Add array::IntoIter as a consuming/by-value array iterator
The iterator is implemented using const generics. It implements the traits `Iterator`, `DoubleEndedIterator`, `ExactSizeIterator`, `FusedIterator` and `TrustedLen`. It also contains a public method `new` to create it from an array. `IntoIterator` was not implemented for arrays yet, as there are still some open questions regarding backwards compatibility. This commit only adds the iterator impl and does not yet offer a convenient way to obtain that iterator.
This commit is contained in:
Lukas Kalbertodt
266
src/libcore/array/iter.rs
Normal file
266
src/libcore/array/iter.rs
Normal file
@@ -0,0 +1,266 @@
|
||||
//! Defines the `IntoIter` owned iterator for arrays.
|
||||
|
||||
use crate::{
|
||||
fmt,
|
||||
iter::{ExactSizeIterator, FusedIterator, TrustedLen},
|
||||
mem::{self, MaybeUninit},
|
||||
ops::Range,
|
||||
ptr,
|
||||
};
|
||||
use super::LengthAtMost32;
|
||||
|
||||
|
||||
/// A by-value [array] iterator.
|
||||
///
|
||||
/// [array]: ../../std/primitive.array.html
|
||||
#[unstable(feature = "array_value_iter", issue = "0")]
|
||||
pub struct IntoIter<T, const N: usize>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
/// This is the array we are iterating over.
|
||||
///
|
||||
/// Elements with index `i` where `alive.start <= i < alive.end` have not
|
||||
/// been yielded yet and are valid array entries. Elements with indices `i
|
||||
/// < alive.start` or `i >= alive.end` have been yielded already and must
|
||||
/// not be accessed anymore! Those dead elements might even be in a
|
||||
/// completely uninitialized state!
|
||||
///
|
||||
/// So the invariants are:
|
||||
/// - `data[alive]` is alive (i.e. contains valid elements)
|
||||
/// - `data[..alive.start]` and `data[alive.end..]` are dead (i.e. the
|
||||
/// elements were already read and must not be touched anymore!)
|
||||
data: [MaybeUninit<T>; N],
|
||||
|
||||
/// The elements in `data` that have not been yielded yet.
|
||||
///
|
||||
/// Invariants:
|
||||
/// - `alive.start <= alive.end`
|
||||
/// - `alive.end <= N`
|
||||
alive: Range<usize>,
|
||||
}
|
||||
|
||||
impl<T, const N: usize> IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
/// Creates a new iterator over the given `array`.
|
||||
///
|
||||
/// *Note*: this method might never get stabilized and/or removed in the
|
||||
/// future as there will likely be another, preferred way of obtaining this
|
||||
/// iterator (either via `IntoIterator` for arrays or via another way).
|
||||
#[unstable(feature = "array_value_iter", issue = "0")]
|
||||
pub fn new(array: [T; N]) -> Self {
|
||||
// The transmute here is actually safe. The docs of `MaybeUninit`
|
||||
// promise:
|
||||
//
|
||||
// > `MaybeUninit<T>` is guaranteed to have the same size and alignment
|
||||
// > as `T`.
|
||||
//
|
||||
// The docs even show a transmute from an array of `MaybeUninit<T>` to
|
||||
// an array of `T`.
|
||||
//
|
||||
// With that, this initialization satisfies the invariants.
|
||||
|
||||
// FIXME(LukasKalbertodt): actually use `mem::transmute` here, once it
|
||||
// works with const generics:
|
||||
// `mem::transmute::<[T; {N}], [MaybeUninit<T>; {N}]>(array)`
|
||||
//
|
||||
// Until then, we do it manually here. We first create a bitwise copy
|
||||
// but cast the pointer so that it is treated as a different type. Then
|
||||
// we forget `array` so that it is not dropped.
|
||||
let data = unsafe {
|
||||
let data = ptr::read(&array as *const [T; N] as *const [MaybeUninit<T>; N]);
|
||||
mem::forget(array);
|
||||
data
|
||||
};
|
||||
|
||||
Self {
|
||||
data,
|
||||
alive: 0..N,
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns an immutable slice of all elements that have not been yielded
|
||||
/// yet.
|
||||
fn as_slice(&self) -> &[T] {
|
||||
// This transmute is safe. As mentioned in `new`, `MaybeUninit` retains
|
||||
// the size and alignment of `T`. Furthermore, we know that all
|
||||
// elements within `alive` are properly initialized.
|
||||
let slice = &self.data[self.alive.clone()];
|
||||
unsafe {
|
||||
mem::transmute::<&[MaybeUninit<T>], &[T]>(slice)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T, const N: usize> Iterator for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
type Item = T;
|
||||
fn next(&mut self) -> Option<Self::Item> {
|
||||
if self.alive.start == self.alive.end {
|
||||
return None;
|
||||
}
|
||||
|
||||
// Bump start index.
|
||||
//
|
||||
// From the check above we know that `alive.start != alive.end`.
|
||||
// Combine this with the invariant `alive.start <= alive.end`, we know
|
||||
// that `alive.start < alive.end`. Increasing `alive.start` by 1
|
||||
// maintains the invariant regarding `alive`. However, due to this
|
||||
// change, for a short time, the alive zone is not `data[alive]`
|
||||
// anymore, but `data[idx..alive.end]`.
|
||||
let idx = self.alive.start;
|
||||
self.alive.start += 1;
|
||||
|
||||
// Read the element from the array. This is safe: `idx` is an index
|
||||
// into the "alive" region of the array. Reading this element means
|
||||
// that `data[idx]` is regarded as dead now (i.e. do not touch). As
|
||||
// `idx` was the start of the alive-zone, the alive zone is now
|
||||
// `data[alive]` again, restoring all invariants.
|
||||
let out = unsafe { self.data.get_unchecked(idx).read() };
|
||||
|
||||
Some(out)
|
||||
}
|
||||
|
||||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||||
let len = self.len();
|
||||
(len, Some(len))
|
||||
}
|
||||
|
||||
fn count(self) -> usize {
|
||||
self.len()
|
||||
}
|
||||
|
||||
fn last(mut self) -> Option<Self::Item> {
|
||||
self.next_back()
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T, const N: usize> DoubleEndedIterator for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn next_back(&mut self) -> Option<Self::Item> {
|
||||
if self.alive.start == self.alive.end {
|
||||
return None;
|
||||
}
|
||||
|
||||
// Decrease end index.
|
||||
//
|
||||
// From the check above we know that `alive.start != alive.end`.
|
||||
// Combine this with the invariant `alive.start <= alive.end`, we know
|
||||
// that `alive.start < alive.end`. As `alive.start` cannot be negative,
|
||||
// `alive.end` is at least 1, meaning that we can safely decrement it
|
||||
// by one. This also maintains the invariant `alive.start <=
|
||||
// alive.end`. However, due to this change, for a short time, the alive
|
||||
// zone is not `data[alive]` anymore, but `data[alive.start..alive.end
|
||||
// + 1]`.
|
||||
self.alive.end -= 1;
|
||||
|
||||
// Read the element from the array. This is safe: `alive.end` is an
|
||||
// index into the "alive" region of the array. Compare the previous
|
||||
// comment that states that the alive region is
|
||||
// `data[alive.start..alive.end + 1]`. Reading this element means that
|
||||
// `data[alive.end]` is regarded as dead now (i.e. do not touch). As
|
||||
// `alive.end` was the end of the alive-zone, the alive zone is now
|
||||
// `data[alive]` again, restoring all invariants.
|
||||
let out = unsafe { self.data.get_unchecked(self.alive.end).read() };
|
||||
|
||||
Some(out)
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T, const N: usize> Drop for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn drop(&mut self) {
|
||||
// We simply drop each element via `for_each`. This should not incur
|
||||
// any significant runtime overhead and avoids adding another `unsafe`
|
||||
// block.
|
||||
self.by_ref().for_each(drop);
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T, const N: usize> ExactSizeIterator for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn len(&self) -> usize {
|
||||
// Will never underflow due to the invariant `alive.start <=
|
||||
// alive.end`.
|
||||
self.alive.end - self.alive.start
|
||||
}
|
||||
fn is_empty(&self) -> bool {
|
||||
self.alive.is_empty()
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T, const N: usize> FusedIterator for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{}
|
||||
|
||||
// The iterator indeed reports the correct length. The number of "alive"
|
||||
// elements (that will still be yielded) is the length of the range `alive`.
|
||||
// This range is decremented in length in either `next` or `next_back`. It is
|
||||
// always decremented by 1 in those methods, but only if `Some(_)` is returned.
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
unsafe impl<T, const N: usize> TrustedLen for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{}
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T: Clone, const N: usize> Clone for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn clone(&self) -> Self {
|
||||
unsafe {
|
||||
// This creates a new uninitialized array. Note that the `assume_init`
|
||||
// refers to the array, not the individual elements. And it is Ok if
|
||||
// the array is in an uninitialized state as all elements may be
|
||||
// uninitialized (all bit patterns are valid). Compare the
|
||||
// `MaybeUninit` docs for more information.
|
||||
let mut new_data: [MaybeUninit<T>; N] = MaybeUninit::uninit().assume_init();
|
||||
|
||||
// Clone all alive elements.
|
||||
for idx in self.alive.clone() {
|
||||
// The element at `idx` in the old array is alive, so we can
|
||||
// safely call `get_ref()`. We then clone it, and write the
|
||||
// clone into the new array.
|
||||
let clone = self.data.get_unchecked(idx).get_ref().clone();
|
||||
new_data.get_unchecked_mut(idx).write(clone);
|
||||
}
|
||||
|
||||
Self {
|
||||
data: new_data,
|
||||
alive: self.alive.clone(),
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_value_iter_impls", since = "1.38.0")]
|
||||
impl<T: fmt::Debug, const N: usize> fmt::Debug for IntoIter<T, {N}>
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
// Only print the elements that were not yielded yet: we cannot
|
||||
// access the yielded elements anymore.
|
||||
f.debug_tuple("IntoIter")
|
||||
.field(&self.as_slice())
|
||||
.finish()
|
||||
}
|
||||
}
|
||||
432
src/libcore/array/mod.rs
Normal file
432
src/libcore/array/mod.rs
Normal file
@@ -0,0 +1,432 @@
|
||||
//! Implementations of things like `Eq` for fixed-length arrays
|
||||
//! up to a certain length. Eventually we should able to generalize
|
||||
//! to all lengths.
|
||||
//!
|
||||
//! *[See also the array primitive type](../../std/primitive.array.html).*
|
||||
|
||||
#![stable(feature = "core_array", since = "1.36.0")]
|
||||
|
||||
use crate::borrow::{Borrow, BorrowMut};
|
||||
use crate::cmp::Ordering;
|
||||
use crate::convert::{Infallible, TryFrom};
|
||||
use crate::fmt;
|
||||
use crate::hash::{Hash, self};
|
||||
use crate::marker::Unsize;
|
||||
use crate::slice::{Iter, IterMut};
|
||||
|
||||
#[cfg(not(bootstrap))]
|
||||
mod iter;
|
||||
|
||||
#[cfg(not(bootstrap))]
|
||||
#[unstable(feature = "array_value_iter", issue = "0")]
|
||||
pub use iter::IntoIter;
|
||||
|
||||
/// Utility trait implemented only on arrays of fixed size
|
||||
///
|
||||
/// This trait can be used to implement other traits on fixed-size arrays
|
||||
/// without causing much metadata bloat.
|
||||
///
|
||||
/// The trait is marked unsafe in order to restrict implementors to fixed-size
|
||||
/// arrays. User of this trait can assume that implementors have the exact
|
||||
/// layout in memory of a fixed size array (for example, for unsafe
|
||||
/// initialization).
|
||||
///
|
||||
/// Note that the traits [`AsRef`] and [`AsMut`] provide similar methods for types that
|
||||
/// may not be fixed-size arrays. Implementors should prefer those traits
|
||||
/// instead.
|
||||
///
|
||||
/// [`AsRef`]: ../convert/trait.AsRef.html
|
||||
/// [`AsMut`]: ../convert/trait.AsMut.html
|
||||
#[unstable(feature = "fixed_size_array", issue = "27778")]
|
||||
pub unsafe trait FixedSizeArray<T> {
|
||||
/// Converts the array to immutable slice
|
||||
#[unstable(feature = "fixed_size_array", issue = "27778")]
|
||||
fn as_slice(&self) -> &[T];
|
||||
/// Converts the array to mutable slice
|
||||
#[unstable(feature = "fixed_size_array", issue = "27778")]
|
||||
fn as_mut_slice(&mut self) -> &mut [T];
|
||||
}
|
||||
|
||||
#[unstable(feature = "fixed_size_array", issue = "27778")]
|
||||
unsafe impl<T, A: Unsize<[T]>> FixedSizeArray<T> for A {
|
||||
#[inline]
|
||||
fn as_slice(&self) -> &[T] {
|
||||
self
|
||||
}
|
||||
#[inline]
|
||||
fn as_mut_slice(&mut self) -> &mut [T] {
|
||||
self
|
||||
}
|
||||
}
|
||||
|
||||
/// The error type returned when a conversion from a slice to an array fails.
|
||||
#[stable(feature = "try_from", since = "1.34.0")]
|
||||
#[derive(Debug, Copy, Clone)]
|
||||
pub struct TryFromSliceError(());
|
||||
|
||||
#[stable(feature = "core_array", since = "1.36.0")]
|
||||
impl fmt::Display for TryFromSliceError {
|
||||
#[inline]
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
fmt::Display::fmt(self.__description(), f)
|
||||
}
|
||||
}
|
||||
|
||||
impl TryFromSliceError {
|
||||
#[unstable(feature = "array_error_internals",
|
||||
reason = "available through Error trait and this method should not \
|
||||
be exposed publicly",
|
||||
issue = "0")]
|
||||
#[inline]
|
||||
#[doc(hidden)]
|
||||
pub fn __description(&self) -> &str {
|
||||
"could not convert slice to array"
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "try_from_slice_error", since = "1.36.0")]
|
||||
impl From<Infallible> for TryFromSliceError {
|
||||
fn from(x: Infallible) -> TryFromSliceError {
|
||||
match x {}
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T, const N: usize> AsRef<[T]> for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn as_ref(&self) -> &[T] {
|
||||
&self[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T, const N: usize> AsMut<[T]> for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn as_mut(&mut self) -> &mut [T] {
|
||||
&mut self[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_borrow", since = "1.4.0")]
|
||||
impl<T, const N: usize> Borrow<[T]> for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn borrow(&self) -> &[T] {
|
||||
self
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "array_borrow", since = "1.4.0")]
|
||||
impl<T, const N: usize> BorrowMut<[T]> for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn borrow_mut(&mut self) -> &mut [T] {
|
||||
self
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "try_from", since = "1.34.0")]
|
||||
impl<T, const N: usize> TryFrom<&[T]> for [T; N]
|
||||
where
|
||||
T: Copy,
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
type Error = TryFromSliceError;
|
||||
|
||||
fn try_from(slice: &[T]) -> Result<[T; N], TryFromSliceError> {
|
||||
<&Self>::try_from(slice).map(|r| *r)
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "try_from", since = "1.34.0")]
|
||||
impl<'a, T, const N: usize> TryFrom<&'a [T]> for &'a [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
type Error = TryFromSliceError;
|
||||
|
||||
fn try_from(slice: &[T]) -> Result<&[T; N], TryFromSliceError> {
|
||||
if slice.len() == N {
|
||||
let ptr = slice.as_ptr() as *const [T; N];
|
||||
unsafe { Ok(&*ptr) }
|
||||
} else {
|
||||
Err(TryFromSliceError(()))
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "try_from", since = "1.34.0")]
|
||||
impl<'a, T, const N: usize> TryFrom<&'a mut [T]> for &'a mut [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
type Error = TryFromSliceError;
|
||||
|
||||
fn try_from(slice: &mut [T]) -> Result<&mut [T; N], TryFromSliceError> {
|
||||
if slice.len() == N {
|
||||
let ptr = slice.as_mut_ptr() as *mut [T; N];
|
||||
unsafe { Ok(&mut *ptr) }
|
||||
} else {
|
||||
Err(TryFromSliceError(()))
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T: Hash, const N: usize> Hash for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn hash<H: hash::Hasher>(&self, state: &mut H) {
|
||||
Hash::hash(&self[..], state)
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T: fmt::Debug, const N: usize> fmt::Debug for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
fmt::Debug::fmt(&&self[..], f)
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<'a, T, const N: usize> IntoIterator for &'a [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
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, const N: usize> IntoIterator for &'a mut [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
type Item = &'a mut T;
|
||||
type IntoIter = IterMut<'a, T>;
|
||||
|
||||
fn into_iter(self) -> IterMut<'a, T> {
|
||||
self.iter_mut()
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<A, B, const N: usize> PartialEq<[B; N]> for [A; N]
|
||||
where
|
||||
A: PartialEq<B>,
|
||||
[A; N]: LengthAtMost32,
|
||||
[B; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &[B; N]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &[B; N]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<A, B, const N: usize> PartialEq<[B]> for [A; N]
|
||||
where
|
||||
A: PartialEq<B>,
|
||||
[A; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &[B]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &[B]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<A, B, const N: usize> PartialEq<[A; N]> for [B]
|
||||
where
|
||||
B: PartialEq<A>,
|
||||
[A; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &[A; N]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &[A; N]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<'b, A, B, const N: usize> PartialEq<&'b [B]> for [A; N]
|
||||
where
|
||||
A: PartialEq<B>,
|
||||
[A; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &&'b [B]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &&'b [B]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<'b, A, B, const N: usize> PartialEq<[A; N]> for &'b [B]
|
||||
where
|
||||
B: PartialEq<A>,
|
||||
[A; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &[A; N]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &[A; N]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<'b, A, B, const N: usize> PartialEq<&'b mut [B]> for [A; N]
|
||||
where
|
||||
A: PartialEq<B>,
|
||||
[A; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &&'b mut [B]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &&'b mut [B]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<'b, A, B, const N: usize> PartialEq<[A; N]> for &'b mut [B]
|
||||
where
|
||||
B: PartialEq<A>,
|
||||
[A; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn eq(&self, other: &[A; N]) -> bool {
|
||||
self[..] == other[..]
|
||||
}
|
||||
#[inline]
|
||||
fn ne(&self, other: &[A; N]) -> bool {
|
||||
self[..] != other[..]
|
||||
}
|
||||
}
|
||||
|
||||
// NOTE: some less important impls are omitted to reduce code bloat
|
||||
// __impl_slice_eq2! { [A; $N], &'b [B; $N] }
|
||||
// __impl_slice_eq2! { [A; $N], &'b mut [B; $N] }
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T: Eq, const N: usize> Eq for [T; N] where [T; N]: LengthAtMost32 {}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T: PartialOrd, const N: usize> PartialOrd for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn partial_cmp(&self, other: &[T; N]) -> Option<Ordering> {
|
||||
PartialOrd::partial_cmp(&&self[..], &&other[..])
|
||||
}
|
||||
#[inline]
|
||||
fn lt(&self, other: &[T; N]) -> bool {
|
||||
PartialOrd::lt(&&self[..], &&other[..])
|
||||
}
|
||||
#[inline]
|
||||
fn le(&self, other: &[T; N]) -> bool {
|
||||
PartialOrd::le(&&self[..], &&other[..])
|
||||
}
|
||||
#[inline]
|
||||
fn ge(&self, other: &[T; N]) -> bool {
|
||||
PartialOrd::ge(&&self[..], &&other[..])
|
||||
}
|
||||
#[inline]
|
||||
fn gt(&self, other: &[T; N]) -> bool {
|
||||
PartialOrd::gt(&&self[..], &&other[..])
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl<T: Ord, const N: usize> Ord for [T; N]
|
||||
where
|
||||
[T; N]: LengthAtMost32,
|
||||
{
|
||||
#[inline]
|
||||
fn cmp(&self, other: &[T; N]) -> Ordering {
|
||||
Ord::cmp(&&self[..], &&other[..])
|
||||
}
|
||||
}
|
||||
|
||||
/// Implemented for lengths where trait impls are allowed on arrays in core/std
|
||||
#[rustc_on_unimplemented(
|
||||
message="arrays only have std trait implementations for lengths 0..=32",
|
||||
)]
|
||||
#[unstable(feature = "const_generic_impls_guard", issue = "0",
|
||||
reason = "will never be stable, just a temporary step until const generics are stable")]
|
||||
pub trait LengthAtMost32 {}
|
||||
|
||||
macro_rules! array_impls {
|
||||
($($N:literal)+) => {
|
||||
$(
|
||||
#[unstable(feature = "const_generic_impls_guard", issue = "0")]
|
||||
impl<T> LengthAtMost32 for [T; $N] {}
|
||||
)+
|
||||
}
|
||||
}
|
||||
|
||||
array_impls! {
|
||||
0 1 2 3 4 5 6 7 8 9
|
||||
10 11 12 13 14 15 16 17 18 19
|
||||
20 21 22 23 24 25 26 27 28 29
|
||||
30 31 32
|
||||
}
|
||||
|
||||
// The Default impls cannot be generated using the array_impls! macro because
|
||||
// they require array literals.
|
||||
|
||||
macro_rules! array_impl_default {
|
||||
{$n:expr, $t:ident $($ts:ident)*} => {
|
||||
#[stable(since = "1.4.0", feature = "array_default")]
|
||||
impl<T> Default for [T; $n] where T: Default {
|
||||
fn default() -> [T; $n] {
|
||||
[$t::default(), $($ts::default()),*]
|
||||
}
|
||||
}
|
||||
array_impl_default!{($n - 1), $($ts)*}
|
||||
};
|
||||
{$n:expr,} => {
|
||||
#[stable(since = "1.4.0", feature = "array_default")]
|
||||
impl<T> Default for [T; $n] {
|
||||
fn default() -> [T; $n] { [] }
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
array_impl_default!{32, T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T}
|
||||
Reference in New Issue
Block a user