boost/boost/type_traits/add_reference.hpp

   1
   2 // (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
   3 // Permission to copy, use, modify, sell and distribute this software is
   4 // granted provided this copyright notice appears in all copies. This software
   5 // is provided "as is" without express or implied warranty, and with no claim
   6 // as to its suitability for any purpose.
   7 //
   8 // See http://www.boost.org for most recent version including documentation.
   9
  10 #ifndef BOOST_TT_ADD_REFERENCE_HPP_INCLUDED
  11 #define BOOST_TT_ADD_REFERENCE_HPP_INCLUDED
  12
  13 #include "boost/type_traits/is_reference.hpp"
  14 #include "boost/detail/workaround.hpp"
  15 #include "boost/config.hpp"
  16
  17 // should be the last #include
  18 #include "boost/type_traits/detail/type_trait_def.hpp"
  19
  20 namespace boost {
  21
  22 namespace detail {
  23
  24 #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) && defined(BOOST_MSVC6_MEMBER_TEMPLATES)
  25
  26 template <bool x>
  27 struct reference_adder
  28 {
  29     template <typename T> struct result_
  30     {
  31         typedef T& type;
  32     };
  33 };
  34
  35 template <>
  36 struct reference_adder<true>
  37 {
  38     template <typename T> struct result_
  39     {
  40         typedef T type;
  41     };
  42 };
  43
  44 template <typename T>
  45 struct add_reference_impl
  46 {
  47     typedef typename reference_adder<
  48           ::boost::is_reference<T>::value
  49         >::template result_<T> result;
  50
  51     typedef typename result::type type;
  52 };
  53
  54 #else
  55
  56 template <typename T>
  57 struct add_reference_impl
  58 {
  59     typedef T& type;
  60 };
  61
  62 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  63 BOOST_TT_AUX_TYPE_TRAIT_IMPL_PARTIAL_SPEC1_1(typename T,add_reference,T&,T&)
  64 #endif
  65
  66 #endif
  67
  68 // these full specialisations are always required:
  69 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void,void)
  70 #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
  71 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void const,void const)
  72 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void volatile,void volatile)
  73 BOOST_TT_AUX_TYPE_TRAIT_IMPL_SPEC1(add_reference,void const volatile,void const volatile)
  74 #endif
  75
  76 } // namespace detail
  77
  78 BOOST_TT_AUX_TYPE_TRAIT_DEF1(add_reference,T,typename detail::add_reference_impl<T>::type)
  79
  80 // agurt, 07/mar/03: workaround Borland's ill-formed sensitivity to an additional
  81 // level of indirection, here
  82 #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x561))
  83 BOOST_TT_AUX_TYPE_TRAIT_PARTIAL_SPEC1_1(typename T,add_reference,T&,T&)
  84 #endif
  85
  86 } // namespace boost
  87
  88 #include "boost/type_traits/detail/type_trait_undef.hpp"
  89
  90 #endif // BOOST_TT_ADD_REFERENCE_HPP_INCLUDED