Trait TakeKernel

Source

pub trait TakeKernel: VTable {
    // Required method
    fn take(
        &self,
        array: &Self::Array,
        indices: &dyn Array,
    ) -> VortexResult<ArrayRef>;
}

Required Methods§

Source

fn take( &self, array: &Self::Array, indices: &dyn Array, ) -> VortexResult<ArrayRef>

Create a new array by taking the values from the array at the given indices.

§Panics

Using indices that are invalid for the given array will cause a panic.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§

Source §

impl TakeKernel for FixedSizeListVTable

Take implementation for FixedSizeListArray.

Unlike ListView, FixedSizeListArray must rebuild the elements array because it requires that elements start at offset 0 and be perfectly packed without gaps. We expand list indices into element indices and push them down to the child elements array.

Source §

impl TakeKernel for ListVTable

Take implementation for ListArray.

This implementation converts the ListArray to a ListViewArray and then delegates to its take implementation. This approach avoids the need to rebuild the elements array.

The resulting ListViewArray can represent non-contiguous and out-of-order lists, which would violate ListArray’s invariants (but not ListViewArray’s).

Source §

impl TakeKernel for ListViewVTable

ListViewArray take implementation.

This implementation is deliberately simple and read-optimized. We just take the offsets and sizes at the requested indices and reuse the original elements array. This works because ListView (unlike List) allows non-contiguous and out-of-order lists.

We don’t slice the elements array because it would require computing min/max offsets and adjusting all offsets accordingly, which is not really worth the small potential memory we would be able to get back.

The trade-off is that we may keep unreferenced elements in memory, but this is acceptable since we’re optimizing for read performance and the data isn’t being copied.

Source §