media/kiss_fft/kiss_fft.h

   1 #ifndef KISS_FFT_H
   2 #define KISS_FFT_H
   3
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <math.h>
   7 #include <string.h>
   8
   9 #ifdef __cplusplus
  10 extern "C" {
  11 #endif
  12
  13 /*
  14  ATTENTION!
  15  If you would like a :
  16  -- a utility that will handle the caching of fft objects
  17  -- real-only (no imaginary time component ) FFT
  18  -- a multi-dimensional FFT
  19  -- a command-line utility to perform ffts
  20  -- a command-line utility to perform fast-convolution filtering
  21
  22  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
  23   in the tools/ directory.
  24 */
  25
  26 #ifdef USE_SIMD
  27 # include <xmmintrin.h>
  28 # define kiss_fft_scalar __m128
  29 #define KISS_FFT_MALLOC(nbytes) _mm_malloc(nbytes,16)
  30 #define KISS_FFT_FREE _mm_free
  31 #else
  32 #define KISS_FFT_MALLOC malloc
  33 #define KISS_FFT_FREE free
  34 #endif
  35
  36
  37 #ifdef FIXED_POINT
  38 #include <sys/types.h>
  39 # if (FIXED_POINT == 32)
  40 #  define kiss_fft_scalar int32_t
  41 # else
  42 #  define kiss_fft_scalar int16_t
  43 # endif
  44 #else
  45 # ifndef kiss_fft_scalar
  46 /*  default is float */
  47 #   define kiss_fft_scalar float
  48 # endif
  49 #endif
  50
  51 typedef struct {
  52     kiss_fft_scalar r;
  53     kiss_fft_scalar i;
  54 }kiss_fft_cpx;
  55
  56 typedef struct kiss_fft_state* kiss_fft_cfg;
  57
  58 /*
  59  *  kiss_fft_alloc
  60  *
  61  *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
  62  *
  63  *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
  64  *
  65  *  The return value from fft_alloc is a cfg buffer used internally
  66  *  by the fft routine or NULL.
  67  *
  68  *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
  69  *  The returned value should be free()d when done to avoid memory leaks.
  70  *
  71  *  The state can be placed in a user supplied buffer 'mem':
  72  *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
  73  *      then the function places the cfg in mem and the size used in *lenmem
  74  *      and returns mem.
  75  *
  76  *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
  77  *      then the function returns NULL and places the minimum cfg
  78  *      buffer size in *lenmem.
  79  * */
  80
  81 kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
  82
  83 /*
  84  * kiss_fft(cfg,in_out_buf)
  85  *
  86  * Perform an FFT on a complex input buffer.
  87  * for a forward FFT,
  88  * fin should be  f[0] , f[1] , ... ,f[nfft-1]
  89  * fout will be   F[0] , F[1] , ... ,F[nfft-1]
  90  * Note that each element is complex and can be accessed like
  91     f[k].r and f[k].i
  92  * */
  93 void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
  94
  95 /*
  96  A more generic version of the above function. It reads its input from every Nth sample.
  97  * */
  98 void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
  99
 100 /* If kiss_fft_alloc allocated a buffer, it is one contiguous
 101    buffer and can be simply free()d when no longer needed*/
 102 #define kiss_fft_free free
 103
 104 /*
 105  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up
 106  your compiler output to call this before you exit.
 107 */
 108 void kiss_fft_cleanup(void);
 109
 110
 111 /*
 112  * Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
 113  */
 114 int kiss_fft_next_fast_size(int n);
 115
 116 /* for real ffts, we need an even size */
 117 #define kiss_fftr_next_fast_size_real(n) \
 118         (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)
 119
 120 #ifdef __cplusplus
 121 }
 122 #endif
 123
 124 #endif