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Diffstat (limited to 'Src/external_dependencies/openmpt-trunk/soundlib/TinyFFT.h')
| -rw-r--r-- | Src/external_dependencies/openmpt-trunk/soundlib/TinyFFT.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/Src/external_dependencies/openmpt-trunk/soundlib/TinyFFT.h b/Src/external_dependencies/openmpt-trunk/soundlib/TinyFFT.h new file mode 100644 index 00000000..5f0e8f90 --- /dev/null +++ b/Src/external_dependencies/openmpt-trunk/soundlib/TinyFFT.h @@ -0,0 +1,42 @@ +/* + * TinyFFT.h + * --------- + * Purpose: A simple FFT implementation for power-of-two FFTs + * Notes : This is a C++ adaption of Ryuhei Mori's BSD 2-clause licensed TinyFFT + * available from https://github.com/ryuhei-mori/tinyfft + * Authors: Ryuhei Mori + * OpenMPT Devs + * The OpenMPT source code is released under the BSD license. Read LICENSE for more details. + */ + + +#pragma once + +#include "openmpt/all/BuildSettings.hpp" +#include <complex> + +OPENMPT_NAMESPACE_BEGIN + +class TinyFFT +{ + static constexpr std::complex<double> I{0.0, 1.0}; + std::vector<std::complex<double>> w; // Pre-computed twiddle factors + const uint32 k; // log2 of FFT size + + void GenerateTwiddleFactors(uint32 i, uint32 b, std::complex<double> z); + +public: + TinyFFT(const uint32 fftSize); + + uint32 Size() const noexcept; + + // Computes in-place FFT of size 2^k of A, result is in bit-reversed order. + void FFT(std::vector<std::complex<double>> &A) const; + + // Computes in-place IFFT of size 2^k of A, input is expected to be in bit-reversed order. + void IFFT(std::vector<std::complex<double>> &A) const; + + static void Normalize(std::vector<std::complex<double>> &data); +}; + +OPENMPT_NAMESPACE_END |