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https://github.com/mborgerding/kissfft.git
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49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
#ifndef KISS_FFT_H
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#define KISS_FFT_H
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#ifdef FIXED_POINT
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# define kiss_fft_scalar short
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# define FIXED_POINT_FRAC_BITS 15
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#else
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# ifndef kiss_fft_scalar
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# define kiss_fft_scalar float
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# endif
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#endif
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typedef struct {
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kiss_fft_scalar r;
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kiss_fft_scalar i;
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}kiss_fft_cpx;
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/*
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* fft_alloc
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*
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* Initialize a radix 2 FFT (or IFFT) algorithm.
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*
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* The return value from fft_alloc is a cfg buffer used internally
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* by the fft routine.
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*
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* Call free() on it when done using it to avoid memory leaks.
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* */
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void* kiss_fft_alloc(int nfft,int inverse_fft);
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// free() the state when done using it
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/*
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* kiss_fft(cfg,in_out_buf)
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*
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* Perform an in-place FFT on a complex input buffer.
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* for a forward FFT,
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* the input should be f[0] , f[1] , ... ,f[nfft-1]
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* the output will be F[0] , F[1] , ... ,F[nfft-1]
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* Note that each element is complex.
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* */
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void kiss_fft( const void* cfg_from_alloc , kiss_fft_cpx *f ); // call for each buffer
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// when done with the cfg for a given fft size and direction, simply free it
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#define kiss_fft_free free
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#endif
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