#ifndef KISS_FFT_H
#define KISS_FFT_H

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>

#ifdef __cplusplus
extern "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) _mm_malloc(nbytes,16)
#define KISS_FFT_FREE _mm_free
#else
#define KISS_FFT_MALLOC malloc
#define KISS_FFT_FREE free
#endif


#ifdef FIXED_POINT
#include <sys/types.h>
# if (FIXED_POINT == 32)
#  define kiss_fft_scalar int32_t
# else
#  define kiss_fft_scalar int16_t
# endif
#else
# ifndef kiss_fft_scalar
    /*  default is float */
#   define kiss_fft_scalar float
# endif
#endif

    typedef 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);


    /*
    * Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
    */
    int kiss_fft_next_fast_size(int n);

    /* for real ffts, we need an even size */
#define kiss_fftr_next_fast_size_real(n) \
        (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)

#ifdef __cplusplus
}
#endif

#endif