MidiExport.cs

using System;
using System.Collections.Generic;
using UnityEngine;

namespace MidiExport { 
    public class MidiExport
    {
        public static System.Text.Encoding ascii = System.Text.Encoding.ASCII;

        public int fileType = 1;
        public int ticksPerBeat = 960;

        public List<MidiTrack> midiTracks = new List<MidiTrack>();
        public MidiExport(int fileType = 1, int ticksPerBeat = 960)
        {
            this.fileType = fileType;
            this.ticksPerBeat = ticksPerBeat;
        }

        public List<byte> createBytes()
        {
            List<byte> data = new List<byte>();
            data.AddRange(createHeader());
            foreach (MidiTrack track in midiTracks)
            {
                data.AddRange(track.createBytes());
            }

            return data;
        }

        public List<byte> createHeader()
        {
            List<byte> data = new List<byte>();

            List<byte> header = new List<byte>();
            header.AddRange(toBEShort(fileType));
            header.AddRange(toBEShort(midiTracks.Count));
            header.AddRange(toBEShort(ticksPerBeat));

            data.AddRange(writeChunk("MThd",header));

            return data;
        }

        public static List<byte> writeChunk(string name, List<byte> data)
        {
            List<byte> _data = new List<byte>();

            _data.AddRange(ascii.GetBytes(name));
            _data.AddRange(toBEULong(data.Count));
            _data.AddRange(data);
            return _data;
        }

        public static List<byte> toBEULong(int val)
        {
            List<byte> data = new List<byte>();
            byte[] LEdata = BitConverter.GetBytes((System.UInt32)val);

            for (int x = LEdata.Length-1; x >= 0; x--)
            {
                data.Add(LEdata[x]);
            }

            return data;
        }

        public static List<byte> toBEShort(int val)
        {
            List<byte> data = new List<byte>();
            byte[] LEdata = BitConverter.GetBytes((System.Int16)val);

            for (int x = LEdata.Length - 1; x >= 0; x--)
            {
                data.Add(LEdata[x]);
            }

            return data;
        }

        public static List<byte> encodeVariableInt(int val)
        {
            if (val < 0) throw new FormatException("Variable int must be positive.");

            List<byte> data = new List<byte>();
            while (val > 0)
            {
                data.Add((byte)(val & 0x7f));
                val >>= 7;
            }

            if (data.Count > 0)
            {
                data.Reverse();
                for (int x = 0; x < data.Count - 1; x++)
                {
                    data[x] |= 0x80;
                }
            }
            else
            {
                data.Add(0x00);
            }

            return data;
        }
    }

    public class MidiTrack
    {
        public List<MidiMessage> messages = new List<MidiMessage>();
        public List<byte> createBytes()
        {
            List<byte> data = new List<byte>();
            byte runningStatusByte = 0x00;
            bool statusByteSet = false;
            foreach (MidiMessage message in messages)
            {
                if (message.time < 0)
                {
                    message.time = 0;
                }
                data.AddRange(MidiExport.encodeVariableInt(message.time));
                if (message.type.Equals("sysex"))
                {
                    statusByteSet = false;
                    data.Add(0xf0);
                    data.AddRange(MidiExport.encodeVariableInt(message.data.Length + 1));
                    data.AddRange(message.data);
                    data.Add(0xf7);
                } else
                {
                    List<byte> raw = new List<byte>();
                    raw = message.createBytes();
                   
                    byte temp = raw[0];
                    if (statusByteSet && !message.is_meta && raw[0] < 0xf0 && raw[0] == runningStatusByte)
                    {
                        raw.RemoveAt(0);
                        data.AddRange(raw);
                    } else
                    {
                        data.AddRange(raw);
                    }
                    runningStatusByte = temp;
                    statusByteSet = true;
                }
             }

            return MidiExport.writeChunk("MTrk",data);
        } 
    }

    public class MidiMessage
    {
        public string type = "";
        public int time = 0;
        public bool is_meta = false;
        private byte code = 0x00;
        //MetaMessages:
        //#############
        //sequence_number 0x00
        public int number = 0;
        //text 0x01
        public string text = "";
        //copyright 0x02 -> text
        //track_name 0x03
        public string name = "";
        //instrument_name 0x04 -> track_name
        //lyrics 0x05 -> text
        //marker 0x06 -> text
        //cue_marker 0x07 -> text
        //device_name 0x08 -> track_name
        //channel_prefix 0x20
        public int channel = 0;
        //midi_port 0x21
        public int port = 0;
        //end_of_track 0x2f
        //set_tempo 0x51
        public int tempo = 500000;
        //smpte_offset 0x54 (Ignore)
        //public int frame_rate = 24; public int hours = 0; public int minutes = 0; public int seconds = 0; public int frames = 0; public int sub_frames = 0;
        //time_signature 0x58
        public int numerator = 4; public int denominator = 2; public int clocks_per_click = 24; public int notated_32nd_notes_per_beat = 8;
        //key_signature 0x59
        public int key = 0; bool is_major = true;

        //Messages:
        //#########
        //note_off 0x80 (channel, note, velocity)
        public int note = 0; public int velocity = 0;
        //note_on 0x90 (channel, note, velocity)
        //polytouch 0xa0 (channel, note, value)
        public int value = 0;
        //control_change 0xb0 (channel, control, value)
        public int control = 0;
        //program_change 0xc0 (channel, program)
        public int program = 0;
        //aftertouch 0xd0 (channel, value)
        //pitchwheel 0xe0 (channel, pitch)
        public int pitch = 0;
        //sysex 0xf0 (data)
        public byte[] data;

        //Others not needed..
        public MidiMessage(string type, string[] args, int time, byte[] data = null)
        {
            is_meta = false;
            this.type = type;
            this.time = time;

            //Meta Messages
            if (type.Equals("sequence_number")) { is_meta = true; code = 0x00; number = int.Parse(args[0]); }
            if (type.Equals("text") || type.Equals("copyright") || type.Equals("lyrics") || type.Equals("marker") || type.Equals("cue_marker"))
            {
                is_meta = true;
                text = args[0];
            }
            if (type.Equals("text")) code = 0x01;
            if (type.Equals("copyright")) code = 0x02;
            if (type.Equals("lyrics")) code = 0x05;
            if (type.Equals("marker")) code = 0x06;
            if (type.Equals("cue_marker")) code = 0x07;

            if (type.Equals("track_name") || type.Equals("instrument_name") || type.Equals("device_name"))
            {
                is_meta = true; code = 0x03;
                name = args[0];
            }
            if (type.Equals("instrument_name")) code = 0x04;
            if (type.Equals("device_name")) code = 0x08;

            if (type.Equals("channel_prefix")) { code = 0x20; channel = int.Parse(args[0]); is_meta = true; }
            if (type.Equals("midi_port")) { code = 0x21; port = int.Parse(args[0]); is_meta = true; }
            if (type.Equals("end_of_track")) { code = 0x2f; is_meta = true; }
            if (type.Equals("set_tempo")) { code = 0x51; tempo = int.Parse(args[0]); is_meta = true; }

            if (type.Equals("time_signature"))
            {
                is_meta = true; code = 0x58;
                numerator = int.Parse(args[0]);  //4
                denominator = int.Parse(args[1]); //4 
                clocks_per_click = int.Parse(args[2]); //24
                notated_32nd_notes_per_beat = int.Parse(args[3]); //8
            }

            if (type.Equals("key_signature"))
            {
                is_meta = true; code = 0x59;
                key = int.Parse(args[0]);
                is_major = args[1].Equals("0"); //"0" or "1"
            }


            //Normal Messages
            if (type.Equals("note_off")) { code = 0x80; channel = int.Parse(args[0]); note = int.Parse(args[1]); velocity = int.Parse(args[2]); }
            if (type.Equals("note_on")) { code = 0x90; channel = int.Parse(args[0]); note = int.Parse(args[1]); velocity = int.Parse(args[2]); }
            if (type.Equals("polytouch")) { code = 0xa0; channel = int.Parse(args[0]); note = int.Parse(args[1]); value = int.Parse(args[2]); }
            if (type.Equals("control_change")) { code = 0xb0; channel = int.Parse(args[0]); control = int.Parse(args[1]); value = int.Parse(args[2]); }
            if (type.Equals("program_change")) { code = 0xc0; channel = int.Parse(args[0]); program = int.Parse(args[1]); }
            if (type.Equals("aftertouch")) { code = 0xd0; channel = int.Parse(args[0]); value = int.Parse(args[1]); }
            if (type.Equals("pitchwheel")) { code = 0xe0; channel = int.Parse(args[0]); pitch = int.Parse(args[1]); }
            if (type.Equals("sysex")) { code = 0xf0; this.data = data; }

        }

        public List<byte> createBytes()
        {
            List<byte> data;
            if (is_meta) data = createMetaBytes();
            else data = createMessageBytes();

            return data;
        }

        public List<byte> createMetaBytes()
        {
            List<byte> data = new List<byte>();

            if (type.Equals("sequence_number"))
            {
                data.Add((byte)(number >> 8));
                data.Add((byte)(number & 0xff));
            }
            if (type.Equals("text") || type.Equals("copyright") || type.Equals("lyrics") || type.Equals("marker") || type.Equals("cue_marker"))
            {
                if (text == null) text = "";
                data.AddRange(MidiExport.ascii.GetBytes(text));
            }

            if (type.Equals("track_name") || type.Equals("instrument_name") || type.Equals("device_name"))
            {
                data.AddRange(MidiExport.ascii.GetBytes(name));
            }
            if (type.Equals("channel_prefix"))
            {
                data.Add((byte)channel);
            }
            if (type.Equals("midi_port"))
            {
                data.Add((byte)port);
            }
            if (type.Equals("set_tempo"))
            {
                //return [tempo >> 16, tempo >> 8 & 0xff, tempo & 0xff]
                data.Add((byte)(tempo >> 16));
                data.Add((byte)((tempo >> 8)& 0xff));
                data.Add((byte)(tempo & 0xff));
            }

            if (type.Equals("time_signature"))
            {
                data.Add((byte)numerator);
                data.Add((byte)Math.Log(denominator, 2));
                data.Add((byte)clocks_per_click);
                data.Add((byte)notated_32nd_notes_per_beat);
            }

            if (type.Equals("key_signature"))
            {
                data.Add((byte)(key & 0xff));
                data.Add(is_major ? (byte)0x00 : (byte)0x01);
            }

            int dataLength = data.Count;
            data.InsertRange(0, MidiExport.encodeVariableInt(dataLength));
            data.Insert(0, code);
            data.Insert(0, 0xff);
            
            return data;
        }


        public List<byte> createMessageBytes()
        {
           
            List<byte> data = new List<byte>();
            /* if (type.Equals("note_off")) { code = 0x80; channel = int.Parse(args[0]); note = int.Parse(args[1]); velocity = int.Parse(args[2]); }
            if (type.Equals("note_on")) { code = 0x90; channel = int.Parse(args[0]); note = int.Parse(args[1]); velocity = int.Parse(args[2]); }
            if (type.Equals("polytouch")) { code = 0xa0; channel = int.Parse(args[0]); note = int.Parse(args[1]); value = int.Parse(args[2]); }
            if (type.Equals("control_change")) { code = 0xb0; channel = int.Parse(args[0]); control = int.Parse(args[1]); value = int.Parse(args[2]); }
            if (type.Equals("program_change")) { code = 0xc0; channel = int.Parse(args[0]); program = int.Parse(args[1]); }
            if (type.Equals("aftertouch")) { code = 0xd0; channel = int.Parse(args[0]); value = int.Parse(args[1]); }
            if (type.Equals("pitchwheel")) { code = 0xe0; channel = int.Parse(args[0]); pitch = int.Parse(args[1]); }
            if (type.Equals("sysex")) { code = 0xf0; this.data = data; }
              
             */
            if (type.Equals("note_off") || type.Equals("note_on"))
            {
                data.Add((byte)(code | (byte)channel));
                data.Add((byte)note); data.Add((byte)velocity);
            }
           
            if (type.Equals("polytouch")) 
            {
                data.Add((byte)(code | (byte)channel));
                data.Add((byte)note); data.Add((byte)value);
            }
            if (type.Equals("control_change"))
            {
                data.Add((byte)(code | (byte)channel));
                data.Add((byte)control); data.Add((byte)value);
            }
            if (type.Equals("program_change"))
            {
                data.Add((byte)(code | (byte)channel));
                data.Add((byte)program);
            }
            if (type.Equals("aftertouch"))
            {
                data.Add((byte)(code | (byte)channel));
                data.Add((byte)value);
            }
            if (type.Equals("pitchwheel"))  //14 bit signed integer
            {
                data.Add((byte)(code | (byte)channel));
                //data.Add((byte)pitch);
                pitch -= -8192;
                data.Add((byte)(pitch & 0x7f));
                data.Add((byte)(pitch >> 7));
            }
            if (type.Equals("sysex"))
            {
                data.AddRange(this.data);
            }


            return data;
        }
    }
}