Function encoding_mem_check_utf16_for_latin1_and_bidi 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn encoding_mem_check_utf16_for_latin1_and_bidi(
    buffer: *const u16,
    len: usize,
) -> Latin1Bidi

Checks whether a potentially invalid UTF-16 buffer contains code points that trigger right-to-left processing or is all-Latin1.

Possibly more efficient than performing the checks separately.

Returns Latin1Bidi::Latin1 if is_utf16_latin1() would return true. Otherwise, returns Latin1Bidi::Bidi if is_utf16_bidi() would return true. Otherwise, returns Latin1Bidi::LeftToRight.

Undefined behavior

UB ensues if buffer and buffer_len don’t designate a valid memory block or if buffer is NULL. (If buffer_len is 0, buffer may be bogus but still has to be non-NULL and aligned.)