From f88e873f55362bdc85b1461cf573e8cd3fc087fa Mon Sep 17 00:00:00 2001
From: Maxime Coste <frrrwww@gmail.com>
Date: Sat, 28 Feb 2015 17:08:19 +0000
Subject: [PATCH] Add IndexSequence and make_index_sequence utilities

---
 src/utils.hh | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/utils.hh b/src/utils.hh
index fbf39e10..c441cdf3 100644
--- a/src/utils.hh
+++ b/src/utils.hh
@@ -14,6 +14,28 @@ std::unique_ptr<T> make_unique(Args&&... args)
     return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
 }
 
+template<size_t... I>
+struct IndexSequence
+{
+    using Next = IndexSequence<I..., sizeof...(I)>;
+};
+
+template<size_t N>
+struct MakeIndexSequence
+{
+    using Type = typename MakeIndexSequence<N-1>::Type::Next;
+};
+
+template<>
+struct MakeIndexSequence<0>
+{
+    using Type = IndexSequence<>;
+};
+
+template<size_t N>
+constexpr typename MakeIndexSequence<N>::Type
+make_index_sequence() { return typename MakeIndexSequence<N>::Type{}; }
+
 // *** Singleton ***
 //
 // Singleton helper class, every singleton type T should inherit