code: public int backpatchHeader(long FileOffset, RiffChunkHeader data)
  	{
  		if (file == null)
  		{
  			return DDC_INVALID_CALL;
  		}
  		try
  		{
  			file.seek(FileOffset);
  		}
  		catch (IOException ioe)
  		{
  			return DDC_FILE_ERROR;
  		}
  		return writeHeader_internally(data);
  	}
docs: Write Data to specified offset.