Arduino MIDI in handling

gistfile1.txt

byte currentData[3];
byte currentCommand = 0;
byte commandChannel = 0;

byte currentNote = 255;

short length = 0;

bool midiFlicker = false;

void updateMidi()
{
    digitalWrite(PIN_LED_RED, midiFlicker ? LOW : HIGH );
    while (Serial.available() > 0)
    {
        midiFlicker = !midiFlicker;
        byte midiByte = Serial.read();
        // Command byte?
        if (midiByte & 0x80)
        {
            currentCommand = midiByte & 0xF0; 
            commandChannel = midiByte & 0x0F;                  
            length = 0;
        }
        else
        {
            // Data byte
            if (length < 3)
            {
                currentData[length++] = midiByte;
            }

            switch (currentCommand)
            {
                case 0x80:  // note off
                    if (length == 2)
                    {
                        noteOff(currentData[0],currentData[1]);
                        length = 0;                        
                    }
                    break;

                case 0x90:
                    if (length == 2)
                    {
                          noteOn(currentData[0],currentData[1]);
                          currentNote = currentData[0];
                          length = 0;
                    }
                    break;

                case 0xC0:
                    if (length == 1)
                    {
                        programChange(currentData[0]);
                        length =0;
                    }
                    break;
            }
        }
    }
}


void noteOn( byte note, byte velocity )
{
    // ... do something with the note on 
}

void noteOff( byte note, byte velocity )
{
    // ... do something with the note off
}

void programChange( byte prog )
{
    // ... do something with the program change
}