def test_chars_invalid_length(self):
u = Fields()
u.add(CH(5, 'string'))
with pytest.raises(ValueError):
u.unpack(bytearray.fromhex('31 32')) # Too few bytes
with pytest.raises(ValueError):
u.unpack(bytearray.fromhex('31 32 33 34')) # Too few bytes
def test_basic_unpack(self):
u = Fields()
u.add(CH(4, 'string'))
u.unpack(bytearray.fromhex('41 42 43 44'))
assert u.string == 'ABCD'
def test_chars_invalid_unicode(self):
u = Fields()
u.add(CH(2, 'string'))
with pytest.raises(ValueError):
u.unpack(bytearray.fromhex('d8 00')) # UTF16 reserved code point
def test_chars_trailing_zeroes_removed(self):
u = Fields()
u.add(CH(10, 'string'))
u.unpack(bytearray.fromhex('41 42 43 44 45 00 00 00 00 00'))
assert u.string == 'ABCDE'
class UbxFrame(object):
CID = UbxCID(0, 0)
NAME = 'UBX'
SYNC_1 = 0xb5
SYNC_2 = 0x62
@classmethod
def construct(cls, data):
obj = cls()
obj.data = data
obj.unpack()
return obj
@classmethod
def MATCHES(cls, cid):
return cls.CID == cid
def __init__(self):
super().__init__()
self.data = bytearray()
# TODO: Do we need checksum as member?
self.checksum = Checksum()
self.f = Fields()
def to_bytes(self):
self._calc_checksum()
msg = bytearray([UbxFrame.SYNC_1, UbxFrame.SYNC_2])
msg.append(self.CID.cls)
msg.append(self.CID.id)
length = len(self.data)
msg.append((length >> 0) % 0xFF)
msg.append((length >> 8) % 0xFF)
msg += self.data
msg.append(self.cka)
msg.append(self.ckb)
return msg
def get(self, name):
return self.f.get(name)
def pack(self):
self.data = self.f.pack()
def unpack(self):
self.f.unpack(self.data)
def _calc_checksum(self):
self.checksum.reset()
self.checksum.add(self.CID.cls)
self.checksum.add(self.CID.id)
length = len(self.data)
self.checksum.add((length >> 0) & 0xFF)
self.checksum.add((length >> 8) & 0xFF)
for d in self.data:
self.checksum.add(d)
self.cka, self.ckb = self.checksum.value()
def __str__(self):
res = f'{self.NAME} {self.CID}'
res += str(self.f)
return res