boost/type_traits/is_polymorphic.hpp
// (C) Copyright John Maddock 2000.
// Use, modification and distribution are subject to 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).
//
// See http://www.boost.org/libs/type_traits for most recent version including documentation.
#ifndef BOOST_TT_IS_POLYMORPHIC_HPP
#define BOOST_TT_IS_POLYMORPHIC_HPP
#include <boost/type_traits/intrinsics.hpp>
#ifndef BOOST_IS_POLYMORPHIC
#include <boost/type_traits/is_class.hpp>
#include <boost/type_traits/remove_cv.hpp>
#endif
// should be the last #include
#include <boost/type_traits/detail/bool_trait_def.hpp>
#include <boost/detail/workaround.hpp>
namespace boost{
#ifndef BOOST_IS_POLYMORPHIC
namespace detail{
template <class T>
struct is_polymorphic_imp1
{
# if BOOST_WORKAROUND(__MWERKS__, <= 0x2407) // CWPro7 should return false always.
typedef char d1, (&d2)[2];
# else
typedef typename remove_cv<T>::type ncvT;
struct d1 : public ncvT
{
d1();
# if !defined(__GNUC__) // this raises warnings with some classes, and buys nothing with GCC
~d1()throw();
# endif
char padding[256];
private:
// keep some picky compilers happy:
d1(const d1&);
d1& operator=(const d1&);
};
struct d2 : public ncvT
{
d2();
virtual ~d2()throw();
# if !defined(BOOST_MSVC) && !defined(__ICL)
// for some reason this messes up VC++ when T has virtual bases,
// probably likewise for compilers that use the same ABI:
struct unique{};
virtual void unique_name_to_boost5487629(unique*);
# endif
char padding[256];
private:
// keep some picky compilers happy:
d2(const d2&);
d2& operator=(const d2&);
};
# endif
BOOST_STATIC_CONSTANT(bool, value = (sizeof(d2) == sizeof(d1)));
};
template <class T>
struct is_polymorphic_imp2
{
BOOST_STATIC_CONSTANT(bool, value = false);
};
template <bool is_class>
struct is_polymorphic_selector
{
template <class T>
struct rebind
{
typedef is_polymorphic_imp2<T> type;
};
};
template <>
struct is_polymorphic_selector<true>
{
template <class T>
struct rebind
{
typedef is_polymorphic_imp1<T> type;
};
};
template <class T>
struct is_polymorphic_imp
{
typedef is_polymorphic_selector< ::boost::is_class<T>::value> selector;
typedef typename selector::template rebind<T> binder;
typedef typename binder::type imp_type;
BOOST_STATIC_CONSTANT(bool, value = imp_type::value);
};
} // namespace detail
BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_polymorphic,T,::boost::detail::is_polymorphic_imp<T>::value)
#else // BOOST_IS_POLYMORPHIC
BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_polymorphic,T,BOOST_IS_POLYMORPHIC(T))
#endif
} // namespace boost
#include <boost/type_traits/detail/bool_trait_undef.hpp>
#endif