// 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/detail/iterator.hpp> #include <boost/type_traits/detail/bool_trait_def.hpp> #include <boost/iterator/detail/any_conversion_eater.hpp> // should be the last #include #include <boost/iterator/detail/config_def.hpp> #ifndef BOOST_NO_IS_CONVERTIBLE namespace boost { 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(Value&, 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 boost::detail::iterator_traits<It>::value_type const >::template rebind<It> {}; } // namespace detail // Define the trait with full mpl lambda capability and various broken // compiler workarounds BOOST_TT_AUX_BOOL_TRAIT_DEF1( is_readable_iterator,T,::boost::detail::is_readable_iterator_impl2<T>::value) } // namespace boost #endif #include <boost/iterator/detail/config_undef.hpp> #endif // IS_READABLE_ITERATOR_DWA2003112_HPP