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C# MIDI Toolkit

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18 Apr 2007MIT18 min read 3.1M   41.7K   303  
A toolkit for creating MIDI applications with C#.
#region License

/* Copyright (c) 2006 Leslie Sanford
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy 
 * of this software and associated documentation files (the "Software"), to 
 * deal in the Software without restriction, including without limitation the 
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
 * sell copies of the Software, and to permit persons to whom the Software is 
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in 
 * all copies or substantial portions of the Software. 
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
 * THE SOFTWARE.
 */

#endregion

#region Contact

/*
 * Leslie Sanford
 * Email: jabberdabber@hotmail.com
 */

#endregion

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.InteropServices;
using Multimedia;

namespace Multimedia.Midi
{
    public class OutputStream : OutputDeviceBase
    {
        [DllImport("winmm.dll")]
        private static extern int midiStreamOpen(ref int handle, ref int deviceID, int reserved,
            OutputDevice.MidiOutProc proc, int instance, uint flag);

        [DllImport("winmm.dll")]
        private static extern int midiStreamClose(int handle);

        [DllImport("winmm.dll")]
        private static extern int midiStreamOut(int handle, IntPtr headerPtr, int sizeOfMidiHeader);

        [DllImport("winmm.dll")]
        private static extern int midiStreamPause(int handle);

        [DllImport("winmm.dll")]
        private static extern int midiStreamPosition(int handle, ref Time t, int sizeOfTime);

        [DllImport("winmm.dll")]
        private static extern int midiStreamProperty(int handle, ref Property p, uint flags);

        [DllImport("winmm.dll")]
        private static extern int midiStreamRestart(int handle);

        [DllImport("winmm.dll")]
        private static extern int midiStreamStop(int handle);

        [StructLayout(LayoutKind.Sequential)]
        private struct Property
        {
            public int sizeOfProperty;
            public int property;
        }

        private const uint MIDIPROP_SET = 0x80000000;
        private const uint MIDIPROP_GET = 0x40000000;
        private const uint MIDIPROP_TIMEDIV = 0x00000001;
        private const uint MIDIPROP_TEMPO = 0x00000002;

        private const byte MEVT_CALLBACK = 0x40;

        private const byte MEVT_SHORTMSG = 0x00;
        private const byte MEVT_TEMPO = 0x01;
        private const byte MEVT_NOP = 0x02;
        private const byte MEVT_LONGMSG = 0x80;
        private const byte MEVT_COMMENT = 0x82;
        private const byte MEVT_VERSION = 0x84;

        private const int MOM_POSITIONCB = 0x3CA;

        private const int SizeOfMidiEvent = 12;

        private const int EventTypeIndex = 11;

        private const int EventCodeOffset = 8;

        private MidiOutProc midiOutProc;

        private int offsetTicks = 0;

        private byte[] streamID = new byte[4];

        private List<byte> events = new List<byte>();

        private MidiHeaderBuilder headerBuilder = new MidiHeaderBuilder();

        public event EventHandler<NoOpEventArgs> NoOpOccurred;

        public OutputStream(int deviceID)
        {
            midiOutProc = HandleMessage;

            int result = midiStreamOpen(ref hndle, ref deviceID, 1, midiOutProc, 0, CALLBACK_FUNCTION);

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                throw new OutputDeviceException(result);
            }
        }

        protected override void Dispose(bool disposing)
        {
            if(disposing)
            {
                int result = midiStreamClose(Handle);

                if(result != DeviceException.MMSYSERR_NOERROR)
                {
                    throw new OutputDeviceException(result);
                }
            }
            else
            {
                if(!IsDisposed)
                {
                    midiStreamClose(Handle);
                }
            }

            base.Dispose(disposing);
        }       

        public override void Close()
        {
            #region Guard

            if(!IsDisposed)
            {
                return;
            }

            #endregion

            Dispose();
        }

        public void StartPlaying()
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            int result = midiStreamRestart(Handle);

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                throw new OutputDeviceException(result);
            }
        }

        public void PausePlaying()
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            int result = midiStreamPause(Handle);

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                throw new OutputDeviceException(result);
            }
        }

        public void StopPlaying()
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            int result = midiStreamStop(Handle);

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                throw new OutputDeviceException(result);
            }
        }

        public override void Reset()
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            offsetTicks = 0;
            events.Clear();

            base.Reset();
        }

        public void Write(MidiEvent e)
        {
            switch(e.MidiMessage.MessageType)
            {
                case MessageType.Channel:
                case MessageType.SystemCommon:
                case MessageType.SystemRealtime:
                    Write(e.DeltaTicks, (ShortMessage)e.MidiMessage);
                    break;

                case MessageType.SystemExclusive:
                    Write(e.DeltaTicks, (SysExMessage)e.MidiMessage);
                    break;

                case MessageType.Meta:
                    Write(e.DeltaTicks, (MetaMessage)e.MidiMessage);
                    break;
            }
        }

        private void Write(int deltaTicks, ShortMessage message)
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            // Delta time.
            events.AddRange(BitConverter.GetBytes(deltaTicks + offsetTicks));

            // Stream ID.
            events.AddRange(streamID);

            // Event code.
            byte[] eventCode = message.GetBytes();
            eventCode[eventCode.Length - 1] = MEVT_SHORTMSG;            
            events.AddRange(eventCode);            

            offsetTicks = 0;
        }

        private void Write(int deltaTicks, SysExMessage message)
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            // Delta time.
            events.AddRange(BitConverter.GetBytes(deltaTicks + offsetTicks));

            // Stream ID.
            events.AddRange(streamID);

            // Event code.
            byte[] eventCode = BitConverter.GetBytes(message.Length);
            eventCode[eventCode.Length - 1] = MEVT_LONGMSG;
            events.AddRange(eventCode);

            byte[] sysExData;

            if(message.Length % 4 != 0)
            {
                sysExData = new byte[message.Length + (message.Length % 4)];
                message.GetBytes().CopyTo(sysExData, 0);
            }
            else
            {
                sysExData = message.GetBytes();
            }

            // SysEx data.
            events.AddRange(sysExData);

            offsetTicks = 0;
        }

        private void Write(int deltaTicks, MetaMessage message)
        {
            if(message.MetaType == MetaType.Tempo)
            {
                // Delta time.
                events.AddRange(BitConverter.GetBytes(deltaTicks + offsetTicks));

                // Stream ID.
                events.AddRange(streamID);

                TempoChangeBuilder builder = new TempoChangeBuilder(message);

                byte[] t = BitConverter.GetBytes(builder.Tempo);

                t[t.Length - 1] = MEVT_SHORTMSG | MEVT_TEMPO;

                // Event code.
                events.AddRange(t);

                offsetTicks = 0;
            }
            else
            {
                offsetTicks += deltaTicks;
            }
        }

        public void WriteNoOp(int deltaTicks, int data)
        {
            // Delta time.
            events.AddRange(BitConverter.GetBytes(deltaTicks + offsetTicks));

            // Stream ID.
            events.AddRange(streamID);

            // Event code.
            byte[] eventCode = BitConverter.GetBytes(data);
            eventCode[eventCode.Length - 1] = (byte)(MEVT_NOP | MEVT_CALLBACK);
            events.AddRange(eventCode);

            offsetTicks = 0;            
        }

        public void Flush()
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            headerBuilder.InitializeBuffer(events);
            headerBuilder.Build();

            events.Clear();

            int result = midiOutPrepareHeader(Handle, headerBuilder.Result, SizeOfMidiHeader);

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                headerBuilder.Destroy();

                throw new OutputDeviceException(result);
            }

            result = midiStreamOut(Handle, headerBuilder.Result, SizeOfMidiHeader);

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                midiOutUnprepareHeader(Handle, headerBuilder.Result, SizeOfMidiHeader);

                headerBuilder.Destroy();

                throw new OutputDeviceException(result);
            }
        }

        public Time GetTime(TimeType type)
        {
            #region Require

            if(IsDisposed)
            {
                throw new ObjectDisposedException("OutputStream");
            }

            #endregion

            Time t = new Time();

            t.type = (int)type;

            int result = midiStreamPosition(Handle, ref t, Marshal.SizeOf(typeof(Time)));

            if(result != DeviceException.MMSYSERR_NOERROR)
            {
                throw new OutputDeviceException(result);
            }

            return t;
        }

        protected virtual void OnNoOpOccurred(NoOpEventArgs e)
        {
            EventHandler<NoOpEventArgs> handler = NoOpOccurred;

            if(handler != null)
            {
                handler(this, e);
            }
        }

        protected override void HandleMessage(int handle, int msg, int instance, int param1, int param2)
        {
            if(msg == MOM_POSITIONCB)
            {
                IntPtr headerPtr = new IntPtr(param1);
                MidiHeader header = (MidiHeader)Marshal.PtrToStructure(headerPtr, typeof(MidiHeader));

                byte[] midiEvent = new byte[SizeOfMidiEvent];

                for(int i = 0; i < midiEvent.Length; i++)
                {
                    midiEvent[i] = Marshal.ReadByte(header.data, header.offset + i);
                }

                // If this is a NoOp event.
                if((midiEvent[EventTypeIndex] & MEVT_NOP) == MEVT_NOP)
                {
                    // Clear the event type byte.
                    midiEvent[EventTypeIndex] = 0;

                    NoOpEventArgs e = new NoOpEventArgs(BitConverter.ToInt32(midiEvent, EventCodeOffset));

                    if(SynchronizingObject != null)
                    {
                        SynchronizingObject.BeginInvoke(
                            new GenericDelegate<NoOpEventArgs>(OnNoOpOccurred),
                            new object[] { e });
                    }
                    else
                    {
                        OnNoOpOccurred(e);
                    }
                }
            }
            else
            {
                base.HandleMessage(handle, msg, instance, param1, param2);
            }
        }

        public int Division
        {
            get
            {
                #region Require

                if(IsDisposed)
                {
                    throw new ObjectDisposedException("OutputStream");
                }

                #endregion

                Property d = new Property();

                d.sizeOfProperty = Marshal.SizeOf(typeof(Property));

                int result = midiStreamProperty(Handle, ref d, MIDIPROP_GET | MIDIPROP_TIMEDIV);

                if(result != DeviceException.MMSYSERR_NOERROR)
                {
                    throw new OutputDeviceException(result);
                }

                return d.property;
            }
            set
            {
                #region Require

                if(IsDisposed)
                {
                    throw new ObjectDisposedException("OutputStream");
                }
                else if((value % PpqnClock.PpqnMinValue) != 0)
                {
                    throw new ArgumentException();
                }

                #endregion

                Property d = new Property();

                d.sizeOfProperty = Marshal.SizeOf(typeof(Property));
                d.property = value;

                int result = midiStreamProperty(Handle, ref d, MIDIPROP_SET | MIDIPROP_TIMEDIV);

                if(result != DeviceException.MMSYSERR_NOERROR)
                {
                    throw new OutputDeviceException(result);
                }
            }
        }

        public int Tempo
        {
            get
            {
                #region Require

                if(IsDisposed)
                {
                    throw new ObjectDisposedException("OutputStream");
                }

                #endregion

                Property t = new Property();
                t.sizeOfProperty = Marshal.SizeOf(typeof(Property));

                int result = midiStreamProperty(Handle, ref t, MIDIPROP_GET | MIDIPROP_TEMPO);

                if(result != DeviceException.MMSYSERR_NOERROR)
                {
                    throw new OutputDeviceException(result);
                }

                return t.property;
            }
            set
            {
                #region Require

                if(IsDisposed)
                {
                    throw new ObjectDisposedException("OutputStream");
                }
                else if(value < 0)
                {
                    throw new ArgumentOutOfRangeException("Tempo", value,
                        "Tempo out of range.");
                }

                #endregion

                Property t = new Property();
                t.sizeOfProperty = Marshal.SizeOf(typeof(Property));
                t.property = value;

                int result = midiStreamProperty(Handle, ref t, MIDIPROP_SET | MIDIPROP_TEMPO);

                if(result != DeviceException.MMSYSERR_NOERROR)
                {
                    throw new OutputDeviceException(result);
                }
            }
        }
    }
}

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License

This article, along with any associated source code and files, is licensed under The MIT License


Written By
United States United States
Aside from dabbling in BASIC on his old Atari 1040ST years ago, Leslie's programming experience didn't really begin until he discovered the Internet in the late 90s. There he found a treasure trove of information about two of his favorite interests: MIDI and sound synthesis.

After spending a good deal of time calculating formulas he found on the Internet for creating new sounds by hand, he decided that an easier way would be to program the computer to do the work for him. This led him to learn C. He discovered that beyond using programming as a tool for synthesizing sound, he loved programming in and of itself.

Eventually he taught himself C++ and C#, and along the way he immersed himself in the ideas of object oriented programming. Like many of us, he gotten bitten by the design patterns bug and a copy of GOF is never far from his hands.

Now his primary interest is in creating a complete MIDI toolkit using the C# language. He hopes to create something that will become an indispensable tool for those wanting to write MIDI applications for the .NET framework.

Besides programming, his other interests are photography and playing his Les Paul guitars.

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