AKAZE optimizations

modules/features2d/src/kaze/utils.h

@@ -74,4 +74,24 @@ inline int fRound(float flt) {
   return (int)(flt + 0.5f);
 }
 
+/* ************************************************************************* */
+/**
+ * @brief Exponentiation by squaring
+ * @param flt Exponentiation base
+ * @return dst Exponentiation value
+ */
+inline int fastpow(int base, int exp) {
+    int res = 1;
+    while(exp > 0) {
+        if(exp & 1) {
+            exp--;
+            res *= base;
+        } else {
+            exp /= 2;
+            base *= base;
+        }
+    }
+    return res;
+}
+
 #endif