The Python2.5's codecs.StreamReaderWriter combines StreamReader and StreamWriter. The wrapper will read narrow str strings from the underlying stream and decode them to unicode strings. On writing unicode data to the wrapper, it will encode them to narrow str strings.
The user of the wrapper should specify character sets by supplying class definitions for the respective stream reader and writer.
The codecs module defines a function codecs.open(name, encoding) that returns an instance of StreamReaderWriter configured with the supplied encoding.