// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

use crate::ArrayData;

use crate::transform::_MutableArrayData;

use arrow_buffer::ArrowNativeType;

use num_integer::Integer;

use num_traits::CheckedAdd;

pub(super) fn build_extend<T: ArrowNativeType + Integer + CheckedAdd>(

    array: &ArrayData,

) -> crate::transform::Extend<'_> {

    let offsets = array.buffer::<T>(0);

    let sizes = array.buffer::<T>(1);

    Box::new(

        move |mutable: &mut _MutableArrayData, _index: usize, start: usize, len: usize| {

            let offset_buffer = &mut mutable.buffer1;

            let sizes_buffer = &mut mutable.buffer2;

            for &offset in &offsets[start..start + len] {

                offset_buffer.push(offset);

            }

            // sizes

            for &size in &sizes[start..start + len] {

                sizes_buffer.push(size);

            }

            // the beauty of views is that we don't need to copy child_data, we just splat

            // the offsets and sizes.

        },

    )

}

pub(super) fn extend_nulls<T: ArrowNativeType>(mutable: &mut _MutableArrayData, len: usize) {

    let offset_buffer = &mut mutable.buffer1;

    let sizes_buffer = &mut mutable.buffer2;

    // We push 0 as a placeholder for NULL values in both the offsets and sizes

    (0..len).for_each(|_| offset_buffer.push(T::default()));

    (0..len).for_each(|_| sizes_buffer.push(T::default()));

}