Index: base/template_util.h |
diff --git a/base/template_util.h b/base/template_util.h |
index 1bfc1ac814a23ceb186a9fcf6fa5924281d92783..af4cdd5a21c4993dca662b7c717dfcc25b7f1714 100644 |
--- a/base/template_util.h |
+++ b/base/template_util.h |
@@ -29,6 +29,20 @@ template <class T> struct is_non_const_reference : std::false_type {}; |
template <class T> struct is_non_const_reference<T&> : std::true_type {}; |
template <class T> struct is_non_const_reference<const T&> : std::false_type {}; |
+// underlying_number |
+// Casts an enum to its underlying integral type, leaves other numbers alone. |
+// Useful for scoped enums, which don't cast implicitly. |
+template <typename T, |
+ typename std::enable_if<std::is_enum<T>::value, int>::type = 0> |
+constexpr typename std::underlying_type<T>::type underlying_number(T val) { |
+ return static_cast<typename std::underlying_type<T>::type>(val); |
+} |
+template <typename T, |
+ typename std::enable_if<std::is_arithmetic<T>::value, int>::type = 0> |
+constexpr T underlying_number(T val) { |
+ return val; |
+} |
+ |
// is_assignable |
namespace internal { |