private void readTrack(DataInputStream dataInputStream, Track track)
throws InvalidMidiDataException, IOException {
// search for a "MTrk" chunk
while (true) {
int nMagic = dataInputStream.readInt();
if (nMagic == MidiConstants.TRACK_MAGIC) {
break;
}
int nChunkLength = dataInputStream.readInt();
if (nChunkLength % 2 != 0) {
nChunkLength++;
}
dataInputStream.skip(nChunkLength);
}
int nTrackChunkLength = dataInputStream.readInt();
long lTicks = 0;
long[] alRemainingBytes = new long[1];
alRemainingBytes[0] = nTrackChunkLength;
int[] anRunningStatusByte = new int[1];
// indicates no running status in effect
anRunningStatusByte[0] = -1;
while (alRemainingBytes[0] > 0) {
long lDeltaTicks = readVariableLengthQuantity(dataInputStream, alRemainingBytes);
// TDebug.out("delta ticks: " + lDeltaTicks);
lTicks += lDeltaTicks;
MidiEvent event = readEvent(dataInputStream, alRemainingBytes, anRunningStatusByte, lTicks);
track.add(event);
}
}
public MidiFileFormat getMidiFileFormat(InputStream inputStream)
throws InvalidMidiDataException, IOException {
DataInputStream dataInputStream = new DataInputStream(inputStream);
int nHeaderMagic = dataInputStream.readInt();
if (nHeaderMagic != MidiConstants.HEADER_MAGIC) {
throw new InvalidMidiDataException("not a MIDI file: wrong header magic");
}
int nHeaderLength = dataInputStream.readInt();
if (nHeaderLength < 6) {
throw new InvalidMidiDataException("corrupt MIDI file: wrong header length");
}
int nType = dataInputStream.readShort();
if (nType < 0 || nType > 2) {
throw new InvalidMidiDataException("corrupt MIDI file: illegal type");
}
if (nType == 2) {
throw new InvalidMidiDataException("this implementation doesn't support type 2 MIDI files");
}
int nNumTracks = dataInputStream.readShort();
if (nNumTracks <= 0) {
throw new InvalidMidiDataException("corrupt MIDI file: number of tracks must be positive");
}
if (nType == 0 && nNumTracks != 1) {
throw new InvalidMidiDataException(
"corrupt MIDI file: type 0 files must contain exactely one track");
}
int nDivision = dataInputStream.readUnsignedShort();
float fDivisionType = -1.0F;
int nResolution = -1;
if ((nDivision & 0x8000) != 0) // frame division
{
int nFrameType = -((nDivision >>> 8) & 0xFF);
switch (nFrameType) {
case 24:
fDivisionType = Sequence.SMPTE_24;
break;
case 25:
fDivisionType = Sequence.SMPTE_25;
break;
case 29:
fDivisionType = Sequence.SMPTE_30DROP;
break;
case 30:
fDivisionType = Sequence.SMPTE_30;
break;
default:
throw new InvalidMidiDataException("corrupt MIDI file: illegal frame division type");
}
nResolution = nDivision & 0xff;
} else // BPM division
{
fDivisionType = Sequence.PPQ;
nResolution = nDivision & 0x7fff;
}
// skip additional bytes in the header
dataInputStream.skip(nHeaderLength - 6);
MidiFileFormat midiFileFormat =
new TMidiFileFormat(
nType,
fDivisionType,
nResolution,
MidiFileFormat.UNKNOWN_LENGTH,
MidiFileFormat.UNKNOWN_LENGTH,
nNumTracks);
return midiFileFormat;
}