From 02a42f282e7269387f2d79e5c24f755147a47b71 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 13 Nov 2015 13:47:13 +1100
Subject: [PATCH] maths: use SFINAE for round_to instead of assert

---
 maths.hpp | 14 ++++++++++++--
 maths.ipp | 10 ----------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/maths.hpp b/maths.hpp
index 9a9bfee8..277b19b5 100644
--- a/maths.hpp
+++ b/maths.hpp
@@ -89,8 +89,18 @@ rootsquare [[gnu::pure]] (T a, T b);
 //-----------------------------------------------------------------------------
 // Rounding
 template <typename T, typename U>
-typename std::common_type<T, U>::type
-round_to [[gnu::pure]] (T value, U size);
+inline
+typename std::common_type<
+    std::enable_if_t<std::is_integral<T>::value,T>,
+    std::enable_if_t<std::is_integral<U>::value,U>
+>::type
+round_to [[gnu::const]] (T value, U size)
+{
+    if (value % size == 0)
+        return value;
+
+    return value + (size - value % size);
+}
 
 
 template <typename T>
diff --git a/maths.ipp b/maths.ipp
index 7cddf28a..a62eeb7c 100644
--- a/maths.ipp
+++ b/maths.ipp
@@ -22,16 +22,6 @@
 
 #include <type_traits>
 
-//-----------------------------------------------------------------------------
-template <typename T, typename U>
-typename std::common_type<T,U>::type
-round_to (T value, U size) {
-    static_assert (std::is_integral<T>::value, "align requires integral types");
-    static_assert (std::is_integral<U>::value, "align requires integral types");
-
-    return divup (value, size) * size;
-}
-
 
 //-----------------------------------------------------------------------------
 template <typename T>