//- loading -------------------------------------------------------------------
//read in a midi seqence from a standard midi file
public static Sequence readMidiFile(String filename)
{
MidiInStream stream = new MidiInStream(filename);
//read midi file header
String sig = stream.getString(4);
uint hdrsize = stream.getFour();
int fileFormat = stream.getTwo();
int trackCount = stream.getTwo();
int division = stream.getTwo();
if (!sig.Equals("MThd") || hdrsize != 6)
{
throw new MidiFileException(filename + " is not a valid MIDI file ", 0);
}
Sequence seq = new Sequence(division);
loadTrackZeroData(stream, seq);
//read midi track data
for (int trackNum = 1; trackNum < trackCount; trackNum++)
{
curTrackNum = trackNum;
loadTrackData(stream, seq, trackNum);
}
finalizeTracks(seq);
return(seq);
}
//read data for a single event in a track's data, convert the event's delta time to an absolute track time
private static Event loadEventData(MidiInStream stream)
{
Event evt = null;
int status = stream.getOne();
if (status < 0x80) //running status
{
stream.pushBack(1);
status = runningStatus;
}
if (status >= 0x80 && status < 0xff) //message event
{
Message msg = loadMessageData(stream, status);
runningStatus = status;
evt = new MessageEvent(msg);
}
else if (status == 0xff) //meta event
{
evt = loadMetaEventData(stream); //this may return null for unrecognized events
}
else
{
throw new MidiFileException(stream.filename + " has an invalid event at", stream.getDataPos() - 8);
}
return(evt);
}
//read data from a single track chunk
private static void loadTrackData(MidiInStream stream, Sequence seq, int trackNum)
{
//read track header
String trackSig = stream.getString(4);
uint trackDataLength = stream.getFour();
if (!trackSig.Equals("MTrk"))
{
throw new MidiFileException(stream.filename + " has an invalid track at ", stream.getDataPos() - 8);
}
Track track = seq.addTrack(); //get new track from sequence
track.setName("Track " + trackNum.ToString());
int currentTime = 0; //event time in ticks
runningStatus = 0;
sysexCont = false;
prevSysEx = null;
Event evt = null;
int startpos = stream.getDataPos();
while ((stream.getDataPos() - startpos) < trackDataLength)
{
currentTime += (int)stream.getVariableLengthVal(); //add delta time to current num of ticks
evt = loadEventData(stream);
if ((evt != null) && !(evt is EndofTrackEvent ||
evt is MarkerEvent || evt is CuePointEvent || //these are ignored in tracks other than track 0
evt is TempoEvent || evt is SMPTEOffsetEvent ||
evt is TimeSignatureEvent || evt is KeySignatureEvent))
{
track.addEvent(evt, currentTime);
}
}
//last event in track must be an "end of track" event
if ((evt != null) && !(evt is EndofTrackEvent))
{
throw new MidiFileException(stream.filename + ": track " + curTrackNum.ToString() +
"missing end of track event at ", stream.getDataPos() - 8);
}
}
//build the tempo, meter and marker maps from tempo message from track 0
private static void loadTrackZeroData(MidiInStream stream, Sequence seq)
{
//read track header
String trackSig = stream.getString(4);
uint trackDataLength = stream.getFour();
if (!trackSig.Equals("MTrk"))
{
throw new MidiFileException(stream.filename + " has an invalid track 0 at ", stream.getDataPos() - 8);
}
int currentTime = 0; //event time in ticks
runningStatus = 0;
sysexCont = false;
prevSysEx = null;
Event evt;
Meter prevMeter = null;
int startpos = stream.getDataPos();
while ((stream.getDataPos() - startpos) < trackDataLength)
{
currentTime += (int)stream.getVariableLengthVal(); //add delta time to current num of ticks
evt = loadEventData(stream);
if (evt is TempoEvent)
{
Tempo tempo = new Tempo(currentTime, ((TempoEvent)evt).tempo);
seq.tempoMap.addTempo(tempo);
}
else if (evt is SMPTEOffsetEvent) //not handling smpte timing yet
{
}
else if (evt is TimeSignatureEvent)
{
int keysig = (prevMeter != null) ? prevMeter.keysig : 0;
Meter meter = new Meter(currentTime, ((TimeSignatureEvent)evt).numer, ((TimeSignatureEvent)evt).denom, keysig);
seq.meterMap.addMeter(meter);
prevMeter = meter;
}
else if (evt is KeySignatureEvent)
{
int numer = 4;
int denom = 4;
if (prevMeter != null)
{
numer = prevMeter.numer;
denom = prevMeter.denom;
}
Meter meter = new Meter(currentTime, numer, denom, ((KeySignatureEvent)evt).keySig);
seq.meterMap.addMeter(meter);
prevMeter = meter;
}
else if (evt is MarkerEvent)
{
}
else if (evt is CuePointEvent)
{
}
}
}
//read data for known meta events & skip any we don't recognize
private static MetaEvent loadMetaEventData(MidiInStream stream)
{
MetaEvent meta = null;
int metatype = stream.getOne();
int metalen = (int)stream.getVariableLengthVal();
switch (metatype)
{
case 0x00:
if (metalen == 0)
{
meta = new SequenceNumberEvent(curTrackNum);
}
if (metalen >= 2)
{
int val = stream.getTwo();
metalen -= 2;
meta = new SequenceNumberEvent(val);
}
break;
//text events
case 0x01:
String txt = stream.getString(metalen);
metalen = 0;
meta = new TextEvent(txt);
break;
case 0x02:
String copyright = stream.getString(metalen);
metalen = 0;
meta = new CopyrightEvent(copyright);
break;
case 0x03:
String trackname = stream.getString(metalen);
metalen = 0;
meta = new TrackNameEvent(trackname);
break;
case 0x04:
String instrument = stream.getString(metalen);
metalen = 0;
meta = new InstrumentEvent(instrument);
break;
case 0x05:
String lyric = stream.getString(metalen);
metalen = 0;
meta = new LyricEvent(lyric);
break;
case 0x06:
String marker = stream.getString(metalen);
metalen = 0;
meta = new MarkerEvent(marker);
break;
case 0x07:
String cue = stream.getString(metalen);
metalen = 0;
meta = new CuePointEvent(cue);
break;
case 0x08:
String patchname = stream.getString(metalen);
metalen = 0;
meta = new PatchNameEvent(patchname);
break;
case 0x09:
String devname = stream.getString(metalen);
metalen = 0;
meta = new DeviceNameEvent(devname);
break;
//obsolete events
case 0x20:
int chanNum = stream.getOne();
metalen -= 1;
meta = new MidiChannelEvent(chanNum);
break;
case 0x21:
int portNum = stream.getOne();
metalen -= 1;
meta = new MidiPortEvent(portNum);
break;
//end of track event
case 0x2f:
meta = new EndofTrackEvent();
break;
//timing events
case 0x51:
int t1 = stream.getTwo();
int t2 = stream.getOne();
int tempo = (t1 * 256) + t2;
metalen -= 3;
meta = new TempoEvent(tempo);
break;
case 0x54:
int hr = stream.getOne();
int rr = (hr / 32) % 4;
int hh = hr % 32;
int mn = stream.getOne();
int se = stream.getOne();
int fr = stream.getOne();
int ff = stream.getOne();
metalen -= 5;
meta = new SMPTEOffsetEvent(rr, hh, mn, se, fr, ff);
break;
case 0x58:
int nn = stream.getOne();
int b1 = stream.getOne();
int dd = (int)Math.Pow(2.0, b1);
int cc = stream.getOne();
int bb = stream.getOne();
metalen -= 4;
meta = new TimeSignatureEvent(nn, dd, cc, bb);
break;
case 0x59:
int sf = stream.getOne();
int mi = stream.getOne();
metalen -= 2;
meta = new KeySignatureEvent(sf, mi);
break;
//other people's events
case 0x7f:
List <byte> propdata = stream.getRange(metalen);
metalen = 0;
meta = new ProprietaryEvent(propdata);
break;
//skip any other events
default:
break;
}
stream.skipBytes(metalen); //skip unknown events & any extra bytes at the end of known events
runningStatus = 0; //meta events cancel running status
return(meta);
}
//read data for a midi message (80 - ff), handle sysex continuation and escape sequences
private static Message loadMessageData(MidiInStream stream, int status)
{
Message msg = null;
if (status < 0xF0) //midi channel message
{
int msgtype = status / 16;
int channel = status % 16;
int b1 = stream.getOne();
int b2 = 0;
if ((msgtype != 0xC) && (msgtype != 0xD))
{
b2 = stream.getOne();
}
msg = Message.getChannelMessage(msgtype, channel, b1, b2);
}
else if (status == 0xF0) //sysex message
{
int len = stream.getOne();
List <byte> sysExData = stream.getRange(len);
sysexCont = (sysExData[sysExData.Count - 1] != 0xf7); //is the last byte of sysex data a F7?
msg = new SysExMessage(sysExData);
prevSysEx = (SysExMessage)msg;
runningStatus = 0; //sysex msg cancel running status
}
else if (status == 0xF7)
{
if (sysexCont) //sysex continuation - append this data to prev sysex message
{
int len = stream.getOne();
List <byte> contData = stream.getRange(len);
sysexCont = (contData[contData.Count - 1] != 0xf7); //is the last byte of sysex data a F7?
prevSysEx.sysExData.AddRange(contData);
}
else
{ //escape sequence
int len = stream.getOne();
List <byte> escData = stream.getRange(len);
msg = new EscapeMessage(escData);
}
runningStatus = 0;
}
else
{ //system common msgs shouldn't occur here, but if they do, we need to skip them
int b1 = 0;
int b2 = 0;
int datalen = SystemMessage.SysMsgLen[status - 0xF0] - 1;
if (datalen > 0)
{
b1 = stream.getOne();
}
if (datalen > 1)
{
b2 = stream.getOne();
b1 = ((b1 % 128) * 128) + (b2 % 128);
}
msg = new SystemMessage(status, b1);
runningStatus = 0;
}
return(msg);
}
