/// <summary>
/// Constructs a MidiEvent from a BinaryStream
/// </summary>
/// <param name="br">The binary stream of MIDI data</param>
/// <param name="previous">The previous MIDI event (pass null for first event)</param>
/// <returns>A new MidiEvent</returns>
public static MidiEvent ReadNextEvent(BinaryReader br, MidiEvent previous)
{
int deltaTime = MidiEvent.ReadVarInt(br);
MidiCommandCode commandCode;
int channel = 1;
byte b = br.ReadByte();
if ((b & 0x80) == 0)
{
// a running command - command & channel are same as previous
commandCode = previous.CommandCode;
channel = previous.Channel;
br.BaseStream.Position--; // need to push this back
}
else
{
if ((b & 0xF0) == 0xF0)
{
// both bytes are used for command code in this case
commandCode = (MidiCommandCode)b;
}
else
{
commandCode = (MidiCommandCode)(b & 0xF0);
channel = (b & 0x0F) + 1;
}
}
MidiEvent me;
switch (commandCode)
{
case MidiCommandCode.NoteOn:
me = new NoteOnEvent(br);
break;
case MidiCommandCode.NoteOff:
case MidiCommandCode.KeyAfterTouch:
me = new NoteEvent(br);
break;
case MidiCommandCode.ControlChange:
me = new ControlChangeEvent(br);
break;
case MidiCommandCode.PatchChange:
me = new PatchChangeEvent(br);
break;
case MidiCommandCode.ChannelAfterTouch:
me = new ChannelAfterTouchEvent(br);
break;
case MidiCommandCode.PitchWheelChange:
me = new PitchWheelChangeEvent(br);
break;
case MidiCommandCode.TimingClock:
case MidiCommandCode.StartSequence:
case MidiCommandCode.ContinueSequence:
case MidiCommandCode.StopSequence:
me = new MidiEvent();
break;
case MidiCommandCode.Sysex:
me = SysexEvent.ReadSysexEvent(br);
break;
case MidiCommandCode.MetaEvent:
me = MetaEvent.ReadMetaEvent(br);
break;
default:
throw new FormatException(String.Format("Unsupported MIDI Command Code {0:X2}", (byte)commandCode));
}
me.channel = channel;
me.deltaTime = deltaTime;
me.commandCode = commandCode;
return(me);
}
