diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs index e07f6dbd35d..138bc63737e 100644 --- a/src/libcollections/slice.rs +++ b/src/libcollections/slice.rs @@ -87,6 +87,7 @@ #![doc(primitive = "slice")] +use alloc::boxed::Box; use core::cmp; use core::mem::size_of; use core::mem; @@ -298,6 +299,23 @@ impl<'a, T: Clone> CloneableVector for &'a [T] { fn into_vec(self) -> Vec { self.to_vec() } } +#[experimental] +pub trait BoxedSlice { + /// Convert `self` into a vector without clones or allocation. + fn into_vec(self) -> Vec; +} + +impl BoxedSlice for Box<[T]> { + #[experimental] + fn into_vec(mut self) -> Vec { + unsafe { + let xs = Vec::from_raw_parts(self.len(), self.len(), self.as_mut_ptr()); + mem::forget(self); + xs + } + } +} + /// Extension methods for vectors containing `Clone` elements. pub trait ImmutableCloneableVector { /// Partitions the vector into two vectors `(a, b)`, where all @@ -2308,6 +2326,13 @@ mod tests { let y: &mut [int] = []; assert!(y.last_mut().is_none()); } + + #[test] + fn test_into_vec() { + let xs = box [1u, 2, 3]; + let ys = xs.into_vec(); + assert_eq!(ys.as_slice(), [1u, 2, 3]); + } } #[cfg(test)] diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs index a19efac4edc..d0105e3b24a 100644 --- a/src/libcollections/vec.rs +++ b/src/libcollections/vec.rs @@ -14,6 +14,7 @@ use core::prelude::*; +use alloc::boxed::Box; use alloc::heap::{EMPTY, allocate, reallocate, deallocate}; use core::cmp::max; use core::default::Default; @@ -757,6 +758,20 @@ impl Vec { } } + /// Convert the vector into Box<[T]>. + /// + /// Note that this will drop any excess capacity. Calling this and converting back to a vector + /// with `into_vec()` is equivalent to calling `shrink_to_fit()`. + #[experimental] + pub fn into_boxed_slice(mut self) -> Box<[T]> { + self.shrink_to_fit(); + unsafe { + let xs: Box<[T]> = mem::transmute(self.as_mut_slice()); + mem::forget(self); + xs + } + } + /// Deprecated, call `push` instead #[inline] #[deprecated = "call .push() instead"] @@ -2631,6 +2646,13 @@ mod tests { assert!(vec2 == vec!((), (), ())); } + #[test] + fn test_into_boxed_slice() { + let xs = vec![1u, 2, 3]; + let ys = xs.into_boxed_slice(); + assert_eq!(ys.as_slice(), [1u, 2, 3]); + } + #[bench] fn bench_new(b: &mut Bencher) { b.iter(|| { diff --git a/src/libstd/prelude.rs b/src/libstd/prelude.rs index abfb2de13c5..db9f3114cda 100644 --- a/src/libstd/prelude.rs +++ b/src/libstd/prelude.rs @@ -88,7 +88,7 @@ #[doc(no_inline)] pub use slice::{MutableCloneableSlice, MutableOrdSlice}; #[doc(no_inline)] pub use slice::{ImmutableSlice, MutableSlice}; #[doc(no_inline)] pub use slice::{ImmutablePartialEqSlice, ImmutableOrdSlice}; -#[doc(no_inline)] pub use slice::{AsSlice, VectorVector}; +#[doc(no_inline)] pub use slice::{AsSlice, VectorVector, BoxedSlice}; #[doc(no_inline)] pub use slice::MutableSliceAllocating; #[doc(no_inline)] pub use string::String; #[doc(no_inline)] pub use vec::Vec;