Check for overflow in Score * int multiplication (#969)

[stockfish] / src / types.h

diff --git a/src/types.h b/src/types.h
index 595290dfeaf87a854e36c789249758b78bd2c036..4d113e1b9edfe703c44453abafa59b47a24fc7ff 100644 (file)
--- a/src/types.h
+++ b/src/types.h
@@ -285,19 +285,19 @@ inline Value mg_value(Score s) {
 #define ENABLE_BASE_OPERATORS_ON(T)                             \
 inline T operator+(T d1, T d2) { return T(int(d1) + int(d2)); } \
 inline T operator-(T d1, T d2) { return T(int(d1) - int(d2)); } \
-inline T operator*(int i, T d) { return T(i * int(d)); }        \
-inline T operator*(T d, int i) { return T(int(d) * i); }        \
 inline T operator-(T d) { return T(-int(d)); }                  \
 inline T& operator+=(T& d1, T d2) { return d1 = d1 + d2; }      \
 inline T& operator-=(T& d1, T d2) { return d1 = d1 - d2; }      \
-inline T& operator*=(T& d, int i) { return d = T(int(d) * i); }
 
 #define ENABLE_FULL_OPERATORS_ON(T)                             \
 ENABLE_BASE_OPERATORS_ON(T)                                     \
+inline T operator*(int i, T d) { return T(i * int(d)); }        \
+inline T operator*(T d, int i) { return T(int(d) * i); }        \
 inline T& operator++(T& d) { return d = T(int(d) + 1); }        \
 inline T& operator--(T& d) { return d = T(int(d) - 1); }        \
 inline T operator/(T d, int i) { return T(int(d) / i); }        \
 inline int operator/(T d1, T d2) { return int(d1) / int(d2); }  \
+inline T& operator*=(T& d, int i) { return d = T(int(d) * i); } \
 inline T& operator/=(T& d, int i) { return d = T(int(d) / i); }
 
 ENABLE_FULL_OPERATORS_ON(Value)
@@ -329,6 +329,17 @@ inline Score operator/(Score s, int i) {
   return make_score(mg_value(s) / i, eg_value(s) / i);
 }
 
+/// Multiplication of a Score by an integer. We check for overflow in debug mode.
+inline Score operator*(Score s, int i) {
+  Score result = Score(int(s) * i);
+
+  assert(eg_value(result) == (i * eg_value(s)));
+  assert(mg_value(result) == (i * mg_value(s)));
+  assert((i == 0) || (result / i) == s );
+
+  return result;
+}
+
 inline Color operator~(Color c) {
   return Color(c ^ BLACK); // Toggle color
 }