48 lines
1.4 KiB
Rust
48 lines
1.4 KiB
Rust
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use std::mem;
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// Univariant C-like enum
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#[repr(i32)]
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enum Univariant {
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X = 17
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}
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#[repr(u16)]
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enum UnivariantWithoutDescr {
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Y
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}
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pub fn main() {
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{
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assert_eq!(4, mem::size_of::<Univariant>());
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assert_eq!(17, Univariant::X as i32);
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let enums: &[Univariant] =
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&[Univariant::X, Univariant::X, Univariant::X];
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let ints: &[i32] = unsafe { mem::transmute(enums) };
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// check it has the same memory layout as i32
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assert_eq!(&[17, 17, 17], ints);
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}
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{
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assert_eq!(2, mem::size_of::<UnivariantWithoutDescr>());
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let descr = UnivariantWithoutDescr::Y as u16;
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let enums: &[UnivariantWithoutDescr] =
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&[UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y, UnivariantWithoutDescr::Y];
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let ints: &[u16] = unsafe { mem::transmute(enums) };
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// check it has the same memory layout as u16
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assert_eq!(&[descr, descr, descr], ints);
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}
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}
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