bluss
9fc6737e1b
We have a recommendation from the unsafe-wg (no rule yet), that repr(C) for unions should work this way, so that we can cast from the union type to one of its fields.
44 lines
960 B
Rust
44 lines
960 B
Rust
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use array::Array;
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#[derive(Copy, Clone)]
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#[repr(C)] // for cast from self ptr to value
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pub union MaybeUninitCopy<T>
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where T: Copy
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{
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empty: (),
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value: T,
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}
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impl<T> MaybeUninitCopy<T>
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where T: Copy
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{
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/// Create a new MaybeUninit with uninitialized interior
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pub unsafe fn uninitialized() -> Self {
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Self { empty: () }
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}
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/// Create a new MaybeUninit from the value `v`.
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pub fn from(value: T) -> Self {
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Self { value }
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}
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// Raw pointer casts written so that we don't reference or access the
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// uninitialized interior value
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/// Return a raw pointer to the start of the interior array
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pub fn ptr(&self) -> *const T::Item
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where T: Array
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{
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self as *const _ as *const T::Item
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}
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/// Return a mut raw pointer to the start of the interior array
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pub fn ptr_mut(&mut self) -> *mut T::Item
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where T: Array
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{
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self as *mut _ as *mut T::Item
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}
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}
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