Imported Upstream version 1.65.0upstream/1.65.0

Change-Id: Icf8400b375482cb11bcf77440a6934ba360d6ba4
Signed-off-by: DongHun Kwak <dh0128.kwak@samsung.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/boost/poly_collection/detail/is_invocable.hpp b/boost/poly_collection/detail/is_invocable.hpp
new file mode 100644
index 0000000000..c93ba476b7
--- /dev/null
+++ b/boost/poly_collection/detail/is_invocable.hpp
@@ -0,0 +1,97 @@
+/* Copyright 2016-2017 Joaquin M Lopez Munoz.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See http://www.boost.org/libs/poly_collection for library home page.
+ */
+
+#ifndef BOOST_POLY_COLLECTION_DETAIL_IS_INVOCABLE_HPP
+#define BOOST_POLY_COLLECTION_DETAIL_IS_INVOCABLE_HPP
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <functional>
+#include <type_traits>
+
+/* technique explained at
+ * http://bannalia.blogspot.com/2016/09/compile-time-checking-existence-of.html 
+ */
+
+namespace boost{
+namespace poly_collection{
+namespace detail{
+namespace is_invocable_fallback{
+
+template <typename F,typename... Args>
+struct is_invocable:
+  std::is_constructible<
+    std::function<void(Args...)>,
+    std::reference_wrapper<typename std::remove_reference<F>::type>
+  >
+{};
+
+template <typename R,typename F,typename... Args>
+struct is_invocable_r:
+  std::is_constructible<
+    std::function<R(Args...)>,
+    std::reference_wrapper<typename std::remove_reference<F>::type>
+  >
+{};
+
+struct hook{};
+
+}}}}
+
+namespace std{
+
+template<>
+struct is_void< ::boost::poly_collection::detail::is_invocable_fallback::hook>:
+  std::false_type
+{      
+  template<typename F,typename... Args>
+  static constexpr bool is_invocable_f()
+  {
+    using namespace ::boost::poly_collection::detail::is_invocable_fallback;
+    return is_invocable<F,Args...>::value;
+  }
+
+  template<typename R,typename F,typename... Args>
+  static constexpr bool is_invocable_r_f()
+  {
+    using namespace ::boost::poly_collection::detail::is_invocable_fallback;
+    return is_invocable_r<R,F,Args...>::value;
+  }
+};
+
+} /* namespace std */
+
+namespace boost{
+
+namespace poly_collection{
+
+namespace detail{
+
+template<typename F,typename... Args>
+struct is_invocable:std::integral_constant<
+  bool,
+  std::is_void<is_invocable_fallback::hook>::template
+    is_invocable_f<F,Args...>()
+>{};
+
+template<typename R,typename F,typename... Args>
+struct is_invocable_r:std::integral_constant<
+  bool,
+  std::is_void<is_invocable_fallback::hook>::template
+    is_invocable_r_f<R,F,Args...>()
+>{};
+
+} /* namespace poly_collection::detail */
+
+} /* namespace poly_collection */
+
+} /* namespace boost */
+
+#endif