diff options
| -rw-r--r-- | glucometerutils/support/freestyle.py | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/glucometerutils/support/freestyle.py b/glucometerutils/support/freestyle.py index d722c35..7610729 100644 --- a/glucometerutils/support/freestyle.py +++ b/glucometerutils/support/freestyle.py @@ -15,7 +15,8 @@ import csv import datetime import logging import re -import struct + +import construct from glucometerutils import exceptions from glucometerutils.support import hiddevice @@ -24,7 +25,13 @@ from glucometerutils.support import hiddevice # protocol. _INIT_SEQUENCE = (0x04, 0x05, 0x15, 0x01) -_STRUCT_PREAMBLE = struct.Struct('<BB') +_LIFESCAN_MESSAGE = construct.Struct( + 'hid_report' / construct.Const(construct.Byte, 0), + 'message_type' / construct.Byte, + 'command' / construct.Padded( + 63, # command can only be up to 62 bytes, but one is used for length. + construct.Prefixed(construct.Byte, construct.GreedyBytes)), +) _TEXT_COMPLETION_RE = re.compile('CMD (?:OK|Fail!)') _TEXT_REPLY_FORMAT = re.compile( @@ -93,12 +100,8 @@ class FreeStyleHidDevice(hiddevice.HidDevice): message_type: (int) The first byte sent with the report to the device. command: (bytes) The command to send out the device. """ - cmdlen = len(command) - assert cmdlen <= 62 - - # First byte in the written buffer is the report number. - usb_packet = b'\x00' + _STRUCT_PREAMBLE.pack( - message_type, cmdlen) + command + bytes(62 - cmdlen) + usb_packet = _LIFESCAN_MESSAGE.build( + {'message_type': message_type, 'command': command}) self._write(usb_packet) |