51 pub fn decode_utf8(src: &[u8]) -> Option<(char, usize)> {  in decode_utf8()  function
135     match decode_utf8(&src[start..]) {  in decode_last_utf8()
153         decode_last_utf8, decode_utf8, TAG_CONT, TAG_FOUR, TAG_THREE, TAG_TWO,
161             let (got_cp, got_len) = decode_utf8(&tmp[..encoded_len]).unwrap();  in prop_roundtrip()
195             let (got_cp, _) = decode_utf8(&tmp[..n]).unwrap();  in prop_decode_matches_std()
223         assert_eq!(decode_utf8(&[0xFF]), None);  in reject_invalid()
225         assert_eq!(decode_utf8(&[0xED, 0xA0, 0x81]), None);  in reject_invalid()
227         assert_eq!(decode_utf8(&[0xD4, 0xC2]), None);  in reject_invalid()
229         assert_eq!(decode_utf8(&[0xC3]), None); // 2 bytes  in reject_invalid()
230         assert_eq!(decode_utf8(&[0xEF, 0xBF]), None); // 3 bytes  in reject_invalid()
231         assert_eq!(decode_utf8(&[0xF4, 0x8F, 0xBF]), None); // 4 bytes  in reject_invalid()
233         assert_eq!(decode_utf8(&[TAG_TWO, TAG_CONT | b'a']), None);  in reject_invalid()
234         assert_eq!(decode_utf8(&[TAG_THREE, TAG_CONT, TAG_CONT | b'a']), None);  in reject_invalid()
236             decode_utf8(&[TAG_FOUR, TAG_CONT, TAG_CONT, TAG_CONT | b'a',]),  in reject_invalid()