Function alignment

crates/vm/src/stdlib/_ctypes.rs:809–906

(tp: Either<PyTypeRef, PyObjectRef>, vm: &VirtualMachine)

    #[pyfunction]
    fn alignment(tp: Either<PyTypeRef, PyObjectRef>, vm: &VirtualMachine) -> PyResult<usize> {
        use crate::builtins::PyType;

        let obj = match &tp {
            Either::A(t) => t.as_object(),
            Either::B(o) => o.as_ref(),
        };

        // 1. Check TypeDataSlot on class (for instances)
        if let Some(stg_info) = obj.class().stg_info_opt() {
            return Ok(stg_info.align);
        }

        // 2. Check TypeDataSlot on type itself (for type objects)
        if let Some(type_obj) = obj.downcast_ref::<PyType>()
            && let Some(stg_info) = type_obj.stg_info_opt()
        {
            return Ok(stg_info.align);
        }

        // 3. Fallback for simple types
        if obj.fast_isinstance(PyCSimple::static_type())
            && let Ok(stg) = obj.class().stg_info(vm)
        {
            return Ok(stg.align);
        }
        if obj.fast_isinstance(PyCArray::static_type())
            && let Ok(stg) = obj.class().stg_info(vm)
        {
            return Ok(stg.align);
        }
        if obj.fast_isinstance(PyCStructure::static_type()) {
            // Calculate alignment from _fields_
            let cls = obj.class();
            return alignment(Either::A(cls.to_owned()), vm);
        }
        if obj.fast_isinstance(PyCPointer::static_type()) {
            // Pointer alignment is always pointer size
            return Ok(core::mem::align_of::<usize>());
        }
        if obj.fast_isinstance(PyCUnion::static_type()) {
            // Calculate alignment from _fields_
            let cls = obj.class();
            return alignment(Either::A(cls.to_owned()), vm);
        }

        // Get the type object to check
        let type_obj: PyObjectRef = match &tp {
            Either::A(t) => t.clone().into(),
            Either::B(obj) => obj.class().to_owned().into(),
        };

        // For type objects, try to get alignment from _type_ attribute
        if let Ok(type_attr) = type_obj.get_attr("_type_", vm) {
            // Array/Pointer: _type_ is the element type (a PyType)
            if let Ok(elem_type) = type_attr.clone().downcast::<crate::builtins::PyType>() {
                return alignment(Either::A(elem_type), vm);
            }