ceph/src/boost/libs/range/include/boost/range/has_range_iterator.hpp

   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<range_const_iterator<
  41                                 BOOST_DEDUCED_TYPENAME remove_const<T>::type> >,
  42                     has_type<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<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