#ifndef KISS_FFT_H#define KISS_FFT_H#include <stdlib.h>#include <stdio.h>#include <math.h>#include <memory.h>#include <malloc.h>#ifdef __cplusplusextern "C" {#endif/* ATTENTION! If you would like a : -- a utility that will handle the caching of fft objects -- real-only (no imaginary time component ) FFT -- a multi-dimensional FFT -- a command-line utility to perform ffts -- a command-line utility to perform fast-convolution filtering Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c  in the tools/ directory.*/#ifdef USE_SIMD# include <xmmintrin.h># define kiss_fft_scalar __m128#define KISS_FFT_MALLOC(nbytes) memalign(16,nbytes)#else	#define KISS_FFT_MALLOC malloc#endif	#ifdef FIXED_POINT#include <sys/types.h>	#  define kiss_fft_scalar int16_t#else# ifndef kiss_fft_scalar/*  default is float */#   define kiss_fft_scalar float# endif#endiftypedef struct {    kiss_fft_scalar r;    kiss_fft_scalar i;}kiss_fft_cpx;typedef struct kiss_fft_state* kiss_fft_cfg;/*  *  kiss_fft_alloc *   *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer. * *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL); * *  The return value from fft_alloc is a cfg buffer used internally *  by the fft routine or NULL. * *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc. *  The returned value should be free()d when done to avoid memory leaks. *   *  The state can be placed in a user supplied buffer 'mem': *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough, *      then the function places the cfg in mem and the size used in *lenmem *      and returns mem. *   *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough), *      then the function returns NULL and places the minimum cfg  *      buffer size in *lenmem. * */kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem); /* * kiss_fft(cfg,in_out_buf) * * Perform an FFT on a complex input buffer. * for a forward FFT, * fin should be  f[0] , f[1] , ... ,f[nfft-1] * fout will be   F[0] , F[1] , ... ,F[nfft-1] * Note that each element is complex and can be accessed like    f[k].r and f[k].i * */void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);/* A more generic version of the above function. It reads its input from every Nth sample. * */void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);/* If kiss_fft_alloc allocated a buffer, it is one contiguous    buffer and can be simply free()d when no longer needed*/#define kiss_fft_free free/* Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up  your compiler output to call this before you exit.*/void kiss_fft_cleanup(void);	#ifdef __cplusplus} #endif#endif