Function hash_primitive_values

datafusion/spark/src/function/hash/utils.rs:34–59

(
    array: &PrimitiveArray<P>,
    hashes: &mut [u64],
    transform: F,
    hash_method: H,
)

/// value into a byte slice before feeding it to `hash_method`.
#[inline]
pub(crate) fn hash_primitive_values<P, F, B, H>(
    array: &PrimitiveArray<P>,
    hashes: &mut [u64],
    transform: F,
    hash_method: H,
) where
    P: ArrowPrimitiveType,
    F: Fn(P::Native) -> B,
    B: AsRef<[u8]>,
    H: Fn(B, u64) -> u64,
{
    let values = array.values();
    if array.null_count() == 0 {
        // Fast path: no nulls, skip null checks
        for (i, hash) in hashes.iter_mut().enumerate() {
            *hash = hash_method(transform(values[i]), *hash);
        }
    } else {
        // Slow path: check each row for null
        for (i, hash) in hashes.iter_mut().enumerate() {
            if !array.is_null(i) {
                *hash = hash_method(transform(values[i]), *hash);
            }
        }
    }
}

/// Hash an array by calling `value_at(array, i)` to produce a byte slice for
/// each non-null row. Used for byte-slice arrays (Utf8/Binary/FixedSizeBinary