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/*
* Copyright (c) 2003-2004, Mark Borgerding. All rights reserved.
* This file is part of KISS FFT - https://github.com/mborgerding/kissfft
*
* SPDX-License-Identifier: BSD-3-Clause
* See COPYING file for more information.
*/
#include "kfc.h"
typedef struct cached_fft *kfc_cfg;
struct cached_fft
{
int nfft;
int inverse;
kiss_fft_cfg cfg;
kfc_cfg next;
};
static kfc_cfg cache_root=NULL;
static int ncached=0;
static kiss_fft_cfg find_cached_fft(int nfft,int inverse)
{
size_t len;
kfc_cfg cur=cache_root;
kfc_cfg prev=NULL;
while ( cur ) {
if ( cur->nfft == nfft && inverse == cur->inverse )
break;/*found the right node*/
prev = cur;
cur = prev->next;
}
if (cur== NULL) {
/* no cached node found, need to create a new one*/
kiss_fft_alloc(nfft,inverse,0,&len);
#ifdef USE_SIMD
int padding = (16-sizeof(struct cached_fft)) & 15;
// make sure the cfg aligns on a 16 byte boundary
len += padding;
#endif
cur = (kfc_cfg)KISS_FFT_MALLOC((sizeof(struct cached_fft) + len ));
if (cur == NULL)
return NULL;
cur->cfg = (kiss_fft_cfg)(cur+1);
#ifdef USE_SIMD
cur->cfg = (kiss_fft_cfg) ((char*)(cur+1)+padding);
#endif
kiss_fft_alloc(nfft,inverse,cur->cfg,&len);
cur->nfft=nfft;
cur->inverse=inverse;
cur->next = NULL;
if ( prev )
prev->next = cur;
else
cache_root = cur;
++ncached;
}
return cur->cfg;
}
void kfc_cleanup(void)
{
kfc_cfg cur=cache_root;
kfc_cfg next=NULL;
while (cur){
next = cur->next;
free(cur);
cur=next;
}
ncached=0;
cache_root = NULL;
}
void kfc_fft(int nfft, const kiss_fft_cpx * fin,kiss_fft_cpx * fout)
{
kiss_fft( find_cached_fft(nfft,0),fin,fout );
}
void kfc_ifft(int nfft, const kiss_fft_cpx * fin,kiss_fft_cpx * fout)
{
kiss_fft( find_cached_fft(nfft,1),fin,fout );
}
#ifdef KFC_TEST
static void check(int nc)
{
if (ncached != nc) {
fprintf(stderr,"ncached should be %d,but it is %d\n",nc,ncached);
exit(1);
}
}
int main(void)
{
kiss_fft_cpx buf1[1024],buf2[1024];
memset(buf1,0,sizeof(buf1));
check(0);
kfc_fft(512,buf1,buf2);
check(1);
kfc_fft(512,buf1,buf2);
check(1);
kfc_ifft(512,buf1,buf2);
check(2);
kfc_cleanup();
check(0);
return 0;
}
#endif
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