arrow-data 60.0.0

// 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::data::ArrayData;
use arrow_schema::{DataType, UnionFields, UnionMode};

use super::equal_range;

#[expect(clippy::too_many_arguments)]
fn equal_dense(
    lhs: &ArrayData,
    rhs: &ArrayData,
    lhs_type_ids: &[i8],
    rhs_type_ids: &[i8],
    lhs_offsets: &[i32],
    rhs_offsets: &[i32],
    lhs_fields: &UnionFields,
    rhs_fields: &UnionFields,
) -> bool {
    let offsets = lhs_offsets.iter().zip(rhs_offsets.iter());

    lhs_type_ids
        .iter()
        .zip(rhs_type_ids.iter())
        .zip(offsets)
        .all(|((l_type_id, r_type_id), (l_offset, r_offset))| {
            let lhs_child_index = lhs_fields
                .iter()
                .position(|(r, _)| r == *l_type_id)
                .unwrap();
            let rhs_child_index = rhs_fields
                .iter()
                .position(|(r, _)| r == *r_type_id)
                .unwrap();
            let lhs_values = &lhs.child_data()[lhs_child_index];
            let rhs_values = &rhs.child_data()[rhs_child_index];

            equal_range(
                lhs_values,
                rhs_values,
                *l_offset as usize,
                *r_offset as usize,
                1,
            )
        })
}

/// Compares `type_ids.len()` slots of two sparse unions whose type ids over that
/// range are already known to be equal.
///
/// Only the child selected by each slot's type id contributes to the logical
/// value of a sparse union; the values held by the other children at that slot
/// are arbitrary and must not affect equality. Consecutive slots that select the
/// same child are compared as a single range of that child.
fn equal_sparse(
    lhs: &ArrayData,
    rhs: &ArrayData,
    type_ids: &[i8],
    fields: &UnionFields,
    lhs_start: usize,
    rhs_start: usize,
) -> bool {
    let mut run_start = 0;
    type_ids.chunk_by(|a, b| a == b).all(|run| {
        let start = run_start;
        run_start += run.len();

        // Both sides share the same `UnionFields` (checked when comparing the
        // data types), so the type id maps to the same child index on each side.
        let child_index = fields.iter().position(|(id, _)| id == run[0]).unwrap();
        equal_range(
            &lhs.child_data()[child_index],
            &rhs.child_data()[child_index],
            lhs_start + lhs.offset() + start,
            rhs_start + rhs.offset() + start,
            run.len(),
        )
    })
}

pub(super) fn union_equal(
    lhs: &ArrayData,
    rhs: &ArrayData,
    lhs_start: usize,
    rhs_start: usize,
    len: usize,
) -> bool {
    let lhs_type_ids = lhs.buffer::<i8>(0);
    let rhs_type_ids = rhs.buffer::<i8>(0);

    let lhs_type_id_range = &lhs_type_ids[lhs_start..lhs_start + len];
    let rhs_type_id_range = &rhs_type_ids[rhs_start..rhs_start + len];

    match (lhs.data_type(), rhs.data_type()) {
        (
            DataType::Union(lhs_fields, UnionMode::Dense),
            DataType::Union(rhs_fields, UnionMode::Dense),
        ) => {
            let lhs_offsets = lhs.buffer::<i32>(1);
            let rhs_offsets = rhs.buffer::<i32>(1);

            let lhs_offsets_range = &lhs_offsets[lhs_start..lhs_start + len];
            let rhs_offsets_range = &rhs_offsets[rhs_start..rhs_start + len];

            lhs_type_id_range == rhs_type_id_range
                && equal_dense(
                    lhs,
                    rhs,
                    lhs_type_id_range,
                    rhs_type_id_range,
                    lhs_offsets_range,
                    rhs_offsets_range,
                    lhs_fields,
                    rhs_fields,
                )
        }
        (DataType::Union(fields, UnionMode::Sparse), DataType::Union(_, UnionMode::Sparse)) => {
            lhs_type_id_range == rhs_type_id_range
                && equal_sparse(lhs, rhs, lhs_type_id_range, fields, lhs_start, rhs_start)
        }
        _ => unimplemented!(
            "Logical equality not yet implemented between dense and sparse union arrays"
        ),
    }
}