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// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use cast;
use unstable::intrinsics::TyDesc;
/// The representation of a Rust managed box
pub struct Box<T> {
ref_count: uint,
type_desc: *TyDesc,
prev: *mut Box<T>,
next: *mut Box<T>,
data: T
}
/// The representation of a Rust vector
pub struct Vec<T> {
fill: uint,
alloc: uint,
data: T
}
/// The representation of a Rust string
pub type String = Vec<u8>;
/// The representation of a Rust slice
pub struct Slice<T> {
data: *T,
len: uint
}
/// The representation of a Rust closure
pub struct Closure {
code: *(),
env: *(),
}
/// This trait is meant to map equivalences between raw structs and their
/// corresponding rust values.
pub trait Repr<T> {
/// This function "unwraps" a rust value (without consuming it) into its raw
/// struct representation. This can be used to read/write different values
/// for the struct. This is a safe method because by default it does not
/// give write-access to the struct returned.
#[inline]
fn repr(&self) -> T { unsafe { cast::transmute_copy(self) } }
}
impl<'a, T> Repr<Slice<T>> for &'a [T] {}
impl<'a> Repr<Slice<u8>> for &'a str {}
impl<T> Repr<*Box<T>> for @T {}
impl<T> Repr<*Vec<T>> for ~[T] {}
impl Repr<*String> for ~str {}
// sure would be nice to have this
// impl<T> Repr<*Vec<T>> for ~[T] {}
#[cfg(test)]
mod tests {
use super::*;
use cast;
#[test]
fn synthesize_closure() {
unsafe {
let x = 10;
let f: |int| -> int = |y| x + y;
assert_eq!(f(20), 30);
let original_closure: Closure = cast::transmute(f);
let actual_function_pointer = original_closure.code;
let environment = original_closure.env;
let new_closure = Closure {
code: actual_function_pointer,
env: environment
};
let new_f: |int| -> int = cast::transmute(new_closure);
assert_eq!(new_f(20), 30);
}
}
}
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