def test_chars_too_long(self):
u = Fields()
u.add(CH(6, 'string'))
u.string = '1234567' # One byte too long
with pytest.raises(ValueError):
u.pack()
def test_chars_padding_added(self):
u = Fields()
u.add(CH(6, 'string'))
u.string = '1234'
data = u.pack()
assert data == bytearray.fromhex('31 32 33 34 00 00')
def test_basic_pack(self):
u = Fields()
u.add(CH(4, 'string'))
u.string = '1234'
data = u.pack()
assert data == bytearray.fromhex("31 32 33 34")
def test_pack2(self):
u = Fields()
u.add(I4('test'))
u.add(U1('val'))
u.add(Padding(2, 'res1'))
u.test = 0x76543210
u.val = 0xAF
data = u.pack()
assert data == bytearray.fromhex('10 32 54 76 AF 00 00')
def test_pack1(self):
u = Fields()
u.add(I4('test'))
u.add(U1('val'))
u.add(Padding(3, 'res1'))
u.add(U4('test2'))
u.test = 0x76543210
u.val = 0xAF
u.test2 = 0xcafebabe
data = u.pack()
print(data)
assert data == bytearray.fromhex('10 32 54 76 AF 00 00 00 be ba fe ca')
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