luabind/value_wrapper.hpp

   1 // Copyright (c) 2005 Daniel Wallin and Arvid Norberg
   2
   3 // Permission is hereby granted, free of charge, to any person obtaining a
   4 // copy of this software and associated documentation files (the "Software"),
   5 // to deal in the Software without restriction, including without limitation
   6 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
   7 // and/or sell copies of the Software, and to permit persons to whom the
   8 // Software is furnished to do so, subject to the following conditions:
   9
  10 // The above copyright notice and this permission notice shall be included
  11 // in all copies or substantial portions of the Software.
  12
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
  14 // ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
  15 // TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
  16 // PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
  17 // SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
  18 // ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  19 // ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
  21 // OR OTHER DEALINGS IN THE SOFTWARE.
  22
  23 #ifndef LUABIND_VALUE_WRAPPER_050419_HPP
  24 #define LUABIND_VALUE_WRAPPER_050419_HPP
  25
  26 #include <boost/mpl/integral_c.hpp>
  27 #include <boost/mpl/bool.hpp>
  28 #include <boost/mpl/aux_/msvc_eti_base.hpp>
  29
  30 #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  31 # define LUABIND_USE_VALUE_WRAPPER_TAG
  32 #else
  33 #endif
  34
  35 #ifdef LUABIND_USE_VALUE_WRAPPER_TAG
  36 # include <boost/mpl/identity.hpp>
  37 # include <boost/mpl/eval_if.hpp>
  38 # include <boost/mpl/has_xxx.hpp>
  39 # include <boost/mpl/not.hpp>
  40 # include <boost/mpl/and.hpp>
  41 # include <boost/mpl/or.hpp>
  42 # include <boost/type_traits/is_reference.hpp>
  43 # include <boost/type_traits/is_pointer.hpp>
  44 # include <boost/type_traits/is_array.hpp>
  45 #endif
  46
  47 namespace luabind {
  48
  49 //
  50 // Concept ``ValueWrapper``
  51 //
  52
  53 #ifdef LUABIND_USE_VALUE_WRAPPER_TAG
  54 template<class T>
  55 struct value_wrapper_traits;
  56
  57 namespace detail
  58 {
  59
  60   BOOST_MPL_HAS_XXX_TRAIT_DEF(value_wrapper_tag);
  61
  62   struct unspecialized_value_wrapper_traits
  63   {
  64       typedef boost::mpl::false_ is_specialized;
  65   };
  66
  67   template<class T>
  68   struct value_wrapper_traits_aux
  69   {
  70       typedef value_wrapper_traits<typename T::value_wrapper_tag> type;
  71   };
  72
  73 } // namespace detail
  74 #endif
  75
  76 template<class T>
  77 struct value_wrapper_traits
  78 #ifdef LUABIND_USE_VALUE_WRAPPER_TAG
  79   : boost::mpl::eval_if<
  80         boost::mpl::and_<
  81             boost::mpl::not_<
  82                 boost::mpl::or_<
  83                     boost::is_reference<T>
  84                   , boost::is_pointer<T>
  85                   , boost::is_array<T>
  86                 >
  87             >
  88           , detail::has_value_wrapper_tag<T>
  89         >
  90       , detail::value_wrapper_traits_aux<T>
  91       , boost::mpl::identity<detail::unspecialized_value_wrapper_traits>
  92     >::type
  93 {};
  94 #else
  95 {
  96     typedef boost::mpl::false_ is_specialized;
  97 };
  98 #endif
  99
 100 template<class T>
 101 struct is_value_wrapper
 102   : boost::mpl::aux::msvc_eti_base<
 103         typename value_wrapper_traits<T>::is_specialized
 104     >::type
 105 {};
 106
 107 } // namespace luabind
 108
 109 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
 110
 111 # include <boost/type_traits/remove_const.hpp>
 112 # include <boost/type_traits/remove_reference.hpp>
 113
 114 namespace luabind {
 115
 116 template<class T>
 117 struct is_value_wrapper_arg
 118   : is_value_wrapper<
 119       typename boost::remove_const<
 120           typename boost::remove_reference<T>::type
 121       >::type
 122     >
 123 {};
 124
 125 } // namespace luabind
 126
 127 #else
 128
 129 # include <luabind/detail/yes_no.hpp>
 130 # include <boost/type_traits/add_reference.hpp>
 131
 132 namespace luabind {
 133
 134 namespace detail
 135 {
 136   template<class T>
 137   typename is_value_wrapper<T>::type is_value_wrapper_arg_check(T const*);
 138
 139   yes_t to_yesno(boost::mpl::true_);
 140   no_t to_yesno(boost::mpl::false_);
 141
 142   template<class T>
 143   struct is_value_wrapper_arg_aux
 144   {
 145       static typename boost::add_reference<T>::type x;
 146
 147       BOOST_STATIC_CONSTANT(bool, value =
 148           sizeof(to_yesno(is_value_wrapper_arg_check(&x)))
 149             == sizeof(yes_t)
 150       );
 151
 152       typedef boost::mpl::bool_<value> type;
 153   };
 154
 155 } // namespace detail
 156
 157 template<class T>
 158 struct is_value_wrapper_arg
 159   : detail::is_value_wrapper_arg_aux<T>::type
 160 {
 161 };
 162
 163 } // namespace luabind
 164
 165 #endif
 166
 167 #endif // LUABIND_VALUE_WRAPPER_050419_HPP
 168