1 #ifndef BOOST_TT_IS_ABSTRACT_CLASS_HPP 2 #define BOOST_TT_IS_ABSTRACT_CLASS_HPP 3 4 #if defined(_MSC_VER) 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://www.open-std.org/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 support 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 <cstddef> // size_t 52 #include <boost/type_traits/intrinsics.hpp> 53 #include <boost/type_traits/integral_constant.hpp> 54 #ifndef BOOST_IS_ABSTRACT 55 #include <boost/static_assert.hpp> 56 #include <boost/type_traits/detail/yes_no_type.hpp> 57 #include <boost/type_traits/is_class.hpp> 58 #ifdef BOOST_NO_IS_ABSTRACT 59 #include <boost/type_traits/is_polymorphic.hpp> 60 #endif 61 #endif 62 63 namespace boost { 64 65 namespace detail{ 66 67 #ifdef BOOST_IS_ABSTRACT 68 template <class T> 69 struct is_abstract_imp 70 { 71 BOOST_STATIC_CONSTANT(bool, value = BOOST_IS_ABSTRACT(T)); 72 }; 73 #elif !defined(BOOST_NO_IS_ABSTRACT) 74 template<class T> 75 struct is_abstract_imp2 76 { 77 // Deduction fails if T is void, function type, 78 // reference type (14.8.2/2)or an abstract class type 79 // according to review status issue #337 80 // 81 template<class U> 82 static type_traits::no_type check_sig(U (*)[1]); 83 template<class U> 84 static type_traits::yes_type check_sig(...); 85 // 86 // T must be a complete type, further if T is a template then 87 // it must be instantiated in order for us to get the right answer: 88 // 89 BOOST_STATIC_ASSERT(sizeof(T) != 0); 90 91 // GCC2 won't even parse this template if we embed the computation 92 // of s1 in the computation of value. 93 #ifdef __GNUC__ 94 BOOST_STATIC_CONSTANT(std::size_t, s1 = sizeof(is_abstract_imp2<T>::template check_sig<T>(0))); 95 #else 96 #if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000) 97 #pragma warning(push) 98 #pragma warning(disable:6334) 99 #endif 100 BOOST_STATIC_CONSTANT(std::size_t, s1 = sizeof(check_sig<T>(0))); 101 #if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000) 102 #pragma warning(pop) 103 #endif 104 #endif 105 106 BOOST_STATIC_CONSTANT(bool, value = 107 (s1 == sizeof(type_traits::yes_type))); 108 }; 109 110 template <bool v> 111 struct is_abstract_select 112 { 113 template <class T> 114 struct rebind 115 { 116 typedef is_abstract_imp2<T> type; 117 }; 118 }; 119 template <> 120 struct is_abstract_select<false> 121 { 122 template <class T> 123 struct rebind 124 { 125 typedef false_type type; 126 }; 127 }; 128 129 template <class T> 130 struct is_abstract_imp 131 { 132 typedef is_abstract_select< ::boost::is_class<T>::value> selector; 133 typedef typename selector::template rebind<T> binder; 134 typedef typename binder::type type; 135 136 BOOST_STATIC_CONSTANT(bool, value = type::value); 137 }; 138 139 #endif 140 } 141 142 #ifndef BOOST_NO_IS_ABSTRACT 143 template <class T> struct is_abstract : public integral_constant<bool, ::boost::detail::is_abstract_imp<T>::value> {}; 144 #else 145 template <class T> struct is_abstract : public integral_constant<bool, ::boost::detail::is_polymorphic_imp<T>::value> {}; 146 #endif 147 148 } // namespace boost 149 150 #endif //BOOST_TT_IS_ABSTRACT_CLASS_HPP 151