JUCE/modules/juce_audio_basics/midi/ump/juce_UMPDispatcher.h

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

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
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   You may also use this code under the terms of the AGPLv3:
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  ==============================================================================
*/

#ifndef DOXYGEN

namespace juce::universal_midi_packets
{

/**
    Parses a raw stream of uint32_t, and calls a user-provided callback every time
    a full Universal MIDI Packet is encountered.

    @tags{Audio}
*/
class Dispatcher
{
public:
    /** Clears the dispatcher. */
    void reset() { currentPacketLen = 0; }

    /** Calls `callback` with a View of each packet encountered in the range delimited
        by `begin` and `end`.

        If the range ends part-way through a packet, the next call to `dispatch` will
        continue from that point in the packet (unless `reset` is called first).
    */
    template <typename PacketCallbackFunction>
    void dispatch (const uint32_t* begin,
                   const uint32_t* end,
                   double timeStamp,
                   PacketCallbackFunction&& callback)
    {
        std::for_each (begin, end, [&] (uint32_t word)
        {
            nextPacket[currentPacketLen++] = word;

            if (currentPacketLen == Utils::getNumWordsForMessageType (nextPacket.front()))
            {
                callback (View (nextPacket.data()), timeStamp);
                currentPacketLen = 0;
            }
        });
    }

private:
    std::array<uint32_t, 4> nextPacket;
    size_t currentPacketLen = 0;
};

//==============================================================================
/**
    Parses a stream of bytes representing a sequence of bytestream-encoded MIDI 1.0 messages,
    converting the messages to UMP format and passing the packets to a user-provided callback
    as they become ready.

    @tags{Audio}
*/
class BytestreamToUMPDispatcher
{
public:
    /** Initialises the dispatcher.

        Channel messages will be converted to the requested protocol format `pp`.
        `storageSize` bytes will be allocated to store incomplete messages.
    */
    explicit BytestreamToUMPDispatcher (PacketProtocol pp, int storageSize)
        : concatenator (storageSize),
          converter (pp)
    {}

    void reset()
    {
        concatenator.reset();
        converter.reset();
    }

    /** Calls `callback` with a View of each converted packet as it becomes ready.

        @param begin        the first byte in a range of bytes representing bytestream-encoded MIDI messages.
        @param end          one-past the last byte in a range of bytes representing bytestream-encoded MIDI messages.
        @param timestamp    a timestamp to apply to the created packets.
        @param callback     a callback which will be passed a View pointing to each new packet as it becomes ready.
    */
    template <typename PacketCallbackFunction>
    void dispatch (const uint8_t* begin,
                   const uint8_t* end,
                   double timestamp,
                   PacketCallbackFunction&& callback)
    {
        using CallbackPtr = decltype (std::addressof (callback));

        struct Callback
        {
            Callback (BytestreamToUMPDispatcher& d, CallbackPtr c)
                : dispatch (d), callbackPtr (c) {}

            void handleIncomingMidiMessage (void*, const MidiMessage& msg) const
            {
                Conversion::toMidi1 (BytestreamMidiView (&msg), [&] (const View& view)
                {
                    dispatch.converter.convert (view, *callbackPtr);
                });
            }

            void handlePartialSysexMessage (void*, const uint8_t*, int, double) const {}

            BytestreamToUMPDispatcher& dispatch;
            CallbackPtr callbackPtr = nullptr;
        };

        Callback inputCallback { *this, &callback };
        concatenator.pushMidiData (begin, int (end - begin), timestamp, (void*) nullptr, inputCallback);
    }

private:
    MidiDataConcatenator concatenator;
    GenericUMPConverter converter;
};

//==============================================================================
/**
    Parses a stream of 32-bit words representing a sequence of UMP-encoded MIDI messages,
    converting the messages to MIDI 1.0 bytestream format and passing them to a user-provided
    callback as they become ready.

    @tags{Audio}
*/
class ToBytestreamDispatcher
{
public:
    /** Initialises the dispatcher.

        `storageSize` bytes will be allocated to store incomplete messages.
    */
    explicit ToBytestreamDispatcher (int storageSize)
        : converter (storageSize) {}

    /** Clears the dispatcher. */
    void reset()
    {
        dispatcher.reset();
        converter.reset();
    }

    /** Calls `callback` with converted bytestream-formatted MidiMessage whenever
        a new message becomes available.

        @param begin        the first word in a stream of words representing UMP-encoded MIDI packets.
        @param end          one-past the last word in a stream of words representing UMP-encoded MIDI packets.
        @param timestamp    a timestamp to apply to converted messages.
        @param callback     a callback which will be passed a MidiMessage each time a new message becomes ready.
    */
    template <typename BytestreamMessageCallback>
    void dispatch (const uint32_t* begin,
                   const uint32_t* end,
                   double timestamp,
                   BytestreamMessageCallback&& callback)
    {
        dispatcher.dispatch (begin, end, timestamp, [&] (const View& view, double time)
        {
            converter.convert (view, time, callback);
        });
    }

private:
    Dispatcher dispatcher;
    ToBytestreamConverter converter;
};

} // namespace juce::universal_midi_packets

#endif