libcollections

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+// Copyright 2012-2015 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.
+
+//! A dynamically-sized view into a contiguous sequence, `[T]`.
+//!
+//! Slices are a view into a block of memory represented as a pointer and a
+//! length.
+//!
+//! ```
+//! // slicing a Vec
+//! let vec = vec![1, 2, 3];
+//! let int_slice = &vec[..];
+//! // coercing an array to a slice
+//! let str_slice: &[&str] = &["one", "two", "three"];
+//! ```
+//!
+//! Slices are either mutable or shared. The shared slice type is `&[T]`,
+//! while the mutable slice type is `&mut [T]`, where `T` represents the element
+//! type. For example, you can mutate the block of memory that a mutable slice
+//! points to:
+//!
+//! ```
+//! let x = &mut [1, 2, 3];
+//! x[1] = 7;
+//! assert_eq!(x, &[1, 7, 3]);
+//! ```
+//!
+//! Here are some of the things this module contains:
+//!
+//! ## Structs
+//!
+//! There are several structs that are useful for slices, such as `Iter`, which
+//! represents iteration over a slice.
+//!
+//! ## Trait Implementations
+//!
+//! There are several implementations of common traits for slices. Some examples
+//! include:
+//!
+//! * `Clone`
+//! * `Eq`, `Ord` - for slices whose element type are `Eq` or `Ord`.
+//! * `Hash` - for slices whose element type is `Hash`
+//!
+//! ## Iteration
+//!
+//! The slices implement `IntoIterator`. The iterator yields references to the
+//! slice elements.
+//!
+//! ```
+//! let numbers = &[0, 1, 2];
+//! for n in numbers {
+//!     println!("{} is a number!", n);
+//! }
+//! ```
+//!
+//! The mutable slice yields mutable references to the elements:
+//!
+//! ```
+//! let mut scores = [7, 8, 9];
+//! for score in &mut scores[..] {
+//!     *score += 1;
+//! }
+//! ```
+//!
+//! This iterator yields mutable references to the slice's elements, so while
+//! the element type of the slice is `i32`, the element type of the iterator is
+//! `&mut i32`.
+//!
+//! * `.iter()` and `.iter_mut()` are the explicit methods to return the default
+//!   iterators.
+//! * Further methods that return iterators are `.split()`, `.splitn()`,
+//!   `.chunks()`, `.windows()` and more.
+//!
+//! *[See also the slice primitive type](../../std/primitive.slice.html).*
+#![stable(feature = "rust1", since = "1.0.0")]
+
+// Many of the usings in this module are only used in the test configuration.
+// It's cleaner to just turn off the unused_imports warning than to fix them.
+#![cfg_attr(test, allow(unused_imports, dead_code))]
+
+use alloc::boxed::Box;
+use core::cmp::Ordering::{self, Greater, Less};
+use core::cmp;
+use core::mem::size_of;
+use core::mem;
+use core::ptr;
+use core::slice as core_slice;
+
+use borrow::{Borrow, BorrowMut, ToOwned};
+use vec::Vec;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{Chunks, Windows};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{Iter, IterMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{SplitMut, ChunksMut, Split};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{SplitN, RSplitN, SplitNMut, RSplitNMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{from_raw_parts, from_raw_parts_mut};
+
+////////////////////////////////////////////////////////////////////////////////
+// Basic slice extension methods
+////////////////////////////////////////////////////////////////////////////////
+
+// HACK(japaric) needed for the implementation of `vec!` macro during testing
+// NB see the hack module in this file for more details
+#[cfg(test)]
+pub use self::hack::into_vec;
+
+// HACK(japaric) needed for the implementation of `Vec::clone` during testing
+// NB see the hack module in this file for more details
+#[cfg(test)]
+pub use self::hack::to_vec;
+
+// HACK(japaric): With cfg(test) `impl [T]` is not available, these three
+// functions are actually methods that are in `impl [T]` but not in
+// `core::slice::SliceExt` - we need to supply these functions for the
+// `test_permutations` test
+mod hack {
+    use alloc::boxed::Box;
+    use core::mem;
+
+    #[cfg(test)]
+    use string::ToString;
+    use vec::Vec;
+
+    pub fn into_vec<T>(mut b: Box<[T]>) -> Vec<T> {
+        unsafe {
+            let xs = Vec::from_raw_parts(b.as_mut_ptr(), b.len(), b.len());
+            mem::forget(b);
+            xs
+        }
+    }
+
+    #[inline]
+    pub fn to_vec<T>(s: &[T]) -> Vec<T>
+        where T: Clone
+    {
+        let mut vector = Vec::with_capacity(s.len());
+        vector.extend_from_slice(s);
+        vector
+    }
+}
+
+/// Allocating extension methods for slices.
+#[lang = "slice"]
+#[cfg(not(test))]
+impl<T> [T] {
+    /// Returns the number of elements in the slice.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// let a = [1, 2, 3];
+    /// assert_eq!(a.len(), 3);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn len(&self) -> usize {
+        core_slice::SliceExt::len(self)
+    }
+
+    /// Returns true if the slice has a length of 0
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// let a = [1, 2, 3];
+    /// assert!(!a.is_empty());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        core_slice::SliceExt::is_empty(self)
+    }
+
+    /// Returns the first element of a slice, or `None` if it is empty.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30];
+    /// assert_eq!(Some(&10), v.first());
+    ///
+    /// let w: &[i32] = &[];
+    /// assert_eq!(None, w.first());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn first(&self) -> Option<&T> {
+        core_slice::SliceExt::first(self)
+    }
+
+    /// Returns a mutable pointer to the first element of a slice, or `None` if it is empty
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn first_mut(&mut self) -> Option<&mut T> {
+        core_slice::SliceExt::first_mut(self)
+    }
+
+    /// Returns the first and all the rest of the elements of a slice.
+    #[stable(feature = "slice_splits", since = "1.5.0")]
+    #[inline]
+    pub fn split_first(&self) -> Option<(&T, &[T])> {
+        core_slice::SliceExt::split_first(self)
+    }
+
+    /// Returns the first and all the rest of the elements of a slice.
+    #[stable(feature = "slice_splits", since = "1.5.0")]
+    #[inline]
+    pub fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])> {
+        core_slice::SliceExt::split_first_mut(self)
+    }
+
+    /// Returns the last and all the rest of the elements of a slice.
+    #[stable(feature = "slice_splits", since = "1.5.0")]
+    #[inline]
+    pub fn split_last(&self) -> Option<(&T, &[T])> {
+        core_slice::SliceExt::split_last(self)
+
+    }
+
+    /// Returns the last and all the rest of the elements of a slice.
+    #[stable(feature = "slice_splits", since = "1.5.0")]
+    #[inline]
+    pub fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])> {
+        core_slice::SliceExt::split_last_mut(self)
+    }
+
+    /// Returns the last element of a slice, or `None` if it is empty.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30];
+    /// assert_eq!(Some(&30), v.last());
+    ///
+    /// let w: &[i32] = &[];
+    /// assert_eq!(None, w.last());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn last(&self) -> Option<&T> {
+        core_slice::SliceExt::last(self)
+    }
+
+    /// Returns a mutable pointer to the last item in the slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn last_mut(&mut self) -> Option<&mut T> {
+        core_slice::SliceExt::last_mut(self)
+    }
+
+    /// Returns the element of a slice at the given index, or `None` if the
+    /// index is out of bounds.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30];
+    /// assert_eq!(Some(&40), v.get(1));
+    /// assert_eq!(None, v.get(3));
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn get(&self, index: usize) -> Option<&T> {
+        core_slice::SliceExt::get(self, index)
+    }
+
+    /// Returns a mutable reference to the element at the given index,
+    /// or `None` if the index is out of bounds
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn get_mut(&mut self, index: usize) -> Option<&mut T> {
+        core_slice::SliceExt::get_mut(self, index)
+    }
+
+    /// Returns a pointer to the element at the given index, without doing
+    /// bounds checking.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub unsafe fn get_unchecked(&self, index: usize) -> &T {
+        core_slice::SliceExt::get_unchecked(self, index)
+    }
+
+    /// Returns an unsafe mutable pointer to the element in index
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut T {
+        core_slice::SliceExt::get_unchecked_mut(self, index)
+    }
+
+    /// Returns an raw pointer to the slice's buffer
+    ///
+    /// The caller must ensure that the slice outlives the pointer this
+    /// function returns, or else it will end up pointing to garbage.
+    ///
+    /// Modifying the slice may cause its buffer to be reallocated, which
+    /// would also make any pointers to it invalid.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn as_ptr(&self) -> *const T {
+        core_slice::SliceExt::as_ptr(self)
+    }
+
+    /// Returns an unsafe mutable pointer to the slice's buffer.
+    ///
+    /// The caller must ensure that the slice outlives the pointer this
+    /// function returns, or else it will end up pointing to garbage.
+    ///
+    /// Modifying the slice may cause its buffer to be reallocated, which
+    /// would also make any pointers to it invalid.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn as_mut_ptr(&mut self) -> *mut T {
+        core_slice::SliceExt::as_mut_ptr(self)
+    }
+
+    /// Swaps two elements in a slice.
+    ///
+    /// # Arguments
+    ///
+    /// * a - The index of the first element
+    /// * b - The index of the second element
+    ///
+    /// # Panics
+    ///
+    /// Panics if `a` or `b` are out of bounds.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// let mut v = ["a", "b", "c", "d"];
+    /// v.swap(1, 3);
+    /// assert!(v == ["a", "d", "c", "b"]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn swap(&mut self, a: usize, b: usize) {
+        core_slice::SliceExt::swap(self, a, b)
+    }
+
+    /// Reverse the order of elements in a slice, in place.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// let mut v = [1, 2, 3];
+    /// v.reverse();
+    /// assert!(v == [3, 2, 1]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn reverse(&mut self) {
+        core_slice::SliceExt::reverse(self)
+    }
+
+    /// Returns an iterator over the slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn iter(&self) -> Iter<T> {
+        core_slice::SliceExt::iter(self)
+    }
+
+    /// Returns an iterator that allows modifying each value
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn iter_mut(&mut self) -> IterMut<T> {
+        core_slice::SliceExt::iter_mut(self)
+    }
+
+    /// Returns an iterator over all contiguous windows of length
+    /// `size`. The windows overlap. If the slice is shorter than
+    /// `size`, the iterator returns no values.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `size` is 0.
+    ///
+    /// # Example
+    ///
+    /// Print the adjacent pairs of a slice (i.e. `[1,2]`, `[2,3]`,
+    /// `[3,4]`):
+    ///
+    /// ```rust
+    /// let v = &[1, 2, 3, 4];
+    /// for win in v.windows(2) {
+    ///     println!("{:?}", win);
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn windows(&self, size: usize) -> Windows<T> {
+        core_slice::SliceExt::windows(self, size)
+    }
+
+    /// Returns an iterator over `size` elements of the slice at a
+    /// time. The chunks are slices and do not overlap. If `size` does not divide the
+    /// length of the slice, then the last chunk will not have length
+    /// `size`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `size` is 0.
+    ///
+    /// # Example
+    ///
+    /// Print the slice two elements at a time (i.e. `[1,2]`,
+    /// `[3,4]`, `[5]`):
+    ///
+    /// ```rust
+    /// let v = &[1, 2, 3, 4, 5];
+    /// for win in v.chunks(2) {
+    ///     println!("{:?}", win);
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn chunks(&self, size: usize) -> Chunks<T> {
+        core_slice::SliceExt::chunks(self, size)
+    }
+
+    /// Returns an iterator over `chunk_size` elements of the slice at a time.
+    /// The chunks are mutable slices, and do not overlap. If `chunk_size` does
+    /// not divide the length of the slice, then the last chunk will not
+    /// have length `chunk_size`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `chunk_size` is 0.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<T> {
+        core_slice::SliceExt::chunks_mut(self, chunk_size)
+    }
+
+    /// Divides one slice into two at an index.
+    ///
+    /// The first will contain all indices from `[0, mid)` (excluding
+    /// the index `mid` itself) and the second will contain all
+    /// indices from `[mid, len)` (excluding the index `len` itself).
+    ///
+    /// # Panics
+    ///
+    /// Panics if `mid > len`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30, 20, 50];
+    /// let (v1, v2) = v.split_at(2);
+    /// assert_eq!([10, 40], v1);
+    /// assert_eq!([30, 20, 50], v2);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn split_at(&self, mid: usize) -> (&[T], &[T]) {
+        core_slice::SliceExt::split_at(self, mid)
+    }
+
+    /// Divides one `&mut` into two at an index.
+    ///
+    /// The first will contain all indices from `[0, mid)` (excluding
+    /// the index `mid` itself) and the second will contain all
+    /// indices from `[mid, len)` (excluding the index `len` itself).
+    ///
+    /// # Panics
+    ///
+    /// Panics if `mid > len`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// let mut v = [1, 2, 3, 4, 5, 6];
+    ///
+    /// // scoped to restrict the lifetime of the borrows
+    /// {
+    ///    let (left, right) = v.split_at_mut(0);
+    ///    assert!(left == []);
+    ///    assert!(right == [1, 2, 3, 4, 5, 6]);
+    /// }
+    ///
+    /// {
+    ///     let (left, right) = v.split_at_mut(2);
+    ///     assert!(left == [1, 2]);
+    ///     assert!(right == [3, 4, 5, 6]);
+    /// }
+    ///
+    /// {
+    ///     let (left, right) = v.split_at_mut(6);
+    ///     assert!(left == [1, 2, 3, 4, 5, 6]);
+    ///     assert!(right == []);
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T]) {
+        core_slice::SliceExt::split_at_mut(self, mid)
+    }
+
+    /// Returns an iterator over subslices separated by elements that match
+    /// `pred`.  The matched element is not contained in the subslices.
+    ///
+    /// # Examples
+    ///
+    /// Print the slice split by numbers divisible by 3 (i.e. `[10, 40]`,
+    /// `[20]`, `[50]`):
+    ///
+    /// ```
+    /// let v = [10, 40, 30, 20, 60, 50];
+    /// for group in v.split(|num| *num % 3 == 0) {
+    ///     println!("{:?}", group);
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn split<F>(&self, pred: F) -> Split<T, F>
+        where F: FnMut(&T) -> bool
+    {
+        core_slice::SliceExt::split(self, pred)
+    }
+
+    /// Returns an iterator over mutable subslices separated by elements that
+    /// match `pred`.  The matched element is not contained in the subslices.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn split_mut<F>(&mut self, pred: F) -> SplitMut<T, F>
+        where F: FnMut(&T) -> bool
+    {
+        core_slice::SliceExt::split_mut(self, pred)
+    }
+
+    /// Returns an iterator over subslices separated by elements that match
+    /// `pred`, limited to returning at most `n` items.  The matched element is
+    /// not contained in the subslices.
+    ///
+    /// The last element returned, if any, will contain the remainder of the
+    /// slice.
+    ///
+    /// # Examples
+    ///
+    /// Print the slice split once by numbers divisible by 3 (i.e. `[10, 40]`,
+    /// `[20, 60, 50]`):
+    ///
+    /// ```
+    /// let v = [10, 40, 30, 20, 60, 50];
+    /// for group in v.splitn(2, |num| *num % 3 == 0) {
+    ///     println!("{:?}", group);
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<T, F>
+        where F: FnMut(&T) -> bool
+    {
+        core_slice::SliceExt::splitn(self, n, pred)
+    }
+
+    /// Returns an iterator over subslices separated by elements that match
+    /// `pred`, limited to returning at most `n` items.  The matched element is
+    /// not contained in the subslices.
+    ///
+    /// The last element returned, if any, will contain the remainder of the
+    /// slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn splitn_mut<F>(&mut self, n: usize, pred: F) -> SplitNMut<T, F>
+        where F: FnMut(&T) -> bool
+    {
+        core_slice::SliceExt::splitn_mut(self, n, pred)
+    }
+
+    /// Returns an iterator over subslices separated by elements that match
+    /// `pred` limited to returning at most `n` items. This starts at the end of
+    /// the slice and works backwards.  The matched element is not contained in
+    /// the subslices.
+    ///
+    /// The last element returned, if any, will contain the remainder of the
+    /// slice.
+    ///
+    /// # Examples
+    ///
+    /// Print the slice split once, starting from the end, by numbers divisible
+    /// by 3 (i.e. `[50]`, `[10, 40, 30, 20]`):
+    ///
+    /// ```
+    /// let v = [10, 40, 30, 20, 60, 50];
+    /// for group in v.rsplitn(2, |num| *num % 3 == 0) {
+    ///     println!("{:?}", group);
+    /// }
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<T, F>
+        where F: FnMut(&T) -> bool
+    {
+        core_slice::SliceExt::rsplitn(self, n, pred)
+    }
+
+    /// Returns an iterator over subslices separated by elements that match
+    /// `pred` limited to returning at most `n` items. This starts at the end of
+    /// the slice and works backwards.  The matched element is not contained in
+    /// the subslices.
+    ///
+    /// The last element returned, if any, will contain the remainder of the
+    /// slice.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn rsplitn_mut<F>(&mut self, n: usize, pred: F) -> RSplitNMut<T, F>
+        where F: FnMut(&T) -> bool
+    {
+        core_slice::SliceExt::rsplitn_mut(self, n, pred)
+    }
+
+    /// Returns true if the slice contains an element with the given value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30];
+    /// assert!(v.contains(&30));
+    /// assert!(!v.contains(&50));
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn contains(&self, x: &T) -> bool
+        where T: PartialEq
+    {
+        core_slice::SliceExt::contains(self, x)
+    }
+
+    /// Returns true if `needle` is a prefix of the slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30];
+    /// assert!(v.starts_with(&[10]));
+    /// assert!(v.starts_with(&[10, 40]));
+    /// assert!(!v.starts_with(&[50]));
+    /// assert!(!v.starts_with(&[10, 50]));
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn starts_with(&self, needle: &[T]) -> bool
+        where T: PartialEq
+    {
+        core_slice::SliceExt::starts_with(self, needle)
+    }
+
+    /// Returns true if `needle` is a suffix of the slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = [10, 40, 30];
+    /// assert!(v.ends_with(&[30]));
+    /// assert!(v.ends_with(&[40, 30]));
+    /// assert!(!v.ends_with(&[50]));
+    /// assert!(!v.ends_with(&[50, 30]));
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn ends_with(&self, needle: &[T]) -> bool
+        where T: PartialEq
+    {
+        core_slice::SliceExt::ends_with(self, needle)
+    }
+
+    /// Binary search a sorted slice for a given element.
+    ///
+    /// If the value is found then `Ok` is returned, containing the
+    /// index of the matching element; if the value is not found then
+    /// `Err` is returned, containing the index where a matching
+    /// element could be inserted while maintaining sorted order.
+    ///
+    /// # Example
+    ///
+    /// Looks up a series of four elements. The first is found, with a
+    /// uniquely determined position; the second and third are not
+    /// found; the fourth could match any position in `[1,4]`.
+    ///
+    /// ```rust
+    /// let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
+    ///
+    /// assert_eq!(s.binary_search(&13),  Ok(9));
+    /// assert_eq!(s.binary_search(&4),   Err(7));
+    /// assert_eq!(s.binary_search(&100), Err(13));
+    /// let r = s.binary_search(&1);
+    /// assert!(match r { Ok(1...4) => true, _ => false, });
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn binary_search(&self, x: &T) -> Result<usize, usize>
+        where T: Ord
+    {
+        core_slice::SliceExt::binary_search(self, x)
+    }
+
+    /// Binary search a sorted slice with a comparator function.
+    ///
+    /// The comparator function should implement an order consistent
+    /// with the sort order of the underlying slice, returning an
+    /// order code that indicates whether its argument is `Less`,
+    /// `Equal` or `Greater` the desired target.
+    ///
+    /// If a matching value is found then returns `Ok`, containing
+    /// the index for the matched element; if no match is found then
+    /// `Err` is returned, containing the index where a matching
+    /// element could be inserted while maintaining sorted order.
+    ///
+    /// # Example
+    ///
+    /// Looks up a series of four elements. The first is found, with a
+    /// uniquely determined position; the second and third are not
+    /// found; the fourth could match any position in `[1,4]`.
+    ///
+    /// ```rust
+    /// let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
+    ///
+    /// let seek = 13;
+    /// assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
+    /// let seek = 4;
+    /// assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
+    /// let seek = 100;
+    /// assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
+    /// let seek = 1;
+    /// let r = s.binary_search_by(|probe| probe.cmp(&seek));
+    /// assert!(match r { Ok(1...4) => true, _ => false, });
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn binary_search_by<F>(&self, f: F) -> Result<usize, usize>
+        where F: FnMut(&T) -> Ordering
+    {
+        core_slice::SliceExt::binary_search_by(self, f)
+    }
+
+    /// Sorts the slice, in place.
+    ///
+    /// This is equivalent to `self.sort_by(|a, b| a.cmp(b))`.
+    ///
+    /// This is a stable sort.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let mut v = [-5, 4, 1, -3, 2];
+    ///
+    /// v.sort();
+    /// assert!(v == [-5, -3, 1, 2, 4]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn sort(&mut self)
+        where T: Ord
+    {
+        self.sort_by(|a, b| a.cmp(b))
+    }
+
+    /// Sorts the slice, in place, using `key` to extract a key by which to
+    /// order the sort by.
+    ///
+    /// This sort is `O(n log n)` worst-case and stable, but allocates
+    /// approximately `2 * n`, where `n` is the length of `self`.
+    ///
+    /// This is a stable sort.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let mut v = [-5i32, 4, 1, -3, 2];
+    ///
+    /// v.sort_by_key(|k| k.abs());
+    /// assert!(v == [1, 2, -3, 4, -5]);
+    /// ```
+    #[stable(feature = "slice_sort_by_key", since = "1.7.0")]
+    #[inline]
+    pub fn sort_by_key<B, F>(&mut self, mut f: F)
+        where F: FnMut(&T) -> B, B: Ord
+    {
+        self.sort_by(|a, b| f(a).cmp(&f(b)))
+    }
+
+    /// Sorts the slice, in place, using `compare` to compare
+    /// elements.
+    ///
+    /// This sort is `O(n log n)` worst-case and stable, but allocates
+    /// approximately `2 * n`, where `n` is the length of `self`.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let mut v = [5, 4, 1, 3, 2];
+    /// v.sort_by(|a, b| a.cmp(b));
+    /// assert!(v == [1, 2, 3, 4, 5]);
+    ///
+    /// // reverse sorting
+    /// v.sort_by(|a, b| b.cmp(a));
+    /// assert!(v == [5, 4, 3, 2, 1]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn sort_by<F>(&mut self, compare: F)
+        where F: FnMut(&T, &T) -> Ordering
+    {
+        merge_sort(self, compare)
+    }
+
+    /// Copies the elements from `src` into `self`.
+    ///
+    /// The length of this slice must be the same as the slice passed in.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the two slices have different lengths.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// let mut dst = [0, 0, 0];
+    /// let src = [1, 2, 3];
+    ///
+    /// dst.clone_from_slice(&src);
+    /// assert!(dst == [1, 2, 3]);
+    /// ```
+    #[stable(feature = "clone_from_slice", since = "1.7.0")]
+    pub fn clone_from_slice(&mut self, src: &[T]) where T: Clone {
+        core_slice::SliceExt::clone_from_slice(self, src)
+    }
+
+    /// Copies all elements from `src` into `self`, using a memcpy.
+    ///
+    /// The length of `src` must be the same as `self`.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the two slices have different lengths.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// #![feature(copy_from_slice)]
+    /// let mut dst = [0, 0, 0];
+    /// let src = [1, 2, 3];
+    ///
+    /// dst.copy_from_slice(&src);
+    /// assert_eq!(src, dst);
+    /// ```
+    #[unstable(feature = "copy_from_slice", issue = "31755")]
+    pub fn copy_from_slice(&mut self, src: &[T]) where T: Copy {
+        core_slice::SliceExt::copy_from_slice(self, src)
+    }
+
+
+    /// Copies `self` into a new `Vec`.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn to_vec(&self) -> Vec<T>
+        where T: Clone
+    {
+        // NB see hack module in this file
+        hack::to_vec(self)
+    }
+
+    /// Converts `self` into a vector without clones or allocation.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn into_vec(self: Box<Self>) -> Vec<T> {
+        // NB see hack module in this file
+        hack::into_vec(self)
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Extension traits for slices over specific kinds of data
+////////////////////////////////////////////////////////////////////////////////
+#[unstable(feature = "slice_concat_ext",
+           reason = "trait should not have to exist",
+           issue = "27747")]
+/// An extension trait for concatenating slices
+pub trait SliceConcatExt<T: ?Sized> {
+    #[unstable(feature = "slice_concat_ext",
+               reason = "trait should not have to exist",
+               issue = "27747")]
+    /// The resulting type after concatenation
+    type Output;
+
+    /// Flattens a slice of `T` into a single value `Self::Output`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(["hello", "world"].concat(), "helloworld");
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn concat(&self) -> Self::Output;
+
+    /// Flattens a slice of `T` into a single value `Self::Output`, placing a
+    /// given separator between each.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(["hello", "world"].join(" "), "hello world");
+    /// ```
+    #[stable(feature = "rename_connect_to_join", since = "1.3.0")]
+    fn join(&self, sep: &T) -> Self::Output;
+
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[rustc_deprecated(since = "1.3.0", reason = "renamed to join")]
+    fn connect(&self, sep: &T) -> Self::Output;
+}
+
+#[unstable(feature = "slice_concat_ext",
+           reason = "trait should not have to exist",
+           issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> SliceConcatExt<T> for [V] {
+    type Output = Vec<T>;
+
+    fn concat(&self) -> Vec<T> {
+        let size = self.iter().fold(0, |acc, v| acc + v.borrow().len());
+        let mut result = Vec::with_capacity(size);
+        for v in self {
+            result.extend_from_slice(v.borrow())
+        }
+        result
+    }
+
+    fn join(&self, sep: &T) -> Vec<T> {
+        let size = self.iter().fold(0, |acc, v| acc + v.borrow().len());
+        let mut result = Vec::with_capacity(size + self.len());
+        let mut first = true;
+        for v in self {
+            if first {
+                first = false
+            } else {
+                result.push(sep.clone())
+            }
+            result.extend_from_slice(v.borrow())
+        }
+        result
+    }
+
+    fn connect(&self, sep: &T) -> Vec<T> {
+        self.join(sep)
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Standard trait implementations for slices
+////////////////////////////////////////////////////////////////////////////////
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Borrow<[T]> for Vec<T> {
+    fn borrow(&self) -> &[T] {
+        &self[..]
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BorrowMut<[T]> for Vec<T> {
+    fn borrow_mut(&mut self) -> &mut [T] {
+        &mut self[..]
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone> ToOwned for [T] {
+    type Owned = Vec<T>;
+    #[cfg(not(test))]
+    fn to_owned(&self) -> Vec<T> {
+        self.to_vec()
+    }
+
+    // HACK(japaric): with cfg(test) the inherent `[T]::to_vec`, which is required for this method
+    // definition, is not available. Since we don't require this method for testing purposes, I'll
+    // just stub it
+    // NB see the slice::hack module in slice.rs for more information
+    #[cfg(test)]
+    fn to_owned(&self) -> Vec<T> {
+        panic!("not available with cfg(test)")
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Sorting
+////////////////////////////////////////////////////////////////////////////////
+
+fn insertion_sort<T, F>(v: &mut [T], mut compare: F)
+    where F: FnMut(&T, &T) -> Ordering
+{
+    let len = v.len() as isize;
+    let buf_v = v.as_mut_ptr();
+
+    // 1 <= i < len;
+    for i in 1..len {
+        // j satisfies: 0 <= j <= i;
+        let mut j = i;
+        unsafe {
+            // `i` is in bounds.
+            let read_ptr = buf_v.offset(i) as *const T;
+
+            // find where to insert, we need to do strict <,
+            // rather than <=, to maintain stability.
+
+            // 0 <= j - 1 < len, so .offset(j - 1) is in bounds.
+            while j > 0 && compare(&*read_ptr, &*buf_v.offset(j - 1)) == Less {
+                j -= 1;
+            }
+
+            // shift everything to the right, to make space to
+            // insert this value.
+
+            // j + 1 could be `len` (for the last `i`), but in
+            // that case, `i == j` so we don't copy. The
+            // `.offset(j)` is always in bounds.
+
+            if i != j {
+                let tmp = ptr::read(read_ptr);
+                ptr::copy(&*buf_v.offset(j), buf_v.offset(j + 1), (i - j) as usize);
+                ptr::copy_nonoverlapping(&tmp, buf_v.offset(j), 1);
+                mem::forget(tmp);
+            }
+        }
+    }
+}
+
+fn merge_sort<T, F>(v: &mut [T], mut compare: F)
+    where F: FnMut(&T, &T) -> Ordering
+{
+    // warning: this wildly uses unsafe.
+    const BASE_INSERTION: usize = 32;
+    const LARGE_INSERTION: usize = 16;
+
+    // FIXME #12092: smaller insertion runs seems to make sorting
+    // vectors of large elements a little faster on some platforms,
+    // but hasn't been tested/tuned extensively
+    let insertion = if size_of::<T>() <= 16 {
+        BASE_INSERTION
+    } else {
+        LARGE_INSERTION
+    };
+
+    let len = v.len();
+
+    // short vectors get sorted in-place via insertion sort to avoid allocations
+    if len <= insertion {
+        insertion_sort(v, compare);
+        return;
+    }
+
+    // allocate some memory to use as scratch memory, we keep the
+    // length 0 so we can keep shallow copies of the contents of `v`
+    // without risking the dtors running on an object twice if
+    // `compare` panics.
+    let mut working_space = Vec::with_capacity(2 * len);
+    // these both are buffers of length `len`.
+    let mut buf_dat = working_space.as_mut_ptr();
+    let mut buf_tmp = unsafe { buf_dat.offset(len as isize) };
+
+    // length `len`.
+    let buf_v = v.as_ptr();
+
+    // step 1. sort short runs with insertion sort. This takes the
+    // values from `v` and sorts them into `buf_dat`, leaving that
+    // with sorted runs of length INSERTION.
+
+    // We could hardcode the sorting comparisons here, and we could
+    // manipulate/step the pointers themselves, rather than repeatedly
+    // .offset-ing.
+    for start in (0..len).step_by(insertion) {
+        // start <= i < len;
+        for i in start..cmp::min(start + insertion, len) {
+            // j satisfies: start <= j <= i;
+            let mut j = i as isize;
+            unsafe {
+                // `i` is in bounds.
+                let read_ptr = buf_v.offset(i as isize);
+
+                // find where to insert, we need to do strict <,
+                // rather than <=, to maintain stability.
+
+                // start <= j - 1 < len, so .offset(j - 1) is in
+                // bounds.
+                while j > start as isize && compare(&*read_ptr, &*buf_dat.offset(j - 1)) == Less {
+                    j -= 1;
+                }
+
+                // shift everything to the right, to make space to
+                // insert this value.
+
+                // j + 1 could be `len` (for the last `i`), but in
+                // that case, `i == j` so we don't copy. The
+                // `.offset(j)` is always in bounds.
+                ptr::copy(&*buf_dat.offset(j), buf_dat.offset(j + 1), i - j as usize);
+                ptr::copy_nonoverlapping(read_ptr, buf_dat.offset(j), 1);
+            }
+        }
+    }
+
+    // step 2. merge the sorted runs.
+    let mut width = insertion;
+    while width < len {
+        // merge the sorted runs of length `width` in `buf_dat` two at
+        // a time, placing the result in `buf_tmp`.
+
+        // 0 <= start <= len.
+        for start in (0..len).step_by(2 * width) {
+            // manipulate pointers directly for speed (rather than
+            // using a `for` loop with `range` and `.offset` inside
+            // that loop).
+            unsafe {
+                // the end of the first run & start of the
+                // second. Offset of `len` is defined, since this is
+                // precisely one byte past the end of the object.
+                let right_start = buf_dat.offset(cmp::min(start + width, len) as isize);
+                // end of the second. Similar reasoning to the above re safety.
+                let right_end_idx = cmp::min(start + 2 * width, len);
+                let right_end = buf_dat.offset(right_end_idx as isize);
+
+                // the pointers to the elements under consideration
+                // from the two runs.
+
+                // both of these are in bounds.
+                let mut left = buf_dat.offset(start as isize);
+                let mut right = right_start;
+
+                // where we're putting the results, it is a run of
+                // length `2*width`, so we step it once for each step
+                // of either `left` or `right`.  `buf_tmp` has length
+                // `len`, so these are in bounds.
+                let mut out = buf_tmp.offset(start as isize);
+                let out_end = buf_tmp.offset(right_end_idx as isize);
+
+                // If left[last] <= right[0], they are already in order:
+                // fast-forward the left side (the right side is handled
+                // in the loop).
+                // If `right` is not empty then left is not empty, and
+                // the offsets are in bounds.
+                if right != right_end && compare(&*right.offset(-1), &*right) != Greater {
+                    let elems = (right_start as usize - left as usize) / mem::size_of::<T>();
+                    ptr::copy_nonoverlapping(&*left, out, elems);
+                    out = out.offset(elems as isize);
+                    left = right_start;
+                }
+
+                while out < out_end {
+                    // Either the left or the right run are exhausted,
+                    // so just copy the remainder from the other run
+                    // and move on; this gives a huge speed-up (order
+                    // of 25%) for mostly sorted vectors (the best
+                    // case).
+                    if left == right_start {
+                        // the number remaining in this run.
+                        let elems = (right_end as usize - right as usize) / mem::size_of::<T>();
+                        ptr::copy_nonoverlapping(&*right, out, elems);
+                        break;
+                    } else if right == right_end {
+                        let elems = (right_start as usize - left as usize) / mem::size_of::<T>();
+                        ptr::copy_nonoverlapping(&*left, out, elems);
+                        break;
+                    }
+
+                    // check which side is smaller, and that's the
+                    // next element for the new run.
+
+                    // `left < right_start` and `right < right_end`,
+                    // so these are valid.
+                    let to_copy = if compare(&*left, &*right) == Greater {
+                        step(&mut right)
+                    } else {
+                        step(&mut left)
+                    };
+                    ptr::copy_nonoverlapping(&*to_copy, out, 1);
+                    step(&mut out);
+                }
+            }
+        }
+
+        mem::swap(&mut buf_dat, &mut buf_tmp);
+
+        width *= 2;
+    }
+
+    // write the result to `v` in one go, so that there are never two copies
+    // of the same object in `v`.
+    unsafe {
+        ptr::copy_nonoverlapping(&*buf_dat, v.as_mut_ptr(), len);
+    }
+
+    // increment the pointer, returning the old pointer.
+    #[inline(always)]
+    unsafe fn step<T>(ptr: &mut *mut T) -> *mut T {
+        let old = *ptr;
+        *ptr = ptr.offset(1);
+        old
+    }
+}