// Start the port and setup buffers to receives Sysex
public string Start()
{
// Allocate buffer array
if (buffers == null)
{
const int numBuffers = 4;
const int bufferSize = 4096; // ZZZ Param?
buffers = new MidiBuffer[numBuffers];
// Allocate and prepare the buffers
for (int b = 0; b < buffers.Length; b++)
{
// Create buffer
buffers[b] = new MidiBuffer(bufferSize, (IntPtr)b);
// Prepare the buffer and give it to windows
EMMError st = buffers[b].AddMidiInBuffer(handle);
if (st != EMMError.NOERROR)
{
return(WindowsUtil.StrError(st));
}
}
}
// Finally, start the port
return(WindowsUtil.StrError(NativeMethods.midiInStart(handle)));
}
// Send a message
public string Send(MidiMessage m)
{
var st = EMMError.NOERROR;
if (m is MidiSysexMessage)
{
// Sysex messages are sent using a buffer.
var sysex = m as MidiSysexMessage;
var buffer = new MidiBuffer(sysex.Body);
using (buffer)
{
// Prepare the buffer
st = buffer.PrepareForMidiOut(handle);
if (st == EMMError.NOERROR)
{
// Send the sysex
st = NativeMethods.midiOutLongMsg(handle, buffer.Header, buffer.HeaderSize);
}
if (st == EMMError.NOERROR)
{
// Wait until it is sent
// Note: this is simple but weak... If performance becomes necessary
// we can declare a callback, not wait here (just queue the buffer) and
// unprepare it when we receive the appropriate message in the callback
while (!buffer.IsFree())
{
Thread.Sleep(1);
}
// unprepare the buffer
st = buffer.UnprepareForMidiOut(handle);
}
}
}
else
{
uint sm = m.GetAsShortMessage();
if (sm != uint.MaxValue)
{
st = NativeMethods.midiOutShortMsg(handle, sm);
}
}
return(WindowsUtil.StrError(st));
}
// Forward callback to user-provided function
private void MidiProc(IntPtr hMidiIn,
EMMMidiMessages wMsg,
IntPtr dwInstance,
IntPtr dwParam1,
IntPtr dwParam2)
{
if (wMsg == EMMMidiMessages.MIM_DATA)
{
if (MidiInputReceived != null)
{
// Make a midi event out of the incoming params
MidiEvent e = MidiInParser.ParseMimDataMessage((uint)dwParam1, (uint)dwParam2);
// Give it to the user
MidiInputReceived.Invoke(this, new WindowsMidiEventArgs(e, dwParam1, dwParam2));
}
}
else if (wMsg == EMMMidiMessages.MIMLONG_DATA)
{
// The first parameter is a pointer to a buffer descriptor
var header = dwParam1;
// Find this buffer in our buffer set
int index = (int)MidiBuffer.GetUserData(header);
if (index < 0 || index >= buffers.Length)
{
throw new InvalidOperationException("midiInputPort: MIMLONG_DATA buffer not found - index " + index);
}
var buffer = buffers[index];
if (buffer != null)
{
// Get data from buffer
var data = buffer.GetRecordedData();
if (data.Length == 0)
{
// This happens on Reset(), all the buffers are freed by windows and we get a MIMLONG_DATA for each of them.
// Free the buffer.
buffer.RemoveMidiInBuffer(handle);
buffer.Dispose();
buffers[index] = null;
}
else
{
// Give the buffer back to windows, we are done with it
buffer.AddMidiInBuffer(handle);
// If we have a callback, either generate a sysex or
// memorize the data if we don't have a full sysex
if (MidiInputReceived != null)
{
MidiSysexMessage sysex = null;
if (data[0] == (byte)EMidiCommand.SystemExclusive)
{
// This buffer contains the beginning of the sysex - check we don't have an ongoing sysex
if (this.partialSysex != null)
{
throw new InvalidOperationException("midiInputPort: Beginning of new sysex received while previous one still on-going");
}
if (data[data.Length - 1] == (byte)EMidiCommand.EndOfSystemExclusive)
{
// This buffer contains a full sysex
sysex = new MidiSysexMessage(data);
}
else
{
// This buffer contains the beginning of a sysex
this.partialSysex = data;
}
}
else
{
// This buffer is a continuation of a sysex. Verify we have an ongoing sysex
if (this.partialSysex == null)
{
throw new InvalidOperationException("midiInputPort: Continuation sysex without beginning");
}
// Concatenate the partial data and the new data
var dataSoFar = new byte[partialSysex.Length + data.Length];
partialSysex.CopyTo(dataSoFar, 0);
data.CopyTo(dataSoFar, dataSoFar.Length);
if (data[data.Length - 1] == (byte)EMidiCommand.EndOfSystemExclusive)
{
// This buffer concludes the sysex
sysex = new MidiSysexMessage(dataSoFar);
this.partialSysex = null;
}
else
{
// This buffer contains a partial sysex, add it to the partial sysex
this.partialSysex = dataSoFar;
}
}
// Create sysex event if we have a sysex
if (sysex != null)
{
// Make a midi event out of the sysex
var e = new MidiEvent(sysex, (uint)dwParam2);
// Give it to the user
MidiInputReceived.Invoke(this, new WindowsMidiEventArgs(e, dwParam1, dwParam2));
}
}
}
}
}
}
