1 use libc::c_int;
2 use std::marker::PhantomData;
3 
4 /// A slot in a type's "extra data" structure.
5 ///
6 /// It is parameterized over the type containing the extra data as well as the
7 /// type of the data in the slot.
8 pub struct Index<T, U>(c_int, PhantomData<(T, U)>);
9 
10 impl<T, U> Copy for Index<T, U> {}
11 
12 impl<T, U> Clone for Index<T, U> {
13     fn clone(&self) -> Index<T, U> {
14         *self
15     }
16 }
17 
18 impl<T, U> Index<T, U> {
19     pub unsafe fn from_raw(idx: c_int) -> Index<T, U> {
20         Index(idx, PhantomData)
21     }
22 
23     pub fn as_raw(&self) -> c_int {
24         self.0
25     }
26 }
27