43 lines
1.2 KiB
C++
43 lines
1.2 KiB
C++
/*
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* TinyFFT.h
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* ---------
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* Purpose: A simple FFT implementation for power-of-two FFTs
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* Notes : This is a C++ adaption of Ryuhei Mori's BSD 2-clause licensed TinyFFT
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* available from https://github.com/ryuhei-mori/tinyfft
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* Authors: Ryuhei Mori
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* OpenMPT Devs
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* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
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*/
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#pragma once
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#include "openmpt/all/BuildSettings.hpp"
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#include <complex>
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OPENMPT_NAMESPACE_BEGIN
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class TinyFFT
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{
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static constexpr std::complex<double> I{0.0, 1.0};
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std::vector<std::complex<double>> w; // Pre-computed twiddle factors
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const uint32 k; // log2 of FFT size
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void GenerateTwiddleFactors(uint32 i, uint32 b, std::complex<double> z);
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public:
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TinyFFT(const uint32 fftSize);
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uint32 Size() const noexcept;
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// Computes in-place FFT of size 2^k of A, result is in bit-reversed order.
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void FFT(std::vector<std::complex<double>> &A) const;
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// Computes in-place IFFT of size 2^k of A, input is expected to be in bit-reversed order.
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void IFFT(std::vector<std::complex<double>> &A) const;
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static void Normalize(std::vector<std::complex<double>> &data);
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};
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OPENMPT_NAMESPACE_END
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