Trait PackedValue

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pub unsafe trait PackedValue:
    'static
    + Copy
    + Send
    + Sync {
    type Value: Packable;

    const WIDTH: usize;
Show 18 methods
    // Required methods
    fn from_fn<F>(f: F) -> Self
       where F: FnMut(usize) -> Self::Value;
    fn from_slice(slice: &[Self::Value]) -> &Self;
    fn from_slice_mut(slice: &mut [Self::Value]) -> &mut Self;
    fn as_slice(&self) -> &[Self::Value];
    fn as_slice_mut(&mut self) -> &mut [Self::Value];

    // Provided methods
    fn broadcast(value: Self::Value) -> Self { ... }
    fn extract(&self, lane: usize) -> Self::Value { ... }
    fn pack_slice(buf: &[Self::Value]) -> &[Self] { ... }
    fn pack_slice_mut(buf: &mut [Self::Value]) -> &mut [Self] { ... }
    fn pack_maybe_uninit_slice_mut(
        buf: &mut [MaybeUninit<Self::Value>],
    ) -> &mut [MaybeUninit<Self>] { ... }
    fn pack_slice_with_suffix(buf: &[Self::Value]) -> (&[Self], &[Self::Value]) { ... }
    fn pack_slice_with_suffix_mut(
        buf: &mut [Self::Value],
    ) -> (&mut [Self], &mut [Self::Value]) { ... }
    fn pack_maybe_uninit_slice_with_suffix_mut(
        buf: &mut [MaybeUninit<Self::Value>],
    ) -> (&mut [MaybeUninit<Self>], &mut [MaybeUninit<Self::Value>]) { ... }
    fn unpack_slice(buf: &[Self]) -> &[Self::Value] { ... }
    fn pack_columns<const N: usize>(rows: &[[Self::Value; N]]) -> [Self; N] { ... }
    fn pack_columns_fn<const N: usize>(
        row_fn: impl Fn(usize) -> [Self::Value; N],
    ) -> [Self; N] { ... }
    fn unpack_into<const N: usize>(
        packed: &[Self; N],
        rows: &mut [[Self::Value; N]],
    ) { ... }
    fn unpack_iter<const N: usize>(
        packed: [Self; N],
    ) -> impl Iterator<Item = [Self::Value; N]> { ... }
}

Expand description

A trait for array-like structs made up of multiple scalar elements.

§Safety

If P implements PackedField then P must be castable to/from [P::Value; P::WIDTH] without UB.

Required Associated Constants§

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const WIDTH: usize

Number of scalar values packed together.

Required Associated Types§

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type Value: Packable

The scalar type that is packed into this value.

Required Methods§

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fn from_fn<F>(f: F) -> Self
where F: FnMut(usize) -> Self::Value,

Constructs a packed value using a function to generate each element.

Similar to core::array::from_fn.

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fn from_slice(slice: &[Self::Value]) -> &Self

Interprets a slice of scalar values as a packed value reference.

§Panics:

This function will panic if slice.len() != Self::WIDTH

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fn from_slice_mut(slice: &mut [Self::Value]) -> &mut Self

Interprets a mutable slice of scalar values as a mutable packed value.

§Panics:

This function will panic if slice.len() != Self::WIDTH

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fn as_slice(&self) -> &[Self::Value]

Returns the underlying scalar values as an immutable slice.

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fn as_slice_mut(&mut self) -> &mut [Self::Value]

Returns the underlying scalar values as a mutable slice.

Provided Methods§

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fn broadcast(value: Self::Value) -> Self

Create a packed value with all lanes set to the same scalar value.

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fn extract(&self, lane: usize) -> Self::Value

Extract the scalar value at the given SIMD lane.

This is equivalent to self.as_slice()[lane] but more explicit about the SIMD extraction semantics.

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fn pack_slice(buf: &[Self::Value]) -> &[Self]

Packs a slice of scalar values into a slice of packed values.

§Panics

Panics if the slice length is not divisible by WIDTH.

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fn pack_slice_mut(buf: &mut [Self::Value]) -> &mut [Self]

Converts a mutable slice of scalar values into a mutable slice of packed values.

§Panics

Panics if the slice length is not divisible by WIDTH.

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fn pack_maybe_uninit_slice_mut( buf: &mut [MaybeUninit<Self::Value>], ) -> &mut [MaybeUninit<Self>]

Converts a mutable slice of possibly uninitialized scalar values into a mutable slice of possibly uninitialized packed values.

§Panics

Panics if the slice length is not divisible by WIDTH.

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fn pack_slice_with_suffix(buf: &[Self::Value]) -> (&[Self], &[Self::Value])

Packs a slice into packed values and returns the packed portion and any remaining suffix.

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fn pack_slice_with_suffix_mut( buf: &mut [Self::Value], ) -> (&mut [Self], &mut [Self::Value])

Converts a mutable slice of scalar values into a pair:

a slice of packed values covering the largest aligned portion,
and a remainder slice of scalar values that couldn’t be packed.

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fn pack_maybe_uninit_slice_with_suffix_mut( buf: &mut [MaybeUninit<Self::Value>], ) -> (&mut [MaybeUninit<Self>], &mut [MaybeUninit<Self::Value>])

Converts a mutable slice of possibly uninitialized scalar values into a pair:

a slice of possibly uninitialized packed values covering the largest aligned portion,
and a remainder slice of possibly uninitialized scalar values that couldn’t be packed.

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fn unpack_slice(buf: &[Self]) -> &[Self::Value]

Reinterprets a slice of packed values as a flat slice of scalar values.

Each packed value contains Self::WIDTH scalar values, which are laid out contiguously in memory. This function allows direct access to those scalars.

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fn pack_columns<const N: usize>(rows: &[[Self::Value; N]]) -> [Self; N]

Pack columns from WIDTH rows of scalar values into N packed values.

Given WIDTH rows of N scalar values, extract each column and pack it into a single packed value. This is the inverse of unpack_into.

§Panics

Panics if rows.len() != WIDTH.

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fn pack_columns_fn<const N: usize>( row_fn: impl Fn(usize) -> [Self::Value; N], ) -> [Self; N]

Pack columns using a closure that provides each row’s data.

Calls row_fn(lane) for each lane 0..WIDTH to get [Self::Value; N], then transposes columns into packed values. Useful when rows aren’t contiguous in memory (e.g., strided access).

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