sprout42 / StarStruct

            # recreate the struct with the new format

            self._struct = struct.Struct(self.format)

    def pack(self, msg):

        """Pack the provided values into the supplied buffer."""

        # The value to pack could be a raw value, an enum value, or a string

        # that represents the enum value, first ensure that the value provided

        # is a valid value for the referenced enum class.

        item = msg[self.name]

        if isinstance(item, self.ref):

            enum_item = item

        elif isinstance(item, str):

            try:

                enum_item = getattr(self.ref, msg[self.name])

            except AttributeError:

                enum_name = re.match(r"<enum '(\S+)'>", str(self.ref)).group(1)

                msg = '{} is not a valid {}'.format(msg[self.name], enum_name)

                raise ValueError(msg)

        else:

            enum_item = self.ref(item)

        data = self._struct.pack(enum_item.value)

        # If the data does not meet the alignment, add some padding

        missing_bytes = len(data) % self._alignment

        if missing_bytes:

            data += b'\x00' * missing_bytes

        return data

    def unpack(self, msg, buf):

        """Unpack data from the supplied buffer using the initialized format."""

        return (member, unused)

    def make(self, msg):

        """Return the "transformed" value for this element"""

        # Handle the same conditions that pack handles

        item = msg[self.name]

        if isinstance(item, self.ref):

            enum_item = item

        elif isinstance(item, str):

            try:

                enum_item = getattr(self.ref, msg[self.name])

            except AttributeError:

                enum_name = re.match(r"<enum '(\S+)'>", str(self.ref)).group(1)

                msg = '{} is not a valid {}'.format(msg[self.name], enum_name)

                raise ValueError(msg)

        else:

            enum_item = self.ref(item)

        return enum_item