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Telegram/ThirdParty/range-v3/include/range/v3/functional/compose.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_FUNCTIONAL_COMPOSE_HPP
+#define RANGES_V3_FUNCTIONAL_COMPOSE_HPP
+
+#include <type_traits>
+#include <utility>
+
+#include <concepts/concepts.hpp>
+
+#include <range/v3/detail/config.hpp>
+#include <range/v3/functional/invoke.hpp>
+#include <range/v3/utility/static_const.hpp>
+
+#include <range/v3/detail/prologue.hpp>
+
+namespace ranges
+{
+    /// \addtogroup group-functional
+    /// @{
+    template<typename Second, typename First>
+    struct composed
+    {
+    private:
+        RANGES_NO_UNIQUE_ADDRESS
+        First first_;
+        RANGES_NO_UNIQUE_ADDRESS
+        Second second_;
+
+        // clang-format off
+        template<typename A, typename B, typename... Ts>
+        static constexpr auto //
+        CPP_auto_fun(do_)(A &&a, B &&b, std::false_type, Ts &&... ts)
+        (
+            return invoke((B &&) b, invoke((A &&) a, (Ts &&) ts...))
+        )
+        template<typename A, typename B, typename... Ts>
+        static constexpr auto CPP_auto_fun(do_)(A &&a, B &&b, std::true_type, Ts &&... ts)
+        (
+            return (invoke((A &&) a, (Ts &&) ts...), invoke((B &&) b))
+        )
+    public:
+        composed() = default;
+        // clang-format on
+        constexpr composed(Second second, First first)
+          : first_(std::move(first))
+          , second_(std::move(second))
+        {}
+        // clang-format off
+        template<typename... Ts>
+        constexpr auto CPP_auto_fun(operator())(Ts &&... ts)(mutable &)
+        (
+            return composed::do_(first_,
+                                 second_,
+                                 std::is_void<invoke_result_t<First &, Ts...>>{},
+                                 (Ts &&) ts...)
+        )
+        template<typename... Ts>
+        constexpr auto CPP_auto_fun(operator())(Ts &&... ts)(const &)
+        (
+            return composed::do_((First const &)first_,
+                                 (Second const &)second_,
+                                 std::is_void<invoke_result_t<First const &, Ts...>>{},
+                                 (Ts &&) ts...)
+        )
+        template<typename... Ts>
+        constexpr auto CPP_auto_fun(operator())(Ts &&... ts)(mutable &&)
+        (
+            return composed::do_((First &&)first_,
+                                 (Second &&)second_,
+                                 std::is_void<invoke_result_t<First &&, Ts...>>{},
+                                 (Ts &&) ts...)
+        )
+        // clang-format on
+    };
+
+    struct compose_fn
+    {
+        template<typename Second, typename First>
+        constexpr composed<Second, First> operator()(Second second, First first) const
+        {
+            return {std::move(second), std::move(first)};
+        }
+    };
+
+    /// \ingroup group-functional
+    /// \sa `compose_fn`
+    RANGES_INLINE_VARIABLE(compose_fn, compose)
+    /// @}
+} // namespace ranges
+
+#include <range/v3/detail/epilogue.hpp>
+
+#endif