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
63namespace boost {
64
65namespace detail{
66
67#ifdef BOOST_IS_ABSTRACT
68template <class T>
69struct is_abstract_imp
70{
71 BOOST_STATIC_CONSTANT(bool, value = BOOST_IS_ABSTRACT(T));
72};
73#elif !defined(BOOST_NO_IS_ABSTRACT)
74template<class T>
75struct 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
110template <bool v>
111struct is_abstract_select
112{
113 template <class T>
114 struct rebind
115 {
116 typedef is_abstract_imp2<T> type;
117 };
118};
119template <>
120struct is_abstract_select<false>
121{
122 template <class T>
123 struct rebind
124 {
125 typedef false_type type;
126 };
127};
128
129template <class T>
130struct 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
143template <class T> struct is_abstract : public integral_constant<bool, ::boost::detail::is_abstract_imp<T>::value> {};
144#else
145template <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