Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame] | 1 | // (C) Copyright Jeremy Siek 2002. |
| 2 | // Distributed under the Boost Software License, Version 1.0. (See |
| 3 | // accompanying file LICENSE_1_0.txt or copy at |
| 4 | // http://www.boost.org/LICENSE_1_0.txt) |
| 5 | |
Jeff Thompson | 3d613fd | 2013-10-15 15:39:04 -0700 | [diff] [blame^] | 6 | #ifndef NDNBOOST_ITERATOR_CATEGORIES_HPP |
| 7 | # define NDNBOOST_ITERATOR_CATEGORIES_HPP |
Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame] | 8 | |
| 9 | # include <ndnboost/config.hpp> |
| 10 | # include <ndnboost/detail/iterator.hpp> |
| 11 | # include <ndnboost/iterator/detail/config_def.hpp> |
| 12 | |
| 13 | # include <ndnboost/detail/workaround.hpp> |
| 14 | |
| 15 | # include <ndnboost/mpl/eval_if.hpp> |
| 16 | # include <ndnboost/mpl/identity.hpp> |
| 17 | # include <ndnboost/mpl/placeholders.hpp> |
| 18 | # include <ndnboost/mpl/aux_/lambda_support.hpp> |
| 19 | |
| 20 | # include <ndnboost/type_traits/is_convertible.hpp> |
| 21 | |
| 22 | # include <ndnboost/static_assert.hpp> |
| 23 | |
| 24 | namespace ndnboost { |
| 25 | |
| 26 | // |
| 27 | // Traversal Categories |
| 28 | // |
| 29 | |
| 30 | struct no_traversal_tag {}; |
| 31 | |
| 32 | struct incrementable_traversal_tag |
| 33 | : no_traversal_tag |
| 34 | { |
| 35 | // incrementable_traversal_tag() {} |
| 36 | // incrementable_traversal_tag(std::output_iterator_tag const&) {}; |
| 37 | }; |
| 38 | |
| 39 | struct single_pass_traversal_tag |
| 40 | : incrementable_traversal_tag |
| 41 | { |
| 42 | // single_pass_traversal_tag() {} |
| 43 | // single_pass_traversal_tag(std::input_iterator_tag const&) {}; |
| 44 | }; |
| 45 | |
| 46 | struct forward_traversal_tag |
| 47 | : single_pass_traversal_tag |
| 48 | { |
| 49 | // forward_traversal_tag() {} |
| 50 | // forward_traversal_tag(std::forward_iterator_tag const&) {}; |
| 51 | }; |
| 52 | |
| 53 | struct bidirectional_traversal_tag |
| 54 | : forward_traversal_tag |
| 55 | { |
| 56 | // bidirectional_traversal_tag() {}; |
| 57 | // bidirectional_traversal_tag(std::bidirectional_iterator_tag const&) {}; |
| 58 | }; |
| 59 | |
| 60 | struct random_access_traversal_tag |
| 61 | : bidirectional_traversal_tag |
| 62 | { |
| 63 | // random_access_traversal_tag() {}; |
| 64 | // random_access_traversal_tag(std::random_access_iterator_tag const&) {}; |
| 65 | }; |
| 66 | |
| 67 | namespace detail |
| 68 | { |
| 69 | // |
| 70 | // Convert a "strictly old-style" iterator category to a traversal |
| 71 | // tag. This is broken out into a separate metafunction to reduce |
| 72 | // the cost of instantiating iterator_category_to_traversal, below, |
| 73 | // for new-style types. |
| 74 | // |
| 75 | template <class Cat> |
| 76 | struct old_category_to_traversal |
| 77 | : mpl::eval_if< |
| 78 | is_convertible<Cat,std::random_access_iterator_tag> |
| 79 | , mpl::identity<random_access_traversal_tag> |
| 80 | , mpl::eval_if< |
| 81 | is_convertible<Cat,std::bidirectional_iterator_tag> |
| 82 | , mpl::identity<bidirectional_traversal_tag> |
| 83 | , mpl::eval_if< |
| 84 | is_convertible<Cat,std::forward_iterator_tag> |
| 85 | , mpl::identity<forward_traversal_tag> |
| 86 | , mpl::eval_if< |
| 87 | is_convertible<Cat,std::input_iterator_tag> |
| 88 | , mpl::identity<single_pass_traversal_tag> |
| 89 | , mpl::eval_if< |
| 90 | is_convertible<Cat,std::output_iterator_tag> |
| 91 | , mpl::identity<incrementable_traversal_tag> |
| 92 | , void |
| 93 | > |
| 94 | > |
| 95 | > |
| 96 | > |
| 97 | > |
| 98 | {}; |
| 99 | |
Jeff Thompson | 3d613fd | 2013-10-15 15:39:04 -0700 | [diff] [blame^] | 100 | # if NDNBOOST_WORKAROUND(NDNBOOST_MSVC, < 1300) |
Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame] | 101 | template <> |
| 102 | struct old_category_to_traversal<int> |
| 103 | { |
| 104 | typedef int type; |
| 105 | }; |
| 106 | # endif |
| 107 | |
| 108 | template <class Traversal> |
| 109 | struct pure_traversal_tag |
| 110 | : mpl::eval_if< |
| 111 | is_convertible<Traversal,random_access_traversal_tag> |
| 112 | , mpl::identity<random_access_traversal_tag> |
| 113 | , mpl::eval_if< |
| 114 | is_convertible<Traversal,bidirectional_traversal_tag> |
| 115 | , mpl::identity<bidirectional_traversal_tag> |
| 116 | , mpl::eval_if< |
| 117 | is_convertible<Traversal,forward_traversal_tag> |
| 118 | , mpl::identity<forward_traversal_tag> |
| 119 | , mpl::eval_if< |
| 120 | is_convertible<Traversal,single_pass_traversal_tag> |
| 121 | , mpl::identity<single_pass_traversal_tag> |
| 122 | , mpl::eval_if< |
| 123 | is_convertible<Traversal,incrementable_traversal_tag> |
| 124 | , mpl::identity<incrementable_traversal_tag> |
| 125 | , void |
| 126 | > |
| 127 | > |
| 128 | > |
| 129 | > |
| 130 | > |
| 131 | { |
| 132 | }; |
| 133 | |
Jeff Thompson | 3d613fd | 2013-10-15 15:39:04 -0700 | [diff] [blame^] | 134 | # if NDNBOOST_WORKAROUND(NDNBOOST_MSVC, < 1300) |
Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame] | 135 | template <> |
| 136 | struct pure_traversal_tag<int> |
| 137 | { |
| 138 | typedef int type; |
| 139 | }; |
| 140 | # endif |
| 141 | |
| 142 | } // namespace detail |
| 143 | |
| 144 | |
| 145 | // |
| 146 | // Convert an iterator category into a traversal tag |
| 147 | // |
| 148 | template <class Cat> |
| 149 | struct iterator_category_to_traversal |
| 150 | : mpl::eval_if< // if already convertible to a traversal tag, we're done. |
| 151 | is_convertible<Cat,incrementable_traversal_tag> |
| 152 | , mpl::identity<Cat> |
| 153 | , ndnboost::detail::old_category_to_traversal<Cat> |
| 154 | > |
| 155 | {}; |
| 156 | |
| 157 | // Trait to get an iterator's traversal category |
| 158 | template <class Iterator = mpl::_1> |
| 159 | struct iterator_traversal |
| 160 | : iterator_category_to_traversal< |
| 161 | typename ndnboost::detail::iterator_traits<Iterator>::iterator_category |
| 162 | > |
| 163 | {}; |
| 164 | |
Jeff Thompson | 3d613fd | 2013-10-15 15:39:04 -0700 | [diff] [blame^] | 165 | # ifdef NDNBOOST_MPL_CFG_NO_FULL_LAMBDA_SUPPORT |
| 166 | // Hack because NDNBOOST_MPL_AUX_LAMBDA_SUPPORT doesn't seem to work |
Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame] | 167 | // out well. Instantiating the nested apply template also |
| 168 | // requires instantiating iterator_traits on the |
| 169 | // placeholder. Instead we just specialize it as a metafunction |
| 170 | // class. |
| 171 | template <> |
| 172 | struct iterator_traversal<mpl::_1> |
| 173 | { |
| 174 | template <class T> |
| 175 | struct apply : iterator_traversal<T> |
| 176 | {}; |
| 177 | }; |
| 178 | template <> |
| 179 | struct iterator_traversal<mpl::_> |
| 180 | : iterator_traversal<mpl::_1> |
| 181 | {}; |
| 182 | # endif |
| 183 | |
| 184 | } // namespace ndnboost |
| 185 | |
| 186 | #include <ndnboost/iterator/detail/config_undef.hpp> |
| 187 | |
Jeff Thompson | 3d613fd | 2013-10-15 15:39:04 -0700 | [diff] [blame^] | 188 | #endif // NDNBOOST_ITERATOR_CATEGORIES_HPP |