CESU-8

The Compatibility Encoding Scheme for UTF-16: 8-Bit (CESU-8) is a variant of

to UTF-8 converter to UTF-16 data.

The encoding of Unicode non-BMP characters works out to 11101101 1010yyyy 10xxxxxx 11101101 1011xxxx 10xxxxxx (yyyy represents the top five bits of the character minus one). The byte values 0xF0—0xF4 will not appear in CESU-8, as they start the 4-byte encodings used by UTF-8.

CESU-8 is not an official part of the Unicode Standard, because Unicode Technical Reports are informative documents only.^[2] It should be used exclusively for internal processing and never for external data exchange.

Supporting CESU-8 in

Java's Modified UTF-8 is CESU-8 with a special overlong encoding of the NUL character (U+0000) as the two-byte sequence C0 80.^[7]

The

" (since Oracle version 9.0).

Examples

Code point	U+0045	U+0205		U+10400
Character	E	ȅ		𐐀
UTF-8	45	C8	85	F0			90			90			80
UTF-16	0045	0205		D801						DC00
CESU-8	45	C8	85	ED		A0		81		ED		B0		80

References

External links

• Unicode Technical Report #26
• Modified UTF-8 definition
• Graphical View of CESU-8 in ICU's Converter Explorer