def annotation_to_field_instance(
annotation: AnnotationInfo, ) -> Optional[fields.Field[Any]]:
"""Convert a type annotation to a Field object if it represents one."""
if isinstance(annotation.type_class, type):
# We got a class object. Could be a struct or field, ignore everything else.
if issubclass(annotation.type_class, binobj.Struct):
# A Struct class is shorthand for Nested(Struct).
return fields.Nested(annotation.type_class)
if issubclass(annotation.type_class, fields.Field):
# This is a Field class. Initialize it with only the arguments we're certain
# of. This gives us a Field instance.
if annotation.nullable:
kw = {"null_value": fields.DEFAULT} # type: Dict[str, Any]
else:
kw = {}
return annotation.type_class(name=annotation.name,
default=annotation.default_value,
**kw)
# Else: Not a struct or field class -- ignore
return None
if not isinstance(annotation.type_class, fields.Field):
# Not an instance of Field -- ignore
return None
# Else: The annotation is a field instance. Atypical but we'll allow it.
return annotation.type_class
def test_array__load_nested():
"""Try loading an array of structs."""
field = fields.Array(fields.Nested(SubStruct), count=2)
loaded = field.from_bytes(b"\xc0\xff\xee\xde\xad\xbe\xef\x00ABCDEFG"
b"\xfa\xde\xdb\xed\xa5\x51\xed\x00HIJKLMN")
assert loaded == [
{
"first": 0xC0FFEEDEADBEEF00,
"second": "ABCDEFG"
},
{
"first": 0xFADEDBEDA551ED00,
"second": "HIJKLMN"
},
]
def test_array__dump_nested():
"""Try dumping an array of structs."""
field = fields.Array(fields.Nested(SubStruct), count=2)
dumped = field.to_bytes([
{
"first": 0xC0FFEEDEADBEEF00,
"second": "ABCDEFG"
},
{
"first": 0xFADEDBEDA551ED00,
"second": "HIJKLMN"
},
])
assert (dumped == b"\xc0\xff\xee\xde\xad\xbe\xef\x00ABCDEFG"
b"\xfa\xde\xdb\xed\xa5\x51\xed\x00HIJKLMN")
class MainStruct(binobj.Struct):
before = fields.Int16(endian="big")
nested = fields.Nested(SubStruct)
after = fields.Int8()
class NestedConstArrayStruct(binobj.Struct):
field_1 = fields.String(size=16)
field_2 = fields.Array(fields.Nested(ConstArrayStruct), count=4)