1 files changed, 88 insertions, 0 deletions
diff --git a/common/utility.hpp b/common/utility.hpp
new file mode 100644
index 0000000..cbd19e3
--- /dev/null
+++ b/common/utility.hpp
@@ -0,0 +1,88 @@
+#pragma once
+
+namespace rawaccel {
+
+    constexpr double minsd(double a, double b) 
+    {
+        return (a < b) ? a : b;
+    }
+
+    constexpr double maxsd(double a, double b) 
+    {
+        return (b < a) ? a : b;
+    }
+
+    constexpr double clampsd(double v, double lo, double hi) 
+    {
+        return minsd(maxsd(v, lo), hi);
+    }
+
+    template <typename T>
+    constexpr const T& min(const T& a, const T& b)
+    {
+        return (b < a) ? b : a;
+    }
+
+    template <typename T>
+    constexpr const T& max(const T& a, const T& b)
+    {
+        return (b < a) ? a : b;
+    }
+
+    template <typename T>
+    constexpr const T& clamp(const T& v, const T& lo, const T& hi)
+    {
+        return (v < lo) ? lo : (hi < v) ? hi : v;
+    }
+
+    constexpr double lerp(double a, double b, double t)
+    {
+        double x = a + t * (b - a);
+        if ((t > 1) == (a < b)) {
+            return maxsd(x, b);
+        }
+        return minsd(x, b);
+    }
+
+    // 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;
+    }
+
+    // returns x * 2^n if n is in [-1022, 1023] 
+    inline double scalbn(double x, int n)
+    {
+        union { double f; unsigned long long i; } u;
+        u.i = static_cast<unsigned long long>(0x3ff + n) << 52;
+        return x * u.f;
+    }
+
+    inline bool infnan(double x)
+    {
+	    return ilogb(x) == 0x400;
+    }
+
+    struct noop { 
+        template <typename... Ts> 
+        constexpr void operator()(Ts&&...) const noexcept {}
+    };
+
+    template <typename T> struct remove_ref { using type = T; };
+    template <typename T> struct remove_ref<T&> { using type = T; };
+    template <typename T> struct remove_ref<T&&> { using type = T; };
+
+    template <typename T>
+    using remove_ref_t = typename remove_ref<T>::type;
+
+    template <typename T, typename U>
+    struct is_same { static constexpr bool value = false; };
+
+    template <typename T>
+    struct is_same<T, T> { static constexpr bool value = true; };
+
+    template <typename T, typename U>
+    inline constexpr bool is_same_v = is_same<T, U>::value;
+
+}