I am checking out my UTF-8 validation rules to see if they are correct.
Check each character to be a valid UTF-8 initial character.
\x00 to \x7f or \xC2 to \xF4
Allow invalid forms such as \xC0 & \xC1 to decode but consider them invalid.
A first byte of \xE0 or \xF0 with a second byte less than \xA0 is also an
invalid form.
\xED followed by anything >= \xA0 is an encoded surrogate and not a valid
character.
\xEF\xBF\xBE and \xEF\xBF\xBF are invalid Unicode characters.
Anything greater than \xF4\x80\xBF\xBF is beyond the Unicode range.
All UTF-8 characters must be followed by the proper number of valid
continuation characters, if any.
Carl
