apps/codecs/libspeex/kiss_fft.h

   1 #ifndef KISS_FFT_H
   2 #define KISS_FFT_H
   3
   4 #include <stdlib.h>
   5 #include <math.h>
   6 #include "arch.h"
   7
   8 #ifdef __cplusplus
   9 extern "C" {
  10 #endif
  11
  12 /*
  13  ATTENTION!
  14  If you would like a :
  15  -- a utility that will handle the caching of fft objects
  16  -- real-only (no imaginary time component ) FFT
  17  -- a multi-dimensional FFT
  18  -- a command-line utility to perform ffts
  19  -- a command-line utility to perform fast-convolution filtering
  20
  21  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
  22   in the tools/ directory.
  23 */
  24
  25 #ifdef USE_SIMD
  26 # include <xmmintrin.h>
  27 # define kiss_fft_scalar __m128
  28 #define KISS_FFT_MALLOC(nbytes) memalign(16,nbytes)
  29 #else
  30 #define KISS_FFT_MALLOC speex_alloc
  31 #endif
  32
  33
  34 #ifdef FIXED_POINT
  35 #include "arch.h"
  36 #  define kiss_fft_scalar spx_int16_t
  37 #else
  38 # ifndef kiss_fft_scalar
  39 /*  default is float */
  40 #   define kiss_fft_scalar float
  41 # endif
  42 #endif
  43
  44 typedef struct {
  45     kiss_fft_scalar r;
  46     kiss_fft_scalar i;
  47 }kiss_fft_cpx;
  48
  49 typedef struct kiss_fft_state* kiss_fft_cfg;
  50
  51 /*
  52  *  kiss_fft_alloc
  53  *
  54  *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
  55  *
  56  *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
  57  *
  58  *  The return value from fft_alloc is a cfg buffer used internally
  59  *  by the fft routine or NULL.
  60  *
  61  *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
  62  *  The returned value should be free()d when done to avoid memory leaks.
  63  *
  64  *  The state can be placed in a user supplied buffer 'mem':
  65  *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
  66  *      then the function places the cfg in mem and the size used in *lenmem
  67  *      and returns mem.
  68  *
  69  *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
  70  *      then the function returns NULL and places the minimum cfg
  71  *      buffer size in *lenmem.
  72  * */
  73
  74 kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
  75
  76 /*
  77  * kiss_fft(cfg,in_out_buf)
  78  *
  79  * Perform an FFT on a complex input buffer.
  80  * for a forward FFT,
  81  * fin should be  f[0] , f[1] , ... ,f[nfft-1]
  82  * fout will be   F[0] , F[1] , ... ,F[nfft-1]
  83  * Note that each element is complex and can be accessed like
  84     f[k].r and f[k].i
  85  * */
  86 void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
  87
  88 /*
  89  A more generic version of the above function. It reads its input from every Nth sample.
  90  * */
  91 void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
  92
  93 /* If kiss_fft_alloc allocated a buffer, it is one contiguous
  94    buffer and can be simply free()d when no longer needed*/
  95 #define kiss_fft_free speex_free
  96
  97 /*
  98  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up
  99  your compiler output to call this before you exit.
 100 */
 101 void kiss_fft_cleanup(void);
 102
 103
 104 #ifdef __cplusplus
 105 }
 106 #endif
 107
 108 #endif