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https://github.com/mborgerding/kissfft.git
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85 lines
2.6 KiB
C
85 lines
2.6 KiB
C
#ifndef KISS_FFT_H
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#define KISS_FFT_H
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#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include <memory.h>
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#ifdef FIXED_POINT
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# define kiss_fft_scalar short
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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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* kiss_fft_alloc
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*
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* Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
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*
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* typical usage: void * mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
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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 or NULL.
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*
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* If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
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* The returned value should be free()d when done to avoid memory leaks.
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*
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* The state can be placed in a user supplied buffer 'mem':
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* If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
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* then the function places the cfg in mem and the size used in *lenmem
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* and returns mem.
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*
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* If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
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* then the function returns NULL and places the minimum cfg
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* buffer size in *lenmem.
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* */
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void* kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
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/*
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* kiss_fft(cfg,in_out_buf)
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*
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* Perform an FFT on a complex input buffer.
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* for a forward FFT,
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* fin should be f[0] , f[1] , ... ,f[nfft-1]
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* fout will be F[0] , F[1] , ... ,F[nfft-1]
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* Note that each element is complex and can be accessed like
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f[k].r and f[k].i
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* */
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void kiss_fft(const void * cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
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/* allocate a 2-dimensional FFT
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the data should be stored rowwise,
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in other words, an array made up of row[0], then row[1], etc
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*/
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void * kiss_fft2d_alloc(int nrows,int ncols,int inverse_fft,void * mem,size_t * lenmem);
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void kiss_fft2d(const void* cfg_from_alloc , const kiss_fft_cpx *fin,kiss_fft_cpx *fout );
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/* Real optimized version can save about 45% cpu time vs. complex fft of a real seq.
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*/
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void * kiss_fftr_alloc(int nfft,int inverse_fft,void * mem, size_t * lenmem);
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void kiss_fftr(const void * cfg,const kiss_fft_scalar *timedata,kiss_fft_cpx *freqdata);
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void kiss_fftri(const void * cfg,const kiss_fft_cpx *freqdata,kiss_fft_scalar *timedata);
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/* 2d Real optimized version
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*/
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void * kiss_fftr2d_alloc(int nfft,int inverse_fft,void * mem, size_t * lenmem);
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void kiss_fftr2d(const void * cfg,const kiss_fft_scalar *timedata,kiss_fft_cpx *freqdata);
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void kiss_fftr2di(const void * cfg,const kiss_fft_cpx *freqdata,kiss_fft_scalar *timedata);
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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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