RTF was invented long before Unicode. It most certainly isn't ANSI text, RTF only uses ASCII, it uses a rather unholy mix of character sets with non-ASCII characters encoded in hex with a reference to the character set. The mapping is also not perfect, many Unicode codepoints have no corresponding charset.

You'll spend a lifetime creating your own RTF to Unicode converter. Take advantage of an existing solution, most any platform has one. On Windows that would be the RichEdit control. If you use .NET then it is especially simple, use the Ri...