diff options
| -rw-r--r-- | glucometerutils/drivers/freestyle_optium.py | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/glucometerutils/drivers/freestyle_optium.py b/glucometerutils/drivers/freestyle_optium.py index 0be4995..d40a9a1 100644 --- a/glucometerutils/drivers/freestyle_optium.py +++ b/glucometerutils/drivers/freestyle_optium.py @@ -15,6 +15,14 @@ import serial from glucometerutils import common from glucometerutils import exceptions + +class InvalidChecksum(exceptions.InvalidResponse): + def __init__(self, expected, gotten): + self.message = ( + 'Response checksum not matching: %04x expected, %04x gotten' % + (expected, gotten)) + + _CLOCK_RE = re.compile( r'^Clock:\t(?P<month>[A-Z][a-z]{2}) (?P<day>[0-9]{2}) (?P<year>[0-9]{4})\t' r'(?P<time>[0-9]{2}:[0-9]{2}:[0-9]{2})$') @@ -28,7 +36,10 @@ _CLOCK_RE = re.compile( # I don't have β-ketone strips to test. _READING_RE = re.compile( r'^(?P<reading>HI |[0-9]{3}) (?P<month>[A-Z][a-z]{2})[ ey] (?P<day>[0-9]{2}) ' - r'(?P<year>[0-9]{4}) (?P<time>[0-9]{2}:[0-9]{2}) G 0x00') + r'(?P<year>[0-9]{4}) (?P<time>[0-9]{2}:[0-9]{2}) G 0x00$') + +_CHECKSUM_RE = re.compile( + r'^(?P<checksum>0x[0-9A-F]{4}) END$') # There are two date format used by the device. One uses three-letters month # names, and that's easy enough. The other uses three-letters month names, @@ -68,7 +79,7 @@ def _parse_clock(datestr): hour, minute, second = (int(part) for part in match.group('time').split(':')) return datetime.datetime(year, month, day, hour, minute, second) - + class Device(object): def __init__(self, device): @@ -226,6 +237,19 @@ class Device(object): if count != (len(data) - 6): raise exceptions.InvalidResponse('\n'.join(data)) + # Extract the checksum from the last line. + checksum_match = _CHECKSUM_RE.match(data[-1]) + if not checksum_match: + raise exceptions.InvalidResponse('\n'.join(data)) + + expected_checksum = int(checksum_match.group('checksum'), 16) + # exclude the last line in the checksum calculation, as that's the checksum + # itself. The final \r\n is added separately. + calculated_checksum = sum(ord(c) for c in '\r\n'.join(data[:-1])) + 0xd + 0xa + + if expected_checksum != calculated_checksum: + raise InvalidChecksum(expected_checksum, calculated_checksum) + for line in data[5:-1]: match = _READING_RE.match(line) if not match: |