96 lines
2.8 KiB
C++
96 lines
2.8 KiB
C++
#pragma once
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#include "util.hpp"
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#include "../type/type.hpp"
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namespace util {
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// <functional>
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// clang-format off
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namespace detail {
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template <typename> constexpr bool is_reference_wrapper_v = false;
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template <typename U> constexpr bool is_reference_wrapper_v<reference_wrapper<U>> = true;
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template <typename T, typename Type, typename T1, typename... Args>
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constexpr decltype(auto) INVOKE(Type T::*f, T1 &&t1, Args &&... args)
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{
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if constexpr (type::is_member_function_pointer_v<decltype(f)>) {
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if constexpr (type::is_base_of_v<T, type::decay_t<T1>>)
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return (util::forward<T1>(t1).*f)(util::forward<Args>(args)...);
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else if constexpr (is_reference_wrapper_v<type::decay_t<T1>>)
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return (t1.get().*f)(util::forward<Args>(args)...);
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else
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return ((*util::forward<T1>(t1)).*f)(util::forward<Args>(args)...);
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} else {
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static_assert(type::is_member_object_pointer_v<decltype(f)>);
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static_assert(sizeof...(args) == 0);
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if constexpr (type::is_base_of_v<T, type::decay_t<T1>>)
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return util::forward<T1>(t1).*f;
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else if constexpr (is_reference_wrapper_v<type::decay_t<T1>>)
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return t1.get().*f;
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else
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return (*util::forward<T1>(t1)).*f;
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}
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}
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template <typename Fn, typename... Args>
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constexpr decltype(auto) INVOKE(Fn &&f, Args &&... args)
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{
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return util::forward<Fn>(f)(util::forward<Args>(args)...);
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}
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template <typename T> constexpr T &FUN(T &t) noexcept { return t; }
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template <typename T> void FUN(T &&) = delete;
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} // namespace detail
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template <typename Fn, typename... Args>
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constexpr type::invoke_result_t<Fn, Args...> invoke(Fn &&f, Args &&... args)
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noexcept(type::is_nothrow_invocable_v<Fn, Args...>)
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{
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return detail::INVOKE(util::forward<Fn>(f), util::forward<Args>(args)...);
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}
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template <typename T>
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class reference_wrapper {
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public:
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// construct/copy/destroy
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template <typename U,
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typename = decltype(detail::FUN<T>(util::declval<U>()),
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type::enable_if_t<!type::is_same_v<reference_wrapper, type::remove_cvref_t<U>>>())>
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constexpr reference_wrapper(U &&u) noexcept(noexcept(detail::FUN<T>(util::forward<U>(u))))
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: _ptr(util::addressof(detail::FUN<T>(util::forward<U>(u))))
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{}
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reference_wrapper(const reference_wrapper &) noexcept = default;
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// assignment
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reference_wrapper &operator=(const reference_wrapper &) noexcept = default;
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// access
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constexpr operator T &() const noexcept { return *_ptr; }
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constexpr T &get() const noexcept { return *_ptr; }
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template <typename... ArgTypes>
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constexpr type::invoke_result_t<T &, ArgTypes...> operator()(ArgTypes &&... args) const
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{
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return invoke(get(), util::forward<ArgTypes>(args)...);
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}
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// types
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using type = T;
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private:
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T *_ptr;
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};
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// deduction guides
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template <typename T> reference_wrapper(T &) -> reference_wrapper<T>;
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// clang-format on
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} // namespace util
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