v3/view/common.hpp

0001 /// \file
0002 // Range v3 library
0003 //
0004 //  Copyright Eric Niebler 2014-present
0005 //
0006 //  Use, modification and distribution is subject to the
0007 //  Boost Software License, Version 1.0. (See accompanying
0008 //  file LICENSE_1_0.txt or copy at
0009 //  http://www.boost.org/LICENSE_1_0.txt)
0010 //
0011 // Project home: https://github.com/ericniebler/range-v3
0012 //
0013 #ifndef RANGES_V3_VIEW_COMMON_HPP
0014 #define RANGES_V3_VIEW_COMMON_HPP
0015
0016 #include <type_traits>
0017
0018 #include <range/v3/range_fwd.hpp>
0019
0020 #include <range/v3/iterator/common_iterator.hpp>
0021 #include <range/v3/iterator/concepts.hpp>
0022 #include <range/v3/range/access.hpp>
0023 #include <range/v3/range/concepts.hpp>
0024 #include <range/v3/range/primitives.hpp>
0025 #include <range/v3/range/traits.hpp>
0026 #include <range/v3/utility/static_const.hpp>
0027 #include <range/v3/view/all.hpp>
0028 #include <range/v3/view/interface.hpp>
0029 #include <range/v3/view/view.hpp>
0030
0031 #include <range/v3/detail/prologue.hpp>
0032
0033 namespace ranges
0034 {
0035     /// \addtogroup group-views
0036     /// @{
0037
0038     /// \cond
0039     namespace detail
0040     {
0041         // clang-format off
0042         /// \concept random_access_and_sized_range
0043         /// \brief The \c random_access_and_sized_range concept
0044         template<typename R>
0045         CPP_concept random_access_and_sized_range =
0046             random_access_range<R> && sized_range<R>;
0047         // clang-format on
0048
0049         template<typename R>
0050         using common_view_iterator_t =
0051             meta::if_c<random_access_and_sized_range<R>, iterator_t<R>,
0052                        common_iterator_t<iterator_t<R>, sentinel_t<R>>>;
0053
0054         template<typename Rng>
0055         struct is_common_range : meta::bool_<common_range<Rng>>
0056         {};
0057     } // namespace detail
0058     /// \endcond
0059
0060     template<typename Rng, bool = detail::is_common_range<Rng>::value>
0061     struct common_view : view_interface<common_view<Rng>, range_cardinality<Rng>::value>
0062     {
0063     private:
0064         CPP_assert(view_<Rng>);
0065         CPP_assert(!(common_range<Rng> && view_<Rng>));
0066         Rng rng_;
0067
0068         sentinel_t<Rng> end_(std::false_type)
0069         {
0070             return ranges::end(rng_);
0071         }
0072         iterator_t<Rng> end_(std::true_type)
0073         {
0074             return ranges::begin(rng_) + ranges::distance(rng_);
0075         }
0076         template(bool Const = true)(
0077             requires Const AND range<meta::const_if_c<Const, Rng>>)
0078         sentinel_t<meta::const_if_c<Const, Rng>> end_(std::false_type) const
0079         {
0080             return ranges::end(rng_);
0081         }
0082         template(bool Const = true)(
0083             requires Const AND range<meta::const_if_c<Const, Rng>>)
0084         iterator_t<meta::const_if_c<Const, Rng>> end_(std::true_type) const
0085         {
0086             return ranges::begin(rng_) + ranges::distance(rng_);
0087         }
0088
0089     public:
0090         common_view() = default;
0091         explicit common_view(Rng rng)
0092           : rng_(detail::move(rng))
0093         {}
0094         Rng base() const
0095         {
0096             return rng_;
0097         }
0098
0099         detail::common_view_iterator_t<Rng> begin()
0100         {
0101             return detail::common_view_iterator_t<Rng>{ranges::begin(rng_)};
0102         }
0103         detail::common_view_iterator_t<Rng> end()
0104         {
0105             return detail::common_view_iterator_t<Rng>{
0106                 end_(meta::bool_<detail::random_access_and_sized_range<Rng>>{})};
0107         }
0108         CPP_auto_member
0109         auto CPP_fun(size)()(
0110             requires sized_range<Rng>)
0111         {
0112             return ranges::size(rng_);
0113         }
0114
0115         template(bool Const = true)(
0116             requires range<meta::const_if_c<Const, Rng>>)
0117         auto begin() const
0118             -> detail::common_view_iterator_t<meta::const_if_c<Const, Rng>>
0119         {
0120             return detail::common_view_iterator_t<meta::const_if_c<Const, Rng>>{
0121                 ranges::begin(rng_)};
0122         }
0123         template(bool Const = true)(
0124             requires range<meta::const_if_c<Const, Rng>>)
0125         auto end() const
0126             -> detail::common_view_iterator_t<meta::const_if_c<Const, Rng>>
0127         {
0128             return detail::common_view_iterator_t<meta::const_if_c<Const, Rng>>{
0129                 end_(meta::bool_<detail::random_access_and_sized_range<
0130                          meta::const_if_c<Const, Rng>>>{})};
0131         }
0132         CPP_auto_member
0133         auto CPP_fun(size)()(const
0134             requires sized_range<Rng const>)
0135         {
0136             return ranges::size(rng_);
0137         }
0138     };
0139
0140     template<typename Rng, bool B>
0141     RANGES_INLINE_VAR constexpr bool enable_borrowed_range<common_view<Rng, B>> = //
0142         enable_borrowed_range<Rng>;
0143
0144 #if RANGES_CXX_DEDUCTION_GUIDES >= RANGES_CXX_DEDUCTION_GUIDES_17
0145     template(typename Rng)(
0146         requires (!common_range<Rng>)) //
0147         common_view(Rng &&)
0148             ->common_view<views::all_t<Rng>>;
0149 #endif
0150
0151     template<typename Rng>
0152     struct common_view<Rng, true> : identity_adaptor<Rng>
0153     {
0154         CPP_assert(common_range<Rng>);
0155         using identity_adaptor<Rng>::identity_adaptor;
0156     };
0157
0158     namespace views
0159     {
0160         struct cpp20_common_fn
0161         {
0162             template(typename Rng)(
0163                 requires viewable_range<Rng> AND common_range<Rng>)
0164             all_t<Rng> operator()(Rng && rng) const
0165             {
0166                 return all(static_cast<Rng &&>(rng));
0167             }
0168
0169             template(typename Rng)(
0170                 requires viewable_range<Rng> AND (!common_range<Rng>)) //
0171             common_view<all_t<Rng>> operator()(Rng && rng) const
0172             {
0173                 return common_view<all_t<Rng>>{all(static_cast<Rng &&>(rng))};
0174             }
0175         };
0176
0177         struct common_fn
0178         {
0179             template(typename Rng)(
0180                 requires viewable_range<Rng>)
0181             common_view<all_t<Rng>> operator()(Rng && rng) const
0182             {
0183                 return common_view<all_t<Rng>>{all(static_cast<Rng &&>(rng))};
0184             }
0185         };
0186
0187         /// \relates common_fn
0188         /// \ingroup group-views
0189         RANGES_INLINE_VARIABLE(view_closure<common_fn>, common)
0190     } // namespace views
0191     /// @}
0192
0193     /// \cond
0194     template<typename Rng>
0195     using bounded_view RANGES_DEPRECATED(
0196         "The name bounded_view is deprecated. "
0197         "Please use common_view instead.") = common_view<Rng>;
0198     /// \endcond
0199
0200     namespace views
0201     {
0202         /// \cond
0203         namespace
0204         {
0205             RANGES_DEPRECATED(
0206                 "The name views::bounded is deprecated. "
0207                 "Please use views::common instead.")
0208             RANGES_INLINE_VAR constexpr auto & bounded = common;
0209         } // namespace
0210
0211         template<typename Rng>
0212         using bounded_t RANGES_DEPRECATED("The name views::bounded_t is deprecated.") =
0213             decltype(common(std::declval<Rng>()));
0214         /// \endcond
0215     } // namespace views
0216
0217     namespace cpp20
0218     {
0219         namespace views
0220         {
0221             RANGES_INLINE_VARIABLE(
0222                 ranges::views::view_closure<ranges::views::cpp20_common_fn>, common)
0223         }
0224         template(typename Rng)(
0225             requires view_<Rng> && (!common_range<Rng>)) //
0226             using common_view = ranges::common_view<Rng>;
0227     } // namespace cpp20
0228 } // namespace ranges
0229
0230 #include <range/v3/detail/epilogue.hpp>
0231
0232 #include <range/v3/detail/satisfy_boost_range.hpp>
0233 RANGES_SATISFY_BOOST_RANGE(::ranges::common_view)
0234
0235 #endif