Function concat_elements_string_view_array

arrow-string/src/concat_elements.rs:271–304

Concatenates two `StringViewArray`s element-wise. If either element is `Null`, the result element is also `Null`. # Errors - Returns an error if the input arrays have different lengths. - Returns an error if any concatenated value exceeds `u32::MAX` in length. - Returns an error if concatenated strings do not result in a proper UTF-8 string Cannot reuse code with `GenericByteViewBuilder` since `t

(
    left: &StringViewArray,
    right: &StringViewArray,
)

// Cannot reuse code with `GenericByteViewBuilder` since `try_append_value` works with
// `AsRef<T::Native>`, and there is no conversion from `ByteViewType` to this or [u8]
pub fn concat_elements_string_view_array(
    left: &StringViewArray,
    right: &StringViewArray,
) -> Result<StringViewArray, ArrowError> {
    if left.len() != right.len() {
        return Err(ArrowError::ComputeError(format!(
            "Arrays must have the same length: {} != {}",
            left.len(),
            right.len()
        )));
    }

    let mut result = StringViewBuilder::with_capacity(left.len());

    // Avoid reallocations by writing to a reused buffer
    let mut buffer: Vec<u8> = Vec::new();

    let nulls = NullBuffer::union(left.nulls(), right.nulls());

    for i in 0..left.len() {
        if nulls.as_ref().is_some_and(|n| n.is_null(i)) {
            result.append_null();
        } else {
            buffer.clear();
            buffer.extend_from_slice(left.value(i).as_bytes());
            buffer.extend_from_slice(right.value(i).as_bytes());
            let s = std::str::from_utf8(&buffer).map_err(|_| {
                ArrowError::ComputeError("Concatenated values are not valid UTF-8".into())
            })?;
            result.try_append_value(s)?;
        }
    }
    Ok(result.finish())
}

/// Returns the elementwise concatenation of [`Array`]s.
///