#endif
-// Templetized enum operations, we avoid to repeat the same inlines for each
-// different enum.
+// Templetized operators used by enum types like Depth, Piece, Square and so on.
+// We don't want to write the same inline for each different enum. Note that we
+// pass by value (to silence scaring warnings on volatiles), so you really should
+// use only enum types with these functions to avoid hidden copies.
template<typename T>
inline T operator+ (const T d1, const T d2) { return T(int(d1) + int(d2)); }
inline T operator- (const T d1, const T d2) { return T(int(d1) - int(d2)); }
template<typename T>
-inline T operator* (int i, const T d) { return T(int(d) * i); }
+inline T operator* (int i, const T d) { return T(i * int(d)); }
+
+template<typename T>
+inline T operator* (const T d, int i) { return T(int(d) * i); }
template<typename T>
inline T operator/ (const T d, int i) { return T(int(d) / i); }
template<typename T>
inline void operator+= (T& d1, const T d2) { d1 = d1 + d2; }
+template<typename T>
+inline void operator-= (T& d1, const T d2) { d1 = d1 - d2; }
+
template<typename T>
inline void operator*= (T& d, int i) { d = T(int(d) * i); }
template<typename T>
-inline void operator/= (T &d, int i) { d = T(int(d) / i); }
+inline void operator/= (T& d, int i) { d = T(int(d) / i); }
#endif // !defined(TYPES_H_INCLUDED)