def __init__(self, number_bits, field=None, **kwargs):
BaseField.__init__(self, **kwargs)
self._ordered_bitfields = []
self._bitfield_map = {}
if number_bits % 8 != 0:
raise SuitcaseProgrammingError(
"Number of bits must be a factor of "
"8, was %d" % number_bits)
self.number_bits = number_bits
self.number_bytes = number_bits // 8
self.bytes_required = self.number_bytes
if field is None:
field = {
1: UBInt8,
2: UBInt16,
3: UBInt24,
4: UBInt32,
8: UBInt64,
}[self.number_bytes]()
self._field = field.create_instance(self._parent)
placeholders = []
for key, value in six.iteritems(kwargs):
if isinstance(value, _BitFieldFieldPlaceholder):
placeholders.append((key, value))
for key, placeholder in sorted(placeholders,
key=lambda kv: kv[1].sequence_number):
value = placeholder.create_instance()
self._bitfield_map[key] = value
self._ordered_bitfields.append((key, value))
def _length_value_provider():
sio = BytesIO()
target_field.pack(sio)
target_field_length = len(sio.getvalue())
if not target_field_length % self.multiplier == 0:
raise SuitcaseProgrammingError("Payload length not divisible "
"by %s" % self.multiplier)
return (target_field_length // self.multiplier)
def _length_value_provider():
sio = BytesIO()
target_field.pack(sio)
target_field_length = len(sio.getvalue())
if target_field_length != self.get_adjusted_length():
raise SuitcaseProgrammingError(
"Payload length %i does not"
" match length %i specified by type" %
(target_field_length, self.get_adjusted_length()))
return target_field_length
def setval(self, value):
try:
vtype = type(value)
key = self.inverse_dispatch_mapping[vtype]
except KeyError:
raise SuitcaseProgrammingError("The type specified is not in the "
"dispatch table")
# OK, things check out. Set both the value here and the
# type byte value
self._value = value
value._parent = self._parent
self.dispatch_field.setval(key)
def setval(self, value):
raise SuitcaseProgrammingError("Setting the value of a bitfield "
"directly is prohibited")
def setval(self, value):
raise SuitcaseProgrammingError("Cannot set the value of a LengthField")
def setval(self, *args):
raise SuitcaseProgrammingError("One does not simply modify Magic")
def setval(self, *args):
raise SuitcaseProgrammingError("CRC will be set automatically")
