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rust/src/libcore/slice.rs
Alex Crichton b53764c73b std: Clean out deprecated APIs 
Removes all unstable and deprecated APIs prior to the 1.8 release. All APIs that
are deprecated in the 1.8 release are sticking around for the rest of this
cycle.

Some notable changes are:

* The `dynamic_lib` module was moved into `rustc_back` as the compiler still
  relies on a few bits and pieces.
* The `DebugTuple` formatter now special-cases an empty struct name with only
  one field to append a trailing comma.
2016-03-12 12:31:13 -08:00

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// 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 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] {
// SNAP 4d3eebf change this to `0...index.end`
self.index(ops::RangeInclusive::NonEmpty { start: 0, end: 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] {
// SNAP 4d3eebf change this to `0...index.end`
self.index_mut(ops::RangeInclusive::NonEmpty { start: 0, end: 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 = "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 = "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
}
// 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
}
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.
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>>
}
/// 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>>
}
/// 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>>
}
/// 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>>
}
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`.
#[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.
#[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.
#[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 })
}
//
// Boilerplate traits
//
#[stable(feature = "rust1", since = "1.0.0")]
impl<A, B> PartialEq<[B]> for [A] where A: PartialEq<B> {
fn eq(&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
}
fn ne(&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
}
}
#[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 {
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())
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<T: PartialOrd> PartialOrd for [T] {
fn partial_cmp(&self, other: &[T]) -> 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())
}
}
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