/// <summary>
/// Stretches or compresses the MIDI sequence events
/// </summary>
/// <remarks>If <paramref name="adjustTempo"/> is false this will change the playback speed of the MIDI</remarks>
/// <param name="diff">The differential for the size. 1 is the same length, .5 would be half the length and 2 would be twice the length</param>
/// <param name="adjustTempo">Indicates whether or not the tempo should be adjusted to compensate</param>
/// <returns>A new MIDI sequence that is stretched the specified amount</returns>
public MidiSequence Stretch(double diff, bool adjustTempo = false)
{
var result = new MidiSequence();
if (!adjustTempo)
{
foreach (var e in Events)
{
result.Events.Add(new MidiEvent((int)Math.Round(e.Position * diff, MidpointRounding.AwayFromZero), e.Message));
}
}
else
{
byte runningStatus = 0;
foreach (var e in Events)
{
if (0 != e.Message.Status)
{
runningStatus = e.Message.Status;
}
var m = e.Message;
if (-1 == m.PayloadLength)
{
if (0xFF == runningStatus)
{
var mbs = m as MidiMessageMeta;
if (0x51 == mbs.Data1)
{
var mt = 0;
if (BitConverter.IsLittleEndian)
{
mt = (mbs.Data[0] << 16) | (mbs.Data[1] << 8) | mbs.Data[2];
}
else
{
mt = (mbs.Data[2] << 16) | (mbs.Data[1] << 8) | mbs.Data[0];
}
mt = (int)Math.Round(mt / diff, MidpointRounding.AwayFromZero);
var buf = new byte[3];
if (BitConverter.IsLittleEndian)
{
buf[0] = unchecked ((byte)((mt >> 16) & 0xFF));
buf[1] = unchecked ((byte)((mt >> 8) & 0xFF));
buf[2] = unchecked ((byte)((mt) & 0xFF));
}
else
{
buf[0] = unchecked ((byte)((mt) & 0xFF));
buf[1] = unchecked ((byte)((mt >> 8) & 0xFF));
buf[2] = unchecked ((byte)((mt >> 16) & 0xFF));
}
m = new MidiMessageMeta(mbs.Status, mbs.Data1, buf);
}
}
}
result.Events.Add(new MidiEvent((int)Math.Round(e.Position * diff, MidpointRounding.AwayFromZero), m));
}
}
return(result);
}
internal static MidiSequence ReadFrom(Stream stream)
{
MidiSequence result = new MidiSequence();
var rs = (byte)0;
var delta = _ReadVarlen(stream);
if (BitConverter.IsLittleEndian)
{
delta = _Swap(delta);
}
var i = stream.ReadByte();
while (-1 != i)
{
var hasStatus = false;
var b = (byte)i;
if (0x7F < b)
{
hasStatus = true;
rs = b;
i = stream.ReadByte();
if (-1 != i)
{
b = (byte)i;
}
else
{
b = 0;
}
}
var st = hasStatus ? rs : (byte)0;
var m = (MidiMessage)null;
switch (rs & 0xF0)
{
case 0x80:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageNoteOff(b, (byte)stream.ReadByte(), unchecked ((byte)(st & 0x0F)));
break;
case 0x90:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageNoteOn(b, (byte)stream.ReadByte(), unchecked ((byte)(st & 0x0F)));
break;
case 0xA0:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageKeyPressure(b, (byte)stream.ReadByte(), unchecked ((byte)(st & 0x0F)));
break;
case 0xB0:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageCC(b, (byte)stream.ReadByte(), unchecked ((byte)(st & 0x0F)));
break;
case 0xC0:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessagePatchChange(b, unchecked ((byte)(st & 0x0F)));
break;
case 0xD0:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageChannelPressure(b, unchecked ((byte)(st & 0x0F)));
break;
case 0xE0:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageChannelPitch(b, (byte)stream.ReadByte(), unchecked ((byte)(st & 0x0F)));
break;
case 0xF0:
switch (rs & 0xF)
{
case 0xF:
if (i == -1)
{
throw new EndOfStreamException();
}
var l = _ReadVarlen(stream);
//if (BitConverter.IsLittleEndian)
// l = _Swap(l);
var ba = new byte[l];
if (l != stream.Read(ba, 0, ba.Length))
{
throw new EndOfStreamException();
}
m = new MidiMessageMeta(st, b, ba);
break;
case 0x0:
case 0x7:
if (i == -1)
{
throw new EndOfStreamException();
}
l = _ReadVarlen(b, stream);
//if (BitConverter.IsLittleEndian)
// l = _Swap(l);
ba = new byte[l];
if (l != stream.Read(ba, 0, ba.Length))
{
throw new EndOfStreamException();
}
m = new MidiMessageSysex(st, ba);
break;
case 0x2:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageWord(st, b, (byte)stream.ReadByte());
break;
case 0x3:
if (i == -1)
{
throw new EndOfStreamException();
}
m = new MidiMessageByte(st, b);
break;
case 0x6:
case 0x8:
case 0xA:
case 0xB:
case 0xC:
// status *was* specified if we got here
m = new MidiMessage(st);
break;
default:
throw new NotSupportedException("The MIDI message is not recognized.");
}
break;
}
result.Events.Add(new MidiEvent(delta, m));
i = _ReadVarlen(stream);
if (-1 == i)
{
break;
}
delta = i;
i = stream.ReadByte();
}
return(result);
}
