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125 lines
3.2 KiB
C
125 lines
3.2 KiB
C
#ifndef KISS_FFT_H
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#define KISS_FFT_H
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#include <stdlib.h>
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#include <stdio.h>
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#include <math.h>
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#include <string.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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ATTENTION!
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If you would like a :
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-- a utility that will handle the caching of fft objects
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-- real-only (no imaginary time component ) FFT
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-- a multi-dimensional FFT
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-- a command-line utility to perform ffts
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-- a command-line utility to perform fast-convolution filtering
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Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
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in the tools/ directory.
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*/
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#ifdef USE_SIMD
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# include <xmmintrin.h>
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# define kiss_fft_scalar __m128
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#define KISS_FFT_MALLOC(nbytes) _mm_malloc(nbytes,16)
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#define KISS_FFT_FREE _mm_free
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#else
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#define KISS_FFT_MALLOC malloc
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#define KISS_FFT_FREE free
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#endif
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#ifdef FIXED_POINT
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#include <sys/types.h>
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# if (FIXED_POINT == 32)
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# define kiss_fft_scalar int32_t
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# else
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# define kiss_fft_scalar int16_t
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# endif
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#else
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# ifndef kiss_fft_scalar
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/* default is float */
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# define kiss_fft_scalar float
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# endif
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#endif
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typedef struct {
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kiss_fft_scalar r;
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kiss_fft_scalar i;
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}kiss_fft_cpx;
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typedef struct kiss_fft_state* kiss_fft_cfg;
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/*
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* kiss_fft_alloc
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*
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* Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
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*
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* typical usage: kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
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*
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* The return value from fft_alloc is a cfg buffer used internally
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* by the fft routine or NULL.
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*
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* If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using malloc.
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* The returned value should be free()d when done to avoid memory leaks.
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*
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* The state can be placed in a user supplied buffer 'mem':
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* If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
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* then the function places the cfg in mem and the size used in *lenmem
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* and returns mem.
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*
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* If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
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* then the function returns NULL and places the minimum cfg
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* buffer size in *lenmem.
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* */
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kiss_fft_cfg kiss_fft_alloc(int nfft,int inverse_fft,void * mem,size_t * lenmem);
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/*
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* kiss_fft(cfg,in_out_buf)
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*
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* Perform an FFT on a complex input buffer.
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* for a forward FFT,
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* fin should be f[0] , f[1] , ... ,f[nfft-1]
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* fout will be F[0] , F[1] , ... ,F[nfft-1]
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* Note that each element is complex and can be accessed like
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f[k].r and f[k].i
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* */
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void kiss_fft(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout);
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/*
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A more generic version of the above function. It reads its input from every Nth sample.
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* */
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void kiss_fft_stride(kiss_fft_cfg cfg,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,int fin_stride);
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/* If kiss_fft_alloc allocated a buffer, it is one contiguous
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buffer and can be simply free()d when no longer needed*/
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#define kiss_fft_free free
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/*
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Cleans up some memory that gets managed internally. Not necessary to call, but it might clean up
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your compiler output to call this before you exit.
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*/
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void kiss_fft_cleanup(void);
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/*
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* Returns the smallest integer k, such that k>=n and k has only "fast" factors (2,3,5)
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*/
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int kiss_fft_next_fast_size(int n);
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/* for real ffts, we need an even size */
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#define kiss_fftr_next_fast_size_real(n) \
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(kiss_fft_next_fast_size( ((n)+1)>>1)<<1)
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#ifdef __cplusplus
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}
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#endif
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#endif
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