def write_string(self, value: str) -> None:
self.__size = align_offset_to_type(self.__size, FieldTypes.TYPE_STRING)
self.__writer.seek(self.__size)
str_size = len(value)
self.write_uint32(str_size)
self.__writer.write(bytes(value, 'utf-8'))
self.__size += str_size
def write_bytes(self, value: bytes) -> None:
self.__size = align_offset_to_type(self.__size, FieldTypes.TYPE_BYTES)
self.__writer.seek(self.__size)
bytes_size = len(value)
self.write_uint32(bytes_size)
self.__writer.write(value)
self.__size += bytes_size
def read_bytes(self) -> bytes:
self.__cursor = align_offset_to_type(self.__cursor,
FieldTypes.TYPE_BYTES)
self.__reader.seek(self.__cursor)
bytes_length = self.read_uint32()
if self.__cursor + bytes_length > self.__size:
raise RuntimeError(
f'bytes object has an invalid length {self.__size - self.__cursor}, expected {bytes_length}'
)
bytes_value = self.__reader.read(bytes_length)
self.__cursor += bytes_length
return bytes_value
def read_string(self) -> str:
self.__cursor = align_offset_to_type(self.__cursor,
FieldTypes.TYPE_STRING)
self.__reader.seek(self.__cursor)
str_length = self.read_uint32()
if self.__cursor + str_length > self.__size:
raise RuntimeError(
f'str object has an invalid length {self.__size - self.__cursor}, expected {str_length}'
)
str_bytes = self.__reader.read(str_length)
str_value = str(str_bytes, 'utf-8')
self.__cursor += str_length
return str_value
def read_uint64(self) -> int:
self.__cursor = align_offset_to_type(self.__cursor,
FieldTypes.TYPE_UINT64)
self.__reader.seek(self.__cursor)
if self.__cursor + FIELD_SIZES[FieldTypes.TYPE_UINT64] > self.get_size(
):
raise RuntimeError(
f'cannot read uint64 type, expected {FIELD_SIZES[FieldTypes.TYPE_UINT64]} bytes'
)
uint64_bytes = self.__reader.read(FIELD_SIZES[FieldTypes.TYPE_UINT64])
uint64_value = int.from_bytes(uint64_bytes,
byteorder='little',
signed=False)
self.__cursor += FIELD_SIZES[FieldTypes.TYPE_UINT64]
return uint64_value
def write_uint64(self, value: int) -> None:
self.__size = align_offset_to_type(self.__size, FieldTypes.TYPE_UINT64)
self.__writer.seek(self.__size)
formatted_uint64 = value.to_bytes(8, byteorder='little', signed=False)
self.__writer.write(formatted_uint64)
self.__size += FIELD_SIZES[FieldTypes.TYPE_UINT64]