String::Multibyte::EUC_TW is used for manipulation of strings
Byte range of single-byte characters:
First and second byte range of double-byte characters:
Second byte range of four-byte characters:
Third and fourth byte range of four-byte characters:
Character order (invalid code points are excluded):
0x00..0x7F, 0xA1A1..0xFEFE, 0x8EA1A1A1..0x8EB0FEFE.