record_count
def _query_string(self, query_key):
response = self._send_message(_QUERY_REQUEST + query_key, 3)
if response[0:2] != b'\x04\06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 04 06, received %02x %02x' %
(response[0], response[1]))
# Strings are encoded in wide characters (LE), but they should
# only contain ASCII characters. Note that the string is
# null-terminated, so the last character should be dropped.
return response[2:].decode('utf-16-le')[:-1]
def _extract_message(register):
"""Parse the message preamble and verify checksums."""
stx, length = _STRUCT_PREAMBLE.unpack_from(register)
if stx != _STX:
raise lifescan_common.MalformedCommand('invalid STX byte: %02x' % stx)
if length > _REGISTER_SIZE:
raise lifescan_common.MalformedCommand(
'invalid length: %d > REGISTER_SIZE' % length)
# 2 is the length of the checksum, so it should be ignored.
calculated_checksum = lifescan_common.crc_ccitt(register[:(length - 2)])
coda_offset = length - _STRUCT_CODA.size
etx, encoded_checksum = _STRUCT_CODA.unpack_from(register[coda_offset:])
if etx != _ETX:
raise lifescan_common.MalformedCommand('invalid ETX byte: %02x' % etx)
if encoded_checksum != calculated_checksum:
raise exceptions.InvalidChecksum(encoded_checksum, calculated_checksum)
response = register[_STRUCT_PREAMBLE.size:coda_offset]
return response
def _get_reading(self, record_number):
request = (_READ_RECORD_REQUEST_PREFIX +
_STRUCT_RECORDID.pack(record_number) +
_READ_RECORD_REQUEST_SUFFIX)
response = self._send_message(request, 3)
if response[0:2] != b'\x04\06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 04 06, received %02x %02x' %
(response[0], response[1]))
(unused_const1, unused_const2, unused_counter, unused_const3,
unused_counter2, timestamp, value, unused_flags, unused_const4,
unused_const5) = _STRUCT_RECORD.unpack(response)
return common.Reading(_convert_timestamp(timestamp), float(value))
def set_datetime(self, date=datetime.datetime.now()):
epoch = datetime.datetime.utcfromtimestamp(_EPOCH_BASE)
delta = date - epoch
timestamp = int(delta.total_seconds())
timestamp_bytes = _STRUCT_TIMESTAMP.pack(timestamp)
response = self._send_message(_WRITE_RTC_REQUEST + timestamp_bytes, 3)
if response[0:2] != b'\x04\06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 04 06, received %02x %02x' %
(response[0], response[1]))
# The device does not return the new datetime, so confirm by
# calling READ RTC again.
return self.get_datetime()
def zero_log(self):
response = self._send_message(_MEMORY_ERASE_REQUEST, 3)
if response[0:2] != b'\x04\06':
raise lifescan_common.MalformedCommand(
'invalid response, expected 04 06, received %02x %02x' %
(response[0], response[1]))