Function initcap_string

datafusion/functions/src/unicode/initcap.rs:275–301

(input: &str, container: &mut String)

}

fn initcap_string(input: &str, container: &mut String) {
    container.clear();
    let mut prev_is_alphanumeric = false;

    if input.is_ascii() {
        container.reserve(input.len());
        // SAFETY: each byte is ASCII, so the result is valid UTF-8.
        let out = unsafe { container.as_mut_vec() };
        for &b in input.as_bytes() {
            if prev_is_alphanumeric {
                out.push(b.to_ascii_lowercase());
            } else {
                out.push(b.to_ascii_uppercase());
            }
            prev_is_alphanumeric = b.is_ascii_alphanumeric();
        }
    } else {
        for c in input.chars() {
            if prev_is_alphanumeric {
                container.extend(c.to_lowercase());
            } else {
                container.extend(c.to_uppercase());
            }
            prev_is_alphanumeric = c.is_alphanumeric();
        }
    }
}

#[cfg(test)]
mod tests {