Function count_lines 

pub fn count_lines(data: &[u8]) -> u64

Check if a Unicode codepoint (>= 0x80) is printable (matching glibc iswprint). C1 control characters (U+0080-U+009F) are not printable. Count newlines using SIMD-accelerated memchr. GNU wc counts newline bytes (\n), not logical lines.