juce_Limiter.h

/*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.
 
   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy
 
   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce::dsp
{

template <typename SampleType>
class Limiter
{
public:
    //==============================================================================
    Limiter() = default;
 
    //==============================================================================
    void setThreshold (SampleType newThreshold);

    void setRelease (SampleType newRelease);
 
    //==============================================================================
    void prepare (const ProcessSpec& spec);

    void reset();
 
    //==============================================================================
    template <typename ProcessContext>
    void process (const ProcessContext& context) noexcept
    {
        const auto& inputBlock = context.getInputBlock();
        auto& outputBlock      = context.getOutputBlock();
        const auto numChannels = outputBlock.getNumChannels();
        const auto numSamples  = outputBlock.getNumSamples();
 
        jassert (inputBlock.getNumChannels() == numChannels);
        jassert (inputBlock.getNumSamples()  == numSamples);
 
        if (context.isBypassed)
        {
            outputBlock.copyFrom (inputBlock);
            return;
        }
 
        firstStageCompressor.process (context);
 
        auto secondContext = ProcessContextReplacing<SampleType> (outputBlock);
        secondStageCompressor.process (secondContext);
 
        outputBlock.multiplyBy (outputVolume);
 
        for (size_t channel = 0; channel < numChannels; ++channel)
        {
            FloatVectorOperations::clip (outputBlock.getChannelPointer (channel), outputBlock.getChannelPointer (channel),
                                         (SampleType) -1.0, (SampleType) 1.0, (int) numSamples);
        }
    }
 
private:
    //==============================================================================
    void update();
 
    //==============================================================================
    Compressor<SampleType> firstStageCompressor, secondStageCompressor;
    SmoothedValue<SampleType, ValueSmoothingTypes::Linear> outputVolume;
 
    double sampleRate = 44100.0;
    SampleType thresholddB = -10.0, releaseTime = 100.0;
};
 
} // namespace juce::dsp