vortex_array/arrays/listview/vtable/
operations.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use std::ops::Range;
5use std::sync::Arc;
6
7use vortex_scalar::Scalar;
8
9use crate::arrays::{ListViewArray, ListViewVTable};
10use crate::vtable::{OperationsVTable, ValidityHelper};
11use crate::{ArrayRef, IntoArray};
12
13impl OperationsVTable<ListViewVTable> for ListViewVTable {
14    fn slice(array: &ListViewArray, range: Range<usize>) -> ArrayRef {
15        let start = range.start;
16        let end = range.end;
17
18        // We implement slice by simply slicing the views. We leave the child `elements` array alone
19        // since slicing could potentially require calculating which elements are referenced by the
20        // new set of views.
21
22        // SAFETY: The preconditions of `slice` mean that the bounds have already been checked, and
23        // slicing the components of an existing valid array is still valid.
24        // Additionally, slicing elements of a `ListViewArray` that is already zero-copyable to a
25        // `ListArray` does not reorder or create gaps and overlaps, slicing maintains whatever
26        // `is_zero_copy_to_list` flag it already had.
27        unsafe {
28            ListViewArray::new_unchecked(
29                array.elements().clone(),
30                array.offsets().slice(start..end),
31                array.sizes().slice(start..end),
32                array.validity().slice(start..end),
33            )
34            .with_zero_copy_to_list(array.is_zero_copy_to_list())
35        }
36        .into_array()
37    }
38
39    fn scalar_at(array: &ListViewArray, index: usize) -> Scalar {
40        // By the preconditions we know that the list scalar is not null.
41        let list = array.list_elements_at(index);
42        let children: Vec<Scalar> = (0..list.len()).map(|i| list.scalar_at(i)).collect();
43
44        Scalar::list(
45            Arc::new(list.dtype().clone()),
46            children,
47            array.dtype.nullability(),
48        )
49    }
50}
vortex_array/arrays/listview/vtable/operations.rs

vortex_array/arrays/listview/vtable/
operations.rs
