boost/type_traits/is_virtual_base_of.hpp

   1 //  (C) Copyright Daniel Frey and Robert Ramey 2009.
   2 //  Use, modification and distribution are subject to the Boost Software License,
   3 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   4 //  http://www.boost.org/LICENSE_1_0.txt).
   5 //
   6 //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
   7
   8 #ifndef BOOST_TT_IS_VIRTUAL_BASE_OF_HPP_INCLUDED
   9 #define BOOST_TT_IS_VIRTUAL_BASE_OF_HPP_INCLUDED
  10
  11 #include <boost/type_traits/is_base_of.hpp>
  12 #include <boost/type_traits/is_same.hpp>
  13 #include <boost/mpl/and.hpp>
  14 #include <boost/mpl/not.hpp>
  15
  16 // should be the last #include
  17 #include <boost/type_traits/detail/bool_trait_def.hpp>
  18
  19 namespace boost {
  20 namespace detail {
  21
  22
  23 #ifdef BOOST_MSVC
  24 #pragma warning( push )
  25 #pragma warning( disable : 4584 )
  26 #elif defined __GNUC__
  27 #pragma GCC system_header
  28 #endif
  29
  30 template<typename Base, typename Derived, typename tag>
  31 struct is_virtual_base_of_impl
  32 {
  33     BOOST_STATIC_CONSTANT(bool, value = false);
  34 };
  35
  36 template<typename Base, typename Derived>
  37 struct is_virtual_base_of_impl<Base, Derived, mpl::true_>
  38 {
  39 #ifdef __BORLANDC__
  40     struct X : public virtual Derived, public virtual Base
  41     {
  42        X();
  43        X(const X&);
  44        X& operator=(const X&);
  45        ~X();
  46     };
  47     struct Y : public virtual Derived
  48     {
  49        Y();
  50        Y(const Y&);
  51        Y& operator=(const Y&);
  52        ~Y();
  53     };
  54 #else
  55     struct X : Derived, virtual Base
  56     {
  57        X();
  58        X(const X&);
  59        X& operator=(const X&);
  60        ~X();
  61     };
  62     struct Y : Derived
  63     {
  64        Y();
  65        Y(const Y&);
  66        Y& operator=(const Y&);
  67        ~Y();
  68     };
  69 #endif
  70     BOOST_STATIC_CONSTANT(bool, value = (sizeof(X)==sizeof(Y)));
  71 };
  72
  73 template<typename Base, typename Derived>
  74 struct is_virtual_base_of_impl2
  75 {
  76    typedef typename mpl::and_<is_base_of<Base, Derived>, mpl::not_<is_same<Base, Derived> > >::type tag_type;
  77    typedef is_virtual_base_of_impl<Base, Derived, tag_type> imp;
  78    BOOST_STATIC_CONSTANT(bool, value = imp::value);
  79 };
  80
  81 #ifdef BOOST_MSVC
  82 #pragma warning( pop )
  83 #endif
  84
  85 } // namespace detail
  86
  87 BOOST_TT_AUX_BOOL_TRAIT_DEF2(
  88       is_virtual_base_of
  89        , Base
  90        , Derived
  91        , (::boost::detail::is_virtual_base_of_impl2<Base,Derived>::value)
  92 )
  93
  94 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  95 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_2(typename Base,typename Derived,is_virtual_base_of,Base&,Derived,false)
  96 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_2(typename Base,typename Derived,is_virtual_base_of,Base,Derived&,false)
  97 BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_2(typename Base,typename Derived,is_virtual_base_of,Base&,Derived&,false)
  98 #endif
  99
 100 } // namespace boost
 101
 102 #include <boost/type_traits/detail/bool_trait_undef.hpp>
 103
 104 #endif