Trait std::iter::TrustedLen

pub unsafe trait TrustedLen: Iterator { }

🔬 This is a nightly-only experimental API. (trusted_len #37572)

一个使用 size_hint 报告准确长度的迭代器。

迭代器报告一个大小提示，该提示要么是精确的 (下限等于上限)，要么上限是 None。

如果实际的迭代器长度大于 usize::MAX，则上限必须仅为 None。 在这种情况下，下限必须为 usize::MAX，从而导致 Iterator::size_hint() 为 (usize::MAX, None)。

迭代器必须精确地生成它所报告或发散的元素数量，然后才能结束。

Safety

只有在遵守契约的情况下才能实现 trait。 trait 的使用者必须检查 [Iterator::size_hint () ] 的上限。

Implementors

impl<'_> TrustedLen for Bytes<'_>

impl<'_, A> TrustedLen for std::option::Iter<'_, A>

impl<'_, A> TrustedLen for std::option::IterMut<'_, A>

impl<'_, A> TrustedLen for std::result::Iter<'_, A>

impl<'_, A> TrustedLen for std::result::IterMut<'_, A>

impl<'_, I> TrustedLen for &'_ mut I where
    I: TrustedLen + ?Sized, 

impl<'_, T> TrustedLen for DrainSorted<'_, T> where
    T: Ord, 

impl<'_, T> TrustedLen for std::collections::vec_deque::Iter<'_, T>

impl<'_, T> TrustedLen for std::collections::vec_deque::IterMut<'_, T>

impl<'_, T> TrustedLen for Chunks<'_, T>

impl<'_, T> TrustedLen for ChunksExact<'_, T>

impl<'_, T> TrustedLen for ChunksExactMut<'_, T>

impl<'_, T> TrustedLen for ChunksMut<'_, T>

impl<'_, T> TrustedLen for std::slice::Iter<'_, T>

impl<'_, T> TrustedLen for std::slice::IterMut<'_, T>

impl<'_, T> TrustedLen for RChunks<'_, T>

impl<'_, T> TrustedLen for RChunksExact<'_, T>

impl<'_, T> TrustedLen for RChunksExactMut<'_, T>

impl<'_, T> TrustedLen for RChunksMut<'_, T>

impl<'_, T> TrustedLen for Windows<'_, T>

impl<'_, T, A> TrustedLen for Drain<'_, T, A> where
    A: Allocator, 

impl<'_, T, const N: usize> TrustedLen for ArrayChunks<'_, T, N>

impl<'_, T, const N: usize> TrustedLen for ArrayChunksMut<'_, T, N>

impl<'a, I, T> TrustedLen for Cloned<I> where
    T: 'a + Clone,
    I: TrustedLen<Item = &'a T>, 

impl<'a, I, T> TrustedLen for Copied<I> where
    T: 'a + Copy,
    I: TrustedLen<Item = &'a T>, 

impl<'a, T, I, F, const N: usize> TrustedLen for FlatMap<I, &'a [T; N], F> where
    F: FnMut(<I as Iterator>::Item) -> &'a [T; N],
    I: TrustedLen, 

impl<'a, T, I, F, const N: usize> TrustedLen for FlatMap<I, &'a mut [T; N], F> where
    F: FnMut(<I as Iterator>::Item) -> &'a mut [T; N],
    I: TrustedLen, 

impl<A> TrustedLen for Range<A> where
    A: TrustedStep, 

impl<A> TrustedLen for RangeFrom<A> where
    A: TrustedStep, 

impl<A> TrustedLen for RangeInclusive<A> where
    A: TrustedStep, 

impl<A> TrustedLen for std::option::IntoIter<A>

impl<A> TrustedLen for std::result::IntoIter<A>

impl<A> TrustedLen for Repeat<A> where
    A: Clone, 

impl<A, B> TrustedLen for Chain<A, B> where
    B: TrustedLen<Item = <A as Iterator>::Item>,
    A: TrustedLen, 

impl<A, B> TrustedLen for Zip<A, B> where
    B: TrustedLen,
    A: TrustedLen, 

impl<A, F> TrustedLen for OnceWith<F> where
    F: FnOnce() -> A, 

impl<A, F> TrustedLen for RepeatWith<F> where
    F: FnMut() -> A, 

impl<B, I, F> TrustedLen for Map<I, F> where
    F: FnMut(<I as Iterator>::Item) -> B,
    I: TrustedLen, 

impl<I> TrustedLen for Enumerate<I> where
    I: TrustedLen, 

impl<I> TrustedLen for Flatten<I> where
    I: TrustedLen,
    <I as Iterator>::Item: TrustedConstSize, 

impl<I> TrustedLen for Fuse<I> where
    I: TrustedLen, 

impl<I> TrustedLen for Peekable<I> where
    I: TrustedLen, 

impl<I> TrustedLen for Rev<I> where
    I: TrustedLen + DoubleEndedIterator, 

impl<I> TrustedLen for Take<I> where
    I: TrustedLen, 

impl<T> TrustedLen for IntoIterSorted<T> where
    T: Ord, 

impl<T> TrustedLen for std::collections::vec_deque::IntoIter<T>

impl<T> TrustedLen for Empty<T>

impl<T> TrustedLen for Once<T>

impl<T, A> TrustedLen for std::vec::IntoIter<T, A> where
    A: Allocator, 

impl<T, I, F, const N: usize> TrustedLen for FlatMap<I, [T; N], F> where
    F: FnMut(<I as Iterator>::Item) -> [T; N],
    I: TrustedLen, 

impl<T, const N: usize> TrustedLen for std::array::IntoIter<T, N>