ceph/src/boost/boost/parameter/aux_/has_nested_template_fn.hpp

   1 // Copyright Cromwell D. Enage 2019.
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_PARAMETER_AUX_HAS_NESTED_TEMPLATE_FN_HPP
   7 #define BOOST_PARAMETER_AUX_HAS_NESTED_TEMPLATE_FN_HPP
   8
   9 #include <boost/parameter/aux_/yesno.hpp>
  10 #include <boost/parameter/aux_/preprocessor/nullptr.hpp>
  11 #include <boost/parameter/config.hpp>
  12
  13 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  14 #include <boost/mp11/integral.hpp>
  15 #include <boost/mp11/utility.hpp>
  16 #else
  17 #include <boost/mpl/bool.hpp>
  18 #include <boost/mpl/identity.hpp>
  19 #endif
  20
  21 namespace boost { namespace parameter { namespace aux {
  22
  23 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  24     template <template <typename ...> class F>
  25     struct has_nested_template_fn_variadic
  26     {
  27     };
  28 #else
  29     template <template <typename P0, typename P1> class F>
  30     struct has_nested_template_fn_arity_2
  31     {
  32     };
  33 #endif
  34
  35     template <typename T>
  36     class has_nested_template_fn_impl
  37     {
  38         template <typename U>
  39         static ::boost::parameter::aux::no_tag _check(...);
  40
  41 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  42         template <typename U>
  43         static ::boost::parameter::aux::yes_tag
  44             _check(
  45                 ::boost::mp11::mp_identity<U> const volatile*
  46               , ::boost::parameter::aux::has_nested_template_fn_variadic<
  47                     U::template fn
  48                 >* = BOOST_PARAMETER_AUX_PP_NULLPTR
  49             );
  50 #else
  51         template <typename U>
  52         static BOOST_CONSTEXPR ::boost::parameter::aux::yes_tag
  53             _check(
  54                 ::boost::mpl::identity<U> const volatile*
  55               , ::boost::parameter::aux::has_nested_template_fn_arity_2<
  56                     U::template fn
  57                 >* = BOOST_PARAMETER_AUX_PP_NULLPTR
  58             );
  59 #endif
  60
  61      public:
  62 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  63         using type = ::boost::mp11::mp_bool<
  64 #else
  65         typedef ::boost::mpl::bool_<
  66 #endif
  67             sizeof(
  68                 ::boost::parameter::aux::has_nested_template_fn_impl<T>
  69                 ::template _check<T>(
  70                     static_cast<
  71 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  72                         ::boost::mp11::mp_identity<T> const volatile*
  73 #else
  74                         ::boost::mpl::identity<T> const volatile*
  75 #endif
  76                     >(BOOST_PARAMETER_AUX_PP_NULLPTR)
  77                 )
  78             ) == sizeof(::boost::parameter::aux::yes_tag)
  79 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  80         >;
  81 #else
  82         > type;
  83 #endif
  84     };
  85 }}} // namespace boost::parameter::aux
  86
  87 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  88 #include <type_traits>
  89 #else
  90 #include <boost/type_traits/remove_const.hpp>
  91 #endif
  92
  93 namespace boost { namespace parameter { namespace aux {
  94
  95     template <typename T>
  96 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  97     using has_nested_template_fn = typename ::boost::parameter::aux
  98     ::has_nested_template_fn_impl<typename ::std::remove_const<T>::type>
  99     ::type;
 100 #else
 101     struct has_nested_template_fn
 102       : ::boost::parameter::aux::has_nested_template_fn_impl<
 103             typename ::boost::remove_const<T>::type
 104         >::type
 105     {
 106     };
 107 #endif
 108 }}} // namespace boost::parameter::aux
 109
 110 #endif  // include guard
 111