tracktion_MPEStartTrimmer.h

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 /*
    ,--.                     ,--.     ,--.  ,--.
  ,-'  '-.,--.--.,--,--.,---.|  |,-.,-'  '-.`--' ,---. ,--,--,      Copyright 2024
  '-.  .-'|  .--' ,-.  | .--'|     /'-.  .-',--.| .-. ||      \   Tracktion Software
    |  |  |  |  \ '-'  \ `--.|  \  \  |  |  |  |' '-' '|  ||  |       Corporation
    `---' `--'   `--`--'`---'`--'`--' `---' `--' `---' `--''--'    www.tracktion.com
 
    Tracktion Engine uses a GPL/commercial licence - see LICENCE.md for details.
*/
 
namespace tracktion { inline namespace engine
{
 
struct MPEStartTrimmer
{
    static void reconstructExpression (juce::Array<juce::MidiMessage>& mpeMessagesToAddAtStart,
                                       const juce::MidiMessageSequence& data,
                                       int trimIndex, int channel)
    {
        jassert (trimIndex < data.getNumEvents());
 
        const int lastNoteOnIndex = searchBackForNoteOn (data, trimIndex, channel);
 
        if (! wasFound (lastNoteOnIndex))
            return;
 
        const auto& noteOn = data.getEventPointer (lastNoteOnIndex)->message;
        const auto initial = searchBackForExpression (data, lastNoteOnIndex, channel, MessageToStopAt::noteOff);
        const auto mostRecent = searchBackForExpression (data, trimIndex, channel, MessageToStopAt::noteOn);
 
        const int centrePitchbend = juce::MidiMessage::pitchbendToPitchwheelPos (0.0f, 12.f);
 
        mpeMessagesToAddAtStart.add (juce::MidiMessage::controllerEvent       (channel, 74, wasFound (initial.timbre)    ? initial.timbre    : 64));
        mpeMessagesToAddAtStart.add (juce::MidiMessage::channelPressureChange (channel,     wasFound (initial.pressure)  ? initial.pressure  : 0));
        mpeMessagesToAddAtStart.add (juce::MidiMessage::pitchWheel            (channel,     wasFound (initial.pitchBend) ? initial.pitchBend : centrePitchbend));
        mpeMessagesToAddAtStart.add (juce::MidiMessage::noteOn (channel, noteOn.getNoteNumber(), noteOn.getVelocity()));
 
        if (wasFound (mostRecent.timbre))
            mpeMessagesToAddAtStart.add (juce::MidiMessage::controllerEvent (channel, 74, mostRecent.timbre));
 
        if (wasFound (mostRecent.pressure))
            mpeMessagesToAddAtStart.add (juce::MidiMessage::channelPressureChange (channel, mostRecent.pressure));
 
        if (wasFound (mostRecent.pitchBend))
            mpeMessagesToAddAtStart.add (juce::MidiMessage::pitchWheel (channel, mostRecent.pitchBend));
    }
 
    static void reconstructExpression (juce::Array<juce::MidiMessage>& mpeMessagesToAddAtStart,
                                       const choc::midi::Sequence& data,
                                       size_t trimIndex, int channel1to16)
    {
        jassert (trimIndex < data.events.size());
 
        const int lastNoteOnIndex = searchBackForNoteOn (data, (int) trimIndex, (uint8_t) channel1to16);
 
        if (! wasFound (lastNoteOnIndex))
            return;
 
        const auto& noteOn = data.events[(size_t) lastNoteOnIndex].message;
        const auto initial = searchBackForExpression (data, lastNoteOnIndex, (uint8_t) channel1to16, MessageToStopAt::noteOff);
        const auto mostRecent = searchBackForExpression (data, (int) trimIndex, (uint8_t) channel1to16, MessageToStopAt::noteOn);
 
        const int centrePitchbend = juce::MidiMessage::pitchbendToPitchwheelPos (0.0f, 12.f);
 
        mpeMessagesToAddAtStart.add (juce::MidiMessage::controllerEvent       (channel1to16, 74, wasFound (initial.timbre)    ? initial.timbre    : 64));
        mpeMessagesToAddAtStart.add (juce::MidiMessage::channelPressureChange (channel1to16,     wasFound (initial.pressure)  ? initial.pressure  : 0));
        mpeMessagesToAddAtStart.add (juce::MidiMessage::pitchWheel            (channel1to16,     wasFound (initial.pitchBend) ? initial.pitchBend : centrePitchbend));
        mpeMessagesToAddAtStart.add (juce::MidiMessage::noteOn (channel1to16, noteOn.getNoteNumber(), noteOn.getVelocity()));
 
        if (wasFound (mostRecent.timbre))
            mpeMessagesToAddAtStart.add (juce::MidiMessage::controllerEvent (channel1to16, 74, mostRecent.timbre));
 
        if (wasFound (mostRecent.pressure))
            mpeMessagesToAddAtStart.add (juce::MidiMessage::channelPressureChange (channel1to16, mostRecent.pressure));
 
        if (wasFound (mostRecent.pitchBend))
            mpeMessagesToAddAtStart.add (juce::MidiMessage::pitchWheel (channel1to16, mostRecent.pitchBend));
    }
 
private:
    static int searchBackForNoteOn (const juce::MidiMessageSequence& data, int startIndex, int channel)
    {
        while (--startIndex >= 0)
        {
            const auto& m = data.getEventPointer (startIndex)->message;
 
            if (m.getChannel() == channel)
            {
                if (m.isNoteOn (true))
                    return startIndex;
 
                if (m.isNoteOff (true))
                    return notFound;
            }
        }
 
        return notFound;
    }
 
    static int searchBackForNoteOn (const choc::midi::Sequence& data, int startIndex, uint8_t channel1to16)
    {
        while (--startIndex >= 0)
        {
            const auto& e = data.events[(size_t) startIndex];
 
            const auto& m = e.message;
 
            if (! m.isShortMessage())
                continue;
 
            if (m.getChannel1to16() == channel1to16)
            {
                if (m.isNoteOn())
                    return startIndex;
 
                if (m.isNoteOff())
                    return notFound;
            }
        }
 
        return notFound;
    }
 
    struct ExpressionData
    {
        int timbre;
        int pressure;
        int pitchBend;
    };
 
    enum MessageToStopAt
    {
        noteOn,
        noteOff
    };
 
    static ExpressionData searchBackForExpression (const juce::MidiMessageSequence& data,
                                                   int startIndex, int channel, MessageToStopAt stopAt)
    {
        int timbre    = notFound;
        int pressure  = notFound;
        int pitchBend = notFound;
 
        for (int i = startIndex; --i >= 0;) // Find initial note-on timbre value
        {
            const auto& m = data.getEventPointer (i)->message;
 
            if (m.getChannel() != channel)
                continue;
 
            if ((stopAt == noteOn ? m.isNoteOn (true) : m.isNoteOff (true))
                || (wasFound (timbre) && wasFound (pressure) && wasFound (pitchBend)))
                break;
 
            if (m.isController() && m.getControllerNumber() == 74 && ! wasFound (timbre))
                timbre = m.getControllerValue();
 
            else if (m.isChannelPressure() && ! wasFound (pressure))
                pressure = m.getChannelPressureValue();
 
            else if (m.isPitchWheel() && ! wasFound (pitchBend))
                pitchBend = m.getPitchWheelValue();
        }
 
        return { timbre, pressure, pitchBend };
    }
 
    static ExpressionData searchBackForExpression (const choc::midi::Sequence& data,
                                                   int startIndex, uint8_t channel, MessageToStopAt stopAt)
    {
        int timbre    = notFound;
        int pressure  = notFound;
        int pitchBend = notFound;
 
        for (int i = startIndex; --i >= 0;) // Find initial note-on timbre value
        {
            const auto& m = data.events[(size_t) startIndex].message;
 
            if (! m.isShortMessage())
                continue;
 
            if (m.getChannel1to16() != channel)
                continue;
 
            if ((stopAt == noteOn ? m.isNoteOn() : m.isNoteOff())
                || (wasFound (timbre) && wasFound (pressure) && wasFound (pitchBend)))
                break;
 
            if (m.isController() && m.getControllerNumber() == 74 && ! wasFound (timbre))
                timbre = m.getControllerValue();
            else if (m.isChannelPressure() && ! wasFound (pressure))
                pressure = m.getChannelPressureValue();
            else if (m.isPitchWheel() && ! wasFound (pitchBend))
                pitchBend = (int) m.getPitchWheelValue();
        }
 
        return { timbre, pressure, pitchBend };
    }
 
    static constexpr int notFound = -1;
    static bool wasFound (int v) { return v != notFound; }
};
 
}} // namespace tracktion { inline namespace engine