StructAttr is a decorator for classes that adds a deserializer method from_bytes() and a serializer method to_bytes() to the class. It also adds a validate() method, which verifies if all the fields are of the correct type, and optionally tries to convert them to the correct type.
It is designed to work in close cooperation with attrs module, but can used independently. See tests/usage_test.py for examples
For a type to be usable as field type, it needs several methods:
- return the number of bits this field consumes or produces:
cls.bits() -> int
Note: this is a method call to be compatible with Enum-derived classes
- decode data. Either of these (in order of performance):
cls.from_int(data: int) -> cls cls.from_signed_int(data: int) -> cls cls.from_bytes(data: bytes) -> cls
Note: the data in from_bytes is left-aligned (only relevant if bits() % 8 != 0)
- encode data. Either of these (in order of preference):
obj.to_int() -> int obj.to_signed_int() -> int obj.to_bytes() -> bytes
Note: the data from to_bytes must be left-aligned (only relevant if bits() % 8 != 0)
Although this module is designed to work on top of attr-classes, you can use it independently as well. You need to provide an additional parameter to from_bytes() and to_bytes() to indicate the encoding of the class properties from/to bytes.
The extra parameter is a list (or tupple) of objects with the following properties:
- o.name : attribute name to use when accessing the field
- o.type : type of the field