| // Copyright David Abrahams 2003. Use, modification and distribution is |
| // subject to the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| #ifndef IS_READABLE_ITERATOR_DWA2003112_HPP |
| # define IS_READABLE_ITERATOR_DWA2003112_HPP |
| |
| #include <boost/mpl/bool.hpp> |
| #include <boost/mpl/aux_/lambda_support.hpp> |
| #include <boost/type_traits/add_lvalue_reference.hpp> |
| |
| #include <boost/iterator/detail/any_conversion_eater.hpp> |
| |
| #include <iterator> |
| |
| // should be the last #include |
| #include <boost/type_traits/integral_constant.hpp> |
| #include <boost/iterator/detail/config_def.hpp> |
| |
| #ifndef BOOST_NO_IS_CONVERTIBLE |
| |
| namespace boost { |
| |
| namespace iterators { |
| |
| namespace detail |
| { |
| // Guts of is_readable_iterator. Value is the iterator's value_type |
| // and the result is computed in the nested rebind template. |
| template <class Value> |
| struct is_readable_iterator_impl |
| { |
| static char tester(typename add_lvalue_reference<Value>::type, int); |
| static char (& tester(any_conversion_eater, ...) )[2]; |
| |
| template <class It> |
| struct rebind |
| { |
| static It& x; |
| |
| BOOST_STATIC_CONSTANT( |
| bool |
| , value = ( |
| sizeof( |
| is_readable_iterator_impl<Value>::tester(*x, 1) |
| ) == 1 |
| ) |
| ); |
| }; |
| }; |
| |
| #undef BOOST_READABLE_PRESERVER |
| |
| // |
| // void specializations to handle std input and output iterators |
| // |
| template <> |
| struct is_readable_iterator_impl<void> |
| { |
| template <class It> |
| struct rebind : boost::mpl::false_ |
| {}; |
| }; |
| |
| #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS |
| template <> |
| struct is_readable_iterator_impl<const void> |
| { |
| template <class It> |
| struct rebind : boost::mpl::false_ |
| {}; |
| }; |
| |
| template <> |
| struct is_readable_iterator_impl<volatile void> |
| { |
| template <class It> |
| struct rebind : boost::mpl::false_ |
| {}; |
| }; |
| |
| template <> |
| struct is_readable_iterator_impl<const volatile void> |
| { |
| template <class It> |
| struct rebind : boost::mpl::false_ |
| {}; |
| }; |
| #endif |
| |
| // |
| // This level of dispatching is required for Borland. We might save |
| // an instantiation by removing it for others. |
| // |
| template <class It> |
| struct is_readable_iterator_impl2 |
| : is_readable_iterator_impl< |
| BOOST_DEDUCED_TYPENAME std::iterator_traits<It>::value_type const |
| >::template rebind<It> |
| {}; |
| } // namespace detail |
| |
| template< typename T > struct is_readable_iterator |
| : public ::boost::integral_constant<bool,::boost::iterators::detail::is_readable_iterator_impl2<T>::value> |
| { |
| public: |
| BOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_readable_iterator,(T)) |
| }; |
| |
| } // namespace iterators |
| |
| using iterators::is_readable_iterator; |
| |
| } // namespace boost |
| |
| #endif |
| |
| #include <boost/iterator/detail/config_undef.hpp> |
| |
| #endif // IS_READABLE_ITERATOR_DWA2003112_HPP |