Function left_right_byte_length

datafusion/functions/src/unicode/common.rs:117–129

(string: &str, n: i64)

/// Calculate the byte length of the substring of `n` chars from string `string`
#[inline]
fn left_right_byte_length(string: &str, n: i64) -> usize {
    match n.cmp(&0) {
        Ordering::Less => string
            .char_indices()
            .nth_back((n.unsigned_abs().min(usize::MAX as u64) - 1) as usize)
            .map(|(index, _)| index)
            .unwrap_or(0),
        Ordering::Equal => 0,
        Ordering::Greater => {
            byte_offset_of_char(string, n.unsigned_abs().min(usize::MAX as u64) as usize)
        }
    }
}

/// General implementation for `left` and `right` functions
pub(crate) fn general_left_right<F: LeftRightSlicer>(