class MidiOutStreamBase:





    """



    MidiOutStreamBase is Basically an eventhandler. It is the most central

    class in the Midi library. You use it both for writing events to

    an output stream, and as an event handler for an input stream.



    This makes it extremely easy to take input from one stream and

    send it to another. Ie. if you want to read a Midi file, do some

    processing, and send it to a midiport.



    All time values are in absolute values from the opening of a

    stream. To calculate time values, please use the MidiTime and

    MidiDeltaTime classes.



    """



    def __init__(self):

        

        # the time is rather global, so it needs to be stored 

        # here. Otherwise there would be no really simple way to 

        # calculate it. The alternative would be to have each event 

        # handler do it. That sucks even worse!

        self._absolute_time = 0

        self._relative_time = 0

        self._current_track = 0



    # time handling event handlers. They should overwritten with care



    def update_time(self, new_time=0, relative=1):

        """

        Updates the time, if relative is true, new_time is relative, 

        else it's absolute.

        """

        if relative:

            self._relative_time = new_time

            self._absolute_time += new_time

        else:

            self._absolute_time = new_time

            self._relative_time = new_time - self._absolute_time



    def rel_time(self):

        "Returns the relative time"

        return self._relative_time



    def abs_time(self):

        "Returns the absolute time"

        return self._absolute_time



    # track handling event handlers

    

    def set_current_track(self, new_track):

        "Sets the current track number"

        self._current_track = new_track

    

    def get_current_track(self):

        "Returns the current track number"

        return self._current_track

    

    

    #####################

    ## Midi events





    def channel_message(self, message_type, channel, data):

        """The default event handler for channel messages"""

        pass





    #####################

    ## Common events



    def system_exclusive(self, data):



        """The default event handler for system_exclusive messages"""

        pass





    def system_common(self, common_type, common_data):



        """The default event handler for system common messages"""

        pass





    #########################

    # header does not really belong here. But anyhoo!!!

    

    def header(self, format, nTracks, division):



        """

        format: type of midi file in [1,2]

        nTracks: number of tracks

        division: timing division

        """

        pass





    def start_of_track(self, n_track=0):



        """

        n_track: number of track

        """

        pass





    def eof(self):



        """

        End of file. No more events to be processed.

        """

        pass





    #####################

    ## meta events





    def meta_event(self, meta_type, data, time):

        

        """The default event handler for meta_events"""

        pass









if __name__ == '__main__':



    midiOut = MidiOutStreamBase()

    midiOut.update_time(0,0)

    midiOut.note_on(0, 63, 127)

    midiOut.note_off(0, 63, 127)