def _validateChecksum(sentence):
"""
Validates the checksum of an NMEA sentence.
@param sentence: The NMEA sentence to check the checksum of.
@type sentence: C{str}
@raise ValueError: If the sentence has an invalid checksum.
Simply returns on sentences that either don't have a checksum,
or have a valid checksum.
"""
if sentence[-3] == '*': # Sentence has a checksum
reference, source = int(sentence[-2:], 16), sentence[1:-3]
computed = reduce(operator.xor, (ord(x) for x in source))
if computed != reference:
raise base.InvalidChecksum("%02x != %02x" % (computed, reference))
def _validateChecksum(sentence):
"""
Validates the checksum of an NMEA sentence.
@param sentence: The NMEA sentence to check the checksum of.
@type sentence: C{bytes}
@raise ValueError: If the sentence has an invalid checksum.
Simply returns on sentences that either don't have a checksum,
or have a valid checksum.
"""
if sentence[-3:-2] == b"*": # Sentence has a checksum
reference, source = int(sentence[-2:], 16), sentence[1:-3]
computed = reduce(operator.xor, [ord(x) for x in iterbytes(source)])
if computed != reference:
raise base.InvalidChecksum(f"{computed:02x} != {reference:02x}")