def Parse(data):
"""Unpack a TAG Block line or return None.
Makes sure that the line matches the regex and the checksum matches.
Args:
data: Line of text or a dict from at TAG_BLOCK_RE.
Returns:
A NMEA TAG Block dict or None if the line would not parse or has
an invalid checksum.
"""
if isinstance(data, str):
try:
result = TAG_BLOCK_RE.search(data).groupdict()
except AttributeError:
return
elif isinstance(data, dict):
result = data
else:
return
result.update({k: util.MaybeToNumber(v)
for k, v in six.iteritems(result) if k in NUMERIC_FIELDS})
actual = nmea.Checksum(result['metadata'])
expected = result['tag_checksum'].upper()
if actual != expected:
return
return result
def testChecksum(self):
self.assertEqual(nmea.Checksum('$NVXDR,G,142983,,WPTTTG*00'), '00')
self.assertEqual(nmea.Checksum('$GPHDT,143.59,T*0F'), '0F')
self.assertEqual(nmea.Checksum('$INHDT,89.4,T*10'), '10')
self.assertEqual(nmea.Checksum('$INROT,0,A*3F'), '3F')
self.assertEqual(
nmea.Checksum('!AIVDM,1,1,,B,14Qle<001mDoOKD`v:`Rc2;R1d00,0*00'),
'00')
self.assertEqual(
nmea.Checksum(r'\n:121650,s:r17MHOP1,c:1425327399*1D'), '1D')
self.assertEqual(nmea.Checksum(r'\g:2-2-223509,n:453068*26'), '26')
def Parse(data):
"""Unpack a NMEA VDM AIS message line(s)."""
if not isinstance(data, six.string_types):
raise NotImplementedError
try:
result = VDM_RE.search(data).groupdict()
except AttributeError:
return
result.update({
k: util.MaybeToNumber(v)
for k, v in six.iteritems(result) if k in NUMERIC_FIELDS
})
actual = nmea.Checksum(result['vdm'])
expected = result['checksum']
if actual != expected:
return
return result