Function primitive_array_min_max

datafusion/functions-nested/src/min_max.rs:245–283

Computes min or max for each row of a primitive ListArray.

(
    list_array: &GenericListArray<O>,
    is_min: bool,
)

/// Computes min or max for each row of a primitive ListArray.
fn primitive_array_min_max<O: OffsetSizeTrait, T: ArrowPrimitiveType>(
    list_array: &GenericListArray<O>,
    is_min: bool,
) -> Result<ArrayRef> {
    let values_array = list_array.values().as_primitive::<T>();
    let values_slice = values_array.values();
    let values_nulls = values_array.nulls();
    let mut result_builder = PrimitiveBuilder::<T>::with_capacity(list_array.len())
        .with_data_type(values_array.data_type().clone());

    for (row, w) in list_array.offsets().windows(2).enumerate() {
        let row_result = if list_array.is_null(row) {
            None
        } else {
            let start = w[0].as_usize();
            let end = w[1].as_usize();
            let len = end - start;

            match len {
                0 => None,
                _ if len < ARROW_COMPUTE_THRESHOLD => {
                    scalar_min_max::<T>(values_slice, values_nulls, start, end, is_min)
                }
                _ => {
                    let slice = values_array.slice(start, len);
                    if is_min {
                        arrow::compute::min::<T>(&slice)
                    } else {
                        arrow::compute::max::<T>(&slice)
                    }
                }
            }
        };

        result_builder.append_option(row_result);
    }

    Ok(Arc::new(result_builder.finish()) as ArrayRef)
}

/// Computes min or max for a single list row by directly scanning a slice of
/// the flat values buffer.