add libcore from 2016-04-11 nightly

1 files changed, 1832 insertions, 0 deletions

diff --git a/libcore/slice.rs b/libcore/slice.rs
new file mode 100644
index 0000000..25082ee
--- /dev/null
+++ b/libcore/slice.rs
@@ -0,0 +1,1832 @@
+// Copyright 2012-2014 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.
+
+//! Slice management and manipulation
+//!
+//! For more details `std::slice`.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+// How this module is organized.
+//
+// The library infrastructure for slices is fairly messy. There's
+// a lot of stuff defined here. Let's keep it clean.
+//
+// Since slices don't support inherent methods; all operations
+// on them are defined on traits, which are then reexported from
+// the prelude for convenience. So there are a lot of traits here.
+//
+// The layout of this file is thus:
+//
+// * Slice-specific 'extension' traits and their implementations. This
+//   is where most of the slice API resides.
+// * Implementations of a few common traits with important slice ops.
+// * Definitions of a bunch of iterators.
+// * Free functions.
+// * The `raw` and `bytes` submodules.
+// * Boilerplate trait implementations.
+
+use clone::Clone;
+use cmp::{Ordering, PartialEq, PartialOrd, Eq, Ord};
+use cmp::Ordering::{Less, Equal, Greater};
+use cmp;
+use default::Default;
+use fmt;
+use intrinsics::assume;
+use iter::*;
+use ops::{FnMut, self, Index};
+use ops::RangeFull;
+use option::Option;
+use option::Option::{None, Some};
+use result::Result;
+use result::Result::{Ok, Err};
+use ptr;
+use mem;
+use marker::{Copy, Send, Sync, self};
+use raw::Repr;
+// Avoid conflicts with *both* the Slice trait (buggy) and the `slice::raw` module.
+use raw::Slice as RawSlice;
+
+
+//
+// Extension traits
+//
+
+/// Extension methods for slices.
+#[unstable(feature = "core_slice_ext",
+           reason = "stable interface provided by `impl [T]` in later crates",
+           issue = "32110")]
+#[allow(missing_docs)] // documented elsewhere
+pub trait SliceExt {
+    type Item;
+
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_at(&self, mid: usize) -> (&[Self::Item], &[Self::Item]);
+    #[stable(feature = "core", since = "1.6.0")]
+    fn iter(&self) -> Iter<Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split<P>(&self, pred: P) -> Split<Self::Item, P>
+                    where P: FnMut(&Self::Item) -> bool;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn splitn<P>(&self, n: usize, pred: P) -> SplitN<Self::Item, P>
+                     where P: FnMut(&Self::Item) -> bool;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn rsplitn<P>(&self,  n: usize, pred: P) -> RSplitN<Self::Item, P>
+                      where P: FnMut(&Self::Item) -> bool;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn windows(&self, size: usize) -> Windows<Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn chunks(&self, size: usize) -> Chunks<Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn get(&self, index: usize) -> Option<&Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn first(&self) -> Option<&Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_first(&self) -> Option<(&Self::Item, &[Self::Item])>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_last(&self) -> Option<(&Self::Item, &[Self::Item])>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn last(&self) -> Option<&Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    unsafe fn get_unchecked(&self, index: usize) -> &Self::Item;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn as_ptr(&self) -> *const Self::Item;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn binary_search(&self, x: &Self::Item) -> Result<usize, usize>
+        where Self::Item: Ord;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn binary_search_by<F>(&self, f: F) -> Result<usize, usize>
+        where F: FnMut(&Self::Item) -> Ordering;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn len(&self) -> usize;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn is_empty(&self) -> bool { self.len() == 0 }
+    #[stable(feature = "core", since = "1.6.0")]
+    fn get_mut(&mut self, index: usize) -> Option<&mut Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn iter_mut(&mut self) -> IterMut<Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn first_mut(&mut self) -> Option<&mut Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_first_mut(&mut self) -> Option<(&mut Self::Item, &mut [Self::Item])>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_last_mut(&mut self) -> Option<(&mut Self::Item, &mut [Self::Item])>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn last_mut(&mut self) -> Option<&mut Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_mut<P>(&mut self, pred: P) -> SplitMut<Self::Item, P>
+                        where P: FnMut(&Self::Item) -> bool;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn splitn_mut<P>(&mut self, n: usize, pred: P) -> SplitNMut<Self::Item, P>
+                     where P: FnMut(&Self::Item) -> bool;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn rsplitn_mut<P>(&mut self,  n: usize, pred: P) -> RSplitNMut<Self::Item, P>
+                      where P: FnMut(&Self::Item) -> bool;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<Self::Item>;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn swap(&mut self, a: usize, b: usize);
+    #[stable(feature = "core", since = "1.6.0")]
+    fn split_at_mut(&mut self, mid: usize) -> (&mut [Self::Item], &mut [Self::Item]);
+    #[stable(feature = "core", since = "1.6.0")]
+    fn reverse(&mut self);
+    #[stable(feature = "core", since = "1.6.0")]
+    unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut Self::Item;
+    #[stable(feature = "core", since = "1.6.0")]
+    fn as_mut_ptr(&mut self) -> *mut Self::Item;
+
+    #[stable(feature = "core", since = "1.6.0")]
+    fn contains(&self, x: &Self::Item) -> bool where Self::Item: PartialEq;
+
+    #[stable(feature = "core", since = "1.6.0")]
+    fn starts_with(&self, needle: &[Self::Item]) -> bool where Self::Item: PartialEq;
+
+    #[stable(feature = "core", since = "1.6.0")]
+    fn ends_with(&self, needle: &[Self::Item]) -> bool where Self::Item: PartialEq;
+
+    #[stable(feature = "clone_from_slice", since = "1.7.0")]
+    fn clone_from_slice(&mut self, &[Self::Item]) where Self::Item: Clone;
+    #[unstable(feature = "copy_from_slice", issue = "31755")]
+    fn copy_from_slice(&mut self, src: &[Self::Item]) where Self::Item: Copy;
+}
+
+// Use macros to be generic over const/mut
+macro_rules! slice_offset {
+    ($ptr:expr, $by:expr) => {{
+        let ptr = $ptr;
+        if size_from_ptr(ptr) == 0 {
+            ::intrinsics::arith_offset(ptr as *mut i8, $by) as *mut _
+        } else {
+            ptr.offset($by)
+        }
+    }};
+}
+
+macro_rules! slice_ref {
+    ($ptr:expr) => {{
+        let ptr = $ptr;
+        if size_from_ptr(ptr) == 0 {
+            // Use a non-null pointer value
+            &mut *(1 as *mut _)
+        } else {
+            mem::transmute(ptr)
+        }
+    }};
+}
+
+#[unstable(feature = "core_slice_ext",
+           reason = "stable interface provided by `impl [T]` in later crates",
+           issue = "32110")]
+impl<T> SliceExt for [T] {
+    type Item = T;
+
+    #[inline]
+    fn split_at(&self, mid: usize) -> (&[T], &[T]) {
+        (&self[..mid], &self[mid..])
+    }
+
+    #[inline]
+    fn iter(&self) -> Iter<T> {
+        unsafe {
+            let p = if mem::size_of::<T>() == 0 {
+                1 as *const _
+            } else {
+                let p = self.as_ptr();
+                assume(!p.is_null());
+                p
+            };
+
+            Iter {
+                ptr: p,
+                end: slice_offset!(p, self.len() as isize),
+                _marker: marker::PhantomData
+            }
+        }
+    }
+
+    #[inline]
+    fn split<P>(&self, pred: P) -> Split<T, P> where P: FnMut(&T) -> bool {
+        Split {
+            v: self,
+            pred: pred,
+            finished: false
+        }
+    }
+
+    #[inline]
+    fn splitn<P>(&self, n: usize, pred: P) -> SplitN<T, P> where
+        P: FnMut(&T) -> bool,
+    {
+        SplitN {
+            inner: GenericSplitN {
+                iter: self.split(pred),
+                count: n,
+                invert: false
+            }
+        }
+    }
+
+    #[inline]
+    fn rsplitn<P>(&self, n: usize, pred: P) -> RSplitN<T, P> where
+        P: FnMut(&T) -> bool,
+    {
+        RSplitN {
+            inner: GenericSplitN {
+                iter: self.split(pred),
+                count: n,
+                invert: true
+            }
+        }
+    }
+
+    #[inline]
+    fn windows(&self, size: usize) -> Windows<T> {
+        assert!(size != 0);
+        Windows { v: self, size: size }
+    }
+
+    #[inline]
+    fn chunks(&self, size: usize) -> Chunks<T> {
+        assert!(size != 0);
+        Chunks { v: self, size: size }
+    }
+
+    #[inline]
+    fn get(&self, index: usize) -> Option<&T> {
+        if index < self.len() { Some(&self[index]) } else { None }
+    }
+
+    #[inline]
+    fn first(&self) -> Option<&T> {
+        if self.is_empty() { None } else { Some(&self[0]) }
+    }
+
+    #[inline]
+    fn split_first(&self) -> Option<(&T, &[T])> {
+        if self.is_empty() { None } else { Some((&self[0], &self[1..])) }
+    }
+
+    #[inline]
+    fn split_last(&self) -> Option<(&T, &[T])> {
+        let len = self.len();
+        if len == 0 { None } else { Some((&self[len - 1], &self[..(len - 1)])) }
+    }
+
+    #[inline]
+    fn last(&self) -> Option<&T> {
+        if self.is_empty() { None } else { Some(&self[self.len() - 1]) }
+    }
+
+    #[inline]
+    unsafe fn get_unchecked(&self, index: usize) -> &T {
+        &*(self.as_ptr().offset(index as isize))
+    }
+
+    #[inline]
+    fn as_ptr(&self) -> *const T {
+        self as *const [T] as *const T
+    }
+
+    fn binary_search_by<F>(&self, mut f: F) -> Result<usize, usize> where
+        F: FnMut(&T) -> Ordering
+    {
+        let mut base = 0usize;
+        let mut s = self;
+
+        loop {
+            let (head, tail) = s.split_at(s.len() >> 1);
+            if tail.is_empty() {
+                return Err(base)
+            }
+            match f(&tail[0]) {
+                Less => {
+                    base += head.len() + 1;
+                    s = &tail[1..];
+                }
+                Greater => s = head,
+                Equal => return Ok(base + head.len()),
+            }
+        }
+    }
+
+    #[inline]
+    fn len(&self) -> usize { self.repr().len }
+
+    #[inline]
+    fn get_mut(&mut self, index: usize) -> Option<&mut T> {
+        if index < self.len() { Some(&mut self[index]) } else { None }
+    }
+
+    #[inline]
+    fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T]) {
+        let len = self.len();
+        let ptr = self.as_mut_ptr();
+
+        unsafe {
+            assert!(mid <= len);
+
+            (from_raw_parts_mut(ptr, mid),
+             from_raw_parts_mut(ptr.offset(mid as isize), len - mid))
+        }
+    }
+
+    #[inline]
+    fn iter_mut(&mut self) -> IterMut<T> {
+        unsafe {
+            let p = if mem::size_of::<T>() == 0 {
+                1 as *mut _
+            } else {
+                let p = self.as_mut_ptr();
+                assume(!p.is_null());
+                p
+            };
+
+            IterMut {
+                ptr: p,
+                end: slice_offset!(p, self.len() as isize),
+                _marker: marker::PhantomData
+            }
+        }
+    }
+
+    #[inline]
+    fn last_mut(&mut self) -> Option<&mut T> {
+        let len = self.len();
+        if len == 0 { return None; }
+        Some(&mut self[len - 1])
+    }
+
+    #[inline]
+    fn first_mut(&mut self) -> Option<&mut T> {
+        if self.is_empty() { None } else { Some(&mut self[0]) }
+    }
+
+    #[inline]
+    fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])> {
+        if self.is_empty() { None } else {
+            let split = self.split_at_mut(1);
+            Some((&mut split.0[0], split.1))
+        }
+    }
+
+    #[inline]
+    fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])> {
+        let len = self.len();
+        if len == 0 { None } else {
+            let split = self.split_at_mut(len - 1);
+            Some((&mut split.1[0], split.0))
+        }
+    }
+
+    #[inline]
+    fn split_mut<P>(&mut self, pred: P) -> SplitMut<T, P> where P: FnMut(&T) -> bool {
+        SplitMut { v: self, pred: pred, finished: false }
+    }
+
+    #[inline]
+    fn splitn_mut<P>(&mut self, n: usize, pred: P) -> SplitNMut<T, P> where
+        P: FnMut(&T) -> bool
+    {
+        SplitNMut {
+            inner: GenericSplitN {
+                iter: self.split_mut(pred),
+                count: n,
+                invert: false
+            }
+        }
+    }
+
+    #[inline]
+    fn rsplitn_mut<P>(&mut self, n: usize, pred: P) -> RSplitNMut<T, P> where
+        P: FnMut(&T) -> bool,
+    {
+        RSplitNMut {
+            inner: GenericSplitN {
+                iter: self.split_mut(pred),
+                count: n,
+                invert: true
+            }
+        }
+   }
+
+    #[inline]
+    fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<T> {
+        assert!(chunk_size > 0);
+        ChunksMut { v: self, chunk_size: chunk_size }
+    }
+
+    #[inline]
+    fn swap(&mut self, a: usize, b: usize) {
+        unsafe {
+            // Can't take two mutable loans from one vector, so instead just cast
+            // them to their raw pointers to do the swap
+            let pa: *mut T = &mut self[a];
+            let pb: *mut T = &mut self[b];
+            ptr::swap(pa, pb);
+        }
+    }
+
+    fn reverse(&mut self) {
+        let mut i: usize = 0;
+        let ln = self.len();
+        while i < ln / 2 {
+            // Unsafe swap to avoid the bounds check in safe swap.
+            unsafe {
+                let pa: *mut T = self.get_unchecked_mut(i);
+                let pb: *mut T = self.get_unchecked_mut(ln - i - 1);
+                ptr::swap(pa, pb);
+            }
+            i += 1;
+        }
+    }
+
+    #[inline]
+    unsafe fn get_unchecked_mut(&mut self, index: usize) -> &mut T {
+        &mut *self.as_mut_ptr().offset(index as isize)
+    }
+
+    #[inline]
+    fn as_mut_ptr(&mut self) -> *mut T {
+        self as *mut [T] as *mut T
+    }
+
+    #[inline]
+    fn contains(&self, x: &T) -> bool where T: PartialEq {
+        self.iter().any(|elt| *x == *elt)
+    }
+
+    #[inline]
+    fn starts_with(&self, needle: &[T]) -> bool where T: PartialEq {
+        let n = needle.len();
+        self.len() >= n && needle == &self[..n]
+    }
+
+    #[inline]
+    fn ends_with(&self, needle: &[T]) -> bool where T: PartialEq {
+        let (m, n) = (self.len(), needle.len());
+        m >= n && needle == &self[m-n..]
+    }
+
+    fn binary_search(&self, x: &T) -> Result<usize, usize> where T: Ord {
+        self.binary_search_by(|p| p.cmp(x))
+    }
+
+    #[inline]
+    fn clone_from_slice(&mut self, src: &[T]) where T: Clone {
+        assert!(self.len() == src.len(),
+                "destination and source slices have different lengths");
+        // NOTE: We need to explicitly slice them to the same length
+        // for bounds checking to be elided, and the optimizer will
+        // generate memcpy for simple cases (for example T = u8).
+        let len = self.len();
+        let src = &src[..len];
+        for i in 0..len {
+            self[i].clone_from(&src[i]);
+        }
+    }
+
+    #[inline]
+    fn copy_from_slice(&mut self, src: &[T]) where T: Copy {
+        assert!(self.len() == src.len(),
+                "destination and source slices have different lengths");
+        unsafe {
+            ptr::copy_nonoverlapping(
+                src.as_ptr(), self.as_mut_ptr(), self.len());
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::Index<usize> for [T] {
+    type Output = T;
+
+    fn index(&self, index: usize) -> &T {
+        assert!(index < self.len());
+        unsafe { self.get_unchecked(index) }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::IndexMut<usize> for [T] {
+    #[inline]
+    fn index_mut(&mut self, index: usize) -> &mut T {
+        assert!(index < self.len());
+        unsafe { self.get_unchecked_mut(index) }
+    }
+}
+
+#[inline(never)]
+#[cold]
+fn slice_index_len_fail(index: usize, len: usize) -> ! {
+    panic!("index {} out of range for slice of length {}", index, len);
+}
+
+#[inline(never)]
+#[cold]
+fn slice_index_order_fail(index: usize, end: usize) -> ! {
+    panic!("slice index starts at {} but ends at {}", index, end);
+}
+
+// FIXME implement indexing with inclusive ranges
+
+/// Implements slicing with syntax `&self[begin .. end]`.
+///
+/// Returns a slice of self for the index range [`begin`..`end`).
+///
+/// This operation is `O(1)`.
+///
+/// # Panics
+///
+/// Requires that `begin <= end` and `end <= self.len()`,
+/// otherwise slicing will panic.
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::Index<ops::Range<usize>> for [T] {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: ops::Range<usize>) -> &[T] {
+        if index.start > index.end {
+            slice_index_order_fail(index.start, index.end);
+        } else if index.end > self.len() {
+            slice_index_len_fail(index.end, self.len());
+        }
+        unsafe {
+            from_raw_parts (
+                self.as_ptr().offset(index.start as isize),
+                index.end - index.start
+            )
+        }
+    }
+}
+
+/// Implements slicing with syntax `&self[.. end]`.
+///
+/// Returns a slice of self from the beginning until but not including
+/// the index `end`.
+///
+/// Equivalent to `&self[0 .. end]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::Index<ops::RangeTo<usize>> for [T] {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: ops::RangeTo<usize>) -> &[T] {
+        self.index(0 .. index.end)
+    }
+}
+
+/// Implements slicing with syntax `&self[begin ..]`.
+///
+/// Returns a slice of self from and including the index `begin` until the end.
+///
+/// Equivalent to `&self[begin .. self.len()]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::Index<ops::RangeFrom<usize>> for [T] {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: ops::RangeFrom<usize>) -> &[T] {
+        self.index(index.start .. self.len())
+    }
+}
+
+/// Implements slicing with syntax `&self[..]`.
+///
+/// Returns a slice of the whole slice. This operation can not panic.
+///
+/// Equivalent to `&self[0 .. self.len()]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::Index<RangeFull> for [T] {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, _index: RangeFull) -> &[T] {
+        self
+    }
+}
+
+#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+impl<T> ops::Index<ops::RangeInclusive<usize>> for [T] {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: ops::RangeInclusive<usize>) -> &[T] {
+        match index {
+            ops::RangeInclusive::Empty { .. } => &[],
+            ops::RangeInclusive::NonEmpty { end, .. } if end == usize::max_value() =>
+                panic!("attempted to index slice up to maximum usize"),
+            ops::RangeInclusive::NonEmpty { start, end } =>
+                self.index(start .. end+1)
+        }
+    }
+}
+#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+impl<T> ops::Index<ops::RangeToInclusive<usize>> for [T] {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: ops::RangeToInclusive<usize>) -> &[T] {
+        self.index(0...index.end)
+    }
+}
+
+/// Implements mutable slicing with syntax `&mut self[begin .. end]`.
+///
+/// Returns a slice of self for the index range [`begin`..`end`).
+///
+/// This operation is `O(1)`.
+///
+/// # Panics
+///
+/// Requires that `begin <= end` and `end <= self.len()`,
+/// otherwise slicing will panic.
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::IndexMut<ops::Range<usize>> for [T] {
+    #[inline]
+    fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [T] {
+        if index.start > index.end {
+            slice_index_order_fail(index.start, index.end);
+        } else if index.end > self.len() {
+            slice_index_len_fail(index.end, self.len());
+        }
+        unsafe {
+            from_raw_parts_mut(
+                self.as_mut_ptr().offset(index.start as isize),
+                index.end - index.start
+            )
+        }
+    }
+}
+
+/// Implements mutable slicing with syntax `&mut self[.. end]`.
+///
+/// Returns a slice of self from the beginning until but not including
+/// the index `end`.
+///
+/// Equivalent to `&mut self[0 .. end]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::IndexMut<ops::RangeTo<usize>> for [T] {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut [T] {
+        self.index_mut(0 .. index.end)
+    }
+}
+
+/// Implements mutable slicing with syntax `&mut self[begin ..]`.
+///
+/// Returns a slice of self from and including the index `begin` until the end.
+///
+/// Equivalent to `&mut self[begin .. self.len()]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::IndexMut<ops::RangeFrom<usize>> for [T] {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut [T] {
+        let len = self.len();
+        self.index_mut(index.start .. len)
+    }
+}
+
+/// Implements mutable slicing with syntax `&mut self[..]`.
+///
+/// Returns a slice of the whole slice. This operation can not panic.
+///
+/// Equivalent to `&mut self[0 .. self.len()]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ops::IndexMut<RangeFull> for [T] {
+    #[inline]
+    fn index_mut(&mut self, _index: RangeFull) -> &mut [T] {
+        self
+    }
+}
+
+#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+impl<T> ops::IndexMut<ops::RangeInclusive<usize>> for [T] {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut [T] {
+        match index {
+            ops::RangeInclusive::Empty { .. } => &mut [],
+            ops::RangeInclusive::NonEmpty { end, .. } if end == usize::max_value() =>
+                panic!("attempted to index slice up to maximum usize"),
+            ops::RangeInclusive::NonEmpty { start, end } =>
+                self.index_mut(start .. end+1)
+        }
+    }
+}
+#[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
+impl<T> ops::IndexMut<ops::RangeToInclusive<usize>> for [T] {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut [T] {
+        self.index_mut(0...index.end)
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Common traits
+////////////////////////////////////////////////////////////////////////////////
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Default for &'a [T] {
+    fn default() -> &'a [T] { &[] }
+}
+
+#[stable(feature = "mut_slice_default", since = "1.5.0")]
+impl<'a, T> Default for &'a mut [T] {
+    fn default() -> &'a mut [T] { &mut [] }
+}
+
+//
+// Iterators
+//
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> IntoIterator for &'a [T] {
+    type Item = &'a T;
+    type IntoIter = Iter<'a, T>;
+
+    fn into_iter(self) -> Iter<'a, T> {
+        self.iter()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> IntoIterator for &'a mut [T] {
+    type Item = &'a mut T;
+    type IntoIter = IterMut<'a, T>;
+
+    fn into_iter(self) -> IterMut<'a, T> {
+        self.iter_mut()
+    }
+}
+
+#[inline(always)]
+fn size_from_ptr<T>(_: *const T) -> usize {
+    mem::size_of::<T>()
+}
+
+// The shared definition of the `Iter` and `IterMut` iterators
+macro_rules! iterator {
+    (struct $name:ident -> $ptr:ty, $elem:ty) => {
+        #[stable(feature = "rust1", since = "1.0.0")]
+        impl<'a, T> Iterator for $name<'a, T> {
+            type Item = $elem;
+
+            #[inline]
+            fn next(&mut self) -> Option<$elem> {
+                // could be implemented with slices, but this avoids bounds checks
+                unsafe {
+                    if mem::size_of::<T>() != 0 {
+                        assume(!self.ptr.is_null());
+                        assume(!self.end.is_null());
+                    }
+                    if self.ptr == self.end {
+                        None
+                    } else {
+                        let old = self.ptr;
+                        self.ptr = slice_offset!(self.ptr, 1);
+                        Some(slice_ref!(old))
+                    }
+                }
+            }
+
+            #[inline]
+            fn size_hint(&self) -> (usize, Option<usize>) {
+                let diff = (self.end as usize).wrapping_sub(self.ptr as usize);
+                let size = mem::size_of::<T>();
+                let exact = diff / (if size == 0 {1} else {size});
+                (exact, Some(exact))
+            }
+
+            #[inline]
+            fn count(self) -> usize {
+                self.size_hint().0
+            }
+
+            #[inline]
+            fn nth(&mut self, n: usize) -> Option<$elem> {
+                // Call helper method. Can't put the definition here because mut versus const.
+                self.iter_nth(n)
+            }
+
+            #[inline]
+            fn last(mut self) -> Option<$elem> {
+                self.next_back()
+            }
+        }
+
+        #[stable(feature = "rust1", since = "1.0.0")]
+        impl<'a, T> DoubleEndedIterator for $name<'a, T> {
+            #[inline]
+            fn next_back(&mut self) -> Option<$elem> {
+                // could be implemented with slices, but this avoids bounds checks
+                unsafe {
+                    if mem::size_of::<T>() != 0 {
+                        assume(!self.ptr.is_null());
+                        assume(!self.end.is_null());
+                    }
+                    if self.end == self.ptr {
+                        None
+                    } else {
+                        self.end = slice_offset!(self.end, -1);
+                        Some(slice_ref!(self.end))
+                    }
+                }
+            }
+        }
+    }
+}
+
+macro_rules! make_slice {
+    ($start: expr, $end: expr) => {{
+        let start = $start;
+        let diff = ($end as usize).wrapping_sub(start as usize);
+        if size_from_ptr(start) == 0 {
+            // use a non-null pointer value
+            unsafe { from_raw_parts(1 as *const _, diff) }
+        } else {
+            let len = diff / size_from_ptr(start);
+            unsafe { from_raw_parts(start, len) }
+        }
+    }}
+}
+
+macro_rules! make_mut_slice {
+    ($start: expr, $end: expr) => {{
+        let start = $start;
+        let diff = ($end as usize).wrapping_sub(start as usize);
+        if size_from_ptr(start) == 0 {
+            // use a non-null pointer value
+            unsafe { from_raw_parts_mut(1 as *mut _, diff) }
+        } else {
+            let len = diff / size_from_ptr(start);
+            unsafe { from_raw_parts_mut(start, len) }
+        }
+    }}
+}
+
+/// Immutable slice iterator
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Iter<'a, T: 'a> {
+    ptr: *const T,
+    end: *const T,
+    _marker: marker::PhantomData<&'a T>,
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple("Iter")
+            .field(&self.as_slice())
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, T: Sync> Sync for Iter<'a, T> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, T: Sync> Send for Iter<'a, T> {}
+
+impl<'a, T> Iter<'a, T> {
+    /// View the underlying data as a subslice of the original data.
+    ///
+    /// This has the same lifetime as the original slice, and so the
+    /// iterator can continue to be used while this exists.
+    #[stable(feature = "iter_to_slice", since = "1.4.0")]
+    pub fn as_slice(&self) -> &'a [T] {
+        make_slice!(self.ptr, self.end)
+    }
+
+    // Helper function for Iter::nth
+    fn iter_nth(&mut self, n: usize) -> Option<&'a T> {
+        match self.as_slice().get(n) {
+            Some(elem_ref) => unsafe {
+                self.ptr = slice_offset!(self.ptr, (n as isize).wrapping_add(1));
+                Some(elem_ref)
+            },
+            None => {
+                self.ptr = self.end;
+                None
+            }
+        }
+    }
+}
+
+iterator!{struct Iter -> *const T, &'a T}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Clone for Iter<'a, T> {
+    fn clone(&self) -> Iter<'a, T> { Iter { ptr: self.ptr, end: self.end, _marker: self._marker } }
+}
+
+/// Mutable slice iterator.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct IterMut<'a, T: 'a> {
+    ptr: *mut T,
+    end: *mut T,
+    _marker: marker::PhantomData<&'a mut T>,
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug> fmt::Debug for IterMut<'a, T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple("IterMut")
+            .field(&make_slice!(self.ptr, self.end))
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, T: Send> Send for IterMut<'a, T> {}
+
+impl<'a, T> IterMut<'a, T> {
+    /// View the underlying data as a subslice of the original data.
+    ///
+    /// To avoid creating `&mut` references that alias, this is forced
+    /// to consume the iterator. Consider using the `Slice` and
+    /// `SliceMut` implementations for obtaining slices with more
+    /// restricted lifetimes that do not consume the iterator.
+    #[stable(feature = "iter_to_slice", since = "1.4.0")]
+    pub fn into_slice(self) -> &'a mut [T] {
+        make_mut_slice!(self.ptr, self.end)
+    }
+
+    // Helper function for IterMut::nth
+    fn iter_nth(&mut self, n: usize) -> Option<&'a mut T> {
+        match make_mut_slice!(self.ptr, self.end).get_mut(n) {
+            Some(elem_ref) => unsafe {
+                self.ptr = slice_offset!(self.ptr, (n as isize).wrapping_add(1));
+                Some(elem_ref)
+            },
+            None => {
+                self.ptr = self.end;
+                None
+            }
+        }
+    }
+}
+
+iterator!{struct IterMut -> *mut T, &'a mut T}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> ExactSizeIterator for IterMut<'a, T> {}
+
+/// An internal abstraction over the splitting iterators, so that
+/// splitn, splitn_mut etc can be implemented once.
+#[doc(hidden)]
+trait SplitIter: DoubleEndedIterator {
+    /// Mark the underlying iterator as complete, extracting the remaining
+    /// portion of the slice.
+    fn finish(&mut self) -> Option<Self::Item>;
+}
+
+/// An iterator over subslices separated by elements that match a predicate
+/// function.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Split<'a, T:'a, P> where P: FnMut(&T) -> bool {
+    v: &'a [T],
+    pred: P,
+    finished: bool
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for Split<'a, T, P> where P: FnMut(&T) -> bool {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Split")
+            .field("v", &self.v)
+            .field("finished", &self.finished)
+            .finish()
+    }
+}
+
+// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, P> Clone for Split<'a, T, P> where P: Clone + FnMut(&T) -> bool {
+    fn clone(&self) -> Split<'a, T, P> {
+        Split {
+            v: self.v,
+            pred: self.pred.clone(),
+            finished: self.finished,
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, P> Iterator for Split<'a, T, P> where P: FnMut(&T) -> bool {
+    type Item = &'a [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a [T]> {
+        if self.finished { return None; }
+
+        match self.v.iter().position(|x| (self.pred)(x)) {
+            None => self.finish(),
+            Some(idx) => {
+                let ret = Some(&self.v[..idx]);
+                self.v = &self.v[idx + 1..];
+                ret
+            }
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.finished {
+            (0, Some(0))
+        } else {
+            (1, Some(self.v.len() + 1))
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, P> DoubleEndedIterator for Split<'a, T, P> where P: FnMut(&T) -> bool {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a [T]> {
+        if self.finished { return None; }
+
+        match self.v.iter().rposition(|x| (self.pred)(x)) {
+            None => self.finish(),
+            Some(idx) => {
+                let ret = Some(&self.v[idx + 1..]);
+                self.v = &self.v[..idx];
+                ret
+            }
+        }
+    }
+}
+
+impl<'a, T, P> SplitIter for Split<'a, T, P> where P: FnMut(&T) -> bool {
+    #[inline]
+    fn finish(&mut self) -> Option<&'a [T]> {
+        if self.finished { None } else { self.finished = true; Some(self.v) }
+    }
+}
+
+/// An iterator over the subslices of the vector which are separated
+/// by elements that match `pred`.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct SplitMut<'a, T:'a, P> where P: FnMut(&T) -> bool {
+    v: &'a mut [T],
+    pred: P,
+    finished: bool
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for SplitMut<'a, T, P> where P: FnMut(&T) -> bool {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("SplitMut")
+            .field("v", &self.v)
+            .field("finished", &self.finished)
+            .finish()
+    }
+}
+
+impl<'a, T, P> SplitIter for SplitMut<'a, T, P> where P: FnMut(&T) -> bool {
+    #[inline]
+    fn finish(&mut self) -> Option<&'a mut [T]> {
+        if self.finished {
+            None
+        } else {
+            self.finished = true;
+            Some(mem::replace(&mut self.v, &mut []))
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, P> Iterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool {
+    type Item = &'a mut [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a mut [T]> {
+        if self.finished { return None; }
+
+        let idx_opt = { // work around borrowck limitations
+            let pred = &mut self.pred;
+            self.v.iter().position(|x| (*pred)(x))
+        };
+        match idx_opt {
+            None => self.finish(),
+            Some(idx) => {
+                let tmp = mem::replace(&mut self.v, &mut []);
+                let (head, tail) = tmp.split_at_mut(idx);
+                self.v = &mut tail[1..];
+                Some(head)
+            }
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.finished {
+            (0, Some(0))
+        } else {
+            // if the predicate doesn't match anything, we yield one slice
+            // if it matches every element, we yield len+1 empty slices.
+            (1, Some(self.v.len() + 1))
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, P> DoubleEndedIterator for SplitMut<'a, T, P> where
+    P: FnMut(&T) -> bool,
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a mut [T]> {
+        if self.finished { return None; }
+
+        let idx_opt = { // work around borrowck limitations
+            let pred = &mut self.pred;
+            self.v.iter().rposition(|x| (*pred)(x))
+        };
+        match idx_opt {
+            None => self.finish(),
+            Some(idx) => {
+                let tmp = mem::replace(&mut self.v, &mut []);
+                let (head, tail) = tmp.split_at_mut(idx);
+                self.v = head;
+                Some(&mut tail[1..])
+            }
+        }
+    }
+}
+
+/// An private iterator over subslices separated by elements that
+/// match a predicate function, splitting at most a fixed number of
+/// times.
+#[derive(Debug)]
+struct GenericSplitN<I> {
+    iter: I,
+    count: usize,
+    invert: bool
+}
+
+impl<T, I: SplitIter<Item=T>> Iterator for GenericSplitN<I> {
+    type Item = T;
+
+    #[inline]
+    fn next(&mut self) -> Option<T> {
+        match self.count {
+            0 => None,
+            1 => { self.count -= 1; self.iter.finish() }
+            _ => {
+                self.count -= 1;
+                if self.invert {self.iter.next_back()} else {self.iter.next()}
+            }
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (lower, upper_opt) = self.iter.size_hint();
+        (lower, upper_opt.map(|upper| cmp::min(self.count, upper)))
+    }
+}
+
+/// An iterator over subslices separated by elements that match a predicate
+/// function, limited to a given number of splits.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct SplitN<'a, T: 'a, P> where P: FnMut(&T) -> bool {
+    inner: GenericSplitN<Split<'a, T, P>>
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for SplitN<'a, T, P> where P: FnMut(&T) -> bool {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("SplitN")
+            .field("inner", &self.inner)
+            .finish()
+    }
+}
+
+/// An iterator over subslices separated by elements that match a
+/// predicate function, limited to a given number of splits, starting
+/// from the end of the slice.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct RSplitN<'a, T: 'a, P> where P: FnMut(&T) -> bool {
+    inner: GenericSplitN<Split<'a, T, P>>
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for RSplitN<'a, T, P> where P: FnMut(&T) -> bool {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("RSplitN")
+            .field("inner", &self.inner)
+            .finish()
+    }
+}
+
+/// An iterator over subslices separated by elements that match a predicate
+/// function, limited to a given number of splits.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct SplitNMut<'a, T: 'a, P> where P: FnMut(&T) -> bool {
+    inner: GenericSplitN<SplitMut<'a, T, P>>
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for SplitNMut<'a, T, P> where P: FnMut(&T) -> bool {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("SplitNMut")
+            .field("inner", &self.inner)
+            .finish()
+    }
+}
+
+/// An iterator over subslices separated by elements that match a
+/// predicate function, limited to a given number of splits, starting
+/// from the end of the slice.
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct RSplitNMut<'a, T: 'a, P> where P: FnMut(&T) -> bool {
+    inner: GenericSplitN<SplitMut<'a, T, P>>
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<'a, T: 'a + fmt::Debug, P> fmt::Debug for RSplitNMut<'a, T, P> where P: FnMut(&T) -> bool {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("RSplitNMut")
+            .field("inner", &self.inner)
+            .finish()
+    }
+}
+
+macro_rules! forward_iterator {
+    ($name:ident: $elem:ident, $iter_of:ty) => {
+        #[stable(feature = "rust1", since = "1.0.0")]
+        impl<'a, $elem, P> Iterator for $name<'a, $elem, P> where
+            P: FnMut(&T) -> bool
+        {
+            type Item = $iter_of;
+
+            #[inline]
+            fn next(&mut self) -> Option<$iter_of> {
+                self.inner.next()
+            }
+
+            #[inline]
+            fn size_hint(&self) -> (usize, Option<usize>) {
+                self.inner.size_hint()
+            }
+        }
+    }
+}
+
+forward_iterator! { SplitN: T, &'a [T] }
+forward_iterator! { RSplitN: T, &'a [T] }
+forward_iterator! { SplitNMut: T, &'a mut [T] }
+forward_iterator! { RSplitNMut: T, &'a mut [T] }
+
+/// An iterator over overlapping subslices of length `size`.
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Windows<'a, T:'a> {
+    v: &'a [T],
+    size: usize
+}
+
+// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Clone for Windows<'a, T> {
+    fn clone(&self) -> Windows<'a, T> {
+        Windows {
+            v: self.v,
+            size: self.size,
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Iterator for Windows<'a, T> {
+    type Item = &'a [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a [T]> {
+        if self.size > self.v.len() {
+            None
+        } else {
+            let ret = Some(&self.v[..self.size]);
+            self.v = &self.v[1..];
+            ret
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.size > self.v.len() {
+            (0, Some(0))
+        } else {
+            let size = self.v.len() - self.size + 1;
+            (size, Some(size))
+        }
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.size_hint().0
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        let (end, overflow) = self.size.overflowing_add(n);
+        if end > self.v.len() || overflow {
+            self.v = &[];
+            None
+        } else {
+            let nth = &self.v[n..end];
+            self.v = &self.v[n+1..];
+            Some(nth)
+        }
+    }
+
+    #[inline]
+    fn last(self) -> Option<Self::Item> {
+        if self.size > self.v.len() {
+            None
+        } else {
+            let start = self.v.len() - self.size;
+            Some(&self.v[start..])
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> DoubleEndedIterator for Windows<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a [T]> {
+        if self.size > self.v.len() {
+            None
+        } else {
+            let ret = Some(&self.v[self.v.len()-self.size..]);
+            self.v = &self.v[..self.v.len()-1];
+            ret
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> ExactSizeIterator for Windows<'a, T> {}
+
+/// An iterator over a slice in (non-overlapping) chunks (`size` elements at a
+/// time).
+///
+/// When the slice len is not evenly divided by the chunk size, the last slice
+/// of the iteration will be the remainder.
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chunks<'a, T:'a> {
+    v: &'a [T],
+    size: usize
+}
+
+// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Clone for Chunks<'a, T> {
+    fn clone(&self) -> Chunks<'a, T> {
+        Chunks {
+            v: self.v,
+            size: self.size,
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Iterator for Chunks<'a, T> {
+    type Item = &'a [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a [T]> {
+        if self.v.is_empty() {
+            None
+        } else {
+            let chunksz = cmp::min(self.v.len(), self.size);
+            let (fst, snd) = self.v.split_at(chunksz);
+            self.v = snd;
+            Some(fst)
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.v.is_empty() {
+            (0, Some(0))
+        } else {
+            let n = self.v.len() / self.size;
+            let rem = self.v.len() % self.size;
+            let n = if rem > 0 { n+1 } else { n };
+            (n, Some(n))
+        }
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.size_hint().0
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        let (start, overflow) = n.overflowing_mul(self.size);
+        if start >= self.v.len() || overflow {
+            self.v = &[];
+            None
+        } else {
+            let end = match start.checked_add(self.size) {
+                Some(sum) => cmp::min(self.v.len(), sum),
+                None => self.v.len(),
+            };
+            let nth = &self.v[start..end];
+            self.v = &self.v[end..];
+            Some(nth)
+        }
+    }
+
+    #[inline]
+    fn last(self) -> Option<Self::Item> {
+        if self.v.is_empty() {
+            None
+        } else {
+            let start = (self.v.len() - 1) / self.size * self.size;
+            Some(&self.v[start..])
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> DoubleEndedIterator for Chunks<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a [T]> {
+        if self.v.is_empty() {
+            None
+        } else {
+            let remainder = self.v.len() % self.size;
+            let chunksz = if remainder != 0 { remainder } else { self.size };
+            let (fst, snd) = self.v.split_at(self.v.len() - chunksz);
+            self.v = fst;
+            Some(snd)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> ExactSizeIterator for Chunks<'a, T> {}
+
+/// An iterator over a slice in (non-overlapping) mutable chunks (`size`
+/// elements at a time). When the slice len is not evenly divided by the chunk
+/// size, the last slice of the iteration will be the remainder.
+#[derive(Debug)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct ChunksMut<'a, T:'a> {
+    v: &'a mut [T],
+    chunk_size: usize
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> Iterator for ChunksMut<'a, T> {
+    type Item = &'a mut [T];
+
+    #[inline]
+    fn next(&mut self) -> Option<&'a mut [T]> {
+        if self.v.is_empty() {
+            None
+        } else {
+            let sz = cmp::min(self.v.len(), self.chunk_size);
+            let tmp = mem::replace(&mut self.v, &mut []);
+            let (head, tail) = tmp.split_at_mut(sz);
+            self.v = tail;
+            Some(head)
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.v.is_empty() {
+            (0, Some(0))
+        } else {
+            let n = self.v.len() / self.chunk_size;
+            let rem = self.v.len() % self.chunk_size;
+            let n = if rem > 0 { n + 1 } else { n };
+            (n, Some(n))
+        }
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.size_hint().0
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<&'a mut [T]> {
+        let (start, overflow) = n.overflowing_mul(self.chunk_size);
+        if start >= self.v.len() || overflow {
+            self.v = &mut [];
+            None
+        } else {
+            let end = match start.checked_add(self.chunk_size) {
+                Some(sum) => cmp::min(self.v.len(), sum),
+                None => self.v.len(),
+            };
+            let tmp = mem::replace(&mut self.v, &mut []);
+            let (head, tail) = tmp.split_at_mut(end);
+            let (_, nth) =  head.split_at_mut(start);
+            self.v = tail;
+            Some(nth)
+        }
+    }
+
+    #[inline]
+    fn last(self) -> Option<Self::Item> {
+        if self.v.is_empty() {
+            None
+        } else {
+            let start = (self.v.len() - 1) / self.chunk_size * self.chunk_size;
+            Some(&mut self.v[start..])
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> DoubleEndedIterator for ChunksMut<'a, T> {
+    #[inline]
+    fn next_back(&mut self) -> Option<&'a mut [T]> {
+        if self.v.is_empty() {
+            None
+        } else {
+            let remainder = self.v.len() % self.chunk_size;
+            let sz = if remainder != 0 { remainder } else { self.chunk_size };
+            let tmp = mem::replace(&mut self.v, &mut []);
+            let tmp_len = tmp.len();
+            let (head, tail) = tmp.split_at_mut(tmp_len - sz);
+            self.v = head;
+            Some(tail)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T> ExactSizeIterator for ChunksMut<'a, T> {}
+
+//
+// Free functions
+//
+
+/// Forms a slice from a pointer and a length.
+///
+/// The `len` argument is the number of **elements**, not the number of bytes.
+///
+/// # Safety
+///
+/// This function is unsafe as there is no guarantee that the given pointer is
+/// valid for `len` elements, nor whether the lifetime inferred is a suitable
+/// lifetime for the returned slice.
+///
+/// `p` must be non-null, even for zero-length slices.
+///
+/// # Caveat
+///
+/// The lifetime for the returned slice is inferred from its usage. To
+/// prevent accidental misuse, it's suggested to tie the lifetime to whichever
+/// source lifetime is safe in the context, such as by providing a helper
+/// function taking the lifetime of a host value for the slice, or by explicit
+/// annotation.
+///
+/// # Examples
+///
+/// ```
+/// use std::slice;
+///
+/// // manifest a slice out of thin air!
+/// let ptr = 0x1234 as *const usize;
+/// let amt = 10;
+/// unsafe {
+///     let slice = slice::from_raw_parts(ptr, amt);
+/// }
+/// ```
+#[inline]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub unsafe fn from_raw_parts<'a, T>(p: *const T, len: usize) -> &'a [T] {
+    mem::transmute(RawSlice { data: p, len: len })
+}
+
+/// Performs the same functionality as `from_raw_parts`, except that a mutable
+/// slice is returned.
+///
+/// This function is unsafe for the same reasons as `from_raw_parts`, as well
+/// as not being able to provide a non-aliasing guarantee of the returned
+/// mutable slice.
+#[inline]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub unsafe fn from_raw_parts_mut<'a, T>(p: *mut T, len: usize) -> &'a mut [T] {
+    mem::transmute(RawSlice { data: p, len: len })
+}
+
+//
+// Comparison traits
+//
+
+extern {
+    /// Call implementation provided memcmp
+    ///
+    /// Interprets the data as u8.
+    ///
+    /// Return 0 for equal, < 0 for less than and > 0 for greater
+    /// than.
+    // FIXME(#32610): Return type should be c_int
+    fn memcmp(s1: *const u8, s2: *const u8, n: usize) -> i32;
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<A, B> PartialEq<[B]> for [A] where A: PartialEq<B> {
+    fn eq(&self, other: &[B]) -> bool {
+        SlicePartialEq::equal(self, other)
+    }
+
+    fn ne(&self, other: &[B]) -> bool {
+        SlicePartialEq::not_equal(self, other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Eq> Eq for [T] {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Ord> Ord for [T] {
+    fn cmp(&self, other: &[T]) -> Ordering {
+        SliceOrd::compare(self, other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: PartialOrd> PartialOrd for [T] {
+    fn partial_cmp(&self, other: &[T]) -> Option<Ordering> {
+        SlicePartialOrd::partial_compare(self, other)
+    }
+}
+
+#[doc(hidden)]
+// intermediate trait for specialization of slice's PartialEq
+trait SlicePartialEq<B> {
+    fn equal(&self, other: &[B]) -> bool;
+    fn not_equal(&self, other: &[B]) -> bool;
+}
+
+// Generic slice equality
+impl<A, B> SlicePartialEq<B> for [A]
+    where A: PartialEq<B>
+{
+    default fn equal(&self, other: &[B]) -> bool {
+        if self.len() != other.len() {
+            return false;
+        }
+
+        for i in 0..self.len() {
+            if !self[i].eq(&other[i]) {
+                return false;
+            }
+        }
+
+        true
+    }
+
+    default fn not_equal(&self, other: &[B]) -> bool {
+        if self.len() != other.len() {
+            return true;
+        }
+
+        for i in 0..self.len() {
+            if self[i].ne(&other[i]) {
+                return true;
+            }
+        }
+
+        false
+    }
+}
+
+// Use memcmp for bytewise equality when the types allow
+impl<A> SlicePartialEq<A> for [A]
+    where A: PartialEq<A> + BytewiseEquality
+{
+    fn equal(&self, other: &[A]) -> bool {
+        if self.len() != other.len() {
+            return false;
+        }
+        unsafe {
+            let size = mem::size_of_val(self);
+            memcmp(self.as_ptr() as *const u8,
+                   other.as_ptr() as *const u8, size) == 0
+        }
+    }
+
+    fn not_equal(&self, other: &[A]) -> bool {
+        !self.equal(other)
+    }
+}
+
+#[doc(hidden)]
+// intermediate trait for specialization of slice's PartialOrd
+trait SlicePartialOrd<B> {
+    fn partial_compare(&self, other: &[B]) -> Option<Ordering>;
+}
+
+impl<A> SlicePartialOrd<A> for [A]
+    where A: PartialOrd
+{
+    default fn partial_compare(&self, other: &[A]) -> Option<Ordering> {
+        let l = cmp::min(self.len(), other.len());
+
+        // Slice to the loop iteration range to enable bound check
+        // elimination in the compiler
+        let lhs = &self[..l];
+        let rhs = &other[..l];
+
+        for i in 0..l {
+            match lhs[i].partial_cmp(&rhs[i]) {
+                Some(Ordering::Equal) => (),
+                non_eq => return non_eq,
+            }
+        }
+
+        self.len().partial_cmp(&other.len())
+    }
+}
+
+impl SlicePartialOrd<u8> for [u8] {
+    #[inline]
+    fn partial_compare(&self, other: &[u8]) -> Option<Ordering> {
+        Some(SliceOrd::compare(self, other))
+    }
+}
+
+#[doc(hidden)]
+// intermediate trait for specialization of slice's Ord
+trait SliceOrd<B> {
+    fn compare(&self, other: &[B]) -> Ordering;
+}
+
+impl<A> SliceOrd<A> for [A]
+    where A: Ord
+{
+    default fn compare(&self, other: &[A]) -> Ordering {
+        let l = cmp::min(self.len(), other.len());
+
+        // Slice to the loop iteration range to enable bound check
+        // elimination in the compiler
+        let lhs = &self[..l];
+        let rhs = &other[..l];
+
+        for i in 0..l {
+            match lhs[i].cmp(&rhs[i]) {
+                Ordering::Equal => (),
+                non_eq => return non_eq,
+            }
+        }
+
+        self.len().cmp(&other.len())
+    }
+}
+
+// memcmp compares a sequence of unsigned bytes lexicographically.
+// this matches the order we want for [u8], but no others (not even [i8]).
+impl SliceOrd<u8> for [u8] {
+    #[inline]
+    fn compare(&self, other: &[u8]) -> Ordering {
+        let order = unsafe {
+            memcmp(self.as_ptr(), other.as_ptr(),
+                   cmp::min(self.len(), other.len()))
+        };
+        if order == 0 {
+            self.len().cmp(&other.len())
+        } else if order < 0 {
+            Less
+        } else {
+            Greater
+        }
+    }
+}
+
+#[doc(hidden)]
+/// Trait implemented for types that can be compared for equality using
+/// their bytewise representation
+trait BytewiseEquality { }
+
+macro_rules! impl_marker_for {
+    ($traitname:ident, $($ty:ty)*) => {
+        $(
+            impl $traitname for $ty { }
+        )*
+    }
+}
+
+impl_marker_for!(BytewiseEquality,
+                 u8 i8 u16 i16 u32 i32 u64 i64 usize isize char bool);
+