From 3c3d45d94c66cb922f8c622b28590f9c115f58f1 Mon Sep 17 00:00:00 2001
From: Vraiment <jemc44@gmail.com>
Date: Sun, 30 Jul 2017 23:44:28 -0700
Subject: [PATCH] Added TupleHasType class for template metaprogramming

---
 SDL2pp/Private/Utility.hh | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/SDL2pp/Private/Utility.hh b/SDL2pp/Private/Utility.hh
index 7ba47f0..67e6403 100644
--- a/SDL2pp/Private/Utility.hh
+++ b/SDL2pp/Private/Utility.hh
@@ -28,9 +28,9 @@
 #include <utility>
 #endif
 
+#include <tuple>
 #include <type_traits>
 
-
 namespace SDL2pp {
 /*
  * This is code not to be used directly by users of SDL2pp.
@@ -93,6 +93,25 @@ namespace Private {
 	template <typename T, typename... Tx>
 	using And = typename AndOperation<T, Tx...>::type;
 #endif
+
+/*
+ * Templated class to an specific type in a tuple, returns std::true_type if the
+ * tuple contains T, std::false_type otherwise.
+ */
+template <typename T, typename Tuple>
+struct TupleHasTypeOperation;
+
+template <typename T>
+struct TupleHasTypeOperation<T, std::tuple<>> : std::false_type { };
+
+template <typename T, typename U, typename... Tx>
+struct TupleHasTypeOperation<T, std::tuple<U, Tx...>> : TupleHasTypeOperation<T, std::tuple<Tx...>> { };
+
+template <typename T, typename... Tx>
+struct TupleHasTypeOperation<T, std::tuple<T, Tx...>> : std::true_type { };
+
+template <typename T, typename... Tx>
+using TupleHasType = typename TupleHasTypeOperation<T, Tx...>::type;
 }
 }