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1 | // Copyright 2016 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | ||
12 | use std::mem; | |
13 | ||
14 | // Univariant C-like enum | |
15 | #[repr(i32)] | |
16 | enum Univariant { | |
17 | X = 17 | |
18 | } | |
19 | ||
20 | #[repr(u16)] | |
21 | enum UnivariantWithoutDescr { | |
22 | Y | |
23 | } | |
24 | ||
25 | pub fn main() { | |
26 | { | |
27 | assert_eq!(4, mem::size_of::<Univariant>()); | |
28 | assert_eq!(17, Univariant::X as i32); | |
29 | ||
30 | let enums: &[Univariant] = | |
31 | &[Univariant::X, Univariant::X, Univariant::X]; | |
32 | let ints: &[i32] = unsafe { mem::transmute(enums) }; | |
33 | // check it has the same memory layout as i32 | |
34 | assert_eq!(&[17, 17, 17], ints); | |
35 | } | |
36 | ||
37 | { | |
38 | assert_eq!(2, mem::size_of::<UnivariantWithoutDescr>()); | |
39 | let descr = UnivariantWithoutDescr::Y as u16; | |
40 | ||
41 | let enums: &[UnivariantWithoutDescr] = | |
42 | &[UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y]; | |
43 | let ints: &[u16] = unsafe { mem::transmute(enums) }; | |
44 | // check it has the same memory layout as u16 | |
45 | assert_eq!(&[descr, descr, descr], ints); | |
46 | } | |
47 | } |