Point Cloud Library (PCL)  1.9.1-dev
kiss_fft.h
1 #pragma once
2 
3 #include <stdlib.h>
4 #include <stdio.h>
5 #include <math.h>
6 #include <string.h>
7 
8 #include <pcl/pcl_exports.h>
9 
10 #ifdef __cplusplus
11 extern "C" {
12 #endif
13 
14 /*
15  ATTENTION!
16  If you would like a :
17  -- a utility that will handle the caching of fft objects
18  -- real-only (no imaginary time component ) FFT
19  -- a multi-dimensional FFT
20  -- a command-line utility to perform ffts
21  -- a command-line utility to perform fast-convolution filtering
22 
23  Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
24  in the tools/ directory.
25 */
26 
27 #ifdef USE_SIMD
28 # include <xmmintrin.h>
29 # define kiss_fft_scalar __m128
30 #define KISS_FFT_MALLOC(nbytes) _mm_malloc(nbytes,16)
31 #define KISS_FFT_FREE _mm_free
32 #else
33 #define KISS_FFT_MALLOC malloc
34 #define KISS_FFT_FREE free
35 #endif
36 
37 
38 #ifdef FIXED_POINT
39 #include <sys/types.h>
40 # if (FIXED_POINT == 32)
41 # define kiss_fft_scalar int32_t
42 # else
43 # define kiss_fft_scalar int16_t
44 # endif
45 #else
46 # ifndef kiss_fft_scalar
47 /* default is float */
48 # define kiss_fft_scalar float
49 # endif
50 #endif
51 
52 typedef struct {
53  kiss_fft_scalar r;
54  kiss_fft_scalar i;
56 
57 typedef struct kiss_fft_state* kiss_fft_cfg;
58 
59 /*
60  * kiss_fft_alloc
61  *
62  * Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
63  *
64  * typical usage: kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
65  *
66  * The return value from fft_alloc is a cfg buffer used internally
67  * by the fft routine or NULL.
68  *
69  * If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
70  * The returned value should be free()d when done to avoid memory leaks.
71  *
72  * The state can be placed in a user supplied buffer 'mem':
73  * If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
74  * then the function places the cfg in mem and the size used in *lenmem
75  * and returns mem.
76  *
77  * If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
78  * then the function returns NULL and places the minimum cfg
79  * buffer size in *lenmem.
80  * */
81 
82 kiss_fft_cfg PCL_EXPORTS
83 kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
84 
85 /*
86  * kiss_fft(cfg,in_out_buf)
87  *
88  * Perform an FFT on a complex input buffer.
89  * for a forward FFT,
90  * fin should be f[0] , f[1] , ... ,f[nfft-1]
91  * fout will be F[0] , F[1] , ... ,F[nfft-1]
92  * Note that each element is complex and can be accessed like
93  f[k].r and f[k].i
94  * */
95 void PCL_EXPORTS
96 kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
97 
98 /*
99  A more generic version of the above function. It reads its input from every Nth sample.
100  * */
101 void PCL_EXPORTS
102 kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
103 
104 /* If kiss_fft_alloc allocated a buffer, it is one contiguous
105  buffer and can be simply free()d when no longer needed*/
106 #define kiss_fft_free free
107 
108 /*
109  Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up
110  your compiler output to call this before you exit.
111 */
112 void PCL_EXPORTS
113 kiss_fft_cleanup(void);
114 
115 /*
116  * Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
117  */
118 int PCL_EXPORTS
119 kiss_fft_next_fast_size(int n);
120 
121 /* for real ffts, we need an even size */
122 #define kiss_fftr_next_fast_size_real(n) \
123  (kiss_fft_next_fast_size( ((n)+1)>>1)<<1)
124 
125 #ifdef __cplusplus
126 }
127 #endif
kiss_fft_scalar i
Definition: kiss_fft.h:54
kiss_fft_scalar r
Definition: kiss_fft.h:53