Add variadic min/max

include/boost/beast/core/detail/type_traits.hpp

@@ -180,6 +180,80 @@ struct is_contiguous_container<T, E, void_t<
     >::type>>: std::true_type
 {};
 
+template<class...>
+struct unwidest_unsigned;
+
+template<class U0>
+struct unwidest_unsigned<U0>
+{
+    using type = U0;
+};
+
+template<class U0, class... UN>
+struct unwidest_unsigned<U0, UN...>
+{
+    BOOST_STATIC_ASSERT(std::is_unsigned<U0>::value);
+    using type = typename std::conditional<
+        (sizeof(U0) < sizeof(typename unwidest_unsigned<UN...>::type)),
+        U0, typename unwidest_unsigned<UN...>::type>::type;
+};
+
+template<class...>
+struct widest_unsigned;
+
+template<class U0>
+struct widest_unsigned<U0>
+{
+    using type = U0;
+};
+
+template<class U0, class... UN>
+struct widest_unsigned<U0, UN...>
+{
+    BOOST_STATIC_ASSERT(std::is_unsigned<U0>::value);
+    using type = typename std::conditional<
+        (sizeof(U0) > sizeof(typename widest_unsigned<UN...>::type)),
+        U0, typename widest_unsigned<UN...>::type>::type;
+};
+
+template<class U>
+inline
+constexpr
+U
+min_all(U u)
+{
+    BOOST_STATIC_ASSERT(std::is_unsigned<U>::value);
+    return u;
+}
+
+template<class U0, class U1, class... UN>
+inline
+constexpr
+typename unwidest_unsigned<U0, U1, UN...>::type
+min_all(U0 u0, U1 u1, UN... un)
+{
+    return u0 < u1? min_all(u0, un...) : min_all(u1, un...);
+}
+
+template<class U>
+inline
+constexpr
+U
+max_all(U u)
+{
+    BOOST_STATIC_ASSERT(std::is_unsigned<U>::value);
+    return u;
+}
+
+template<class U0, class U1, class... UN>
+inline
+constexpr
+typename widest_unsigned<U0, U1, UN...>::type
+max_all(U0 u0, U1 u1, UN... un)
+{
+    return u0 > u1? max_all(u0, un...) : max_all(u1, un...);
+}
+
 //------------------------------------------------------------------------------
 
 //