add zero/inf/nan guards

2 files changed, 18 insertions, 2 deletions

diff --git a/common/rawaccel.hpp b/common/rawaccel.hpp
index 67b4e61..f6bc0fd 100644
--- a/common/rawaccel.hpp
+++ b/common/rawaccel.hpp
@@ -218,8 +218,12 @@ namespace rawaccel {
                     movement.y *= scale;
                 }
                 else {
-                    movement.x *= accels.x.apply(fabs(movement.x) * norm);
-                    movement.y *= accels.y.apply(fabs(movement.y) * norm);
+                    if (movement.x != 0) {
+                        movement.x *= accels.x.apply(fabs(movement.x) * norm);
+                    }
+                    if (movement.y != 0) {
+                        movement.y *= accels.y.apply(fabs(movement.y) * norm);
+                    }
                 }
             }
         }
diff --git a/common/utility.hpp b/common/utility.hpp
index 40bc7c4..d7b63cf 100644
--- a/common/utility.hpp
+++ b/common/utility.hpp
@@ -28,3 +28,15 @@ inline constexpr double maxsd(double a, double b) {
 inline constexpr double clampsd(double v, double lo, double hi) {
     return minsd(maxsd(v, lo), hi);
 }
+
+// returns the unbiased exponent of x if x is normal 
+inline int ilogb(double x)
+{
+	union { double f; unsigned long long i; } u = { x };
+	return static_cast<int>((u.i >> 52) & 0x7ff) - 0x3ff;
+}
+
+inline bool infnan(double x)
+{
+	return ilogb(x) == 0x400;
+}