From bce8ef3ed0e168ba7f43f570b07634bc248917c7 Mon Sep 17 00:00:00 2001
From: Adam Demuri <adam.demuri@gmail.com>
Date: Sat, 8 Feb 2020 11:12:07 -0700
Subject: [PATCH] Implement std::is_integral

I tested that this compiles for Arduino UNO, including vectors with
integral and non-integral types.
---
 src/type_traits | 115 +++++++++++++++++++++++++-----------------------
 src/vector      |   6 +--
 2 files changed, 63 insertions(+), 58 deletions(-)

diff --git a/src/type_traits b/src/type_traits
index fa1de40c..885cbfa7 100644
--- a/src/type_traits
+++ b/src/type_traits
@@ -28,61 +28,66 @@
 #pragma GCC visibility push(default)
 
 namespace std{
-
-	struct _UCXXEXPORT __true_type{};
-	struct _UCXXEXPORT __false_type{};
-
-	template <class I> class _UCXXEXPORT __is_integer{
-	public:
-		typedef __false_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <unsigned int>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <signed int>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <short unsigned int>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <short signed int>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <char>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <signed char>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <unsigned char>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <long unsigned int>{
-	public:
-		typedef __true_type value;
-	};
-
-	template <> class _UCXXEXPORT __is_integer <long signed int>{
-	public:
-		typedef __true_type value;
-	};
-
-
+  template<typename _Tp, _Tp __v>
+    struct integral_constant
+    {
+      static constexpr _Tp                  value = __v;
+      typedef _Tp                           value_type;
+      typedef integral_constant<_Tp, __v>   type;
+      constexpr operator value_type() const { return value; }
+    };
+
+  template<typename _Tp, _Tp __v>
+    constexpr _Tp integral_constant<_Tp, __v>::value;
+
+  typedef integral_constant<bool, true>     true_type;
+
+  typedef integral_constant<bool, false>    false_type;
+
+	template <class I>
+    class _UCXXEXPORT __is_integral_helper
+    : public false_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <unsigned int>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <signed int>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <short unsigned int>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <short signed int>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <char>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <signed char>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <unsigned char>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <long unsigned int>
+    : public true_type { };
+
+	template <>
+    class _UCXXEXPORT __is_integral_helper <long signed int>
+    : public true_type { };
+
+  template<typename _Tp>
+    struct is_integral
+    : public __is_integral_helper<_Tp>::type
+    { };
 
 }
 
diff --git a/src/vector b/src/vector
index 1c113e37..7fd38e2c 100644
--- a/src/vector
+++ b/src/vector
@@ -292,13 +292,13 @@ namespace std{
 		}
 
 		template <class InputIterator>
-			inline void _dispatch_insert(iterator position, InputIterator first, InputIterator last, __true_type)
+			inline void _dispatch_insert(iterator position, InputIterator first, InputIterator last, true_type)
 		{
 			_insert_fill(position, first, last);
 		}
 
 		template <class InputIterator>
-			inline void _dispatch_insert(iterator position, InputIterator first, InputIterator last, __false_type)
+			inline void _dispatch_insert(iterator position, InputIterator first, InputIterator last, false_type)
 		{
 				_insert_from_iterator(position, first, last);
 		}
@@ -308,7 +308,7 @@ namespace std{
 		}
 
 		template <class InputIterator> inline void insert(iterator position, InputIterator first, InputIterator last){
-			typedef typename __is_integer<InputIterator>::value __some_type;
+			typedef typename is_integral<InputIterator>::value __some_type;
 			_dispatch_insert(position, first, last, __some_type());
 		}