More restructure

Author: kunitoki

modules/yup_dsp/filters/yup_FirstOrder.h

@@ -0,0 +1,159 @@
+/*
+  ==============================================================================
+
+   This file is part of the YUP library.
+   Copyright (c) 2025 - [email protected]
+
+   YUP is an open source library subject to 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.
+
+   YUP IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
+   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
+   DISCLAIMED.
+
+  ==============================================================================
+*/
+
+#pragma once
+
+namespace yup
+{
+
+//==============================================================================
+/**
+    First-order IIR filter implementation.
+
+    The filter implements the difference equation:
+    y[n] = b0*x[n] + b1*x[n-1] - a1*y[n-1]
+
+    @see FilterBase, FirstOrderCoefficients, FirstOrderState
+*/
+template <typename SampleType, typename CoeffType = double>
+class FirstOrder : public FilterBase<SampleType, CoeffType>
+{
+public:
+    //==============================================================================
+    /** Default constructor */
+    FirstOrder() = default;
+
+    //==============================================================================
+    /**
+        Sets the filter coefficients.
+
+        @param newCoefficients  The new first-order coefficients
+    */
+    void setCoefficients (const FirstOrderCoefficients<CoeffType>& newCoefficients) noexcept
+    {
+        coefficients = newCoefficients;
+    }
+
+    /**
+        Gets the current filter coefficients.
+
+        @returns  The current first-order coefficients
+    */
+    const FirstOrderCoefficients<CoeffType>& getCoefficients() const noexcept
+    {
+        return coefficients;
+    }
+
+    //==============================================================================
+    /** @internal */
+    void reset() noexcept override
+    {
+        state.reset();
+    }
+
+    /** @internal */
+    void prepare (double sampleRate, int maximumBlockSize) noexcept override
+    {
+        this->sampleRate = sampleRate;
+        this->maximumBlockSize = maximumBlockSize;
+        reset();
+    }
+
+    /** @internal */
+    SampleType processSample (SampleType inputSample) noexcept override
+    {
+        const auto inputCoeff = static_cast<CoeffType> (inputSample);
+        const auto outputCoeff = coefficients.b0 * inputCoeff + coefficients.b1 * state.x1 - coefficients.a1 * state.y1;
+
+        state.x1 = inputCoeff;
+        state.y1 = outputCoeff;
+
+        return static_cast<SampleType> (outputCoeff);
+    }
+
+    /** @internal */
+    void processBlock (const SampleType* inputBuffer, SampleType* outputBuffer, int numSamples) noexcept override
+    {
+        auto x1 = state.x1;
+        auto y1 = state.y1;
+        const auto b0 = coefficients.b0;
+        const auto b1 = coefficients.b1;
+        const auto a1 = coefficients.a1;
+
+        for (int i = 0; i < numSamples; ++i)
+        {
+            const auto input = inputBuffer[i];
+            const auto output = b0 * input + b1 * x1 - a1 * y1;
+
+            x1 = input;
+            y1 = output;
+            outputBuffer[i] = output;
+        }
+
+        state.x1 = x1;
+        state.y1 = y1;
+    }
+
+    /** @internal */
+    DspMath::Complex<CoeffType> getComplexResponse (CoeffType frequency) const noexcept override
+    {
+        return coefficients.getComplexResponse (frequency, this->sampleRate);
+    }
+
+    /** @internal */
+    void getPolesZeros (
+        DspMath::ComplexVector<CoeffType>& poles,
+        DspMath::ComplexVector<CoeffType>& zeros) const override
+    {
+        poles.reserve (1);
+        zeros.reserve (1);
+
+        DspMath::extractPolesZerosFromFirstOrder (coefficients.b0, coefficients.b1, coefficients.a1, poles, zeros);
+    }
+
+private:
+    //==============================================================================
+    struct FirstOrderState
+    {
+        CoeffType x1 = 0; // Input delay
+        CoeffType y1 = 0; // Output delay
+
+        /** Resets all state variables to zero */
+        void reset() noexcept
+        {
+            x1 = y1 = static_cast<CoeffType> (0.0);
+        }
+    };
+
+    //==============================================================================
+    FirstOrderCoefficients<CoeffType> coefficients;
+    FirstOrderState state;
+
+    //==============================================================================
+    YUP_LEAK_DETECTOR (FirstOrder)
+};
+
+//==============================================================================
+/** Type aliases for convenience */
+using FirstOrderFloat = FirstOrder<float>;   // float samples, double coefficients (default)
+using FirstOrderDouble = FirstOrder<double>; // double samples, double coefficients (default)
+
+} // namespace yup