Seeking converter function to transform COMPOUND_TEXT into local encoding or UTF8 and back

[Sebastien]

Where can I find a converter function or library which supports the
following string conversions:
- COMPOUND_TEXT to local encoding (defined by $LANG)
- local encoding (defined by $LANG) to COMPOUND_TEXT
- COMPOUND_TEXT to UTF8
- UTF8 to COMPOUND_TEXT

Any pointers/urls very welcome!

-- sebastien