boost/type_traits/add_reference.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_ADD_REFERENCE_HPP_INCLUDED
  10 #define BOOST_TT_ADD_REFERENCE_HPP_INCLUDED
  11
  12 #include <boost/type_traits/is_reference.hpp>
  13 #include <boost/detail/workaround.hpp>
  14 #include <boost/config.hpp>
  15
  16 // should be the last #include
  17 #include <boost/type_traits/detail/type_trait_def.hpp>
  18
  19 namespace boost {
  20
  21 namespace detail {
  22
  23 #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) && defined(BOOST_MSVC6_MEMBER_TEMPLATES)
  24
  25 template <bool x>
  26 struct reference_adder
  27 {
  28     template <typename T> struct result_
  29     {
  30         typedef T& type;
  31     };
  32 };
  33
  34 template <>
  35 struct reference_adder<true>
  36 {
  37     template <typename T> struct result_
  38     {
  39         typedef T type;
  40     };
  41 };
  42
  43 template <typename T>
  44 struct add_reference_impl
  45 {
  46     typedef typename reference_adder<
  47           ::boost::is_reference<T>::value
  48         >::template result_<T> result;
  49
  50     typedef typename result::type type;
  51 };
  52
  53 #else
  54
  55 template <typename T>
  56 struct add_reference_impl
  57 {
  58     typedef T& type;
  59 };
  60
  61 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  62 BOOST_TT_AUX_TYPE_TRAIT_IMPL_PARTIAL_SPEC1_1(typename T,add_reference,T&,T&)
  63 #endif
  64
  65 #endif
  66
  67 // these full specialisations are always required:
  68 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void,void)
  69 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
  70 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void const,void const)
  71 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void volatile,void volatile)
  72 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void const volatile,void const volatile)
  73 #endif
  74
  75 } // namespace detail
  76
  77 BOOST_TT_AUX_TYPE_TRAIT_DEF1(add_reference,T,typename boost::detail::add_reference_impl<T>::type)
  78
  79 // agurt, 07/mar/03: workaround Borland's ill-formed sensitivity to an additional
  80 // level of indirection, here
  81 #if BOOST_WORKAROUND(__BORLANDC__, < 0x600)
  82 BOOST_TT_AUX_TYPE_TRAIT_PARTIAL_SPEC1_1(typename T,add_reference,T&,T&)
  83 #endif
  84
  85 } // namespace boost
  86
  87 #include <boost/type_traits/detail/type_trait_undef.hpp>
  88
  89 #endif // BOOST_TT_ADD_REFERENCE_HPP_INCLUDED