65 lines
1.9 KiB
Rust
65 lines
1.9 KiB
Rust
// Copyright 2013 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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#![allow(missing_docs)]
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#![unstable(feature = "unnamed_feature")]
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//! Contains struct definitions for the layout of compiler built-in types.
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//!
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//! They can be used as targets of transmutes in unsafe code for manipulating
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//! the raw representations directly.
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//!
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//! Their definition should always match the ABI defined in `rustc::back::abi`.
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use marker::Copy;
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use mem;
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/// The representation of a Rust slice
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#[repr(C)]
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pub struct Slice<T> {
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pub data: *const T,
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pub len: uint,
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}
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impl<T> Copy for Slice<T> {}
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/// The representation of a Rust closure
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#[repr(C)]
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#[derive(Copy)]
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pub struct Closure {
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pub code: *mut (),
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pub env: *mut (),
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}
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/// The representation of a Rust trait object.
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///
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/// This struct does not have a `Repr` implementation
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/// because there is no way to refer to all trait objects generically.
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#[repr(C)]
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#[derive(Copy)]
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pub struct TraitObject {
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pub data: *mut (),
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pub vtable: *mut (),
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}
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/// This trait is meant to map equivalences between raw structs and their
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/// corresponding rust values.
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pub trait Repr<T> {
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/// This function "unwraps" a rust value (without consuming it) into its raw
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/// struct representation. This can be used to read/write different values
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/// for the struct. This is a safe method because by default it does not
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/// enable write-access to the fields of the return value in safe code.
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#[inline]
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fn repr(&self) -> T { unsafe { mem::transmute_copy(&self) } }
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}
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impl<T> Repr<Slice<T>> for [T] {}
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impl Repr<Slice<u8>> for str {}
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