ceph/src/boost/libs/convert/include/boost/convert/detail/is_converter.hpp

   1 // Copyright (c) 2009-2016 Vladimir Batov.
   2 // Use, modification and distribution are subject to the Boost Software License,
   3 // Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
   4
   5 #ifndef BOOST_CONVERT_IS_CONVERTER_HPP
   6 #define BOOST_CONVERT_IS_CONVERTER_HPP
   7
   8 #include <boost/convert/detail/forward.hpp>
   9 #include <boost/convert/detail/is_callable.hpp>
  10 #include <boost/utility/enable_if.hpp>
  11 #include <boost/type_traits.hpp>
  12 #include <boost/ref.hpp>
  13
  14 namespace boost { namespace cnv
  15 {
  16     template<typename, typename, typename, typename =void>
  17     struct is_cnv { BOOST_STATIC_CONSTANT(bool, value = false); };
  18
  19     template<typename Class, typename TypeIn, typename TypeOut>
  20     struct is_cnv<Class, TypeIn, TypeOut, typename enable_if<is_class<Class>, void>::type>
  21     {
  22         typedef typename ::boost::unwrap_reference<Class>::type class_type;
  23         typedef void signature_type(TypeIn const&, optional<TypeOut>&);
  24
  25         BOOST_DECLARE_IS_CALLABLE(is_callable, operator());
  26
  27         BOOST_STATIC_CONSTANT(bool, value = (is_callable<class_type, signature_type>::value));
  28     };
  29
  30     template<typename Function, typename TypeIn, typename TypeOut>
  31     struct is_cnv<Function, TypeIn, TypeOut,
  32         typename enable_if_c<is_function<Function>::value && function_types::function_arity<Function>::value == 2,
  33         void>::type>
  34     {
  35         typedef TypeIn                                              in_type;
  36         typedef optional<TypeOut>&                                 out_type;
  37         typedef typename function_traits<Function>::arg1_type  func_in_type;
  38         typedef typename function_traits<Function>::arg2_type func_out_type;
  39
  40         BOOST_STATIC_CONSTANT(bool,  in_good = (is_convertible<in_type, func_in_type>::value));
  41         BOOST_STATIC_CONSTANT(bool, out_good = (is_same<out_type, func_out_type>::value));
  42         BOOST_STATIC_CONSTANT(bool,    value = (in_good && out_good));
  43     };
  44 }}
  45
  46 #endif // BOOST_CONVERT_IS_CONVERTER_HPP
  47