Source codes

1 files changed, 43 insertions, 0 deletions

diff --git a/ComLightLib/utils/typeTraits.hpp b/ComLightLib/utils/typeTraits.hpp
new file mode 100644
index 0000000..c5ddb84
--- /dev/null
+++ b/ComLightLib/utils/typeTraits.hpp
@@ -0,0 +1,43 @@
+#pragma once
+#include <type_traits>
+
+namespace ComLight
+{
+	namespace details
+	{
+		template<class TResult, class TValue>
+		constexpr bool pointersAssignable()
+		{
+			// See this for why `&` is required: https://stackoverflow.com/a/52429468/126995
+			return std::is_assignable<TResult*&, TValue*>::value;
+		}
+	}
+}
+
+// https://en.wikibooks.org/wiki/More_C++_Idioms/Member_Detector
+#define GENERATE_HAS_MEMBER(member)                                               \
+                                                                                  \
+template < class T >                                                              \
+class HasMember_##member                                                          \
+{                                                                                 \
+private:                                                                          \
+    using Yes = char[2];                                                          \
+    using  No = char[1];                                                          \
+                                                                                  \
+    struct Fallback { int member; };                                              \
+    struct Derived : T, Fallback { };                                             \
+                                                                                  \
+    template < class U >                                                          \
+    static No& test ( decltype(U::member)* );                                     \
+    template < typename U >                                                       \
+    static Yes& test ( U* );                                                      \
+                                                                                  \
+public:                                                                           \
+    static constexpr bool RESULT = sizeof(test<Derived>(nullptr)) == sizeof(Yes); \
+};                                                                                \
+                                                                                  \
+template < class T >                                                              \
+struct has_member_##member                                                        \
+: public std::integral_constant<bool, HasMember_##member<T>::RESULT>              \
+{                                                                                 \
+};