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// 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::data::{contains_nulls, ArrayData};

use arrow_schema::DataType;

use super::equal_range;

pub(super) fn fixed_list_equal(

    lhs: &ArrayData,

    rhs: &ArrayData,

    lhs_start: usize,

    rhs_start: usize,

    len: usize,

) -> bool {

    let size = match lhs.data_type() {

        DataType::FixedSizeList(_, i) => *i as usize,

        _ => unreachable!(),

    };

    let lhs_values = &lhs.child_data()[0];

    let rhs_values = &rhs.child_data()[0];

    // Only checking one null mask here because by the time the control flow reaches

    // this point, the equality of the two masks would have already been verified.

    if !contains_nulls(lhs.nulls(), lhs_start, len) {

        equal_range(

            lhs_values,

            rhs_values,

            (lhs_start + lhs.offset()) * size,

            (rhs_start + rhs.offset()) * size,

            size * len,

        )

    } else {

        // get a ref of the null buffer bytes, to use in testing for nullness

        let lhs_nulls = lhs.nulls().unwrap();

        let rhs_nulls = rhs.nulls().unwrap();

        // with nulls, we need to compare item by item whenever it is not null

        (0..len).all(|i| {

            let lhs_pos = lhs_start + i;

            let rhs_pos = rhs_start + i;

            let lhs_is_null = lhs_nulls.is_null(lhs_pos);

            let rhs_is_null = rhs_nulls.is_null(rhs_pos);

            lhs_is_null

                || (lhs_is_null == rhs_is_null)

                    && equal_range(

                        lhs_values,

                        rhs_values,

                        (lhs_pos + lhs.offset()) * size,

                        (rhs_pos + rhs.offset()) * size,

                        size, // 1 * size since we are comparing a single entry

                    )

        })

    }

}