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rust/src/libcore/slice.rs
Jorge Aparicio c1d48a8508 cleanup: &foo[0..a] -> &foo[..a]
2015-01-12 17:59:37 -05:00

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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]
#![doc(primitive = "slice")]
// 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 mem::transmute;
use clone::Clone;
use cmp::{Ordering, PartialEq, PartialOrd, Eq, Ord};
use cmp::Ordering::{Less, Equal, Greater};
use cmp;
use default::Default;
use iter::*;
use marker::Copy;
use num::Int;
use ops::{FnMut, self, Index};
use option::Option;
use option::Option::{None, Some};
use result::Result;
use result::Result::{Ok, Err};
use ptr;
use ptr::PtrExt;
use mem;
use mem::size_of;
use marker::{Sized, 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.
#[allow(missing_docs)] // docs in libcollections
pub trait SliceExt {
type Item;
fn slice<'a>(&'a self, start: uint, end: uint) -> &'a [Self::Item];
fn slice_from<'a>(&'a self, start: uint) -> &'a [Self::Item];
fn slice_to<'a>(&'a self, end: uint) -> &'a [Self::Item];
fn split_at<'a>(&'a self, mid: uint) -> (&'a [Self::Item], &'a [Self::Item]);
fn iter<'a>(&'a self) -> Iter<'a, Self::Item>;
fn split<'a, P>(&'a self, pred: P) -> Split<'a, Self::Item, P>
where P: FnMut(&Self::Item) -> bool;
fn splitn<'a, P>(&'a self, n: uint, pred: P) -> SplitN<'a, Self::Item, P>
where P: FnMut(&Self::Item) -> bool;
fn rsplitn<'a, P>(&'a self, n: uint, pred: P) -> RSplitN<'a, Self::Item, P>
where P: FnMut(&Self::Item) -> bool;
fn windows<'a>(&'a self, size: uint) -> Windows<'a, Self::Item>;
fn chunks<'a>(&'a self, size: uint) -> Chunks<'a, Self::Item>;
fn get<'a>(&'a self, index: uint) -> Option<&'a Self::Item>;
fn first<'a>(&'a self) -> Option<&'a Self::Item>;
fn tail<'a>(&'a self) -> &'a [Self::Item];
fn init<'a>(&'a self) -> &'a [Self::Item];
fn last<'a>(&'a self) -> Option<&'a Self::Item>;
unsafe fn get_unchecked<'a>(&'a self, index: uint) -> &'a Self::Item;
fn as_ptr(&self) -> *const Self::Item;
fn binary_search_by<F>(&self, f: F) -> Result<uint, uint> where
F: FnMut(&Self::Item) -> Ordering;
fn len(&self) -> uint;
fn is_empty(&self) -> bool { self.len() == 0 }
fn get_mut<'a>(&'a mut self, index: uint) -> Option<&'a mut Self::Item>;
fn as_mut_slice<'a>(&'a mut self) -> &'a mut [Self::Item];
fn slice_mut<'a>(&'a mut self, start: uint, end: uint) -> &'a mut [Self::Item];
fn slice_from_mut<'a>(&'a mut self, start: uint) -> &'a mut [Self::Item];
fn slice_to_mut<'a>(&'a mut self, end: uint) -> &'a mut [Self::Item];
fn iter_mut<'a>(&'a mut self) -> IterMut<'a, Self::Item>;
fn first_mut<'a>(&'a mut self) -> Option<&'a mut Self::Item>;
fn tail_mut<'a>(&'a mut self) -> &'a mut [Self::Item];
fn init_mut<'a>(&'a mut self) -> &'a mut [Self::Item];
fn last_mut<'a>(&'a mut self) -> Option<&'a mut Self::Item>;
fn split_mut<'a, P>(&'a mut self, pred: P) -> SplitMut<'a, Self::Item, P>
where P: FnMut(&Self::Item) -> bool;
fn splitn_mut<P>(&mut self, n: uint, pred: P) -> SplitNMut<Self::Item, P>
where P: FnMut(&Self::Item) -> bool;
fn rsplitn_mut<P>(&mut self, n: uint, pred: P) -> RSplitNMut<Self::Item, P>
where P: FnMut(&Self::Item) -> bool;
fn chunks_mut<'a>(&'a mut self, chunk_size: uint) -> ChunksMut<'a, Self::Item>;
fn swap(&mut self, a: uint, b: uint);
fn split_at_mut<'a>(&'a mut self, mid: uint) -> (&'a mut [Self::Item], &'a mut [Self::Item]);
fn reverse(&mut self);
unsafe fn get_unchecked_mut<'a>(&'a mut self, index: uint) -> &'a mut Self::Item;
fn as_mut_ptr(&mut self) -> *mut Self::Item;
fn position_elem(&self, t: &Self::Item) -> Option<uint> where Self::Item: PartialEq;
fn rposition_elem(&self, t: &Self::Item) -> Option<uint> where Self::Item: PartialEq;
fn contains(&self, x: &Self::Item) -> bool where Self::Item: PartialEq;
fn starts_with(&self, needle: &[Self::Item]) -> bool where Self::Item: PartialEq;
fn ends_with(&self, needle: &[Self::Item]) -> bool where Self::Item: PartialEq;
fn binary_search(&self, x: &Self::Item) -> Result<uint, uint> where Self::Item: Ord;
fn next_permutation(&mut self) -> bool where Self::Item: Ord;
fn prev_permutation(&mut self) -> bool where Self::Item: Ord;
fn clone_from_slice(&mut self, &[Self::Item]) -> uint where Self::Item: Clone;
}
#[unstable]
impl<T> SliceExt for [T] {
type Item = T;
#[inline]
fn slice(&self, start: uint, end: uint) -> &[T] {
assert!(start <= end);
assert!(end <= self.len());
unsafe {
transmute(RawSlice {
data: self.as_ptr().offset(start as int),
len: (end - start)
})
}
}
#[inline]
fn slice_from(&self, start: uint) -> &[T] {
self.slice(start, self.len())
}
#[inline]
fn slice_to(&self, end: uint) -> &[T] {
self.slice(0, end)
}
#[inline]
fn split_at(&self, mid: uint) -> (&[T], &[T]) {
(&self[..mid], &self[mid..])
}
#[inline]
fn iter<'a>(&'a self) -> Iter<'a, T> {
unsafe {
let p = self.as_ptr();
if mem::size_of::<T>() == 0 {
Iter {ptr: p,
end: (p as uint + self.len()) as *const T,
marker: marker::ContravariantLifetime::<'a>}
} else {
Iter {ptr: p,
end: p.offset(self.len() as int),
marker: marker::ContravariantLifetime::<'a>}
}
}
}
#[inline]
fn split<'a, P>(&'a self, pred: P) -> Split<'a, T, P> where P: FnMut(&T) -> bool {
Split {
v: self,
pred: pred,
finished: false
}
}
#[inline]
fn splitn<'a, P>(&'a self, n: uint, pred: P) -> SplitN<'a, T, P> where
P: FnMut(&T) -> bool,
{
SplitN {
inner: GenericSplitN {
iter: self.split(pred),
count: n,
invert: false
}
}
}
#[inline]
fn rsplitn<'a, P>(&'a self, n: uint, pred: P) -> RSplitN<'a, T, P> where
P: FnMut(&T) -> bool,
{
RSplitN {
inner: GenericSplitN {
iter: self.split(pred),
count: n,
invert: true
}
}
}
#[inline]
fn windows(&self, size: uint) -> Windows<T> {
assert!(size != 0);
Windows { v: self, size: size }
}
#[inline]
fn chunks(&self, size: uint) -> Chunks<T> {
assert!(size != 0);
Chunks { v: self, size: size }
}
#[inline]
fn get(&self, index: uint) -> Option<&T> {
if index < self.len() { Some(&self[index]) } else { None }
}
#[inline]
fn first(&self) -> Option<&T> {
if self.len() == 0 { None } else { Some(&self[0]) }
}
#[inline]
fn tail(&self) -> &[T] { &self[1..] }
#[inline]
fn init(&self) -> &[T] {
&self[..(self.len() - 1)]
}
#[inline]
fn last(&self) -> Option<&T> {
if self.len() == 0 { None } else { Some(&self[self.len() - 1]) }
}
#[inline]
unsafe fn get_unchecked(&self, index: uint) -> &T {
transmute(self.repr().data.offset(index as int))
}
#[inline]
fn as_ptr(&self) -> *const T {
self.repr().data
}
#[unstable]
fn binary_search_by<F>(&self, mut f: F) -> Result<uint, uint> where
F: FnMut(&T) -> Ordering
{
let mut base : uint = 0;
let mut lim : uint = self.len();
while lim != 0 {
let ix = base + (lim >> 1);
match f(&self[ix]) {
Equal => return Ok(ix),
Less => {
base = ix + 1;
lim -= 1;
}
Greater => ()
}
lim >>= 1;
}
Err(base)
}
#[inline]
fn len(&self) -> uint { self.repr().len }
#[inline]
fn get_mut(&mut self, index: uint) -> Option<&mut T> {
if index < self.len() { Some(&mut self[index]) } else { None }
}
#[inline]
fn as_mut_slice(&mut self) -> &mut [T] { self }
fn slice_mut(&mut self, start: uint, end: uint) -> &mut [T] {
ops::IndexMut::index_mut(self, &ops::Range { start: start, end: end } )
}
#[inline]
fn slice_from_mut(&mut self, start: uint) -> &mut [T] {
ops::IndexMut::index_mut(self, &ops::RangeFrom { start: start } )
}
#[inline]
fn slice_to_mut(&mut self, end: uint) -> &mut [T] {
ops::IndexMut::index_mut(self, &ops::RangeTo { end: end } )
}
#[inline]
fn split_at_mut(&mut self, mid: uint) -> (&mut [T], &mut [T]) {
unsafe {
let self2: &mut [T] = mem::transmute_copy(&self);
(ops::IndexMut::index_mut(self, &ops::RangeTo { end: mid } ),
ops::IndexMut::index_mut(self2, &ops::RangeFrom { start: mid } ))
}
}
#[inline]
fn iter_mut<'a>(&'a mut self) -> IterMut<'a, T> {
unsafe {
let p = self.as_mut_ptr();
if mem::size_of::<T>() == 0 {
IterMut {ptr: p,
end: (p as uint + self.len()) as *mut T,
marker: marker::ContravariantLifetime::<'a>}
} else {
IterMut {ptr: p,
end: p.offset(self.len() as int),
marker: marker::ContravariantLifetime::<'a>}
}
}
}
#[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.len() == 0 { None } else { Some(&mut self[0]) }
}
#[inline]
fn tail_mut(&mut self) -> &mut [T] {
self.slice_from_mut(1)
}
#[inline]
fn init_mut(&mut self) -> &mut [T] {
let len = self.len();
self.slice_to_mut(len-1)
}
#[inline]
fn split_mut<'a, P>(&'a mut self, pred: P) -> SplitMut<'a, T, P> where P: FnMut(&T) -> bool {
SplitMut { v: self, pred: pred, finished: false }
}
#[inline]
fn splitn_mut<'a, P>(&'a mut self, n: uint, pred: P) -> SplitNMut<'a, T, P> where
P: FnMut(&T) -> bool
{
SplitNMut {
inner: GenericSplitN {
iter: self.split_mut(pred),
count: n,
invert: false
}
}
}
#[inline]
fn rsplitn_mut<'a, P>(&'a mut self, n: uint, pred: P) -> RSplitNMut<'a, 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: uint) -> ChunksMut<T> {
assert!(chunk_size > 0);
ChunksMut { v: self, chunk_size: chunk_size }
}
fn swap(&mut self, a: uint, b: uint) {
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: uint = 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: uint) -> &mut T {
transmute((self.repr().data as *mut T).offset(index as int))
}
#[inline]
fn as_mut_ptr(&mut self) -> *mut T {
self.repr().data as *mut T
}
#[inline]
fn position_elem(&self, x: &T) -> Option<uint> where T: PartialEq {
self.iter().position(|y| *x == *y)
}
#[inline]
fn rposition_elem(&self, t: &T) -> Option<uint> where T: PartialEq {
self.iter().rposition(|x| *x == *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)..]
}
#[unstable]
fn binary_search(&self, x: &T) -> Result<uint, uint> where T: Ord {
self.binary_search_by(|p| p.cmp(x))
}
#[unstable]
fn next_permutation(&mut self) -> bool where T: Ord {
// These cases only have 1 permutation each, so we can't do anything.
if self.len() < 2 { return false; }
// Step 1: Identify the longest, rightmost weakly decreasing part of the vector
let mut i = self.len() - 1;
while i > 0 && self[i-1] >= self[i] {
i -= 1;
}
// If that is the entire vector, this is the last-ordered permutation.
if i == 0 {
return false;
}
// Step 2: Find the rightmost element larger than the pivot (i-1)
let mut j = self.len() - 1;
while j >= i && self[j] <= self[i-1] {
j -= 1;
}
// Step 3: Swap that element with the pivot
self.swap(j, i-1);
// Step 4: Reverse the (previously) weakly decreasing part
self.slice_from_mut(i).reverse();
true
}
#[unstable]
fn prev_permutation(&mut self) -> bool where T: Ord {
// These cases only have 1 permutation each, so we can't do anything.
if self.len() < 2 { return false; }
// Step 1: Identify the longest, rightmost weakly increasing part of the vector
let mut i = self.len() - 1;
while i > 0 && self[i-1] <= self[i] {
i -= 1;
}
// If that is the entire vector, this is the first-ordered permutation.
if i == 0 {
return false;
}
// Step 2: Reverse the weakly increasing part
self.slice_from_mut(i).reverse();
// Step 3: Find the rightmost element equal to or bigger than the pivot (i-1)
let mut j = self.len() - 1;
while j >= i && self[j-1] < self[i-1] {
j -= 1;
}
// Step 4: Swap that element with the pivot
self.swap(i-1, j);
true
}
#[inline]
fn clone_from_slice(&mut self, src: &[T]) -> uint where T: Clone {
let min = cmp::min(self.len(), src.len());
let dst = self.slice_to_mut(min);
let src = src.slice_to(min);
for i in range(0, min) {
dst[i].clone_from(&src[i]);
}
min
}
}
impl<T> ops::Index<uint> for [T] {
type Output = T;
fn index(&self, &index: &uint) -> &T {
assert!(index < self.len());
unsafe { mem::transmute(self.repr().data.offset(index as int)) }
}
}
impl<T> ops::IndexMut<uint> for [T] {
type Output = T;
fn index_mut(&mut self, &index: &uint) -> &mut T {
assert!(index < self.len());
unsafe { mem::transmute(self.repr().data.offset(index as int)) }
}
}
impl<T> ops::Index<ops::Range<uint>> for [T] {
type Output = [T];
#[inline]
fn index(&self, index: &ops::Range<uint>) -> &[T] {
assert!(index.start <= index.end);
assert!(index.end <= self.len());
unsafe {
transmute(RawSlice {
data: self.as_ptr().offset(index.start as int),
len: index.end - index.start
})
}
}
}
impl<T> ops::Index<ops::RangeTo<uint>> for [T] {
type Output = [T];
#[inline]
fn index(&self, index: &ops::RangeTo<uint>) -> &[T] {
self.index(&ops::Range{ start: 0, end: index.end })
}
}
impl<T> ops::Index<ops::RangeFrom<uint>> for [T] {
type Output = [T];
#[inline]
fn index(&self, index: &ops::RangeFrom<uint>) -> &[T] {
self.index(&ops::Range{ start: index.start, end: self.len() })
}
}
impl<T> ops::Index<ops::FullRange> for [T] {
type Output = [T];
#[inline]
fn index(&self, _index: &ops::FullRange) -> &[T] {
self
}
}
impl<T> ops::IndexMut<ops::Range<uint>> for [T] {
type Output = [T];
#[inline]
fn index_mut(&mut self, index: &ops::Range<uint>) -> &mut [T] {
assert!(index.start <= index.end);
assert!(index.end <= self.len());
unsafe {
transmute(RawSlice {
data: self.as_ptr().offset(index.start as int),
len: index.end - index.start
})
}
}
}
impl<T> ops::IndexMut<ops::RangeTo<uint>> for [T] {
type Output = [T];
#[inline]
fn index_mut(&mut self, index: &ops::RangeTo<uint>) -> &mut [T] {
self.index_mut(&ops::Range{ start: 0, end: index.end })
}
}
impl<T> ops::IndexMut<ops::RangeFrom<uint>> for [T] {
type Output = [T];
#[inline]
fn index_mut(&mut self, index: &ops::RangeFrom<uint>) -> &mut [T] {
let len = self.len();
self.index_mut(&ops::Range{ start: index.start, end: len })
}
}
impl<T> ops::IndexMut<ops::FullRange> for [T] {
type Output = [T];
#[inline]
fn index_mut(&mut self, _index: &ops::FullRange) -> &mut [T] {
self
}
}
////////////////////////////////////////////////////////////////////////////////
// Common traits
////////////////////////////////////////////////////////////////////////////////
/// Data that is viewable as a slice.
#[unstable = "will be replaced by slice syntax"]
pub trait AsSlice<T> {
/// Work with `self` as a slice.
fn as_slice<'a>(&'a self) -> &'a [T];
}
#[unstable = "trait is experimental"]
impl<T> AsSlice<T> for [T] {
#[inline(always)]
fn as_slice<'a>(&'a self) -> &'a [T] { self }
}
#[unstable = "trait is experimental"]
impl<'a, T, U: ?Sized + AsSlice<T>> AsSlice<T> for &'a U {
#[inline(always)]
fn as_slice(&self) -> &[T] { AsSlice::as_slice(*self) }
}
#[unstable = "trait is experimental"]
impl<'a, T, U: ?Sized + AsSlice<T>> AsSlice<T> for &'a mut U {
#[inline(always)]
fn as_slice(&self) -> &[T] { AsSlice::as_slice(*self) }
}
#[stable]
impl<'a, T> Default for &'a [T] {
#[stable]
fn default() -> &'a [T] { &[] }
}
//
// Iterators
//
// The shared definition of the `Iter` and `IterMut` iterators
macro_rules! iterator {
(struct $name:ident -> $ptr:ty, $elem:ty) => {
#[stable]
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 self.ptr == self.end {
None
} else {
if mem::size_of::<T>() == 0 {
// purposefully don't use 'ptr.offset' because for
// vectors with 0-size elements this would return the
// same pointer.
self.ptr = transmute(self.ptr as uint + 1);
// Use a non-null pointer value
Some(transmute(1u))
} else {
let old = self.ptr;
self.ptr = self.ptr.offset(1);
Some(transmute(old))
}
}
}
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
let diff = (self.end as uint) - (self.ptr as uint);
let size = mem::size_of::<T>();
let exact = diff / (if size == 0 {1} else {size});
(exact, Some(exact))
}
}
#[stable]
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 self.end == self.ptr {
None
} else {
if mem::size_of::<T>() == 0 {
// See above for why 'ptr.offset' isn't used
self.end = transmute(self.end as uint - 1);
// Use a non-null pointer value
Some(transmute(1u))
} else {
self.end = self.end.offset(-1);
Some(transmute(self.end))
}
}
}
}
}
}
}
macro_rules! make_slice {
($t: ty => $result: ty: $start: expr, $end: expr) => {{
let diff = $end as uint - $start as uint;
let len = if mem::size_of::<T>() == 0 {
diff
} else {
diff / mem::size_of::<$t>()
};
unsafe {
transmute::<_, $result>(RawSlice { data: $start as *const T, len: len })
}
}}
}
/// Immutable slice iterator
#[stable]
pub struct Iter<'a, T: 'a> {
ptr: *const T,
end: *const T,
marker: marker::ContravariantLifetime<'a>
}
#[unstable]
impl<'a, T> ops::Index<ops::Range<uint>> for Iter<'a, T> {
type Output = [T];
#[inline]
fn index(&self, index: &ops::Range<uint>) -> &[T] {
self.as_slice().index(index)
}
}
#[unstable]
impl<'a, T> ops::Index<ops::RangeTo<uint>> for Iter<'a, T> {
type Output = [T];
#[inline]
fn index(&self, index: &ops::RangeTo<uint>) -> &[T] {
self.as_slice().index(index)
}
}
#[unstable]
impl<'a, T> ops::Index<ops::RangeFrom<uint>> for Iter<'a, T> {
type Output = [T];
#[inline]
fn index(&self, index: &ops::RangeFrom<uint>) -> &[T] {
self.as_slice().index(index)
}
}
#[unstable]
impl<'a, T> ops::Index<ops::FullRange> for Iter<'a, T> {
type Output = [T];
#[inline]
fn index(&self, _index: &ops::FullRange) -> &[T] {
self.as_slice()
}
}
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.
#[unstable]
pub fn as_slice(&self) -> &'a [T] {
make_slice!(T => &'a [T]: self.ptr, self.end)
}
}
impl<'a,T> Copy for Iter<'a,T> {}
iterator!{struct Iter -> *const T, &'a T}
#[stable]
impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
#[stable]
impl<'a, T> Clone for Iter<'a, T> {
fn clone(&self) -> Iter<'a, T> { *self }
}
#[unstable = "trait is experimental"]
impl<'a, T> RandomAccessIterator for Iter<'a, T> {
#[inline]
fn indexable(&self) -> uint {
let (exact, _) = self.size_hint();
exact
}
#[inline]
fn idx(&mut self, index: uint) -> Option<&'a T> {
unsafe {
if index < self.indexable() {
if mem::size_of::<T>() == 0 {
// Use a non-null pointer value
Some(transmute(1u))
} else {
Some(transmute(self.ptr.offset(index as int)))
}
} else {
None
}
}
}
}
/// Mutable slice iterator.
#[stable]
pub struct IterMut<'a, T: 'a> {
ptr: *mut T,
end: *mut T,
marker: marker::ContravariantLifetime<'a>,
}
#[unstable]
impl<'a, T> ops::Index<ops::Range<uint>> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index(&self, index: &ops::Range<uint>) -> &[T] {
self.index(&ops::FullRange).index(index)
}
}
#[unstable]
impl<'a, T> ops::Index<ops::RangeTo<uint>> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index(&self, index: &ops::RangeTo<uint>) -> &[T] {
self.index(&ops::FullRange).index(index)
}
}
#[unstable]
impl<'a, T> ops::Index<ops::RangeFrom<uint>> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index(&self, index: &ops::RangeFrom<uint>) -> &[T] {
self.index(&ops::FullRange).index(index)
}
}
#[unstable]
impl<'a, T> ops::Index<ops::FullRange> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index(&self, _index: &ops::FullRange) -> &[T] {
make_slice!(T => &[T]: self.ptr, self.end)
}
}
#[unstable]
impl<'a, T> ops::IndexMut<ops::Range<uint>> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index_mut(&mut self, index: &ops::Range<uint>) -> &mut [T] {
self.index_mut(&ops::FullRange).index_mut(index)
}
}
#[unstable]
impl<'a, T> ops::IndexMut<ops::RangeTo<uint>> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index_mut(&mut self, index: &ops::RangeTo<uint>) -> &mut [T] {
self.index_mut(&ops::FullRange).index_mut(index)
}
}
#[unstable]
impl<'a, T> ops::IndexMut<ops::RangeFrom<uint>> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index_mut(&mut self, index: &ops::RangeFrom<uint>) -> &mut [T] {
self.index_mut(&ops::FullRange).index_mut(index)
}
}
#[unstable]
impl<'a, T> ops::IndexMut<ops::FullRange> for IterMut<'a, T> {
type Output = [T];
#[inline]
fn index_mut(&mut self, _index: &ops::FullRange) -> &mut [T] {
make_slice!(T => &mut [T]: self.ptr, self.end)
}
}
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.
#[unstable]
pub fn into_slice(self) -> &'a mut [T] {
make_slice!(T => &'a mut [T]: self.ptr, self.end)
}
}
iterator!{struct IterMut -> *mut T, &'a mut T}
#[stable]
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.
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]
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]
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]
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) -> (uint, Option<uint>) {
if self.finished {
(0, Some(0))
} else {
(1, Some(self.v.len() + 1))
}
}
}
#[stable]
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]
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]
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 = tail.slice_from_mut(1);
Some(head)
}
}
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
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]
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(tail.slice_from_mut(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: uint,
invert: bool
}
impl<T, I: SplitIter<Item=T>> Iterator for GenericSplitN<I> {
type Item = T;
#[inline]
fn next(&mut self) -> Option<T> {
if self.count == 0 {
self.iter.finish()
} else {
self.count -= 1;
if self.invert { self.iter.next_back() } else { self.iter.next() }
}
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
let (lower, upper_opt) = self.iter.size_hint();
(lower, upper_opt.map(|upper| cmp::min(self.count + 1, upper)))
}
}
/// An iterator over subslices separated by elements that match a predicate
/// function, limited to a given number of splits.
#[stable]
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]
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]
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]
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]
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) -> (uint, Option<uint>) {
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(Clone)]
#[stable]
pub struct Windows<'a, T:'a> {
v: &'a [T],
size: uint
}
#[stable]
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) -> (uint, Option<uint>) {
if self.size > self.v.len() {
(0, Some(0))
} else {
let x = self.v.len() - self.size;
(x.saturating_add(1), x.checked_add(1u))
}
}
}
/// 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(Clone)]
#[stable]
pub struct Chunks<'a, T:'a> {
v: &'a [T],
size: uint
}
#[stable]
impl<'a, T> Iterator for Chunks<'a, T> {
type Item = &'a [T];
#[inline]
fn next(&mut self) -> Option<&'a [T]> {
if self.v.len() == 0 {
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) -> (uint, Option<uint>) {
if self.v.len() == 0 {
(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))
}
}
}
#[stable]
impl<'a, T> DoubleEndedIterator for Chunks<'a, T> {
#[inline]
fn next_back(&mut self) -> Option<&'a [T]> {
if self.v.len() == 0 {
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)
}
}
}
#[unstable = "trait is experimental"]
impl<'a, T> RandomAccessIterator for Chunks<'a, T> {
#[inline]
fn indexable(&self) -> uint {
self.v.len()/self.size + if self.v.len() % self.size != 0 { 1 } else { 0 }
}
#[inline]
fn idx(&mut self, index: uint) -> Option<&'a [T]> {
if index < self.indexable() {
let lo = index * self.size;
let mut hi = lo + self.size;
if hi < lo || hi > self.v.len() { hi = self.v.len(); }
Some(&self.v[lo..hi])
} else {
None
}
}
}
/// 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]
pub struct ChunksMut<'a, T:'a> {
v: &'a mut [T],
chunk_size: uint
}
#[stable]
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.len() == 0 {
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) -> (uint, Option<uint>) {
if self.v.len() == 0 {
(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))
}
}
}
#[stable]
impl<'a, T> DoubleEndedIterator for ChunksMut<'a, T> {
#[inline]
fn next_back(&mut self) -> Option<&'a mut [T]> {
if self.v.len() == 0 {
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)
}
}
}
//
// Free functions
//
/// Converts a pointer to A into a slice of length 1 (without copying).
#[unstable]
pub fn ref_slice<'a, A>(s: &'a A) -> &'a [A] {
unsafe {
transmute(RawSlice { data: s, len: 1 })
}
}
/// Converts a pointer to A into a slice of length 1 (without copying).
#[unstable]
pub fn mut_ref_slice<'a, A>(s: &'a mut A) -> &'a mut [A] {
unsafe {
let ptr: *const A = transmute(s);
transmute(RawSlice { data: ptr, len: 1 })
}
}
/// Forms a slice from a pointer and a length.
///
/// The pointer given is actually a reference to the base of the slice. This
/// reference is used to give a concrete lifetime to tie the returned slice to.
/// Typically this should indicate that the slice is valid for as long as the
/// pointer itself is valid.
///
/// The `len` argument is the number of **elements**, not the number of bytes.
///
/// This function is unsafe as there is no guarantee that the given pointer is
/// valid for `len` elements, nor whether the lifetime provided is a suitable
/// lifetime for the returned slice.
///
/// # Example
///
/// ```rust
/// use std::slice;
///
/// // manifest a slice out of thin air!
/// let ptr = 0x1234 as *const uint;
/// let amt = 10;
/// unsafe {
/// let slice = slice::from_raw_buf(&ptr, amt);
/// }
/// ```
#[inline]
#[unstable = "should be renamed to from_raw_parts"]
pub unsafe fn from_raw_buf<'a, T>(p: &'a *const T, len: uint) -> &'a [T] {
transmute(RawSlice { data: *p, len: len })
}
/// Performs the same functionality as `from_raw_buf`, except that a mutable
/// slice is returned.
///
/// This function is unsafe for the same reasons as `from_raw_buf`, as well as
/// not being able to provide a non-aliasing guarantee of the returned mutable
/// slice.
#[inline]
#[unstable = "should be renamed to from_raw_parts_mut"]
pub unsafe fn from_raw_mut_buf<'a, T>(p: &'a *mut T, len: uint) -> &'a mut [T] {
transmute(RawSlice { data: *p as *const T, len: len })
}
//
// Submodules
//
/// Operations on `[u8]`.
#[unstable = "needs review"]
pub mod bytes {
use ptr;
use slice::SliceExt;
/// A trait for operations on mutable `[u8]`s.
pub trait MutableByteVector {
/// Sets all bytes of the receiver to the given value.
fn set_memory(&mut self, value: u8);
}
impl MutableByteVector for [u8] {
#[inline]
#[allow(unstable)]
fn set_memory(&mut self, value: u8) {
unsafe { ptr::set_memory(self.as_mut_ptr(), value, self.len()) };
}
}
/// Copies data from `src` to `dst`
///
/// Panics if the length of `dst` is less than the length of `src`.
#[inline]
pub fn copy_memory(dst: &mut [u8], src: &[u8]) {
let len_src = src.len();
assert!(dst.len() >= len_src);
// `dst` is unaliasable, so we know statically it doesn't overlap
// with `src`.
unsafe {
ptr::copy_nonoverlapping_memory(dst.as_mut_ptr(),
src.as_ptr(),
len_src);
}
}
}
//
// Boilerplate traits
//
#[stable]
impl<A, B> PartialEq<[B]> for [A] where A: PartialEq<B> {
fn eq(&self, other: &[B]) -> bool {
self.len() == other.len() &&
order::eq(self.iter(), other.iter())
}
fn ne(&self, other: &[B]) -> bool {
self.len() != other.len() ||
order::ne(self.iter(), other.iter())
}
}
#[stable]
impl<T: Eq> Eq for [T] {}
#[stable]
impl<T: Ord> Ord for [T] {
fn cmp(&self, other: &[T]) -> Ordering {
order::cmp(self.iter(), other.iter())
}
}
#[stable]
impl<T: PartialOrd> PartialOrd for [T] {
#[inline]
fn partial_cmp(&self, other: &[T]) -> Option<Ordering> {
order::partial_cmp(self.iter(), other.iter())
}
#[inline]
fn lt(&self, other: &[T]) -> bool {
order::lt(self.iter(), other.iter())
}
#[inline]
fn le(&self, other: &[T]) -> bool {
order::le(self.iter(), other.iter())
}
#[inline]
fn ge(&self, other: &[T]) -> bool {
order::ge(self.iter(), other.iter())
}
#[inline]
fn gt(&self, other: &[T]) -> bool {
order::gt(self.iter(), other.iter())
}
}
/// Extension methods for slices containing integers.
#[unstable]
pub trait IntSliceExt<U, S> {
/// Converts the slice to an immutable slice of unsigned integers with the same width.
fn as_unsigned<'a>(&'a self) -> &'a [U];
/// Converts the slice to an immutable slice of signed integers with the same width.
fn as_signed<'a>(&'a self) -> &'a [S];
/// Converts the slice to a mutable slice of unsigned integers with the same width.
fn as_unsigned_mut<'a>(&'a mut self) -> &'a mut [U];
/// Converts the slice to a mutable slice of signed integers with the same width.
fn as_signed_mut<'a>(&'a mut self) -> &'a mut [S];
}
macro_rules! impl_int_slice {
($u:ty, $s:ty, $t:ty) => {
#[unstable]
impl IntSliceExt<$u, $s> for [$t] {
#[inline]
fn as_unsigned(&self) -> &[$u] { unsafe { transmute(self) } }
#[inline]
fn as_signed(&self) -> &[$s] { unsafe { transmute(self) } }
#[inline]
fn as_unsigned_mut(&mut self) -> &mut [$u] { unsafe { transmute(self) } }
#[inline]
fn as_signed_mut(&mut self) -> &mut [$s] { unsafe { transmute(self) } }
}
}
}
macro_rules! impl_int_slices {
($u:ty, $s:ty) => {
impl_int_slice! { $u, $s, $u }
impl_int_slice! { $u, $s, $s }
}
}
impl_int_slices! { u8, i8 }
impl_int_slices! { u16, i16 }
impl_int_slices! { u32, i32 }
impl_int_slices! { u64, i64 }
impl_int_slices! { uint, int }
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