SincResampler.h

/*
 * This file is part of libsidplayfp, a SID player engine.
 *
 * Copyright 2011-2024 Leandro Nini <drfiemost@users.sourceforge.net>
 * Copyright 2007-2010 Antti Lankila
 * Copyright 2004 Dag Lem <resid@nimrod.no>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef SINCRESAMPLER_H
#define SINCRESAMPLER_H

#include "Resampler.h"

#include "../array.h"

namespace reSIDfp
{

class SincResampler final : public Resampler
{
    friend class State;

private:
    static constexpr int RINGSIZE = 2048;

#ifdef RUNTIME_DISPATCH
private:
    using convolve_func_t = auto (*)(const int32_t*, const int16_t*, int) -> int32_t;

    convolve_func_t simd_convolve;
#endif

private:
    matrix_t* firTable;

    int sampleIndex = 0;

    int firRES;

    int firN;

    const int cyclesPerSample;

    int sampleOffset = 0;

    int32_t outputValue = 0;

    int32_t sample[RINGSIZE * 2] = {0};

private:
    int32_t fir(int subcycle);

private:
    SincResampler(const SincResampler&) = delete;
    SincResampler& operator=(const SincResampler&) = delete;

public:
    SincResampler(
        double clockFrequency,
        double samplingFrequency,
        double highestAccurateFrequency);
    ~SincResampler() override;

    bool input(int32_t input) override;

    int32_t output() const override { return outputValue; }

    void reset() override;
};

} // namespace reSIDfp

#endif