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use crate::iter::adapters::{
zip::try_get_unchecked, TrustedRandomAccess, TrustedRandomAccessNoCoerce,
};
use crate::iter::{FusedIterator, TrustedLen};
use crate::ops::Try;
#[stable(feature = "iter_copied", since = "1.36.0")]
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[derive(Clone, Debug)]
pub struct Copied<I> {
it: I,
}
impl<I> Copied<I> {
pub(in crate::iter) fn new(it: I) -> Copied<I> {
Copied { it }
}
}
fn copy_fold<T: Copy, Acc>(mut f: impl FnMut(Acc, T) -> Acc) -> impl FnMut(Acc, &T) -> Acc {
move |acc, &elt| f(acc, elt)
}
fn copy_try_fold<T: Copy, Acc, R>(mut f: impl FnMut(Acc, T) -> R) -> impl FnMut(Acc, &T) -> R {
move |acc, &elt| f(acc, elt)
}
#[stable(feature = "iter_copied", since = "1.36.0")]
impl<'a, I, T: 'a> Iterator for Copied<I>
where
I: Iterator<Item = &'a T>,
T: Copy,
{
type Item = T;
fn next(&mut self) -> Option<T> {
self.it.next().copied()
}
fn size_hint(&self) -> (usize, Option<usize>) {
self.it.size_hint()
}
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
where
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
{
self.it.try_fold(init, copy_try_fold(f))
}
fn fold<Acc, F>(self, init: Acc, f: F) -> Acc
where
F: FnMut(Acc, Self::Item) -> Acc,
{
self.it.fold(init, copy_fold(f))
}
fn nth(&mut self, n: usize) -> Option<T> {
self.it.nth(n).copied()
}
fn last(self) -> Option<T> {
self.it.last().copied()
}
fn count(self) -> usize {
self.it.count()
}
#[inline]
fn advance_by(&mut self, n: usize) -> Result<(), usize> {
self.it.advance_by(n)
}
unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> T
where
Self: TrustedRandomAccessNoCoerce,
{
*unsafe { try_get_unchecked(&mut self.it, idx) }
}
}
#[stable(feature = "iter_copied", since = "1.36.0")]
impl<'a, I, T: 'a> DoubleEndedIterator for Copied<I>
where
I: DoubleEndedIterator<Item = &'a T>,
T: Copy,
{
fn next_back(&mut self) -> Option<T> {
self.it.next_back().copied()
}
fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R
where
Self: Sized,
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
{
self.it.try_rfold(init, copy_try_fold(f))
}
fn rfold<Acc, F>(self, init: Acc, f: F) -> Acc
where
F: FnMut(Acc, Self::Item) -> Acc,
{
self.it.rfold(init, copy_fold(f))
}
#[inline]
fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
self.it.advance_back_by(n)
}
}
#[stable(feature = "iter_copied", since = "1.36.0")]
impl<'a, I, T: 'a> ExactSizeIterator for Copied<I>
where
I: ExactSizeIterator<Item = &'a T>,
T: Copy,
{
fn len(&self) -> usize {
self.it.len()
}
fn is_empty(&self) -> bool {
self.it.is_empty()
}
}
#[stable(feature = "iter_copied", since = "1.36.0")]
impl<'a, I, T: 'a> FusedIterator for Copied<I>
where
I: FusedIterator<Item = &'a T>,
T: Copy,
{
}
#[doc(hidden)]
#[unstable(feature = "trusted_random_access", issue = "none")]
unsafe impl<I> TrustedRandomAccess for Copied<I> where I: TrustedRandomAccess {}
#[doc(hidden)]
#[unstable(feature = "trusted_random_access", issue = "none")]
unsafe impl<I> TrustedRandomAccessNoCoerce for Copied<I>
where
I: TrustedRandomAccessNoCoerce,
{
const MAY_HAVE_SIDE_EFFECT: bool = I::MAY_HAVE_SIDE_EFFECT;
}
#[stable(feature = "iter_copied", since = "1.36.0")]
unsafe impl<'a, I, T: 'a> TrustedLen for Copied<I>
where
I: TrustedLen<Item = &'a T>,
T: Copy,
{
}
