def test_recursive_type(self):
variable_length_integer = Choice('variable length integer', [])
variable_length_integer.children = [
Sequence('final byte:', [
Field(None, length=1, constraints=[Equals(0)]),
Field('value:', length=7)],
value=parse('${value:}')),
Sequence('intermediate byte:', [
Field(None, length=1, constraints=[Equals(1)]),
Field('value:', length=7),
Child('next:', variable_length_integer)],
value=parse('(${value:} << 7) + ${next:}'))]
params = ExpressionParameters([variable_length_integer])
range = EntryValueType(variable_length_integer).range(params)
self.assertEqual(None, range.min)
self.assertEqual(None, range.max)
def test_unknown_range(self):
# In this case 'intermediate byte:' has an unknown range, while
# 'final byte:' has a known range. We should attempt to solve
# the smallest range first...
variable_length_integer = Choice('variable length integer', [])
variable_length_integer.children = [
Sequence('final byte:', [
Field(None, length=1, constraints=[Equals(0)]),
Field('value:', length=7)],
value=parse('${value:}')),
Sequence('intermediate byte:', [
Field(None, length=1, constraints=[Equals(1)]),
Field('least significant:', length=7),
Child('most significant:', variable_length_integer)],
value=parse('(${most significant:} * 128) + ${least significant:}'),
constraints=[Minimum(0)])]
self.assertEqual({'${most significant:}':1, '${least significant:}':0},
_solve(variable_length_integer, 1, 128))
self.assertEqual({'${most significant:}':1, '${least significant:}':1},
_solve(variable_length_integer, 1, 129))
def test_recursive_common(self):
# Test a recursive parser to decode xml style data
embedded = Sequence('embedded', [])
digit = Field('data', 8, constraints=[Minimum(ord('0')), Maximum(ord('9'))])
item = Choice('item', [embedded, digit])
embedded.children = [
Field('', length=8, format=Field.TEXT, constraints=[Equals('<')]),
item,
Field('', length=8, format=Field.TEXT, constraints=[Equals('>')])]
# Lets just test that we can decode things correctly...
list(item.decode(Data('8')))
list(item.decode(Data('<5>')))
list(item.decode(Data('<<7>>')))
self.assertRaises(bdec.DecodeError, list, item.decode(Data('a')))
self.assertRaises(bdec.DecodeError, list, item.decode(Data('<5')))
lookup = ResultParameters([item])
self.assertEqual([Param('result', Param.OUT, EntryType(item))], lookup.get_params(item))
self.assertEqual([Param('result', Param.OUT, EntryType(embedded))], lookup.get_params(embedded))