+#define TRANSITION(old, new) (((old) << 2) | new)
+static const int table[16] = {
+ [TRANSITION(0,1)] = +1,
+ [TRANSITION(1,3)] = +1,
+ [TRANSITION(3,2)] = +1,
+ [TRANSITION(2,0)] = +1,
+
+ [TRANSITION(1,0)] = -1,
+ [TRANSITION(3,1)] = -1,
+ [TRANSITION(2,3)] = -1,
+ [TRANSITION(0,2)] = -1,
+};