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Telegram/ThirdParty/range-v3/include/range/v3/view/ref.hpp

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+/// \file
+// Range v3 library
+//
+//  Copyright Eric Niebler 2013-present
+//
+//  Use, modification and distribution is subject to the
+//  Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//
+// Project home: https://github.com/ericniebler/range-v3
+//
+
+#ifndef RANGES_V3_VIEW_REF_HPP
+#define RANGES_V3_VIEW_REF_HPP
+
+#include <concepts/concepts.hpp>
+
+#include <range/v3/range_fwd.hpp>
+
+#include <range/v3/range/access.hpp>
+#include <range/v3/range/primitives.hpp>
+#include <range/v3/range/traits.hpp>
+#include <range/v3/utility/addressof.hpp>
+#include <range/v3/view/interface.hpp>
+
+#include <range/v3/detail/prologue.hpp>
+
+namespace ranges
+{
+    template<typename Rng>
+    struct ref_view;
+
+    template<typename Rng>
+    RANGES_INLINE_VAR constexpr bool enable_borrowed_range<ref_view<Rng>> = true;
+
+    /// \addtogroup group-views
+    /// @{
+    template<typename Rng>
+    struct ref_view : view_interface<ref_view<Rng>, range_cardinality<Rng>::value>
+    {
+    private:
+        CPP_assert(range<Rng>);
+        static_assert(std::is_object<Rng>::value, "");
+        Rng * rng_ = nullptr; // exposition only
+    public:
+        constexpr ref_view() noexcept = default;
+        constexpr ref_view(Rng & rng) noexcept
+          : rng_(detail::addressof(rng))
+        {}
+        constexpr Rng & base() const noexcept
+        {
+            return *rng_;
+        }
+        constexpr iterator_t<Rng> begin() const noexcept(noexcept(ranges::begin(*rng_)))
+        {
+            return ranges::begin(*rng_);
+        }
+        constexpr sentinel_t<Rng> end() const noexcept(noexcept(ranges::end(*rng_)))
+        {
+            return ranges::end(*rng_);
+        }
+        CPP_member
+        constexpr auto empty() const noexcept(noexcept(ranges::empty(*rng_)))
+            -> CPP_ret(bool)(
+                requires detail::can_empty_<Rng>)
+        {
+            return ranges::empty(*rng_);
+        }
+        CPP_auto_member
+        constexpr auto CPP_fun(size)()(const //
+            noexcept(noexcept(ranges::size(*rng_))) //
+            requires sized_range<Rng>)
+        {
+            return ranges::size(*rng_);
+        }
+        CPP_auto_member
+        constexpr auto CPP_fun(data)()(const //
+            noexcept(noexcept(ranges::data(*rng_))) //
+            requires contiguous_range<Rng>)
+        {
+            return ranges::data(*rng_);
+        }
+    };
+
+#if RANGES_CXX_DEDUCTION_GUIDES >= RANGES_CXX_DEDUCTION_GUIDES_17
+    template(typename R)(
+        requires range<R>)
+    ref_view(R &) //
+        -> ref_view<R>;
+#endif
+
+    namespace views
+    {
+        struct ref_fn
+        {
+            template(typename Rng)(
+                requires range<Rng>)
+            constexpr ref_view<Rng> operator()(Rng & rng) const noexcept
+            {
+                return ref_view<Rng>(rng);
+            }
+            template<typename Rng>
+            void operator()(Rng const && rng) const = delete;
+        };
+
+        /// \relates const_fn
+        /// \ingroup group-views
+        RANGES_INLINE_VARIABLE(ref_fn, ref)
+    } // namespace views
+
+    namespace cpp20
+    {
+        template(typename Rng)(
+            requires std::is_object<Rng>::value) //
+            using ref_view = ranges::ref_view<Rng>;
+    }
+} // namespace ranges
+
+#include <range/v3/detail/satisfy_boost_range.hpp>
+RANGES_SATISFY_BOOST_RANGE(::ranges::ref_view)
+
+#include <range/v3/detail/epilogue.hpp>
+
+#endif