implement `Box::take` · rust-lang/rust@8dfea22 (original) (raw)

`@@ -619,6 +619,37 @@ impl<T, A: Allocator> Box<T, A> {

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`pub fn into_inner(boxed: Self) -> T {

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`*boxed

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+

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`` +

/// Consumes the Box without consuming its allocation, returning the wrapped value and a Box

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/// to the uninitialized memory where the wrapped value used to live.

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///

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`` +

/// This can be used together with write to reuse the allocation for multiple

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/// boxed values.

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///

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/// # Examples

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///

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/// ```

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/// #![feature(box_take)]

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///

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/// let c = Box::new(5);

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///

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/// // take the value out of the box

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/// let (value, uninit) = Box::take(c);

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/// assert_eq!(value, 5);

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///

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/// // reuse the box for a second value

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/// let c = Box::write(uninit, 6);

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/// assert_eq!(*c, 6);

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/// ```

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#[unstable(feature = "box_take", issue = "147212")]

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pub fn take(boxed: Self) -> (T, Box<mem::MaybeUninit, A>) {

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unsafe {

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let (raw, alloc) = Box::into_raw_with_allocator(boxed);

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let value = raw.read();

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let uninit = Box::from_raw_in(raw.cast::<mem::MaybeUninit>(), alloc);

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(value, uninit)

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}

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}

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`impl Box<[T]> {

implement Box::take · rust-lang/rust@8dfea22 (original) (raw)

implement `Box::take` · rust-lang/rust@8dfea22 (original) (raw)