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