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