JUCE/modules/juce_audio_devices/native/juce_MidiDataConcatenator.h

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2015 - ROLI Ltd.

   Permission is granted to use this software under the terms of either:
   a) the GPL v2 (or any later version)
   b) the Affero GPL v3

   Details of these licenses can be found at: www.gnu.org/licenses

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

   ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.juce.com for more information.

  ==============================================================================
*/

#ifndef JUCE_MIDIDATACONCATENATOR_H_INCLUDED
#define JUCE_MIDIDATACONCATENATOR_H_INCLUDED

//==============================================================================
/**
    Helper class that takes chunks of incoming midi bytes, packages them into
    messages, and dispatches them to a midi callback.
*/
class MidiDataConcatenator
{
public:
    //==============================================================================
    MidiDataConcatenator (const int initialBufferSize)
        : pendingData ((size_t) initialBufferSize),
          pendingDataTime (0), pendingBytes (0), runningStatus (0)
    {
    }

    void reset()
    {
        pendingBytes = 0;
        runningStatus = 0;
        pendingDataTime = 0;
    }

    template <typename UserDataType, typename CallbackType>
    void pushMidiData (const void* inputData, int numBytes, double time,
                       UserDataType* input, CallbackType& callback)
    {
        const uint8* d = static_cast<const uint8*> (inputData);

        while (numBytes > 0)
        {
            if (pendingBytes > 0 || d[0] == 0xf0)
            {
                processSysex (d, numBytes, time, input, callback);
                runningStatus = 0;
            }
            else
            {
                int len = 0;
                uint8 data[3];

                while (numBytes > 0)
                {
                    // If there's a realtime message embedded in the middle of
                    // the normal message, handle it now..
                    if (*d >= 0xf8 && *d <= 0xfe)
                    {
                        callback.handleIncomingMidiMessage (input, MidiMessage (*d++, time));
                        --numBytes;
                    }
                    else
                    {
                        if (len == 0 && *d < 0x80 && runningStatus >= 0x80)
                            data[len++] = runningStatus;

                        data[len++] = *d++;
                        --numBytes;

                        const uint8 firstByte = data[0];

                        if (firstByte < 0x80 || firstByte == 0xf7)
                        {
                            len = 0;
                            break;   // ignore this malformed MIDI message..
                        }

                        if (len >= MidiMessage::getMessageLengthFromFirstByte (firstByte))
                            break;
                    }
                }

                if (len > 0)
                {
                    int used = 0;
                    const MidiMessage m (data, len, used, 0, time);

                    if (used <= 0)
                        break; // malformed message..

                    jassert (used == len);
                    callback.handleIncomingMidiMessage (input, m);
                    runningStatus = data[0];
                }
            }
        }
    }

private:
    template <typename UserDataType, typename CallbackType>
    void processSysex (const uint8*& d, int& numBytes, double time,
                       UserDataType* input, CallbackType& callback)
    {
        if (*d == 0xf0)
        {
            pendingBytes = 0;
            pendingDataTime = time;
        }

        pendingData.ensureSize ((size_t) (pendingBytes + numBytes), false);
        uint8* totalMessage = static_cast<uint8*> (pendingData.getData());
        uint8* dest = totalMessage + pendingBytes;

        do
        {
            if (pendingBytes > 0 && *d >= 0x80)
            {
                if (*d == 0xf7)
                {
                    *dest++ = *d++;
                    ++pendingBytes;
                    --numBytes;
                    break;
                }

                if (*d >= 0xfa || *d == 0xf8)
                {
                    callback.handleIncomingMidiMessage (input, MidiMessage (*d, time));
                    ++d;
                    --numBytes;
                }
                else
                {
                    pendingBytes = 0;
                    int used = 0;
                    const MidiMessage m (d, numBytes, used, 0, time);

                    if (used > 0)
                    {
                        callback.handleIncomingMidiMessage (input, m);
                        numBytes -= used;
                        d += used;
                    }

                    break;
                }
            }
            else
            {
                *dest++ = *d++;
                ++pendingBytes;
                --numBytes;
            }
        }
        while (numBytes > 0);

        if (pendingBytes > 0)
        {
            if (totalMessage [pendingBytes - 1] == 0xf7)
            {
                callback.handleIncomingMidiMessage (input, MidiMessage (totalMessage, pendingBytes, pendingDataTime));
                pendingBytes = 0;
            }
            else
            {
                callback.handlePartialSysexMessage (input, totalMessage, pendingBytes, pendingDataTime);
            }
        }
    }

    MemoryBlock pendingData;
    double pendingDataTime;
    int pendingBytes;
    uint8 runningStatus;

    JUCE_DECLARE_NON_COPYABLE (MidiDataConcatenator)
};

#endif   // JUCE_MIDIDATACONCATENATOR_H_INCLUDED