diff options
Diffstat (limited to 'library/alloc/src/collections/vec_deque/into_iter.rs')
-rw-r--r-- | library/alloc/src/collections/vec_deque/into_iter.rs | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/library/alloc/src/collections/vec_deque/into_iter.rs b/library/alloc/src/collections/vec_deque/into_iter.rs index 34bc0ce91..d9e274df0 100644 --- a/library/alloc/src/collections/vec_deque/into_iter.rs +++ b/library/alloc/src/collections/vec_deque/into_iter.rs @@ -1,4 +1,5 @@ use core::iter::{FusedIterator, TrustedLen}; +use core::num::NonZeroUsize; use core::{array, fmt, mem::MaybeUninit, ops::Try, ptr}; use crate::alloc::{Allocator, Global}; @@ -11,7 +12,6 @@ use super::VecDeque; /// (provided by the [`IntoIterator`] trait). See its documentation for more. /// /// [`into_iter`]: VecDeque::into_iter -/// [`IntoIterator`]: core::iter::IntoIterator #[derive(Clone)] #[stable(feature = "rust1", since = "1.0.0")] pub struct IntoIter< @@ -54,15 +54,16 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> { } #[inline] - fn advance_by(&mut self, n: usize) -> Result<(), usize> { - if self.inner.len < n { - let len = self.inner.len; + fn advance_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { + let len = self.inner.len; + let rem = if len < n { self.inner.clear(); - Err(len) + n - len } else { self.inner.drain(..n); - Ok(()) - } + 0 + }; + NonZeroUsize::new(rem).map_or(Ok(()), Err) } #[inline] @@ -182,15 +183,16 @@ impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> { } #[inline] - fn advance_back_by(&mut self, n: usize) -> Result<(), usize> { + fn advance_back_by(&mut self, n: usize) -> Result<(), NonZeroUsize> { let len = self.inner.len; - if len >= n { - self.inner.truncate(len - n); - Ok(()) - } else { + let rem = if len < n { self.inner.clear(); - Err(len) - } + n - len + } else { + self.inner.truncate(len - n); + 0 + }; + NonZeroUsize::new(rem).map_or(Ok(()), Err) } fn try_rfold<B, F, R>(&mut self, mut init: B, mut f: F) -> R |