Imported Upstream version 1.67.0upstream/1.67.0

1 files changed, 107 insertions, 0 deletions

diff --git a/boost/hof/detail/delegate.hpp b/boost/hof/detail/delegate.hpp
new file mode 100644
index 0000000000..af2179680d
--- /dev/null
+++ b/boost/hof/detail/delegate.hpp
@@ -0,0 +1,107 @@
+/*=============================================================================
+    Copyright (c) 2012 Paul Fultz II
+    delgate.h
+    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)
+==============================================================================*/
+
+#ifndef BOOST_HOF_GUARD_FUNCTION_DELGATE_H
+#define BOOST_HOF_GUARD_FUNCTION_DELGATE_H
+
+#include <type_traits>
+#include <utility>
+#include <boost/hof/config.hpp>
+#include <boost/hof/detail/and.hpp>
+#include <boost/hof/detail/holder.hpp>
+#include <boost/hof/detail/forward.hpp>
+#include <boost/hof/detail/using.hpp>
+#include <boost/hof/detail/intrinsics.hpp>
+#include <boost/hof/detail/noexcept.hpp>
+
+
+#define BOOST_HOF_ENABLE_IF_CONVERTIBLE(...) \
+    class=typename std::enable_if<BOOST_HOF_IS_CONVERTIBLE(__VA_ARGS__)>::type
+
+#define BOOST_HOF_ENABLE_IF_CONVERTIBLE_UNPACK(...) \
+    class=typename std::enable_if<BOOST_HOF_AND_UNPACK(BOOST_HOF_IS_CONVERTIBLE(__VA_ARGS__))>::type
+
+#define BOOST_HOF_ENABLE_IF_BASE_OF(...) \
+    class=typename std::enable_if<BOOST_HOF_IS_BASE_OF(__VA_ARGS__)>::type
+
+#define BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(...) \
+    class=typename std::enable_if<BOOST_HOF_IS_CONSTRUCTIBLE(__VA_ARGS__)>::type
+
+#define BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(...) \
+    BOOST_HOF_NOEXCEPT(BOOST_HOF_IS_NOTHROW_CONSTRUCTIBLE(__VA_ARGS__))
+
+#define BOOST_HOF_INHERIT_DEFAULT(C, ...) \
+    template<bool FitPrivateEnableBool_##__LINE__=true, \
+    class=typename std::enable_if<FitPrivateEnableBool_##__LINE__ && boost::hof::detail::is_default_constructible_c<__VA_ARGS__>()>::type> \
+    constexpr C() BOOST_HOF_NOEXCEPT(boost::hof::detail::is_nothrow_default_constructible_c<__VA_ARGS__>()) {}
+
+#define BOOST_HOF_INHERIT_DEFAULT_EMPTY(C, ...) \
+    template<bool FitPrivateEnableBool_##__LINE__=true, \
+    class=typename std::enable_if<FitPrivateEnableBool_##__LINE__ && \
+        boost::hof::detail::is_default_constructible_c<__VA_ARGS__>() && BOOST_HOF_IS_EMPTY(__VA_ARGS__) \
+    >::type> \
+    constexpr C() BOOST_HOF_NOEXCEPT(boost::hof::detail::is_nothrow_default_constructible_c<__VA_ARGS__>()) {}
+
+#if BOOST_HOF_NO_TYPE_PACK_EXPANSION_IN_TEMPLATE
+
+#define BOOST_HOF_DELGATE_PRIMITIVE_CONSTRUCTOR(constexpr_, C, T, var) \
+    template<class... FitXs, typename boost::hof::detail::enable_if_constructible<C, T, FitXs...>::type = 0> \
+    constexpr_ C(FitXs&&... fit_xs) \
+    BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(T, FitXs&&...) \
+    : var((FitXs&&)boost::hof::forward<FitXs>(fit_xs)...) {}
+    
+#else
+#define BOOST_HOF_DELGATE_PRIMITIVE_CONSTRUCTOR(constexpr_, C, T, var) \
+    template<class... FitXs, BOOST_HOF_ENABLE_IF_CONSTRUCTIBLE(T, FitXs&&...)> \
+    constexpr_ C(FitXs&&... fit_xs) \
+    BOOST_HOF_NOEXCEPT_CONSTRUCTIBLE(T, FitXs&&...) \
+    : var(BOOST_HOF_FORWARD(FitXs)(fit_xs)...) {}
+
+#endif
+
+#define BOOST_HOF_DELEGATE_CONSTRUCTOR(C, T, var) BOOST_HOF_DELGATE_PRIMITIVE_CONSTRUCTOR(constexpr, C, T, var)
+
+// Currently its faster to use `BOOST_HOF_DELEGATE_CONSTRUCTOR` than `using
+// Base::Base;`
+#if 1
+#define BOOST_HOF_INHERIT_CONSTRUCTOR(Derived, Base) BOOST_HOF_DELEGATE_CONSTRUCTOR(Derived, Base, Base)
+#else
+#define BOOST_HOF_INHERIT_CONSTRUCTOR(Derived, Base) \
+    using fit_inherit_base = Base; \
+    using fit_inherit_base::fit_inherit_base; \
+    Derived()=default; \
+    template<class FitX, BOOST_HOF_ENABLE_IF_CONVERTIBLE(FitX, Base)> \
+    constexpr Derived(FitX&& fit_x) : Base(BOOST_HOF_FORWARD(FitX)(fit_x)) {}
+#endif
+
+namespace boost { namespace hof {
+namespace detail {
+
+template<class... Xs>
+constexpr bool is_nothrow_default_constructible_c()
+{
+    return BOOST_HOF_AND_UNPACK(BOOST_HOF_IS_NOTHROW_CONSTRUCTIBLE(Xs));
+}
+
+template<class... Xs>
+constexpr bool is_default_constructible_c()
+{
+    return BOOST_HOF_AND_UNPACK(BOOST_HOF_IS_DEFAULT_CONSTRUCTIBLE(Xs));
+}
+
+template<class... Xs>
+BOOST_HOF_USING(is_default_constructible, std::integral_constant<bool, is_default_constructible_c<Xs...>()>);
+
+template<class C, class X, class... Xs>
+struct enable_if_constructible
+: std::enable_if<is_constructible<X, Xs&&...>::value, int>
+{};
+
+}
+}} // namespace boost::hof
+
+#endif