Function take_bits

arrow-select/src/take.rs:455–481

(
    values: &BooleanBuffer,
    indices: &PrimitiveArray<I>,
)

#[inline(never)]
fn take_bits<I: ArrowPrimitiveType>(
    values: &BooleanBuffer,
    indices: &PrimitiveArray<I>,
) -> BooleanBuffer {
    let len = indices.len();

    match indices.nulls().filter(|n| n.null_count() > 0) {
        Some(nulls) => {
            let mut output_buffer = MutableBuffer::new_null(len);
            let output_slice = output_buffer.as_slice_mut();
            nulls.valid_indices().for_each(|idx| {
                // SAFETY: idx is a valid index in indices.nulls() --> idx<indices.len()
                if values.value(unsafe { indices.value_unchecked(idx).as_usize() }) {
                    // SAFETY: MutableBuffer was created with space for indices.len() bit, and idx < indices.len()
                    unsafe { bit_util::set_bit_raw(output_slice.as_mut_ptr(), idx) };
                }
            });
            BooleanBuffer::new(output_buffer.into(), 0, len)
        }
        None => {
            BooleanBuffer::collect_bool(len, |idx: usize| {
                // SAFETY: idx<indices.len()
                values.value(unsafe { indices.value_unchecked(idx).as_usize() })
            })
        }
    }
}

/// `take` implementation for boolean arrays
fn take_boolean<IndexType: ArrowPrimitiveType>(