arrow_data/transform/
list_view.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use crate::ArrayData;
19use crate::transform::_MutableArrayData;
20use arrow_buffer::ArrowNativeType;
21use num_integer::Integer;
22use num_traits::CheckedAdd;
23
24pub(super) fn build_extend<T: ArrowNativeType + Integer + CheckedAdd>(
25    array: &ArrayData,
26) -> crate::transform::Extend<'_> {
27    let offsets = array.buffer::<T>(0);
28    let sizes = array.buffer::<T>(1);
29    Box::new(
30        move |mutable: &mut _MutableArrayData, _index: usize, start: usize, len: usize| {
31            let offset_buffer = &mut mutable.buffer1;
32            let sizes_buffer = &mut mutable.buffer2;
33
34            for &offset in &offsets[start..start + len] {
35                offset_buffer.push(offset);
36            }
37
38            // sizes
39            for &size in &sizes[start..start + len] {
40                sizes_buffer.push(size);
41            }
42
43            // the beauty of views is that we don't need to copy child_data, we just splat
44            // the offsets and sizes.
45        },
46    )
47}
48
49pub(super) fn extend_nulls<T: ArrowNativeType>(mutable: &mut _MutableArrayData, len: usize) {
50    let offset_buffer = &mut mutable.buffer1;
51    let sizes_buffer = &mut mutable.buffer2;
52
53    // We push 0 as a placeholder for NULL values in both the offsets and sizes
54    (0..len).for_each(|_| offset_buffer.push(T::default()));
55    (0..len).for_each(|_| sizes_buffer.push(T::default()));
56}
arrow_data/transform/list_view.rs

arrow_data/transform/
list_view.rs
