juce_Bias.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 FloatType>
class Bias
{
public:
    Bias() noexcept = default;
 
    //==============================================================================
    void setBias (FloatType newBias) noexcept
    {
        jassert (newBias >= static_cast<FloatType> (-1) && newBias <= static_cast<FloatType> (1));
        bias.setTargetValue (newBias);
    }
 
    //==============================================================================
    FloatType getBias() const noexcept              { return bias.getTargetValue(); }

    void setRampDurationSeconds (double newDurationSeconds) noexcept
    {
        if (! approximatelyEqual (rampDurationSeconds, newDurationSeconds))
        {
            rampDurationSeconds = newDurationSeconds;
            updateRamp();
        }
    }
 
    double getRampDurationSeconds() const noexcept  { return rampDurationSeconds; }
 
    //==============================================================================
    void prepare (const ProcessSpec& spec) noexcept
    {
        sampleRate = spec.sampleRate;
        updateRamp();
    }
 
    void reset() noexcept
    {
        bias.reset (sampleRate, rampDurationSeconds);
    }
 
    //==============================================================================
    template <typename SampleType>
    SampleType processSample (SampleType inputSample) noexcept
    {
        return inputSample + bias.getNextValue();
    }
 
    //==============================================================================
    template <typename ProcessContext>
    void process (const ProcessContext& context) noexcept
    {
        auto&& inBlock  = context.getInputBlock();
        auto&& outBlock = context.getOutputBlock();
 
        jassert (inBlock.getNumChannels() == outBlock.getNumChannels());
        jassert (inBlock.getNumSamples()  == outBlock.getNumSamples());
 
        auto len         = inBlock.getNumSamples();
        auto numChannels = inBlock.getNumChannels();
 
        if (context.isBypassed)
        {
            bias.skip (static_cast<int> (len));
 
            if (context.usesSeparateInputAndOutputBlocks())
                outBlock.copyFrom (inBlock);
 
            return;
        }
 
        if (numChannels == 1)
        {
            auto* src = inBlock.getChannelPointer (0);
            auto* dst = outBlock.getChannelPointer (0);
 
            for (size_t i = 0; i < len; ++i)
                dst[i] = src[i] + bias.getNextValue();
        }
        else
        {
            JUCE_BEGIN_IGNORE_WARNINGS_MSVC (6255 6386)
            auto* biases = static_cast<FloatType*> (alloca (sizeof (FloatType) * len));
 
            for (size_t i = 0; i < len; ++i)
                biases[i] = bias.getNextValue();
 
            for (size_t chan = 0; chan < numChannels; ++chan)
                FloatVectorOperations::add (outBlock.getChannelPointer (chan),
                                            inBlock.getChannelPointer (chan),
                                            biases, static_cast<int> (len));
            JUCE_END_IGNORE_WARNINGS_MSVC
        }
    }
 
 
private:
    //==============================================================================
    SmoothedValue<FloatType> bias;
    double sampleRate = 0, rampDurationSeconds = 0;
 
    void updateRamp() noexcept
    {
        if (sampleRate > 0)
            bias.reset (sampleRate, rampDurationSeconds);
    }
};
 
} // namespace juce::dsp