def _text_string_parts(self):
while True:
initial_byte = ord(self.read(1))
if 0x60 <= initial_byte < 0x7c:
yield self.decode_text_string(initial_byte)
elif initial_byte == 0xff:
break
else:
raise BadInitialByteError(
f'bad initial byte 0x{initial_byte:x} in '
f'indefinite-length text string')
async def decode_length(self, initial_byte):
minor = initial_byte & 0x1f
if minor < 24:
return minor
if minor < 28:
kind = minor - 24
length, = uint_unpackers[kind](await self.read(1 << kind))
return length
if initial_byte in {0x5f, 0x7f, 0x9f, 0xbf}:
return None
raise BadInitialByteError(f'bad initial byte 0x{initial_byte:x}')
def decode_text_string(self, initial_byte):
length = self.decode_length(initial_byte)
read = self.read
if length is None:
yield ContextILTextString()
decode_length = self.decode_length
while True:
initial_byte = ord(read(1))
if 0x60 <= initial_byte < 0x7c:
yield self._decode_text(read(decode_length(initial_byte)))
elif initial_byte == 0xff:
break
else:
raise BadInitialByteError(
f'bad initial byte 0x{initial_byte:x} in '
f'indefinite-length byte string')
yield Break
else:
yield self._decode_text(self.read(length))
async def decode_byte_string(self, initial_byte):
length = await self.decode_length(initial_byte)
read = self.read
if length is None:
yield ContextILByteString()
decode_length = self.decode_length
while True:
initial_byte = ord(await read(1))
if 0x40 <= initial_byte < 0x5c:
yield await read(await decode_length(initial_byte))
elif initial_byte == 0xff:
break
else:
raise BadInitialByteError(
f'bad initial byte 0x{initial_byte:x} in '
f'indefinite-length byte string')
yield Break
else:
yield await read(length)
def decode_simple(self, initial_byte):
# Pass initial_byte not length to detect ill-formed simples
value = initial_byte & 0x1f
if value < 20:
yield self._simple_value(value)
elif value < 24:
yield CBORSimple.assigned_values[value]
elif value == 24:
value = ord(self.read(1))
if value < 32:
raise BadSimpleError(
f'simple value 0x{value:x} encoded with extra byte')
yield self._simple_value(value)
elif value < 28:
length = 1 << (value - 24)
float_value, = be_float_unpackers[value - 25](self.read(length))
yield float_value
elif value == 31:
raise MisplacedBreakError(
'break code outside indefinite-length object')
else:
raise BadInitialByteError(f'bad initial byte 0x{initial_byte:x}')
def decode_length(self, initial_byte):
minor = initial_byte & 0x1f
if minor < 24:
return minor
if minor < 28:
kind = minor - 24
length, = uint_unpackers[kind](self.read(1 << kind))
if self._deterministic & DeterministicFlags.LENGTH and length < uint_minima[
kind]:
if initial_byte < 0x20:
raise DeterministicError(
f'value {length:,d} is not minimally encoded')
elif initial_byte < 0x40:
raise DeterministicError(
f'value {-1 - length:,d} is not minimally encoded')
else:
raise DeterministicError(
f'length {length:,d} is not minimally encoded')
return length
if initial_byte in {0x5f, 0x7f, 0x9f, 0xbf}:
return -1
raise BadInitialByteError(f'bad initial byte 0x{initial_byte:x}')
def decode_simple(self, initial_byte):
value = initial_byte & 0x1f
if value < 20:
return self._simple_value(value)
if value < 24:
return CBORSimple.assigned_values[value]
if value == 24:
value = ord(self.read(1))
if value < 32:
raise BadSimpleError(
f'simple value 0x{value:x} encoded with extra byte')
return self._simple_value(value)
if value < 28:
length = 1 << (value - 24)
float_value, = be_float_unpackers[value - 25](self.read(length))
if value > 25 and self._deterministic & DeterministicFlags.FLOAT:
if length != len(pack_cbor_short_float(float_value)) - 1:
raise DeterministicError(
f'float {float_value} is not minimally encoded')
return float_value
if value == 31:
raise MisplacedBreakError(
'break code outside indefinite-length object')
raise BadInitialByteError(f'bad initial byte 0x{initial_byte:x}')