Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame] | 1 | |
| 2 | // (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000. |
| 3 | // Use, modification and distribution are subject to the Boost Software License, |
| 4 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| 5 | // http://www.boost.org/LICENSE_1_0.txt). |
| 6 | // |
| 7 | // See http://www.boost.org/libs/type_traits for most recent version including documentation. |
| 8 | |
| 9 | #ifndef BOOST_TT_IS_EMPTY_HPP_INCLUDED |
| 10 | #define BOOST_TT_IS_EMPTY_HPP_INCLUDED |
| 11 | |
| 12 | #include <ndnboost/type_traits/is_convertible.hpp> |
| 13 | #include <ndnboost/type_traits/detail/ice_or.hpp> |
| 14 | #include <ndnboost/type_traits/config.hpp> |
| 15 | #include <ndnboost/type_traits/intrinsics.hpp> |
| 16 | |
| 17 | #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| 18 | # include <ndnboost/type_traits/remove_cv.hpp> |
| 19 | # include <ndnboost/type_traits/is_class.hpp> |
| 20 | # include <ndnboost/type_traits/add_reference.hpp> |
| 21 | #else |
| 22 | # include <ndnboost/type_traits/is_reference.hpp> |
| 23 | # include <ndnboost/type_traits/is_pointer.hpp> |
| 24 | # include <ndnboost/type_traits/is_member_pointer.hpp> |
| 25 | # include <ndnboost/type_traits/is_array.hpp> |
| 26 | # include <ndnboost/type_traits/is_void.hpp> |
| 27 | # include <ndnboost/type_traits/detail/ice_and.hpp> |
| 28 | # include <ndnboost/type_traits/detail/ice_not.hpp> |
| 29 | #endif |
| 30 | |
| 31 | // should be always the last #include directive |
| 32 | #include <ndnboost/type_traits/detail/bool_trait_def.hpp> |
| 33 | |
| 34 | #ifndef BOOST_INTERNAL_IS_EMPTY |
| 35 | #define BOOST_INTERNAL_IS_EMPTY(T) false |
| 36 | #else |
| 37 | #define BOOST_INTERNAL_IS_EMPTY(T) BOOST_IS_EMPTY(T) |
| 38 | #endif |
| 39 | |
| 40 | namespace ndnboost { |
| 41 | |
| 42 | namespace detail { |
| 43 | |
| 44 | #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| 45 | |
| 46 | #ifdef BOOST_MSVC |
| 47 | #pragma warning(push) |
| 48 | #pragma warning(disable:4624) // destructor could not be generated |
| 49 | #endif |
| 50 | |
| 51 | template <typename T> |
| 52 | struct empty_helper_t1 : public T |
| 53 | { |
| 54 | empty_helper_t1(); // hh compiler bug workaround |
| 55 | int i[256]; |
| 56 | private: |
| 57 | // suppress compiler warnings: |
| 58 | empty_helper_t1(const empty_helper_t1&); |
| 59 | empty_helper_t1& operator=(const empty_helper_t1&); |
| 60 | }; |
| 61 | |
| 62 | #ifdef BOOST_MSVC |
| 63 | #pragma warning(pop) |
| 64 | #endif |
| 65 | |
| 66 | struct empty_helper_t2 { int i[256]; }; |
| 67 | |
| 68 | #if !BOOST_WORKAROUND(__BORLANDC__, < 0x600) |
| 69 | |
| 70 | template <typename T, bool is_a_class = false> |
| 71 | struct empty_helper |
| 72 | { |
| 73 | BOOST_STATIC_CONSTANT(bool, value = false); |
| 74 | }; |
| 75 | |
| 76 | template <typename T> |
| 77 | struct empty_helper<T, true> |
| 78 | { |
| 79 | BOOST_STATIC_CONSTANT( |
| 80 | bool, value = (sizeof(empty_helper_t1<T>) == sizeof(empty_helper_t2)) |
| 81 | ); |
| 82 | }; |
| 83 | |
| 84 | template <typename T> |
| 85 | struct is_empty_impl |
| 86 | { |
| 87 | typedef typename remove_cv<T>::type cvt; |
| 88 | BOOST_STATIC_CONSTANT( |
| 89 | bool, value = ( |
| 90 | ::ndnboost::type_traits::ice_or< |
| 91 | ::ndnboost::detail::empty_helper<cvt,::ndnboost::is_class<T>::value>::value |
| 92 | , BOOST_INTERNAL_IS_EMPTY(cvt) |
| 93 | >::value |
| 94 | )); |
| 95 | }; |
| 96 | |
| 97 | #else // __BORLANDC__ |
| 98 | |
| 99 | template <typename T, bool is_a_class, bool convertible_to_int> |
| 100 | struct empty_helper |
| 101 | { |
| 102 | BOOST_STATIC_CONSTANT(bool, value = false); |
| 103 | }; |
| 104 | |
| 105 | template <typename T> |
| 106 | struct empty_helper<T, true, false> |
| 107 | { |
| 108 | BOOST_STATIC_CONSTANT(bool, value = ( |
| 109 | sizeof(empty_helper_t1<T>) == sizeof(empty_helper_t2) |
| 110 | )); |
| 111 | }; |
| 112 | |
| 113 | template <typename T> |
| 114 | struct is_empty_impl |
| 115 | { |
| 116 | typedef typename remove_cv<T>::type cvt; |
| 117 | typedef typename add_reference<T>::type r_type; |
| 118 | |
| 119 | BOOST_STATIC_CONSTANT( |
| 120 | bool, value = ( |
| 121 | ::ndnboost::type_traits::ice_or< |
| 122 | ::ndnboost::detail::empty_helper< |
| 123 | cvt |
| 124 | , ::ndnboost::is_class<T>::value |
| 125 | , ::ndnboost::is_convertible< r_type,int>::value |
| 126 | >::value |
| 127 | , BOOST_INTERNAL_IS_EMPTY(cvt) |
| 128 | >::value)); |
| 129 | }; |
| 130 | |
| 131 | #endif // __BORLANDC__ |
| 132 | |
| 133 | #else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| 134 | |
| 135 | #ifdef BOOST_MSVC6_MEMBER_TEMPLATES |
| 136 | |
| 137 | template <typename T> |
| 138 | struct empty_helper_t1 : public T |
| 139 | { |
| 140 | empty_helper_t1(); |
| 141 | int i[256]; |
| 142 | }; |
| 143 | |
| 144 | struct empty_helper_t2 { int i[256]; }; |
| 145 | |
| 146 | template <typename T> |
| 147 | struct empty_helper_base |
| 148 | { |
| 149 | enum { value = (sizeof(empty_helper_t1<T>) == sizeof(empty_helper_t2)) }; |
| 150 | }; |
| 151 | |
| 152 | template <typename T> |
| 153 | struct empty_helper_nonbase |
| 154 | { |
| 155 | enum { value = false }; |
| 156 | }; |
| 157 | |
| 158 | template <bool base> |
| 159 | struct empty_helper_chooser |
| 160 | { |
| 161 | template <typename T> struct result_ |
| 162 | { |
| 163 | typedef empty_helper_nonbase<T> type; |
| 164 | }; |
| 165 | }; |
| 166 | |
| 167 | template <> |
| 168 | struct empty_helper_chooser<true> |
| 169 | { |
| 170 | template <typename T> struct result_ |
| 171 | { |
| 172 | typedef empty_helper_base<T> type; |
| 173 | }; |
| 174 | }; |
| 175 | |
| 176 | template <typename T> |
| 177 | struct is_empty_impl |
| 178 | { |
| 179 | typedef ::ndnboost::detail::empty_helper_chooser< |
| 180 | ::ndnboost::type_traits::ice_and< |
| 181 | ::ndnboost::type_traits::ice_not< ::ndnboost::is_reference<T>::value >::value, |
| 182 | ::ndnboost::type_traits::ice_not< ::ndnboost::is_convertible<T,double>::value >::value, |
| 183 | ::ndnboost::type_traits::ice_not< ::ndnboost::is_pointer<T>::value >::value, |
| 184 | ::ndnboost::type_traits::ice_not< ::ndnboost::is_member_pointer<T>::value >::value, |
| 185 | ::ndnboost::type_traits::ice_not< ::ndnboost::is_array<T>::value >::value, |
| 186 | ::ndnboost::type_traits::ice_not< ::ndnboost::is_void<T>::value >::value, |
| 187 | ::ndnboost::type_traits::ice_not< |
| 188 | ::ndnboost::is_convertible<T,void const volatile*>::value |
| 189 | >::value |
| 190 | >::value > chooser; |
| 191 | |
| 192 | typedef typename chooser::template result_<T> result; |
| 193 | typedef typename result::type eh_type; |
| 194 | |
| 195 | BOOST_STATIC_CONSTANT(bool, value = |
| 196 | (::ndnboost::type_traits::ice_or<eh_type::value, BOOST_INTERNAL_IS_EMPTY(T)>::value)); |
| 197 | }; |
| 198 | |
| 199 | #else |
| 200 | |
| 201 | template <typename T> struct is_empty_impl |
| 202 | { |
| 203 | BOOST_STATIC_CONSTANT(bool, value = BOOST_INTERNAL_IS_EMPTY(T)); |
| 204 | }; |
| 205 | |
| 206 | #endif // BOOST_MSVC6_MEMBER_TEMPLATES |
| 207 | |
| 208 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
| 209 | |
| 210 | // these help when the compiler has no partial specialization support: |
| 211 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_empty,void,false) |
| 212 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS |
| 213 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_empty,void const,false) |
| 214 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_empty,void volatile,false) |
| 215 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_empty,void const volatile,false) |
| 216 | #endif |
| 217 | |
| 218 | } // namespace detail |
| 219 | |
| 220 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_empty,T,::ndnboost::detail::is_empty_impl<T>::value) |
| 221 | |
| 222 | } // namespace ndnboost |
| 223 | |
| 224 | #include <ndnboost/type_traits/detail/bool_trait_undef.hpp> |
| 225 | |
| 226 | #undef BOOST_INTERNAL_IS_EMPTY |
| 227 | |
| 228 | #endif // BOOST_TT_IS_EMPTY_HPP_INCLUDED |
| 229 | |