diff options
Diffstat (limited to 'boost/iterator/iterator_categories.hpp')
| -rw-r--r-- | boost/iterator/iterator_categories.hpp | 134 |
1 files changed, 84 insertions, 50 deletions
diff --git a/boost/iterator/iterator_categories.hpp b/boost/iterator/iterator_categories.hpp index 1740d9818a..31b2a9d3ec 100644 --- a/boost/iterator/iterator_categories.hpp +++ b/boost/iterator/iterator_categories.hpp @@ -22,6 +22,7 @@ # include <boost/static_assert.hpp> namespace boost { +namespace iterators { // // Traversal Categories @@ -29,34 +30,34 @@ namespace boost { struct no_traversal_tag {}; -struct incrementable_traversal_tag +struct incrementable_traversal_tag : no_traversal_tag { // incrementable_traversal_tag() {} // incrementable_traversal_tag(std::output_iterator_tag const&) {}; }; - + struct single_pass_traversal_tag : incrementable_traversal_tag { // single_pass_traversal_tag() {} // single_pass_traversal_tag(std::input_iterator_tag const&) {}; }; - + struct forward_traversal_tag : single_pass_traversal_tag { // forward_traversal_tag() {} // forward_traversal_tag(std::forward_iterator_tag const&) {}; }; - + struct bidirectional_traversal_tag : forward_traversal_tag { // bidirectional_traversal_tag() {}; // bidirectional_traversal_tag(std::bidirectional_iterator_tag const&) {}; }; - + struct random_access_traversal_tag : bidirectional_traversal_tag { @@ -65,7 +66,7 @@ struct random_access_traversal_tag }; namespace detail -{ +{ // // Convert a "strictly old-style" iterator category to a traversal // tag. This is broken out into a separate metafunction to reduce @@ -97,51 +98,8 @@ namespace detail > {}; -# if BOOST_WORKAROUND(BOOST_MSVC, < 1300) - template <> - struct old_category_to_traversal<int> - { - typedef int type; - }; -# endif - - template <class Traversal> - struct pure_traversal_tag - : mpl::eval_if< - is_convertible<Traversal,random_access_traversal_tag> - , mpl::identity<random_access_traversal_tag> - , mpl::eval_if< - is_convertible<Traversal,bidirectional_traversal_tag> - , mpl::identity<bidirectional_traversal_tag> - , mpl::eval_if< - is_convertible<Traversal,forward_traversal_tag> - , mpl::identity<forward_traversal_tag> - , mpl::eval_if< - is_convertible<Traversal,single_pass_traversal_tag> - , mpl::identity<single_pass_traversal_tag> - , mpl::eval_if< - is_convertible<Traversal,incrementable_traversal_tag> - , mpl::identity<incrementable_traversal_tag> - , void - > - > - > - > - > - { - }; - -# if BOOST_WORKAROUND(BOOST_MSVC, < 1300) - template <> - struct pure_traversal_tag<int> - { - typedef int type; - }; -# endif - } // namespace detail - // // Convert an iterator category into a traversal tag // @@ -150,7 +108,7 @@ struct iterator_category_to_traversal : mpl::eval_if< // if already convertible to a traversal tag, we're done. is_convertible<Cat,incrementable_traversal_tag> , mpl::identity<Cat> - , boost::detail::old_category_to_traversal<Cat> + , boost::iterators::detail::old_category_to_traversal<Cat> > {}; @@ -181,6 +139,82 @@ struct iterator_traversal<mpl::_> {}; # endif +// +// Convert an iterator traversal to one of the traversal tags. +// +template <class Traversal> +struct pure_traversal_tag + : mpl::eval_if< + is_convertible<Traversal,random_access_traversal_tag> + , mpl::identity<random_access_traversal_tag> + , mpl::eval_if< + is_convertible<Traversal,bidirectional_traversal_tag> + , mpl::identity<bidirectional_traversal_tag> + , mpl::eval_if< + is_convertible<Traversal,forward_traversal_tag> + , mpl::identity<forward_traversal_tag> + , mpl::eval_if< + is_convertible<Traversal,single_pass_traversal_tag> + , mpl::identity<single_pass_traversal_tag> + , mpl::eval_if< + is_convertible<Traversal,incrementable_traversal_tag> + , mpl::identity<incrementable_traversal_tag> + , void + > + > + > + > + > +{ +}; + +// This import is needed for backward compatibility with Boost.Range: +// boost/range/detail/demote_iterator_traversal_tag.hpp +// It should be removed when that header is fixed. +namespace detail { +using iterators::pure_traversal_tag; +} // namespace detail + +// +// Trait to retrieve one of the iterator traversal tags from the iterator category or traversal. +// +template <class Iterator = mpl::_1> +struct pure_iterator_traversal + : pure_traversal_tag<typename iterator_traversal<Iterator>::type> +{}; + +# ifdef BOOST_MPL_CFG_NO_FULL_LAMBDA_SUPPORT +template <> +struct pure_iterator_traversal<mpl::_1> +{ + template <class T> + struct apply : pure_iterator_traversal<T> + {}; +}; +template <> +struct pure_iterator_traversal<mpl::_> + : pure_iterator_traversal<mpl::_1> +{}; +# endif + +} // namespace iterators + +using iterators::no_traversal_tag; +using iterators::incrementable_traversal_tag; +using iterators::single_pass_traversal_tag; +using iterators::forward_traversal_tag; +using iterators::bidirectional_traversal_tag; +using iterators::random_access_traversal_tag; +using iterators::iterator_category_to_traversal; +using iterators::iterator_traversal; + +// This import is needed for backward compatibility with Boost.Range: +// boost/range/detail/demote_iterator_traversal_tag.hpp +// It should be removed when that header is fixed. +namespace detail { +using iterators::pure_traversal_tag; +} // namespace detail + } // namespace boost #include <boost/iterator/detail/config_undef.hpp> |