kiss_fft.h

00001 #ifndef KISS_FFT_H
00002 #define KISS_FFT_H
00003 
00004 #include <stdlib.h>
00005 #include <math.h>
00006 #include "misc.h"
00007 
00008 #ifdef __cplusplus
00009 extern "C" {
00010 #endif
00011 
00012 /*
00013  ATTENTION!
00014  If you would like a :
00015  -- a utility that will handle the caching of fft objects
00016  -- real-only (no imaginary time component ) FFT
00017  -- a multi-dimensional FFT
00018  -- a command-line utility to perform ffts
00019  -- a command-line utility to perform fast-convolution filtering
00020 
00021  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
00022   in the tools/ directory.
00023 */
00024 
00025 #ifdef USE_SIMD
00026 # include <xmmintrin.h>
00027 # define kiss_fft_scalar __m128
00028 #define KISS_FFT_MALLOC(nbytes) memalign(16,nbytes)
00029 #else   
00030 #define KISS_FFT_MALLOC speex_alloc
00031 #endif  
00032 
00033 
00034 #ifdef FIXED_POINT
00035 #include "misc.h"   
00036 #  define kiss_fft_scalar spx_int16_t
00037 #else
00038 # ifndef kiss_fft_scalar
00039 /*  default is float */
00040 #   define kiss_fft_scalar float
00041 # endif
00042 #endif
00043 
00044 typedef struct {
00045     kiss_fft_scalar r;
00046     kiss_fft_scalar i;
00047 }kiss_fft_cpx;
00048 
00049 typedef struct kiss_fft_state* kiss_fft_cfg;
00050 
00051 /* 
00052  *  kiss_fft_alloc
00053  *  
00054  *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
00055  *
00056  *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
00057  *
00058  *  The return value from fft_alloc is a cfg buffer used internally
00059  *  by the fft routine or NULL.
00060  *
00061  *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
00062  *  The returned value should be free()d when done to avoid memory leaks.
00063  *  
00064  *  The state can be placed in a user supplied buffer 'mem':
00065  *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
00066  *      then the function places the cfg in mem and the size used in *lenmem
00067  *      and returns mem.
00068  *  
00069  *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
00070  *      then the function returns NULL and places the minimum cfg 
00071  *      buffer size in *lenmem.
00072  * */
00073 
00074 kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem); 
00075 
00076 /*
00077  * kiss_fft(cfg,in_out_buf)
00078  *
00079  * Perform an FFT on a complex input buffer.
00080  * for a forward FFT,
00081  * fin should be  f[0] , f[1] , ... ,f[nfft-1]
00082  * fout will be   F[0] , F[1] , ... ,F[nfft-1]
00083  * Note that each element is complex and can be accessed like
00084     f[k].r and f[k].i
00085  * */
00086 void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
00087 
00088 /*
00089  A more generic version of the above function. It reads its input from every Nth sample.
00090  * */
00091 void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
00092 
00093 /* If kiss_fft_alloc allocated a buffer, it is one contiguous 
00094    buffer and can be simply free()d when no longer needed*/
00095 #define kiss_fft_free speex_free
00096 
00097 /*
00098  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up 
00099  your compiler output to call this before you exit.
00100 */
00101 void kiss_fft_cleanup(void);
00102     
00103 
00104 #ifdef __cplusplus
00105 } 
00106 #endif
00107 
00108 #endif