drain.rs

// Copyright (c) 2023-2025 Yegor Bugayenko
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

use crate::Drain;
use core::iter::FusedIterator;

impl<'a, K, V> Drop for Drain<'a, K, V> {
    fn drop(&mut self) {
        for pair in &mut self.iter {
            unsafe { pair.assume_init_drop() };
        }
    }
}

impl<'a, K: PartialEq, V> Iterator for Drain<'a, K, V> {
    type Item = (K, V);

    #[inline]
    #[must_use]
    fn next(&mut self) -> Option<Self::Item> {
        self.iter.next().map(|p| unsafe { p.assume_init_read() })
    }

    #[inline]
    fn size_hint(&self) -> (usize, Option<usize>) {
        (self.iter.len(), Some(self.iter.len()))
    }
}

impl<'a, K: PartialEq, V> ExactSizeIterator for Drain<'a, K, V> {
    #[inline]
    fn len(&self) -> usize {
        self.iter.len()
    }
}

impl<'a, K: PartialEq, V> FusedIterator for Drain<'a, K, V> {}