tracktion_TempoDetect.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
{
 
#ifdef __clang__
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wsign-conversion"
 #pragma clang diagnostic ignored "-Wunused-parameter"
 #pragma clang diagnostic ignored "-Wshadow"
 #pragma clang diagnostic ignored "-Wmacro-redefined"
 #pragma clang diagnostic ignored "-Wconversion"
 #pragma clang diagnostic ignored "-Wunused"
 #if __has_warning("-Wzero-as-null-pointer-constant")
  #pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
 #endif
 #pragma clang diagnostic ignored "-Wextra-semi"
#endif
 
#ifdef __GNUC__
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wsign-conversion"
 #pragma GCC diagnostic ignored "-Wshadow"
 #if ! __clang__
  #pragma GCC diagnostic ignored "-Wunused-but-set-variable"
 #endif
 #pragma GCC diagnostic ignored "-Wunused-variable"
 #pragma GCC diagnostic ignored "-Wpedantic"
 #pragma GCC diagnostic ignored "-Wunknown-pragmas"
#endif
 
#include "soundtouch/include/BPMDetect.h"
 
#ifdef __clang__
 #pragma clang diagnostic pop
#endif
 
#ifdef __GNUC__
 #pragma GCC diagnostic pop
#endif
 
class TempoDetect
{
public:
    TempoDetect (int numChannels_, double sampleRate)
        : numChannels (numChannels_),
          bpmDetect (numChannels, (int) sampleRate)
    {
    }
 
    float processReader (juce::AudioFormatReader& reader)
    {
        jassert ((int) reader.numChannels == numChannels);
 
        const SampleCount blockSize = 65536;
        const bool useRightChan = numChannels > 1;
 
        // can't use an AudioScratchBuffer yet
        juce::AudioBuffer<float> buffer (numChannels, blockSize);
 
        SampleCount numLeft = reader.lengthInSamples;
        int startSample = 0;
 
        while (numLeft > 0)
        {
            auto numThisTime = (int) std::min (numLeft, blockSize);
            reader.read (&buffer, 0, numThisTime, startSample, true, useRightChan);
            processSection (buffer, numThisTime);
 
            startSample += numThisTime;
            numLeft -= numThisTime;
        }
 
        return finishAndDetect();
    }
 
    float processAndDetect (const float** const inputSamples, int numSamples)
    {
        processSection (inputSamples, numSamples);
 
        return bpm = bpmDetect.getBpm();
    }
 
    float getBpm() const                            { return  bpm; }
 
    bool isBpmSensible() const                      { return getSensibleRange().contains (bpm); }
    static juce::Range<float> getSensibleRange()    { return { 29, 200 }; }
 
    //==============================================================================
    void processSection (juce::AudioBuffer<float>& buffer, int numSamplesToProcess)
    {
        processSection (buffer.getArrayOfReadPointers(), numSamplesToProcess);
    }
 
    float finishAndDetect()
    {
        return bpm = bpmDetect.getBpm();
    }
 
    void processSection (const float* const* inputSamples, int numSamples)
    {
        AudioScratchBuffer scratch (1, numChannels * numSamples);
        float* interleaved = scratch.buffer.getWritePointer (0);
 
        using Format = juce::AudioData::Format<juce::AudioData::Float32, juce::AudioData::NativeEndian>;
        juce::AudioData::interleaveSamples (juce::AudioData::NonInterleavedSource<Format> { inputSamples,   numChannels },
                                            juce::AudioData::InterleavedDest<Format>      { interleaved,    numChannels },
                                            numSamples);
 
        bpmDetect.inputSamples (interleaved, numSamples);
    }
 
private:
    //==============================================================================
    int numChannels;
    soundtouch::BPMDetect bpmDetect;
    float bpm = -1.0f;
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (TempoDetect)
};
 
}} // namespace tracktion { inline namespace engine