juce_GenericInterpolator.h

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/*
  ==============================================================================
 
   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.
 
   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.
 
   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
{

template <class InterpolatorTraits, int memorySize>
class JUCE_API  GenericInterpolator
{
public:
    GenericInterpolator() noexcept                        { reset(); }
 
    GenericInterpolator (GenericInterpolator&&) noexcept = default;
    GenericInterpolator& operator= (GenericInterpolator&&) noexcept = default;

    static constexpr float getBaseLatency() noexcept
    {
        return InterpolatorTraits::algorithmicLatency;
    }

    void reset() noexcept
    {
        indexBuffer = 0;
        subSamplePos = 1.0;
        std::fill (std::begin (lastInputSamples), std::end (lastInputSamples), 0.0f);
    }

    int process (double speedRatio,
                 const float* inputSamples,
                 float* outputSamples,
                 int numOutputSamplesToProduce) noexcept
    {
        return interpolate (speedRatio, inputSamples, outputSamples, numOutputSamplesToProduce);
    }

    int process (double speedRatio,
                 const float* inputSamples,
                 float* outputSamples,
                 int numOutputSamplesToProduce,
                 int numInputSamplesAvailable,
                 int wrapAround) noexcept
    {
        return interpolate (speedRatio, inputSamples, outputSamples,
                            numOutputSamplesToProduce, numInputSamplesAvailable, wrapAround);
    }

    int processAdding (double speedRatio,
                       const float* inputSamples,
                       float* outputSamples,
                       int numOutputSamplesToProduce,
                       float gain) noexcept
    {
        return interpolateAdding (speedRatio, inputSamples, outputSamples, numOutputSamplesToProduce, gain);
    }

    int processAdding (double speedRatio,
                       const float* inputSamples,
                       float* outputSamples,
                       int numOutputSamplesToProduce,
                       int numInputSamplesAvailable,
                       int wrapAround,
                       float gain) noexcept
    {
        return interpolateAdding (speedRatio, inputSamples, outputSamples,
                                  numOutputSamplesToProduce, numInputSamplesAvailable, wrapAround, gain);
    }
 
private:
    //==============================================================================
    forcedinline void pushInterpolationSample (float newValue) noexcept
    {
        lastInputSamples[indexBuffer] = newValue;
 
        if (++indexBuffer == memorySize)
            indexBuffer = 0;
    }
 
    forcedinline void pushInterpolationSamples (const float* input,
                                                int numOutputSamplesToProduce) noexcept
    {
        if (numOutputSamplesToProduce >= memorySize)
        {
            const auto* const offsetInput = input + (numOutputSamplesToProduce - memorySize);
 
            for (int i = 0; i < memorySize; ++i)
                pushInterpolationSample (offsetInput[i]);
        }
        else
        {
            for (int i = 0; i < numOutputSamplesToProduce; ++i)
                pushInterpolationSample (input[i]);
        }
    }
 
    forcedinline void pushInterpolationSamples (const float* input,
                                                int numOutputSamplesToProduce,
                                                int numInputSamplesAvailable,
                                                int wrapAround) noexcept
    {
        if (numOutputSamplesToProduce >= memorySize)
        {
            if (numInputSamplesAvailable >= memorySize)
            {
                pushInterpolationSamples (input,
                                          numOutputSamplesToProduce);
            }
            else
            {
                pushInterpolationSamples (input + ((numOutputSamplesToProduce - numInputSamplesAvailable) - 1),
                                          numInputSamplesAvailable);
 
                if (wrapAround > 0)
                {
                    numOutputSamplesToProduce -= wrapAround;
 
                    pushInterpolationSamples (input + ((numOutputSamplesToProduce - (memorySize - numInputSamplesAvailable)) - 1),
                                              memorySize - numInputSamplesAvailable);
                }
                else
                {
                    for (int i = numInputSamplesAvailable; i < memorySize; ++i)
                        pushInterpolationSample (0.0f);
                }
            }
        }
        else
        {
            if (numOutputSamplesToProduce > numInputSamplesAvailable)
            {
                for (int i = 0; i < numInputSamplesAvailable; ++i)
                    pushInterpolationSample (input[i]);
 
                const auto extraSamples = numOutputSamplesToProduce - numInputSamplesAvailable;
 
                if (wrapAround > 0)
                {
                    const auto* const offsetInput = input + (numInputSamplesAvailable - wrapAround);
 
                    for (int i = 0; i < extraSamples; ++i)
                        pushInterpolationSample (offsetInput[i]);
                }
                else
                {
                    for (int i = 0; i < extraSamples; ++i)
                        pushInterpolationSample (0.0f);
                }
            }
            else
            {
                for (int i = 0; i < numOutputSamplesToProduce; ++i)
                    pushInterpolationSample (input[i]);
            }
        }
    }
 
    //==============================================================================
    int interpolate (double speedRatio,
                     const float* input,
                     float* output,
                     int numOutputSamplesToProduce) noexcept
    {
        auto pos = subSamplePos;
        int numUsed = 0;
 
        while (numOutputSamplesToProduce > 0)
        {
            while (pos >= 1.0)
            {
                pushInterpolationSample (input[numUsed++]);
                pos -= 1.0;
            }
 
            *output++ = InterpolatorTraits::valueAtOffset (lastInputSamples, (float) pos, indexBuffer);
            pos += speedRatio;
            --numOutputSamplesToProduce;
        }
 
        subSamplePos = pos;
        return numUsed;
    }
 
    int interpolate (double speedRatio,
                     const float* input, float* output,
                     int numOutputSamplesToProduce,
                     int numInputSamplesAvailable,
                     int wrap) noexcept
    {
        auto originalIn = input;
        auto pos = subSamplePos;
        bool exceeded = false;
 
        if (speedRatio < 1.0)
        {
            for (int i = numOutputSamplesToProduce; --i >= 0;)
            {
                if (pos >= 1.0)
                {
                    if (exceeded)
                    {
                        pushInterpolationSample (0.0f);
                    }
                    else
                    {
                        pushInterpolationSample (*input++);
 
                        if (--numInputSamplesAvailable <= 0)
                        {
                            if (wrap > 0)
                            {
                                input -= wrap;
                                numInputSamplesAvailable += wrap;
                            }
                            else
                            {
                                exceeded = true;
                            }
                        }
                    }
 
                    pos -= 1.0;
                }
 
                *output++ = InterpolatorTraits::valueAtOffset (lastInputSamples, (float) pos, indexBuffer);
                pos += speedRatio;
            }
        }
        else
        {
            for (int i = numOutputSamplesToProduce; --i >= 0;)
            {
                while (pos < speedRatio)
                {
                    if (exceeded)
                    {
                        pushInterpolationSample (0);
                    }
                    else
                    {
                        pushInterpolationSample (*input++);
 
                        if (--numInputSamplesAvailable <= 0)
                        {
                            if (wrap > 0)
                            {
                                input -= wrap;
                                numInputSamplesAvailable += wrap;
                            }
                            else
                            {
                                exceeded = true;
                            }
                        }
                    }
 
                    pos += 1.0;
                }
 
                pos -= speedRatio;
                *output++ = InterpolatorTraits::valueAtOffset (lastInputSamples, jmax (0.0f, 1.0f - (float) pos), indexBuffer);
            }
        }
 
        subSamplePos = pos;
 
        if (wrap == 0)
            return (int) (input - originalIn);
 
        return ((int) (input - originalIn) + wrap) % wrap;
    }
 
    int interpolateAdding (double speedRatio,
                           const float* input,
                           float* output,
                           int numOutputSamplesToProduce,
                           int numInputSamplesAvailable,
                           int wrap,
                           float gain) noexcept
    {
        auto originalIn = input;
        auto pos = subSamplePos;
        bool exceeded = false;
 
        if (speedRatio < 1.0)
        {
            for (int i = numOutputSamplesToProduce; --i >= 0;)
            {
                if (pos >= 1.0)
                {
                    if (exceeded)
                    {
                        pushInterpolationSample (0.0);
                    }
                    else
                    {
                        pushInterpolationSample (*input++);
 
                        if (--numInputSamplesAvailable <= 0)
                        {
                            if (wrap > 0)
                            {
                                input -= wrap;
                                numInputSamplesAvailable += wrap;
                            }
                            else
                            {
                                numInputSamplesAvailable = true;
                            }
                        }
                    }
 
                    pos -= 1.0;
                }
 
                *output++ += gain * InterpolatorTraits::valueAtOffset (lastInputSamples, (float) pos, indexBuffer);
                pos += speedRatio;
            }
        }
        else
        {
            for (int i = numOutputSamplesToProduce; --i >= 0;)
            {
                while (pos < speedRatio)
                {
                    if (exceeded)
                    {
                        pushInterpolationSample (0.0);
                    }
                    else
                    {
                        pushInterpolationSample (*input++);
 
                        if (--numInputSamplesAvailable <= 0)
                        {
                            if (wrap > 0)
                            {
                                input -= wrap;
                                numInputSamplesAvailable += wrap;
                            }
                            else
                            {
                                exceeded = true;
                            }
                        }
                    }
 
                    pos += 1.0;
                }
 
                pos -= speedRatio;
                *output++ += gain * InterpolatorTraits::valueAtOffset (lastInputSamples, jmax (0.0f, 1.0f - (float) pos), indexBuffer);
            }
        }
 
        subSamplePos = pos;
 
        if (wrap == 0)
            return (int) (input - originalIn);
 
        return ((int) (input - originalIn) + wrap) % wrap;
    }
 
    int interpolateAdding (double speedRatio,
                           const float* input,
                           float* output,
                           int numOutputSamplesToProduce,
                           float gain) noexcept
    {
        auto pos = subSamplePos;
        int numUsed = 0;
 
        while (numOutputSamplesToProduce > 0)
        {
            while (pos >= 1.0)
            {
                pushInterpolationSample (input[numUsed++]);
                pos -= 1.0;
            }
 
            *output++ += gain * InterpolatorTraits::valueAtOffset (lastInputSamples, (float) pos, indexBuffer);
            pos += speedRatio;
            --numOutputSamplesToProduce;
        }
 
        subSamplePos = pos;
        return numUsed;
    }
 
    //==============================================================================
    float lastInputSamples[(size_t) memorySize];
    double subSamplePos = 1.0;
    int indexBuffer = 0;
 
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (GenericInterpolator)
};
 
} // namespace juce