document some new functions

include/FLAC/seekable_stream_decoder.h

@@ -684,7 +684,17 @@ FLAC_API FLAC__SeekableStreamDecoderState FLAC__seekable_stream_decoder_get_stat
  */
 FLAC_API FLAC__StreamDecoderState FLAC__seekable_stream_decoder_get_stream_decoder_state(const FLAC__SeekableStreamDecoder *decoder);
 
-/*@@@@ document */
+/** Get the current decoder state as a C string.
+ *  This version automatically resolves
+ *  \c FLAC__SEEKABLE_STREAM_DECODER_STREAM_DECODER_ERROR by getting the
+ *  stream decoder's state.
+ *
+ * \param  decoder  A decoder instance to query.
+ * \assert
+ *    \code decoder != NULL \endcode
+ * \retval const char *
+ *    The decoder state as a C string.  Do not modify the contents.
+ */
 FLAC_API const char *FLAC__seekable_stream_decoder_get_resolved_state_string(const FLAC__SeekableStreamDecoder *decoder);
 
 /** Get the "MD5 signature checking" flag.
@@ -756,7 +766,21 @@ FLAC_API unsigned FLAC__seekable_stream_decoder_get_sample_rate(const FLAC__Seek
  */
 FLAC_API unsigned FLAC__seekable_stream_decoder_get_blocksize(const FLAC__SeekableStreamDecoder *decoder);
 
-/*@@@@ document */
+/** Returns the decoder's current read position within the stream.
+ *  The position is the byte offset from the start of the stream.
+ *  Bytes before this position have been fully decoded.  Note that
+ *  there may still be undecoded bytes in the decoder's read FIFO.
+ *  The returned position is correct even after a seek.
+ *
+ * \param  decoder   A decoder instance to query.
+ * \param  position  Address at which to return the desired position.
+ * \assert
+ *    \code decoder != NULL \endcode
+ *    \code position != NULL \endcode
+ * \retval FLAC__bool
+ *    \c true if successful, \c false if there was an error from
+ *    the 'tell' callback.
+ */
 FLAC_API FLAC__bool FLAC__seekable_stream_decoder_get_decode_position(const FLAC__SeekableStreamDecoder *decoder, FLAC__uint64 *position);
 
 /** Initialize the decoder instance.