| 1 | // Boost.Range library |
|---|---|
| 2 | // |
| 3 | // Copyright Neil Groves 2010. Use, modification and |
| 4 | // distribution is subject to the Boost Software License, Version |
| 5 | // 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| 6 | // http://www.boost.org/LICENSE_1_0.txt) |
| 7 | // |
| 8 | // For more information, see http://www.boost.org/libs/range/ |
| 9 | // |
| 10 | // Acknowledgments: |
| 11 | // Ticket #8341: Arno Schoedl - improved handling of has_range_iterator upon |
| 12 | // use-cases where T was const. |
| 13 | #ifndef BOOST_RANGE_HAS_ITERATOR_HPP_INCLUDED |
| 14 | #define BOOST_RANGE_HAS_ITERATOR_HPP_INCLUDED |
| 15 | |
| 16 | #include <boost/mpl/bool.hpp> |
| 17 | #include <boost/mpl/eval_if.hpp> |
| 18 | #include <boost/mpl/has_xxx.hpp> |
| 19 | #include <boost/range/iterator.hpp> |
| 20 | #include <boost/type_traits/remove_reference.hpp> |
| 21 | #include <boost/utility/enable_if.hpp> |
| 22 | |
| 23 | namespace boost |
| 24 | { |
| 25 | namespace range_detail |
| 26 | { |
| 27 | BOOST_MPL_HAS_XXX_TRAIT_DEF(type) |
| 28 | |
| 29 | template<class T, class Enabler = void> |
| 30 | struct has_range_iterator_impl |
| 31 | : boost::mpl::false_ |
| 32 | { |
| 33 | }; |
| 34 | |
| 35 | template<class T> |
| 36 | struct has_range_iterator_impl< |
| 37 | T, |
| 38 | BOOST_DEDUCED_TYPENAME ::boost::enable_if< |
| 39 | BOOST_DEDUCED_TYPENAME mpl::eval_if<is_const<T>, |
| 40 | has_type<boost::range_const_iterator< |
| 41 | BOOST_DEDUCED_TYPENAME remove_const<T>::type> >, |
| 42 | has_type<boost::range_mutable_iterator<T> > |
| 43 | >::type |
| 44 | >::type |
| 45 | > |
| 46 | : boost::mpl::true_ |
| 47 | { |
| 48 | }; |
| 49 | |
| 50 | template<class T, class Enabler = void> |
| 51 | struct has_range_const_iterator_impl |
| 52 | : boost::mpl::false_ |
| 53 | { |
| 54 | }; |
| 55 | |
| 56 | template<class T> |
| 57 | struct has_range_const_iterator_impl< |
| 58 | T, |
| 59 | BOOST_DEDUCED_TYPENAME ::boost::enable_if< |
| 60 | has_type<boost::range_const_iterator<T> > |
| 61 | >::type |
| 62 | > |
| 63 | : boost::mpl::true_ |
| 64 | { |
| 65 | }; |
| 66 | |
| 67 | } // namespace range_detail |
| 68 | |
| 69 | template<class T> |
| 70 | struct has_range_iterator |
| 71 | : range_detail::has_range_iterator_impl< |
| 72 | BOOST_DEDUCED_TYPENAME remove_reference<T>::type> |
| 73 | {}; |
| 74 | |
| 75 | template<class T> |
| 76 | struct has_range_const_iterator |
| 77 | : range_detail::has_range_const_iterator_impl< |
| 78 | BOOST_DEDUCED_TYPENAME remove_reference<T>::type> |
| 79 | {}; |
| 80 | } // namespace boost |
| 81 | |
| 82 | #endif // include guard |
| 83 | |
| 84 |