Function wchar_to_utf8_count

crates/vm/src/stdlib/_io.rs:6985–7019

Find how many UTF-8 bytes correspond to n wide chars.

(data: &[u8], mut len: usize, mut n: u32)

    /// Find how many UTF-8 bytes correspond to n wide chars.
    fn wchar_to_utf8_count(data: &[u8], mut len: usize, mut n: u32) -> usize {
        let mut start: usize = 0;
        loop {
            let mut mid = 0;
            for i in (len / 2)..=len {
                mid = find_last_utf8_boundary(data, i);
                if mid != 0 {
                    break;
                }
            }
            if mid == len {
                return start + len;
            }
            if mid == 0 {
                mid = if len > 1 { len - 1 } else { 1 };
            }
            let wlen = unsafe {
                MultiByteToWideChar(
                    CP_UTF8,
                    0,
                    data[start..].as_ptr(),
                    mid as i32,
                    core::ptr::null_mut(),
                    0,
                )
            } as u32;
            if wlen <= n {
                start += mid;
                len -= mid;
                n -= wlen;
            } else {
                len = mid;
            }
        }
    }

    impl Destructor for WindowsConsoleIO {
        fn slot_del(zelf: &PyObject, vm: &VirtualMachine) -> PyResult<()> {