/// <summary>
/// Loads a MIDI file from the stream.
/// </summary>
/// <param name="stream">The data stream used to load the MIDI file.</param>
/// <param name="loopType">The type of the loop extension to be used.</param>
public MidiFile(Stream stream, MidiFileLoopType loopType)
{
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
Load(stream, 0, loopType);
}
/// <summary>
/// Loads a MIDI file from the file.
/// </summary>
/// <param name="path">The MIDI file name and path.</param>
/// <param name="loopType">The type of the loop extension to be used.</param>
public MidiFile(string path, MidiFileLoopType loopType)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
using (var stream = new FileStream(path, FileMode.Open, FileAccess.Read))
{
Load(stream, 0, loopType);
}
}
public static Message Common(byte status, byte data1, byte data2, MidiFileLoopType loopType)
{
byte channel = (byte)(status & 0x0F);
byte command = (byte)(status & 0xF0);
if (command == 0xB0)
{
switch (loopType)
{
case MidiFileLoopType.RpgMaker:
if (data1 == 111)
{
return(LoopStart());
}
break;
case MidiFileLoopType.IncredibleMachine:
if (data1 == 110)
{
return(LoopStart());
}
if (data1 == 111)
{
return(LoopEnd());
}
break;
case MidiFileLoopType.FinalFantasy:
if (data1 == 116)
{
return(LoopStart());
}
if (data1 == 117)
{
return(LoopEnd());
}
break;
}
}
return(new Message(channel, command, data1, data2));
}
private static void ReadTrack(BinaryReader reader, MidiFileLoopType loopType, out List <Message> messages, out List <int> ticks)
{
var chunkType = reader.ReadFourCC();
if (chunkType != "MTrk")
{
throw new InvalidDataException($"The chunk type must be 'MTrk', but was '{chunkType}'.");
}
reader.ReadInt32BigEndian();
messages = new List <Message>();
ticks = new List <int>();
int tick = 0;
byte lastStatus = 0;
while (true)
{
var delta = reader.ReadIntVariableLength();
var first = reader.ReadByte();
try
{
tick = checked (tick + delta);
}
catch (OverflowException)
{
throw new NotSupportedException("Long MIDI file is not supported.");
}
if ((first & 128) == 0)
{
var command = lastStatus & 0xF0;
if (command == 0xC0 || command == 0xD0)
{
messages.Add(Message.Common(lastStatus, first));
ticks.Add(tick);
}
else
{
var data2 = reader.ReadByte();
messages.Add(Message.Common(lastStatus, first, data2, loopType));
ticks.Add(tick);
}
continue;
}
switch (first)
{
case 0xF0: // System Exclusive
DiscardData(reader);
break;
case 0xF7: // System Exclusive
DiscardData(reader);
break;
case 0xFF: // Meta Event
switch (reader.ReadByte())
{
case 0x2F: // End of Track
reader.ReadByte();
messages.Add(Message.EndOfTrack());
ticks.Add(tick);
return;
case 0x51: // Tempo
messages.Add(Message.TempoChange(ReadTempo(reader)));
ticks.Add(tick);
break;
default:
DiscardData(reader);
break;
}
break;
default:
var command = first & 0xF0;
if (command == 0xC0 || command == 0xD0)
{
var data1 = reader.ReadByte();
messages.Add(Message.Common(first, data1));
ticks.Add(tick);
}
else
{
var data1 = reader.ReadByte();
var data2 = reader.ReadByte();
messages.Add(Message.Common(first, data1, data2, loopType));
ticks.Add(tick);
}
break;
}
lastStatus = first;
}
}
private void Load(Stream stream, int loopPoint, MidiFileLoopType loopType)
{
using (var reader = new BinaryReader(stream, Encoding.ASCII, true))
{
var chunkType = reader.ReadFourCC();
if (chunkType != "MThd")
{
throw new InvalidDataException($"The chunk type must be 'MThd', but was '{chunkType}'.");
}
var size = reader.ReadInt32BigEndian();
if (size != 6)
{
throw new InvalidDataException($"The MThd chunk has invalid data.");
}
var format = reader.ReadInt16BigEndian();
if (!(format == 0 || format == 1))
{
throw new NotSupportedException($"The format {format} is not supported.");
}
trackCount = reader.ReadInt16BigEndian();
resolution = reader.ReadInt16BigEndian();
var messageLists = new List <Message> [trackCount];
var tickLists = new List <int> [trackCount];
for (var i = 0; i < trackCount; i++)
{
List <Message> messageList;
List <int> tickList;
ReadTrack(reader, loopType, out messageList, out tickList);
messageLists[i] = messageList;
tickLists[i] = tickList;
}
if (loopPoint != 0)
{
var tickList = tickLists[0];
var messageList = messageLists[0];
if (loopPoint <= tickList.Last())
{
for (var i = 0; i < tickList.Count; i++)
{
if (tickList[i] >= loopPoint)
{
tickList.Insert(i, loopPoint);
messageList.Insert(i, Message.LoopStart());
break;
}
}
}
else
{
tickList.Add(loopPoint);
messageList.Add(Message.LoopStart());
}
}
MergeTracks(messageLists, tickLists, resolution, out messages, out times);
}
}
