boost/type_traits/is_pod.hpp

   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_POD_HPP_INCLUDED
  10 #define BOOST_TT_IS_POD_HPP_INCLUDED
  11
  12 #include <boost/type_traits/config.hpp>
  13 #include <boost/type_traits/is_void.hpp>
  14 #include <boost/type_traits/is_scalar.hpp>
  15 #include <boost/type_traits/detail/ice_or.hpp>
  16 #include <boost/type_traits/intrinsics.hpp>
  17
  18 #include <cstddef>
  19
  20 // should be the last #include
  21 #include <boost/type_traits/detail/bool_trait_def.hpp>
  22
  23 namespace boost {
  24
  25 // forward declaration, needed by 'is_pod_array_helper' template below
  26 template< typename T > struct is_POD;
  27
  28 namespace detail {
  29
  30 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  31
  32 template <typename T> struct is_pod_impl
  33 {
  34     BOOST_STATIC_CONSTANT(
  35         bool, value =
  36         (::boost::type_traits::ice_or<
  37             ::boost::is_scalar<T>::value,
  38             ::boost::is_void<T>::value,
  39             BOOST_IS_POD(T)
  40          >::value));
  41 };
  42
  43 #if !defined(BOOST_NO_ARRAY_TYPE_SPECIALIZATIONS)
  44 template <typename T, std::size_t sz>
  45 struct is_pod_impl<T[sz]>
  46     : is_pod_impl<T>
  47 {
  48 };
  49 #endif
  50
  51 #else
  52
  53 template <bool is_array = false>
  54 struct is_pod_helper
  55 {
  56     template <typename T> struct result_
  57     {
  58         BOOST_STATIC_CONSTANT(
  59             bool, value =
  60             (::boost::type_traits::ice_or<
  61                 ::boost::is_scalar<T>::value,
  62                 ::boost::is_void<T>::value,
  63                 BOOST_IS_POD(T)
  64             >::value));
  65     };
  66 };
  67
  68 template <bool b>
  69 struct bool_to_yes_no_type
  70 {
  71     typedef ::boost::type_traits::no_type type;
  72 };
  73
  74 template <>
  75 struct bool_to_yes_no_type<true>
  76 {
  77     typedef ::boost::type_traits::yes_type type;
  78 };
  79
  80 template <typename ArrayType>
  81 struct is_pod_array_helper
  82 {
  83     enum { is_pod = ::boost::is_POD<ArrayType>::value }; // MSVC workaround
  84     typedef typename bool_to_yes_no_type<is_pod>::type type;
  85     type instance() const;
  86 };
  87
  88 template <typename T>
  89 is_pod_array_helper<T> is_POD_array(T*);
  90
  91 template <>
  92 struct is_pod_helper<true>
  93 {
  94     template <typename T> struct result_
  95     {
  96         static T& help();
  97         BOOST_STATIC_CONSTANT(bool, value =
  98             sizeof(is_POD_array(help()).instance()) == sizeof(::boost::type_traits::yes_type)
  99             );
 100     };
 101 };
 102
 103
 104 template <typename T> struct is_pod_impl
 105 {
 106    BOOST_STATIC_CONSTANT(
 107        bool, value = (
 108            ::boost::detail::is_pod_helper<
 109               ::boost::is_array<T>::value
 110            >::template result_<T>::value
 111            )
 112        );
 113 };
 114
 115 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
 116
 117 // the following help compilers without partial specialization support:
 118 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,void,true)
 119
 120 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
 121 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,void const,true)
 122 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,void volatile,true)
 123 BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_pod,void const volatile,true)
 124 #endif
 125
 126 } // namespace detail
 127
 128 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_POD,T,::boost::detail::is_pod_impl<T>::value)
 129 BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_pod,T,::boost::detail::is_pod_impl<T>::value)
 130
 131 } // namespace boost
 132
 133 #include <boost/type_traits/detail/bool_trait_undef.hpp>
 134
 135 #endif // BOOST_TT_IS_POD_HPP_INCLUDED