ceph/src/boost/libs/type_erasure/include/boost/type_erasure/detail/extract_concept.hpp

   1 // Boost.TypeErasure library
   2 //
   3 // Copyright 2011 Steven Watanabe
   4 //
   5 // Distributed under the Boost Software License Version 1.0. (See
   6 // accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8 //
   9 // $Id$
  10
  11 #if !defined(BOOST_PP_IS_ITERATING)
  12
  13 #ifndef BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
  14 #define BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
  15
  16 #include <boost/mpl/eval_if.hpp>
  17 #include <boost/mpl/identity.hpp>
  18 #include <boost/type_traits/remove_cv.hpp>
  19 #include <boost/type_traits/remove_reference.hpp>
  20 #include <boost/preprocessor/cat.hpp>
  21 #include <boost/preprocessor/inc.hpp>
  22 #include <boost/preprocessor/iteration/iterate.hpp>
  23 #include <boost/preprocessor/repetition/repeat.hpp>
  24 #include <boost/preprocessor/repetition/enum_params.hpp>
  25 #include <boost/type_erasure/is_placeholder.hpp>
  26 #include <boost/type_erasure/concept_of.hpp>
  27 #include <boost/type_erasure/config.hpp>
  28
  29 namespace boost {
  30 namespace type_erasure {
  31 namespace detail {
  32
  33 template<class T, class U>
  34 struct combine_concepts;
  35
  36 template<class T>
  37 struct combine_concepts<T, T> { typedef T type; };
  38 template<class T>
  39 struct combine_concepts<T, void> { typedef T type; };
  40 template<class T>
  41 struct combine_concepts<void, T> { typedef T type; };
  42 template<>
  43 struct combine_concepts<void, void> { typedef void type; };
  44
  45 template<class T, class U>
  46 struct maybe_extract_concept
  47 {
  48     typedef typename ::boost::mpl::eval_if<
  49         ::boost::type_erasure::is_placeholder<
  50             typename ::boost::remove_cv<
  51                 typename ::boost::remove_reference<T>::type
  52             >::type
  53         >,
  54         ::boost::type_erasure::concept_of<typename ::boost::remove_reference<U>::type>,
  55         ::boost::mpl::identity<void>
  56     >::type type;
  57 };
  58
  59 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
  60
  61 template<class Args, class... U>
  62 struct extract_concept;
  63
  64 template<class R, class T0, class... T, class U0, class... U>
  65 struct extract_concept<R(T0, T...), U0, U...>
  66 {
  67     typedef typename ::boost::type_erasure::detail::combine_concepts<
  68         typename ::boost::type_erasure::detail::maybe_extract_concept<
  69             T0, U0
  70         >::type,
  71         typename ::boost::type_erasure::detail::extract_concept<
  72             void(T...),
  73             U...
  74         >::type
  75     >::type type;
  76 };
  77
  78 template<>
  79 struct extract_concept<void()>
  80 {
  81     typedef void type;
  82 };
  83
  84 #else
  85 //#endif
  86
  87 #define BOOST_PP_FILENAME_1 <boost/type_erasure/detail/extract_concept.hpp>
  88 #define BOOST_PP_ITERATION_LIMITS (1, BOOST_TYPE_ERASURE_MAX_ARITY)
  89 #include BOOST_PP_ITERATE()
  90
  91 #endif
  92
  93 }
  94 }
  95 }
  96
  97 #endif
  98
  99 #else
 100
 101 #define N BOOST_PP_ITERATION()
 102
 103 #define BOOST_TYPE_ERASURE_EXTRACT_CONCEPT(z, n, data)                  \
 104     typedef typename ::boost::type_erasure::detail::combine_concepts<   \
 105         typename ::boost::type_erasure::detail::maybe_extract_concept<  \
 106             BOOST_PP_CAT(T, n), BOOST_PP_CAT(U, n)                      \
 107         >::type,                                                        \
 108         BOOST_PP_CAT(concept, n)                                        \
 109     >::type BOOST_PP_CAT(concept, BOOST_PP_INC(n));
 110
 111 template<
 112     BOOST_PP_ENUM_PARAMS(N, class T),
 113     BOOST_PP_ENUM_PARAMS(N, class U)>
 114 struct BOOST_PP_CAT(extract_concept, N)
 115 {
 116     typedef void concept0;
 117
 118     BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_EXTRACT_CONCEPT, ~)
 119
 120     typedef BOOST_PP_CAT(concept, N) type;
 121 };
 122
 123 #undef BOOST_TYPE_ERASURE_EXTRACT_CONCEPT
 124 #undef N
 125
 126 #endif