// Copyright Daniel Wallin 2006. // 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) // // 2009.10.21 TDS remove depenency on boost::python::detail::referent_storage // #ifndef BOOST_PARAMETER_MAYBE_091021_HPP #define BOOST_PARAMETER_MAYBE_091021_HPP namespace boost { namespace parameter { namespace aux { template <typename T> struct referent_size; }}} // namespace boost::parameter::aux #include <boost/parameter/config.hpp> namespace boost { namespace parameter { namespace aux { template <typename T> struct referent_size<T&> { BOOST_STATIC_CONSTANT(::std::size_t, value = sizeof(T)); }; }}} // namespace boost::parameter::aux #include <boost/type_traits/aligned_storage.hpp> namespace boost { namespace parameter { namespace aux { // A metafunction returning a POD type which can store U, where T == U&. // If T is not a reference type, returns a POD which can store T. template <typename T> struct referent_storage : ::boost::aligned_storage< ::boost::parameter::aux::referent_size<T>::value > { }; }}} // namespace boost::parameter::aux #include <boost/parameter/aux_/is_maybe.hpp> #include <boost/optional/optional.hpp> #if defined(BOOST_PARAMETER_CAN_USE_MP11) #include <type_traits> #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) #include <boost/type_traits/add_lvalue_reference.hpp> #include <boost/type_traits/remove_cv.hpp> #if !BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564)) #include <boost/type_traits/add_const.hpp> #endif #endif // BOOST_PARAMETER_CAN_USE_MP11 namespace boost { namespace parameter { namespace aux { template <typename T> struct maybe : ::boost::parameter::aux::maybe_base { #if defined(BOOST_PARAMETER_CAN_USE_MP11) typedef typename ::std::add_lvalue_reference< typename ::std::add_const<T>::type #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) typedef typename ::boost::add_lvalue_reference< #if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564)) T const #else typename ::boost::add_const<T>::type #endif #endif // BOOST_PARAMETER_CAN_USE_MP11 >::type reference; #if defined(BOOST_PARAMETER_CAN_USE_MP11) typedef typename ::std::remove_cv< typename ::std::remove_reference<reference>::type #else typedef typename ::boost::remove_cv< BOOST_DEDUCED_TYPENAME ::boost::remove_reference<reference>::type #endif >::type non_cv_value; inline explicit maybe(T value_) : value(value_), constructed(false) { } inline maybe() : value(), constructed(false) { } ~maybe() { if (this->constructed) { this->destroy(); } } inline reference construct(reference value_) const { return value_; } template <typename U> reference construct2(U const& value_) const { new (this->m_storage.address()) non_cv_value(value_); this->constructed = true; return *reinterpret_cast<non_cv_value*>( this->m_storage.address() ); } template <typename U> inline reference construct(U const& value_) const { return this->construct2(value_); } void destroy() { reinterpret_cast<non_cv_value*>( this->m_storage.address() )->~non_cv_value(); } typedef reference( ::boost::parameter::aux::maybe<T>::*safe_bool )() const; inline operator safe_bool() const { return this->value ? &::boost::parameter::aux::maybe<T>::get : 0; } inline reference get() const { return this->value.get(); } private: ::boost::optional<T> value; mutable bool constructed; mutable typename ::boost::parameter::aux ::referent_storage<reference>::type m_storage; }; }}} // namespace boost::parameter::aux #endif // include guard