testing kfc (kiss fft cache)

tools/kfc.c

@@ -0,0 +1,91 @@
+#include "kiss_fft.h"
+
+typedef struct
+{
+    int nfft;
+    int inverse;
+    const void * cfg;
+    void * next;
+} cached_fft;
+
+static cached_fft *cache_root=NULL;
+static int ncached=0;
+
+static const void * find_cached_fft(int nfft,int inverse)
+{
+    size_t len;
+    cached_fft * cur=cache_root;
+    cached_fft * prev=NULL;
+    while ( cur ) {
+        if ( cur->nfft == nfft && inverse == cur->inverse )
+            break;//found the right node
+        prev = cur;
+        cur = (cached_fft*)prev->next;
+    }
+    if (cur== NULL) {
+        // no cached node found, need to create a new one
+        kiss_fft_alloc(nfft,inverse,0,&len);
+        cur = (cached_fft*)malloc(sizeof(cached_fft) + len );
+        if (cur == NULL)
+            return NULL;
+        cur->cfg = cur+1;
+        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()
+{
+    cached_fft * cur=cache_root;
+    cached_fft * next=NULL;
+    while (cur){
+        next = (cached_fft*)cur->next;
+        free(cur);
+        cur=(cached_fft*)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(int argc,char ** argv)
+{
+    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