ceph/src/boost/boost/type_traits/integral_promotion.hpp

   1 // Copyright 2005 Alexander Nasonov.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef FILE_boost_type_traits_integral_promotion_hpp_INCLUDED
   7 #define FILE_boost_type_traits_integral_promotion_hpp_INCLUDED
   8
   9 #include <boost/config.hpp>
  10 #include <boost/type_traits/integral_constant.hpp>
  11 #include <boost/type_traits/is_const.hpp>
  12 #include <boost/type_traits/is_enum.hpp>
  13 #include <boost/type_traits/is_volatile.hpp>
  14 #include <boost/type_traits/remove_cv.hpp>
  15
  16 namespace boost {
  17
  18 namespace type_traits { namespace detail {
  19
  20 // 4.5/2
  21 template <class T> struct need_promotion : public boost::is_enum<T> {};
  22
  23 // 4.5/1
  24 template<> struct need_promotion<char              > : public true_type {};
  25 template<> struct need_promotion<signed char       > : public true_type {};
  26 template<> struct need_promotion<unsigned char     > : public true_type {};
  27 template<> struct need_promotion<signed short int  > : public true_type {};
  28 template<> struct need_promotion<unsigned short int> : public true_type {};
  29
  30
  31 // Specializations for non-standard types.
  32 // Type is promoted if it's smaller then int.
  33
  34 #define BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(T) \
  35     template<> struct need_promotion<T>          \
  36         : public integral_constant<bool, (sizeof(T) < sizeof(int))> {};
  37
  38 // Same set of integral types as in boost/type_traits/is_integral.hpp.
  39 // Please, keep in sync.
  40 #if (defined(BOOST_INTEL_CXX_VERSION) && defined(_MSC_VER) && (BOOST_INTEL_CXX_VERSION <= 600)) \
  41     || (defined(__BORLANDC__) && (__BORLANDC__ == 0x600) && (_MSC_VER < 1300))
  42 // TODO: common macro for this #if. Or better yet, PP SEQ of non-standard types.
  43 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(__int8          )
  44 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(unsigned __int8 )
  45 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(__int16         )
  46 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(unsigned __int16)
  47 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(__int32         )
  48 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(unsigned __int32)
  49 #ifdef __BORLANDC__
  50 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(unsigned __int64)
  51 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(         __int64)
  52 #endif
  53 #endif
  54
  55 #if defined(BOOST_HAS_LONG_LONG)
  56 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(boost::ulong_long_type)
  57 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(boost::long_long_type )
  58 #elif defined(BOOST_HAS_MS_INT64)
  59 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(unsigned __int64)
  60 BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE(         __int64)
  61 #endif
  62
  63 #undef BOOST_TT_AUX_PROMOTE_NONSTANDARD_TYPE
  64
  65
  66 #ifndef BOOST_NO_INTRINSIC_WCHAR_T
  67 // 4.5/2
  68 template<> struct need_promotion<wchar_t> : public true_type {};
  69 #endif
  70
  71 // 4.5/3 (integral bit-field) is not supported.
  72
  73 // 4.5/4
  74 template<> struct need_promotion<bool> : public true_type {};
  75
  76
  77 // Get promoted type by index and cv qualifiers.
  78
  79 template<int Index, int IsConst, int IsVolatile> struct promote_from_index;
  80
  81 #define BOOST_TT_AUX_PROMOTE_FROM_INDEX(N,T)                                   \
  82     template<> struct promote_from_index<N,0,0> { typedef T type; };           \
  83     template<> struct promote_from_index<N,0,1> { typedef T volatile type; };  \
  84     template<> struct promote_from_index<N,1,0> { typedef T const type; };     \
  85     template<> struct promote_from_index<N,1,1> { typedef T const volatile type; };
  86
  87
  88 BOOST_TT_AUX_PROMOTE_FROM_INDEX(1, int          )
  89 BOOST_TT_AUX_PROMOTE_FROM_INDEX(2, unsigned int )
  90 BOOST_TT_AUX_PROMOTE_FROM_INDEX(3, long         )
  91 BOOST_TT_AUX_PROMOTE_FROM_INDEX(4, unsigned long)
  92
  93
  94 // WARNING: integral promotions to non-standard types
  95 // long long and __int64 are not defined by the standard.
  96 // Additional specialisations and overloads shouldn't
  97 // introduce ambiguity, though.
  98
  99 #if defined(BOOST_HAS_LONG_LONG)
 100 BOOST_TT_AUX_PROMOTE_FROM_INDEX(5, boost::long_long_type )
 101 BOOST_TT_AUX_PROMOTE_FROM_INDEX(6, boost::ulong_long_type)
 102 #elif defined(BOOST_HAS_MS_INT64)
 103 BOOST_TT_AUX_PROMOTE_FROM_INDEX(7, __int64         )
 104 BOOST_TT_AUX_PROMOTE_FROM_INDEX(8, unsigned __int64)
 105 #endif
 106
 107 #undef BOOST_TT_AUX_PROMOTE_FROM_INDEX
 108
 109
 110 // Define BOOST_TT_AUX_PROMOTED_INDEX_TESTER:
 111 #if !defined(BOOST_MSVC)
 112
 113 template<int N>
 114 struct sized_type_for_promotion
 115 {
 116     typedef char (&type)[N];
 117 };
 118
 119 #define BOOST_TT_AUX_PROMOTED_INDEX_TESTER(I,T) \
 120     sized_type_for_promotion<I>::type promoted_index_tester(T);
 121
 122 #else
 123
 124 #define BOOST_TT_AUX_PROMOTED_INDEX_TESTER(I,T) \
 125     char (&promoted_index_tester(T))[I];
 126
 127 #endif
 128
 129 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(1, int          )
 130 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(2, unsigned int )
 131 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(3, long         )
 132 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(4, unsigned long)
 133
 134 #if defined(BOOST_HAS_LONG_LONG)
 135 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(5, boost::long_long_type )
 136 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(6, boost::ulong_long_type)
 137 #elif defined(BOOST_HAS_MS_INT64)
 138 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(7, __int64         )
 139 BOOST_TT_AUX_PROMOTED_INDEX_TESTER(8, unsigned __int64)
 140 #endif
 141
 142 #undef BOOST_TT_AUX_PROMOTED_INDEX_TESTER
 143
 144
 145 // Get an index of promoted type for type T.
 146 // Precondition: need_promotion<T>
 147 template<class T>
 148 struct promoted_index
 149 {
 150     static T testee; // undefined
 151     BOOST_STATIC_CONSTANT(int, value = sizeof(promoted_index_tester(+testee)) );
 152     // Unary plus promotes testee                    LOOK HERE ---> ^
 153 };
 154
 155 template<class T>
 156 struct integral_promotion_impl
 157 {
 158     typedef BOOST_DEDUCED_TYPENAME promote_from_index<
 159         (boost::type_traits::detail::promoted_index<T>::value)
 160       , (boost::is_const<T>::value)
 161       , (boost::is_volatile<T>::value)
 162       >::type type;
 163 };
 164
 165 template<class T, bool b> struct integral_promotion { typedef T type; };
 166 template<class T> struct integral_promotion<T, true> : public integral_promotion_impl<T>{};
 167
 168 } }
 169
 170 template <class T> struct integral_promotion
 171 {
 172 private:
 173    typedef boost::type_traits::detail::need_promotion<typename remove_cv<T>::type> tag_type;
 174 public:
 175    typedef typename boost::type_traits::detail::integral_promotion<T, tag_type::value>::type type;
 176 };
 177
 178 #if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
 179
 180    template <class T> using integral_promotion_t = typename integral_promotion<T>::type;
 181
 182 #endif
 183
 184 }
 185
 186 #endif // #ifndef FILE_boost_type_traits_integral_promotion_hpp_INCLUDED
 187