1 #ifndef BOOST_TT_IS_ABSTRACT_CLASS_HPP 2 #define BOOST_TT_IS_ABSTRACT_CLASS_HPP 3 4 #if defined(_MSC_VER) && (_MSC_VER >= 1020) 5 # pragma once 6 #endif 7 8 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8 9 // is_abstract_class.hpp: 10 // 11 // (C) Copyright 2002 Rani Sharoni (rani_sharoni@hotmail.com) and Robert Ramey 12 // Use, modification and distribution is subject to the Boost Software 13 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at 14 // http://www.boost.org/LICENSE_1_0.txt) 15 // 16 // See http://www.boost.org for updates, documentation, and revision history. 17 // 18 19 // Compile type discovery whether given type is abstract class or not. 20 // 21 // Requires DR 337 to be supported by compiler 22 // (http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/cwg_active.html#337). 23 // 24 // 25 // Believed (Jan 2004) to work on: 26 // - GCC 3.4 27 // - VC++ 7.1 28 // - compilers with new EDG frontend (Intel C++ 7, Comeau 4.3.2) 29 // 30 // Doesn't work on: 31 // - VC++6, VC++7.0 and less 32 // - GCC 3.3.X and less 33 // - Borland C++ 6 and less 34 // 35 // 36 // History: 37 // - Originally written by Rani Sharoni, see 38 // http://groups.google.com/groups?selm=df893da6.0207110613.75b2fe90%40posting.google.com 39 // At this time supported by EDG (Intel C++ 7, Comeau 4.3.2) and VC7.1. 40 // - Adapted and added into Boost.Serialization library by Robert Ramey 41 // (starting with submission #10). 42 // - Jan 2004: GCC 3.4 fixed to suport DR337 (Giovanni Bajo). 43 // - Jan 2004: modified to be part of Boost.TypeTraits (Pavel Vozenilek). 44 // - Nov 2004: Christoph Ludwig found that the implementation did not work with 45 // template types and gcc-3.4 or VC7.1, fix due to Christoph Ludwig 46 // and John Maddock. 47 // - Dec 2004: Added new config macro BOOST_NO_IS_ABSTRACT which causes the template 48 // to degrade gracefully, rather than trash the compiler (John Maddock). 49 // 50 51 #include <boost/static_assert.hpp> 52 #include <boost/type_traits/detail/yes_no_type.hpp> 53 #include <boost/type_traits/is_class.hpp> 54 #include "boost/type_traits/detail/ice_and.hpp" 55 #ifdef BOOST_NO_IS_ABSTRACT 56 #include <boost/type_traits/is_polymorphic.hpp> 57 #endif 58 // should be the last #include 59 #include "boost/type_traits/detail/bool_trait_def.hpp" 60 61 62 namespace boost { 63 namespace detail{ 64 65 #ifndef BOOST_NO_IS_ABSTRACT 66 template<class T> 67 struct is_abstract_imp2 68 { 69 // Deduction fails if T is void, function type, 70 // reference type (14.8.2/2)or an abstract class type 71 // according to review status issue #337 72 // 73 template<class U> 74 static type_traits::no_type check_sig(U (*)[1]); 75 template<class U> 76 static type_traits::yes_type check_sig(...); 77 // 78 // T must be a complete type, further if T is a template then 79 // it must be instantiated in order for us to get the right answer: 80 // 81 BOOST_STATIC_ASSERT(sizeof(T) != 0); 82 83 // GCC2 won't even parse this template if we embed the computation 84 // of s1 in the computation of value. 85 #ifdef __GNUC__ 86 BOOST_STATIC_CONSTANT(unsigned, s1 = sizeof(is_abstract_imp2<T>::template check_sig<T>(0))); 87 #else 88 BOOST_STATIC_CONSTANT(unsigned, s1 = sizeof(check_sig<T>(0))); 89 #endif 90 91 BOOST_STATIC_CONSTANT(bool, value = 92 (s1 == sizeof(type_traits::yes_type))); 93 }; 94 95 template <bool v> 96 struct is_abstract_select 97 { 98 template <class T> 99 struct rebind 100 { 101 typedef is_abstract_imp2<T> type; 102 }; 103 }; 104 template <> 105 struct is_abstract_select<false> 106 { 107 template <class T> 108 struct rebind 109 { 110 typedef false_type type; 111 }; 112 }; 113 114 template <class T> 115 struct is_abstract_imp 116 { 117 typedef is_abstract_select< ::boost::is_class<T>::value> selector; 118 typedef typename selector::template rebind<T> binder; 119 typedef typename binder::type type; 120 121 BOOST_STATIC_CONSTANT(bool, value = type::value); 122 }; 123 124 #endif 125 } 126 127 #ifndef BOOST_NO_IS_ABSTRACT 128 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_abstract,T,::boost::detail::is_abstract_imp<T>::value) 129 #else 130 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_abstract,T,::boost::detail::is_polymorphic_imp<T>::value) 131 #endif 132 133 } // namespace boost 134 135 #include "boost/type_traits/detail/bool_trait_undef.hpp" 136 137 #endif //BOOST_TT_IS_ABSTRACT_CLASS_HPP 138