JUCE/modules/juce_audio_devices/native/juce_MidiDataConcatenator.h

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

   This file is part of the JUCE library.
   Copyright (c) 2016 - ROLI Ltd.

   Permission is granted to use this software under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license/

   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
   copyright notice and this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.

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

   To release a closed-source product which uses other parts of JUCE not
   licensed under the ISC terms, commercial licenses are available: visit
   www.juce.com for more information.

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

#pragma once

//==============================================================================
/**
    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)
};