1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt).
//
// See http://www.boost.org/libs/type_traits for most recent version including documentation.
#ifndef BOOST_TT_IS_EMPTY_HPP_INCLUDED
#define BOOST_TT_IS_EMPTY_HPP_INCLUDED
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/detail/config.hpp>
#include <boost/type_traits/intrinsics.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_traits/is_class.hpp>
#include <boost/type_traits/add_reference.hpp>
#ifndef BOOST_INTERNAL_IS_EMPTY
#define BOOST_INTERNAL_IS_EMPTY(T) false
#else
#define BOOST_INTERNAL_IS_EMPTY(T) BOOST_IS_EMPTY(T)
#endif
namespace boost {
namespace detail {
#ifdef BOOST_MSVC
#pragma warning(push)
#pragma warning(disable:4624) // destructor could not be generated
#endif
template <typename T>
struct empty_helper_t1 : public T
{
empty_helper_t1(); // hh compiler bug workaround
int i[256];
private:
// suppress compiler warnings:
empty_helper_t1(const empty_helper_t1&);
empty_helper_t1& operator=(const empty_helper_t1&);
};
#ifdef BOOST_MSVC
#pragma warning(pop)
#endif
struct empty_helper_t2 { int i[256]; };
#if !BOOST_WORKAROUND(__BORLANDC__, < 0x600)
template <typename T, bool is_a_class = false>
struct empty_helper
{
BOOST_STATIC_CONSTANT(bool, value = false);
};
template <typename T>
struct empty_helper<T, true>
{
BOOST_STATIC_CONSTANT(
bool, value = (sizeof(empty_helper_t1<T>) == sizeof(empty_helper_t2))
);
};
template <typename T>
struct is_empty_impl
{
typedef typename remove_cv<T>::type cvt;
BOOST_STATIC_CONSTANT(
bool,
value = ( ::boost::detail::empty_helper<cvt,::boost::is_class<T>::value>::value || BOOST_INTERNAL_IS_EMPTY(cvt)));
};
#else // __BORLANDC__
template <typename T, bool is_a_class, bool convertible_to_int>
struct empty_helper
{
BOOST_STATIC_CONSTANT(bool, value = false);
};
template <typename T>
struct empty_helper<T, true, false>
{
BOOST_STATIC_CONSTANT(bool, value = (
sizeof(empty_helper_t1<T>) == sizeof(empty_helper_t2)
));
};
template <typename T>
struct is_empty_impl
{
typedef typename remove_cv<T>::type cvt;
typedef typename add_reference<T>::type r_type;
BOOST_STATIC_CONSTANT(
bool, value = (
::boost::detail::empty_helper<
cvt
, ::boost::is_class<T>::value
, ::boost::is_convertible< r_type,int>::value
>::value || BOOST_INTERNAL_IS_EMPTY(cvt));
};
#endif // __BORLANDC__
} // namespace detail
template <class T> struct is_empty : integral_constant<bool, ::boost::detail::is_empty_impl<T>::value> {};
} // namespace boost
#undef BOOST_INTERNAL_IS_EMPTY
#endif // BOOST_TT_IS_EMPTY_HPP_INCLUDED
|
