use crate::{iter::RawCursor, Storage};
use core::iter::FusedIterator;
pub struct DrainFilter<'a, T, S, F>
where
S: ?Sized + Storage<T>,
F: FnMut(&mut T) -> bool,
{
raw: RawCursor<'a, T, S>,
filter: F,
}
impl<'a, T, S, F> DrainFilter<'a, T, S, F>
where
S: ?Sized + Storage<T>,
F: FnMut(&mut T) -> bool,
{
pub(crate) fn new(raw: RawCursor<'a, T, S>, filter: F) -> Self { Self { raw, filter } }
}
impl<T, S, F> Drop for DrainFilter<'_, T, S, F>
where
S: ?Sized + Storage<T>,
F: FnMut(&mut T) -> bool,
{
fn drop(&mut self) { self.for_each(drop); }
}
impl<T, S, F> FusedIterator for DrainFilter<'_, T, S, F>
where
S: ?Sized + Storage<T>,
F: FnMut(&mut T) -> bool,
{
}
impl<T, S, F> Iterator for DrainFilter<'_, T, S, F>
where
S: ?Sized + Storage<T>,
F: FnMut(&mut T) -> bool,
{
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
loop {
if self.raw.is_empty() {
break None
}
unsafe {
let value = self.raw.front_mut();
if (self.filter)(value) {
break Some(self.raw.take_front())
} else {
self.raw.skip_front();
}
}
}
}
fn size_hint(&self) -> (usize, Option<usize>) {
let len = self.raw.len();
(0, Some(len))
}
}
impl<T, S, F> DoubleEndedIterator for DrainFilter<'_, T, S, F>
where
S: ?Sized + Storage<T>,
F: FnMut(&mut T) -> bool,
{
fn next_back(&mut self) -> Option<Self::Item> {
loop {
if self.raw.is_empty() {
break None
}
unsafe {
let value = self.raw.back_mut();
if (self.filter)(value) {
break Some(self.raw.take_back())
} else {
self.raw.skip_back();
}
}
}
}
}