49 lines
1.3 KiB
Rust
49 lines
1.3 KiB
Rust
// Copyright 2015 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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#![feature(raw)]
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use std::mem;
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use std::raw;
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trait Foo {
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fn foo(&self) {}
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}
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struct Bar;
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impl Foo for Bar {}
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fn main() {
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// Test we can turn a fat pointer to array back into a thin pointer.
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let a: *const [i32] = &[1, 2, 3];
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let b = a as *const [i32; 2];
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unsafe {
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assert_eq!(*b, [1, 2]);
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}
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// Test conversion to an address (usize).
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let a: *const [i32; 3] = &[1, 2, 3];
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let b: *const [i32] = a;
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assert_eq!(a as usize, b as *const () as usize);
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// And conversion to a void pointer/address for trait objects too.
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let a: *mut Foo = &mut Bar;
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let b = a as *mut ();
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let c = a as *const () as usize;
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let d = unsafe {
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let r: raw::TraitObject = mem::transmute(a);
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r.data
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};
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assert_eq!(b, d);
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assert_eq!(c, d as usize);
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}
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