ceph/src/boost/boost/contract/detail/type_traits/optional.hpp

   1
   2 #ifndef BOOST_CONTRACT_DETAIL_OPTIONAL_HPP_
   3 #define BOOST_CONTRACT_DETAIL_OPTIONAL_HPP_
   4
   5 // Copyright (C) 2008-2018 Lorenzo Caminiti
   6 // Distributed under the Boost Software License, Version 1.0 (see accompanying
   7 // file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
   8 // See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
   9
  10 #include <boost/optional.hpp>
  11 #include <boost/type_traits/remove_reference.hpp>
  12 #include <boost/type_traits/integral_constant.hpp>
  13
  14 namespace boost { namespace contract { namespace detail {
  15
  16 template<typename T>
  17 struct is_optional : boost::false_type {};
  18 template<typename T>
  19 struct is_optional<boost::optional<T> > : boost::true_type {};
  20
  21 template<typename T>
  22 struct optional_value_type { typedef T type; };
  23 template<typename T>
  24 struct optional_value_type<boost::optional<T> > { typedef T type; };
  25
  26 template<typename T>
  27 struct remove_value_reference_if_optional { typedef T type; };
  28 template<typename T>
  29 struct remove_value_reference_if_optional<boost::optional<T> >
  30         { typedef typename boost::remove_reference<T>::type type; };
  31
  32 template<typename T>
  33 T& optional_get(T& x) { return x; }
  34 template<typename T>
  35 T& optional_get(boost::optional<T>& x) { return x.get(); }
  36 template<typename T>
  37 T& optional_get(boost::optional<T&>& x) { return x.get(); }
  38
  39 } } } // namespace
  40
  41 #endif // #include guard
  42