1 files changed, 72 insertions, 0 deletions
diff --git a/src/core/math/constexpr.hh b/src/core/math/constexpr.hh
new file mode 100644
index 0000000..4158803
--- /dev/null
+++ b/src/core/math/constexpr.hh
@@ -0,0 +1,72 @@
+#pragma once
+
+#include "core/math/concepts.hh"
+
+namespace math
+{
+template<typename type, std::size_t size>
+constexpr std::size_t array_size(const type (&)[size]);
+} // namespace math
+
+namespace math
+{
+template<std::integral scalar>
+constexpr scalar log2(const scalar x);
+template<std::signed_integral scalar>
+constexpr scalar mod_signed(const scalar x, const scalar m);
+template<math::signed_arithmetic result_scalar, math::arithmetic scalar>
+constexpr result_scalar sign(const scalar x);
+} // namespace math
+
+namespace math
+{
+template<math::arithmetic scalar>
+constexpr scalar degrees(const scalar x);
+template<math::arithmetic scalar>
+constexpr scalar radians(const scalar x);
+} // namespace math
+
+template<typename type, std::size_t size>
+constexpr std::size_t math::array_size(const type (&)[size])
+{
+    return size;
+}
+
+template<std::integral scalar>
+constexpr scalar math::log2(const scalar x)
+{
+    if(x < static_cast<scalar>(2))
+        return static_cast<scalar>(0);
+    return math::log2<scalar>((x + static_cast<scalar>(1)) >> 1) + static_cast<scalar>(1);
+}
+
+template<std::signed_integral scalar>
+constexpr scalar math::mod_signed(const scalar x, const scalar m)
+{
+    auto result = static_cast<scalar>(x % m);
+    if(result < static_cast<scalar>(0))
+        return result + m;
+    return result;
+}
+
+template<math::signed_arithmetic result_scalar, math::arithmetic scalar>
+constexpr result_scalar math::sign(const scalar x)
+{
+    if(x < static_cast<scalar>(0))
+        return static_cast<result_scalar>(-1);
+    if(x > static_cast<scalar>(0))
+        return static_cast<result_scalar>(+1);
+    return static_cast<result_scalar>(0);
+}
+
+template<math::arithmetic scalar>
+constexpr scalar math::degrees(const scalar x)
+{
+    return static_cast<scalar>(static_cast<double>(x) * 180.0 / M_PI);
+}
+
+template<math::arithmetic scalar>
+constexpr scalar math::radians(const scalar x)
+{
+    return static_cast<scalar>(static_cast<double>(x) * M_PI / 180.0);
+}