kiss_fft.h

00001 #ifndef KISS_FFT_H
00002 #define KISS_FFT_H
00003 
00004 #include <stdlib.h>
00005 #include <stdio.h>
00006 #include <math.h>
00007 #include <string.h>
00008 
00009 #ifdef __cplusplus
00010 extern "C" {
00011 #endif
00012 
00013 /*
00014  ATTENTION!
00015  If you would like a :
00016  -- a utility that will handle the caching of fft objects
00017  -- real-only (no imaginary time component ) FFT
00018  -- a multi-dimensional FFT
00019  -- a command-line utility to perform ffts
00020  -- a command-line utility to perform fast-convolution filtering
00021 
00022  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
00023   in the tools/ directory.
00024 */
00025 
00026 #ifdef USE_SIMD
00027 # include <xmmintrin.h>
00028 # define kiss_fft_scalar __m128
00029 #define KISS_FFT_MALLOC(nbytes) _mm_malloc(nbytes,16)
00030 #define KISS_FFT_FREE _mm_free
00031 #else   
00032 #define KISS_FFT_MALLOC(X) (void*)(0) /* Patched. */
00033 #define KISS_FFT_FREE(X) /* Patched. */
00034 #endif  
00035 
00036 
00037 // Patched automatically by download_dependencies.sh so default is 16 bit.
00038 #ifndef FIXED_POINT
00039 #define FIXED_POINT (16)
00040 #endif
00041 // End patch.
00042 
00043 #ifdef FIXED_POINT
00044 #include <sys/types.h>  
00045 # if (FIXED_POINT == 32)
00046 #  define kiss_fft_scalar int32_t
00047 # else  
00048 #  define kiss_fft_scalar int16_t
00049 # endif
00050 #else
00051 # ifndef kiss_fft_scalar
00052 /*  default is float */
00053 #   define kiss_fft_scalar float
00054 # endif
00055 #endif
00056 
00057 typedef struct {
00058     kiss_fft_scalar r;
00059     kiss_fft_scalar i;
00060 }kiss_fft_cpx;
00061 
00062 typedef struct kiss_fft_state* kiss_fft_cfg;
00063 
00064 /* 
00065  *  kiss_fft_alloc
00066  *  
00067  *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
00068  *
00069  *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
00070  *
00071  *  The return value from fft_alloc is a cfg buffer used internally
00072  *  by the fft routine or NULL.
00073  *
00074  *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
00075  *  The returned value should be free()d when done to avoid memory leaks.
00076  *  
00077  *  The state can be placed in a user supplied buffer 'mem':
00078  *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
00079  *      then the function places the cfg in mem and the size used in *lenmem
00080  *      and returns mem.
00081  *  
00082  *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
00083  *      then the function returns NULL and places the minimum cfg 
00084  *      buffer size in *lenmem.
00085  * */
00086 
00087 kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem); 
00088 
00089 /*
00090  * kiss_fft(cfg,in_out_buf)
00091  *
00092  * Perform an FFT on a complex input buffer.
00093  * for a forward FFT,
00094  * fin should be  f[0] , f[1] , ... ,f[nfft-1]
00095  * fout will be   F[0] , F[1] , ... ,F[nfft-1]
00096  * Note that each element is complex and can be accessed like
00097     f[k].r and f[k].i
00098  * */
00099 void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
00100 
00101 /*
00102  A more generic version of the above function. It reads its input from every Nth sample.
00103  * */
00104 void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
00105 
00106 /* If kiss_fft_alloc allocated a buffer, it is one contiguous 
00107    buffer and can be simply free()d when no longer needed*/
00108 #define kiss_fft_free free
00109 
00110 /*
00111  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up 
00112  your compiler output to call this before you exit.
00113 */
00114 void kiss_fft_cleanup(void);
00115     
00116 
00117 /*
00118  * Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
00119  */
00120 int kiss_fft_next_fast_size(int n);
00121 
00122 /* for real ffts, we need an even size */
00123 #define kiss_fftr_next_fast_size_real(n) \
00124         (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)
00125 
00126 #ifdef __cplusplus
00127 } 
00128 #endif
00129 
00130 #endif