library/alloc/src/collections/vec_deque/into_iter.rs

   1 use core::fmt;
   2 use core::iter::FusedIterator;
   3
   4 use super::VecDeque;
   5
   6 /// An owning iterator over the elements of a `VecDeque`.
   7 ///
   8 /// This `struct` is created by the [`into_iter`] method on [`VecDeque`]
   9 /// (provided by the `IntoIterator` trait). See its documentation for more.
  10 ///
  11 /// [`into_iter`]: VecDeque::into_iter
  12 #[derive(Clone)]
  13 #[stable(feature = "rust1", since = "1.0.0")]
  14 pub struct IntoIter<T> {
  15     pub(crate) inner: VecDeque<T>,
  16 }
  17
  18 #[stable(feature = "collection_debug", since = "1.17.0")]
  19 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
  20     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  21         f.debug_tuple("IntoIter").field(&self.inner).finish()
  22     }
  23 }
  24
  25 #[stable(feature = "rust1", since = "1.0.0")]
  26 impl<T> Iterator for IntoIter<T> {
  27     type Item = T;
  28
  29     #[inline]
  30     fn next(&mut self) -> Option<T> {
  31         self.inner.pop_front()
  32     }
  33
  34     #[inline]
  35     fn size_hint(&self) -> (usize, Option<usize>) {
  36         let len = self.inner.len();
  37         (len, Some(len))
  38     }
  39 }
  40
  41 #[stable(feature = "rust1", since = "1.0.0")]
  42 impl<T> DoubleEndedIterator for IntoIter<T> {
  43     #[inline]
  44     fn next_back(&mut self) -> Option<T> {
  45         self.inner.pop_back()
  46     }
  47 }
  48
  49 #[stable(feature = "rust1", since = "1.0.0")]
  50 impl<T> ExactSizeIterator for IntoIter<T> {
  51     fn is_empty(&self) -> bool {
  52         self.inner.is_empty()
  53     }
  54 }
  55
  56 #[stable(feature = "fused", since = "1.26.0")]
  57 impl<T> FusedIterator for IntoIter<T> {}