init commit

dotprod_port.c

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+/* 16-bit signed integer dot product
+ * Portable C version
+ * Copyright 2004 Phil Karn
+ * May be used under the terms of the GNU Lesser General Public License (LGPL)
+ */
+#include <stdlib.h>
+#include "fec.h"
+
+struct dotprod {
+  int len; /* Number of coefficients */
+
+  signed short *coeffs;
+};
+
+/* Create and return a descriptor for use with the dot product function */
+void *initdp_port(signed short coeffs[],int len){
+  struct dotprod *dp;
+  int j;
+
+  if(len == 0)
+    return NULL;
+
+  dp = (struct dotprod *)calloc(1,sizeof(struct dotprod));
+  dp->len = len;
+
+  /* Just one copy of the coefficients for the C version */
+  dp->coeffs = (signed short *)calloc(len,sizeof(signed short));
+  for(j=0;j<len;j++)
+    dp->coeffs[j] = coeffs[j];
+  return (void *)dp;
+}
+
+
+/* Free a dot product descriptor created earlier */
+void freedp_port(void *p){
+  struct dotprod *dp = (struct dotprod *)p;
+
+  if(dp->coeffs != NULL)
+      free(dp->coeffs);
+  free(dp);
+}
+
+/* Compute a dot product given a descriptor and an input array
+ * The length is taken from the descriptor
+ */
+long dotprod_port(void *p,signed short a[]){
+  struct dotprod *dp = (struct dotprod *)p;
+  long corr;
+  int i;
+
+  corr = 0;
+  for(i=0;i<dp->len;i++){
+    corr += (long)a[i] * dp->coeffs[i];
+  }
+  return corr;
+}
+
+