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use crate::{iter::RawCursor, Storage};
use core::iter::FusedIterator;
pub struct Drain<'a, S: ?Sized + Storage> {
raw: RawCursor<'a, S>,
}
impl<'a, S: ?Sized + Storage> Drain<'a, S> {
pub(crate) fn new(raw: RawCursor<'a, S>) -> Self { Self { raw } }
}
impl<S: ?Sized + Storage> FusedIterator for Drain<'_, S> {}
impl<S: ?Sized + Storage> ExactSizeIterator for Drain<'_, S> {
#[cfg(feature = "nightly")]
fn is_empty(&self) -> bool { self.raw.is_empty() }
}
impl<S: ?Sized + Storage> Drop for Drain<'_, S> {
fn drop(&mut self) { self.for_each(drop); }
}
impl<S: ?Sized + Storage> Iterator for Drain<'_, S> {
type Item = S::Item;
fn next(&mut self) -> Option<Self::Item> {
if self.raw.is_empty() {
None
} else {
unsafe { Some(self.raw.take_front()) }
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let len = self.raw.len();
(len, Some(len))
}
}
impl<S: ?Sized + Storage> DoubleEndedIterator for Drain<'_, S> {
fn next_back(&mut self) -> Option<Self::Item> {
if self.raw.is_empty() {
None
} else {
unsafe { Some(self.raw.take_back()) }
}
}
}