From 751f06dc3eeeb72e8ada322d023c828c434e19df Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 20 Mar 2015 01:32:28 +1100
Subject: [PATCH] traits: add try_signed convertor

---
 types/traits.hpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/types/traits.hpp b/types/traits.hpp
index 4c47e119..b711fd66 100644
--- a/types/traits.hpp
+++ b/types/traits.hpp
@@ -60,6 +60,17 @@ template <> struct try_unsigned<double> { typedef double type; };
 template <> struct try_unsigned<float > { typedef float  type; };
 
 
+///----------------------------------------------------------------------------
+/// find the signed version of a type if one exists
+template <typename T>
+struct try_signed
+{
+    typedef typename std::make_signed<T>::type type;
+};
+
+template <> struct try_signed<double> { typedef double type; };
+template <> struct try_signed<float > { typedef float  type; };
+
 ///----------------------------------------------------------------------------
 /// checks if a type can be converted in all cases without modification
 template <typename T, typename U> struct is_lossless_cast : std::enable_if<