cl_generic_vec/iter/
drain.rs

1use crate::{iter::RawCursor, Storage};
2
3use core::iter::FusedIterator;
4
5/// This struct is created by [`GenericVec::drain`](crate::GenericVec::drain).
6/// See its documentation for more.
7pub struct Drain<'a, S: ?Sized + Storage> {
8    raw: RawCursor<'a, S>,
9}
10
11impl<'a, S: ?Sized + Storage> Drain<'a, S> {
12    pub(crate) fn new(raw: RawCursor<'a, S>) -> Self { Self { raw } }
13}
14
15impl<S: ?Sized + Storage> FusedIterator for Drain<'_, S> {}
16
17impl<S: ?Sized + Storage> ExactSizeIterator for Drain<'_, S> {
18    #[cfg(feature = "nightly")]
19    fn is_empty(&self) -> bool { self.raw.is_empty() }
20}
21
22impl<S: ?Sized + Storage> Drop for Drain<'_, S> {
23    fn drop(&mut self) { self.for_each(drop); }
24}
25
26impl<S: ?Sized + Storage> Iterator for Drain<'_, S> {
27    type Item = S::Item;
28
29    fn next(&mut self) -> Option<Self::Item> {
30        if self.raw.is_empty() {
31            None
32        } else {
33            unsafe { Some(self.raw.take_front()) }
34        }
35    }
36
37    fn size_hint(&self) -> (usize, Option<usize>) {
38        let len = self.raw.len();
39        (len, Some(len))
40    }
41}
42
43impl<S: ?Sized + Storage> DoubleEndedIterator for Drain<'_, S> {
44    fn next_back(&mut self) -> Option<Self::Item> {
45        if self.raw.is_empty() {
46            None
47        } else {
48            unsafe { Some(self.raw.take_back()) }
49        }
50    }
51}