private static MidiTrack ParseMidiTrack(MidiFileFormatReader mffr, uint trackNumber)
{
uint time = 0;
uint runningStatus = 0;
MidiTrack result = new MidiTrack();
//
// Verify magic number
//
string marker = mffr.ReadString(4);
if (marker != MidiFileFormat.midiTrackMarker)
{
throw new FormatException(string.Format("Invalid track marker for file {0}, expected {1} found {2}", mffr.Filename, MidiFileFormat.midiTrackMarker, marker));
}
//
// Get the length of the track (bytes)
//
uint length = mffr.ReadUInt32();
//
// Read all the events in the track
//
for (mffr.ResetBytesRead(); mffr.BytesRead < length;)
{
// Parse event
MidiEvent midiEvent = ParseMidiEvent(mffr, trackNumber, time, runningStatus);
// Adjust time
time = midiEvent.TrackTime;
// Running status
runningStatus = midiEvent.Message.RunningStatus;
// Add to list
result.EventList.AddLast(midiEvent);
}
return(result);
}
static private MidiMetaMessage ParseMidiMetaMessage(MidiFileFormatReader mffr)
{
MidiMetaMessage result = null;
// Get message type
EMetaEventType type = (EMetaEventType)mffr.ReadUInt8();
// Get body length
uint length = mffr.ReadVarLengthQuantity();
switch (type)
{
case EMetaEventType.TrackSequenceNumber:
result = new MidiMetaTrackSequenceNumberMessage(mffr.ReadUInt16());
break;
case EMetaEventType.TextEvent:
case EMetaEventType.Copyright:
case EMetaEventType.SequenceTrackName:
case EMetaEventType.TrackInstrumentName:
case EMetaEventType.Lyric:
case EMetaEventType.Marker:
case EMetaEventType.CuePoint:
case EMetaEventType.ProgramName:
case EMetaEventType.DeviceName:
case EMetaEventType.MidiChannel:
result = new MidiMetaTextMessage(type, mffr.ReadString(length));
break;
case EMetaEventType.MidiPort:
result = new MidiMetaMidiPortMessage(mffr.ReadUInt8());
break;
case EMetaEventType.EndTrack:
// No extra data for the end of track message
result = new MidiMetaMessage(type);
break;
case EMetaEventType.SetTempo:
result = new MidiMetaTempoMessage(mffr.ReadUInt24());
break;
case EMetaEventType.SmpteOffset:
break;
case EMetaEventType.TimeSignature:
result = new MidiMetaTimeSignatureMessage(mffr.ReadUInt8(), mffr.ReadUInt8(), mffr.ReadUInt8(), mffr.ReadUInt8());
break;
case EMetaEventType.KeySignature:
result = new MidiMetaKeySignatureMessage(mffr.ReadUInt8(), (mffr.ReadUInt8() != 0));
break;
case EMetaEventType.SequencerSpecific:
// Read body
byte[] body = new byte[length];
for (int i = 0; i < length; i++)
{
body[i] = mffr.ReadUInt8();
}
result = new MidiMetaMessage(type, body);
break;
default:
throw new FormatException(string.Format("Found unknown or unsupported metaevent code {0}", type));
}
return(result);
}
public static MidiSequence ParseMidiFile(string filename)
{
MidiFileFormatReader mffr = new MidiFileFormatReader(filename);
using (mffr)
{
//
// Verify magic number
//
string marker = mffr.ReadString(4);
if (marker != MidiFileFormat.midiFileMarker)
{
throw new FormatException(string.Format("Invalid marker for file {0}, expected {1} found {2}", filename, MidiFileFormat.midiFileMarker, marker));
}
// Verify header size
uint headerLength = mffr.ReadUInt32();
if (headerLength != MidiFileFormat.midiFileHeaderLength)
{
throw new FormatException(string.Format("Invalid header length for file {0}, expected {1} found {2}", filename, MidiFileFormat.midiFileHeaderLength, headerLength));
}
//
// Parse header
//
//
// The 6 next bytes are 16-bits values, defining
// the format, #tracks, and ppqn
//
uint midiVersion = mffr.ReadUInt16(); // Midi version (0, 1, 2)
uint numberOfTracks = mffr.ReadUInt16(); // Number of tracks
uint resolution = mffr.ReadUInt16(); // PPQN
uint ppqn = 0;
uint smpteTempo = 0;
//
// ppqn: Pulse per quarter note: The number of tics
// per quarter notes. The length of a tic is the
// tempo (length of a quarter note) divided by ppqn.
//
//
// if ppqn is < 0, then it is NOT a ppqn, it is a
// tempo in SMTPE format (??)
//
if (0 != (resolution & 0x8000))
{
ppqn = 0;
smpteTempo = resolution & 0x7FFF;
}
else
{
ppqn = resolution;
smpteTempo = 0;
}
//
// Create the midi sequence
//
MidiSequence result = new MidiSequence(midiVersion, ppqn, smpteTempo, filename);
//
// Create and parse the tracks
//
for (uint t = 0; t < numberOfTracks; t++)
{
result.Tracks.Add(ParseMidiTrack(mffr, t));
}
// Return the sequence
return(result);
}
}
