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Jeff Thompsona28eed82013-08-22 16:21:10 -07001// Copyright David Abrahams 2004. Use, modification and distribution is
2// subject to the Boost Software License, Version 1.0. (See accompanying
3// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
4#ifndef IS_INCREMENTABLE_DWA200415_HPP
5# define IS_INCREMENTABLE_DWA200415_HPP
6
7# include <ndnboost/type_traits/detail/template_arity_spec.hpp>
8# include <ndnboost/type_traits/remove_cv.hpp>
9# include <ndnboost/mpl/aux_/lambda_support.hpp>
10# include <ndnboost/mpl/bool.hpp>
11# include <ndnboost/detail/workaround.hpp>
12
13// Must be the last include
14# include <ndnboost/type_traits/detail/bool_trait_def.hpp>
15
16namespace ndnboost { namespace detail {
17
18// is_incrementable<T> metafunction
19//
20// Requires: Given x of type T&, if the expression ++x is well-formed
21// it must have complete type; otherwise, it must neither be ambiguous
22// nor violate access.
23
24// This namespace ensures that ADL doesn't mess things up.
25namespace is_incrementable_
26{
27 // a type returned from operator++ when no increment is found in the
28 // type's own namespace
29 struct tag {};
30
31 // any soaks up implicit conversions and makes the following
32 // operator++ less-preferred than any other such operator that
33 // might be found via ADL.
34 struct any { template <class T> any(T const&); };
35
36 // This is a last-resort operator++ for when none other is found
Jeff Thompson3d613fd2013-10-15 15:39:04 -070037# if NDNBOOST_WORKAROUND(__GNUC__, == 4) && __GNUC_MINOR__ == 0 && __GNUC_PATCHLEVEL__ == 2
Jeff Thompsona28eed82013-08-22 16:21:10 -070038
39}
40
41namespace is_incrementable_2
42{
43 is_incrementable_::tag operator++(is_incrementable_::any const&);
44 is_incrementable_::tag operator++(is_incrementable_::any const&,int);
45}
46using namespace is_incrementable_2;
47
48namespace is_incrementable_
49{
50
51# else
52
53 tag operator++(any const&);
54 tag operator++(any const&,int);
55
56# endif
57
Jeff Thompson3d613fd2013-10-15 15:39:04 -070058# if NDNBOOST_WORKAROUND(__MWERKS__, NDNBOOST_TESTED_AT(0x3202)) \
59 || NDNBOOST_WORKAROUND(NDNBOOST_MSVC, <= 1300)
60# define NDNBOOST_comma(a,b) (a)
Jeff Thompsona28eed82013-08-22 16:21:10 -070061# else
62 // In case an operator++ is found that returns void, we'll use ++x,0
63 tag operator,(tag,int);
Jeff Thompson3d613fd2013-10-15 15:39:04 -070064# define NDNBOOST_comma(a,b) (a,b)
Jeff Thompsona28eed82013-08-22 16:21:10 -070065# endif
66
Jeff Thompson3d613fd2013-10-15 15:39:04 -070067# if defined(NDNBOOST_MSVC)
Jeff Thompsona28eed82013-08-22 16:21:10 -070068# pragma warning(push)
69# pragma warning(disable:4913) // Warning about operator,
70# endif
71
72 // two check overloads help us identify which operator++ was picked
73 char (& check_(tag) )[2];
74
75 template <class T>
76 char check_(T const&);
77
78
79 template <class T>
80 struct impl
81 {
82 static typename ndnboost::remove_cv<T>::type& x;
83
Jeff Thompson3d613fd2013-10-15 15:39:04 -070084 NDNBOOST_STATIC_CONSTANT(
Jeff Thompsona28eed82013-08-22 16:21:10 -070085 bool
Jeff Thompson3d613fd2013-10-15 15:39:04 -070086 , value = sizeof(is_incrementable_::check_(NDNBOOST_comma(++x,0))) == 1
Jeff Thompsona28eed82013-08-22 16:21:10 -070087 );
88 };
89
90 template <class T>
91 struct postfix_impl
92 {
93 static typename ndnboost::remove_cv<T>::type& x;
94
Jeff Thompson3d613fd2013-10-15 15:39:04 -070095 NDNBOOST_STATIC_CONSTANT(
Jeff Thompsona28eed82013-08-22 16:21:10 -070096 bool
Jeff Thompson3d613fd2013-10-15 15:39:04 -070097 , value = sizeof(is_incrementable_::check_(NDNBOOST_comma(x++,0))) == 1
Jeff Thompsona28eed82013-08-22 16:21:10 -070098 );
99 };
100
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700101# if defined(NDNBOOST_MSVC)
Jeff Thompsona28eed82013-08-22 16:21:10 -0700102# pragma warning(pop)
103# endif
104
105}
106
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700107# undef NDNBOOST_comma
Jeff Thompsona28eed82013-08-22 16:21:10 -0700108
109template<typename T>
110struct is_incrementable
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700111NDNBOOST_TT_AUX_BOOL_C_BASE(::ndnboost::detail::is_incrementable_::impl<T>::value)
Jeff Thompsona28eed82013-08-22 16:21:10 -0700112{
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700113 NDNBOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(::ndnboost::detail::is_incrementable_::impl<T>::value)
114 NDNBOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_incrementable,(T))
Jeff Thompsona28eed82013-08-22 16:21:10 -0700115};
116
117template<typename T>
118struct is_postfix_incrementable
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700119NDNBOOST_TT_AUX_BOOL_C_BASE(::ndnboost::detail::is_incrementable_::impl<T>::value)
Jeff Thompsona28eed82013-08-22 16:21:10 -0700120{
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700121 NDNBOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(::ndnboost::detail::is_incrementable_::postfix_impl<T>::value)
122 NDNBOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_postfix_incrementable,(T))
Jeff Thompsona28eed82013-08-22 16:21:10 -0700123};
124
125} // namespace detail
126
Jeff Thompson3d613fd2013-10-15 15:39:04 -0700127NDNBOOST_TT_AUX_TEMPLATE_ARITY_SPEC(1, ::ndnboost::detail::is_incrementable)
128NDNBOOST_TT_AUX_TEMPLATE_ARITY_SPEC(1, ::ndnboost::detail::is_postfix_incrementable)
Jeff Thompsona28eed82013-08-22 16:21:10 -0700129
130} // namespace ndnboost
131
132# include <ndnboost/type_traits/detail/bool_trait_undef.hpp>
133
134#endif // IS_INCREMENTABLE_DWA200415_HPP