ceph/src/boost/libs/type_erasure/include/boost/type_erasure/detail/storage.hpp

   1 // Boost.TypeErasure library
   2 //
   3 // Copyright 2011 Steven Watanabe
   4 //
   5 // Distributed under the Boost Software License Version 1.0. (See
   6 // accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8 //
   9 // $Id$
  10
  11 #ifndef BOOST_TYPE_ERASURE_DETAIL_STORAGE_HPP_INCLUDED
  12 #define BOOST_TYPE_ERASURE_DETAIL_STORAGE_HPP_INCLUDED
  13
  14 #include <boost/config.hpp>
  15 #include <boost/type_traits/remove_reference.hpp>
  16 #include <boost/type_traits/remove_cv.hpp>
  17
  18 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  19 #   include <utility> // for std::forward, std::move
  20 #endif
  21
  22 #ifdef BOOST_MSVC
  23 #pragma warning(push)
  24 #pragma warning(disable:4521)
  25 #endif
  26
  27 namespace boost {
  28 namespace type_erasure {
  29 namespace detail {
  30
  31 struct storage
  32 {
  33     storage() {}
  34 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  35     storage(storage& other) : data(other.data) {}
  36     storage(const storage& other) : data(other.data) {}
  37     storage(storage&& other) : data(other.data) {}
  38     storage& operator=(const storage& other) { data = other.data; return *this; }
  39     template<class T>
  40     explicit storage(T&& arg) : data(new typename remove_cv<
  41         typename remove_reference<T>::type>::type(std::forward<T>(arg))) {}
  42 #else
  43     template<class T>
  44     explicit storage(const T& arg) : data(new T(arg)) {}
  45 #endif
  46     void* data;
  47 };
  48
  49
  50 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  51
  52 template<class T>
  53 T extract(T arg) { return std::forward<T>(arg); }
  54
  55 #else
  56
  57 template<class T>
  58 T extract(T arg) { return arg; }
  59
  60 #endif
  61
  62 template<class T>
  63 T extract(storage& arg)
  64 {
  65     return *static_cast<typename ::boost::remove_reference<T>::type*>(arg.data);
  66 }
  67
  68 template<class T>
  69 T extract(const storage& arg)
  70 {
  71     return *static_cast<const typename ::boost::remove_reference<T>::type*>(arg.data);
  72 }
  73
  74 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
  75
  76 template<class T>
  77 T extract(storage&& arg)
  78 {
  79     return std::move(*static_cast<typename ::boost::remove_reference<T>::type*>(arg.data));
  80 }
  81
  82 #endif
  83
  84 }
  85 }
  86 }
  87
  88 #ifdef BOOST_MSVC
  89 #pragma warning(pop)
  90 #endif
  91
  92 #endif