def parse_data(self, data):
"""
Populates the TSRequest object with the data supplied. Need to override the default ASN1Sequence class
as this structure has optional values which hasn't been implemented in the generic structure
:param data: An ASN.1 data structure to be parsed
"""
type_byte = struct.unpack('B', data[:1])[0]
if type_byte != self.type:
raise AsnStructureException("Expecting %s type to be (%x), was (%x)" % (self.name, self.type, type_byte))
decoded_data, total_bytes = asn_helper.unpack_asn1(data)
# Remove the bytes from the original type and length for comparison later
total_bytes -= total_bytes - len(decoded_data)
version_offset = asn_helper.parse_context_field(decoded_data, self['version'])
new_offset = version_offset
# Get the remaining values in the structure
while new_offset != total_bytes:
invalid_sequence = True
field_data = decoded_data[new_offset:]
sequence_byte = struct.unpack('B', field_data[:1])[0]
for field in self.fields:
field_info = self.fields[field]
if sequence_byte == field_info.sequence:
invalid_sequence = False
value_offset = asn_helper.parse_context_field(field_data, self[field])
new_offset += value_offset
if invalid_sequence:
raise AsnStructureException('Unknown sequence byte (%x) in sequence' % sequence_byte)
def test_unpack_long_form_three_octets(self):
test_data = hex_to_byte('02 83 01 00 00') + hex_to_byte('31') * 65536
expected_data = b'1' * 65536
expected_octets = 65541
actual_data, actual_octets = unpack_asn1(test_data)
assert actual_data == expected_data
assert actual_octets == expected_octets
def test_unpack_long_form_two_octets(self):
test_data = hex_to_byte('02 82 01 00') + hex_to_byte('31') * 256
expected_data = b'1' * 256
expected_octets = 260
actual_data, actual_octets = unpack_asn1(test_data)
assert actual_data == expected_data
assert actual_octets == expected_octets
def test_unpack_long_form_one_octet(self):
test_data = hex_to_byte('02 81 80') + hex_to_byte('31') * 128
expected_data = b'1' * 128
expected_octets = 131
actual_data, actual_octets = unpack_asn1(test_data)
assert actual_data == expected_data
assert actual_octets == expected_octets
def test_unpack_short_form(self):
test_data = hex_to_byte('02 01 31')
expected_data = b'1'
expected_octets = 3
actual_data, actual_octets = unpack_asn1(test_data)
assert actual_data == expected_data
assert actual_octets == expected_octets
def test_unpack_long_form_fource_octets(self):
test_data = hex_to_byte(
'02 84 01 00 00 00') + hex_to_byte('31') * 16777216
expected_data = b'1' * 16777216
expected_octets = 16777222
actual_data, actual_octets = unpack_asn1(test_data)
assert actual_data == expected_data
assert actual_octets == expected_octets