mirror of
https://github.com/libSDL2pp/libSDL2pp.git
synced 2025-08-03 10:55:57 -04:00
519 lines
14 KiB
C++
519 lines
14 KiB
C++
// -*- C++ -*-
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//===-------------------------- optional ----------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SDL2PP_LIBCPP_OPTIONAL
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#define SDL2PP_LIBCPP_OPTIONAL
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#include <cassert>
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#include <functional>
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#include <initializer_list>
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#include <new>
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#include <stdexcept>
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#include <type_traits>
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namespace sdl2pp_libcpp_optional {
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class bad_optional_access
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: public std::logic_error
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{
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public:
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explicit bad_optional_access(const std::string& __arg)
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: std::logic_error(__arg) {}
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explicit bad_optional_access(const char* __arg)
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: std::logic_error(__arg) {}
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// Remove explicitly defaulted copy constructor and assignment operator:
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// noexcept specification doesn't work well with libstdc++
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//bad_optional_access(const bad_optional_access&) noexcept = default;
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//bad_optional_access& operator=(const bad_optional_access&) noexcept = default;
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// Get the key function ~bad_optional_access() into the dylib even if not compiling for C++1y
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virtual ~bad_optional_access() noexcept {}
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};
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struct in_place_t {};
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constexpr in_place_t in_place{};
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struct nullopt_t
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{
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explicit constexpr nullopt_t(int) noexcept {}
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};
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constexpr nullopt_t nullopt{0};
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template <class _Tp, bool = std::is_trivially_destructible<_Tp>::value>
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class __optional_storage
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{
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protected:
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typedef _Tp value_type;
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union
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{
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char __null_state_;
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value_type __val_;
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};
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bool __engaged_ = false;
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~__optional_storage()
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{
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if (__engaged_)
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__val_.~value_type();
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}
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constexpr __optional_storage() noexcept
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: __null_state_('\0') {}
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__optional_storage(const __optional_storage& __x)
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: __engaged_(__x.__engaged_)
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{
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if (__engaged_)
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::new(std::addressof(__val_)) value_type(__x.__val_);
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}
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__optional_storage(__optional_storage&& __x)
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noexcept(std::is_nothrow_move_constructible<value_type>::value)
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: __engaged_(__x.__engaged_)
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{
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if (__engaged_)
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::new(std::addressof(__val_)) value_type(std::move(__x.__val_));
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}
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constexpr __optional_storage(const value_type& __v)
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: __val_(__v),
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__engaged_(true) {}
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constexpr __optional_storage(value_type&& __v)
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: __val_(std::move(__v)),
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__engaged_(true) {}
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template <class... _Args>
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constexpr
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explicit __optional_storage(in_place_t, _Args&&... __args)
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: __val_(std::forward<_Args>(__args)...),
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__engaged_(true) {}
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};
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template <class _Tp>
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class __optional_storage<_Tp, true>
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{
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protected:
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typedef _Tp value_type;
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union
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{
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char __null_state_;
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value_type __val_;
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};
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bool __engaged_ = false;
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constexpr __optional_storage() noexcept
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: __null_state_('\0') {}
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__optional_storage(const __optional_storage& __x)
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: __engaged_(__x.__engaged_)
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{
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if (__engaged_)
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::new(std::addressof(__val_)) value_type(__x.__val_);
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}
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__optional_storage(__optional_storage&& __x)
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noexcept(std::is_nothrow_move_constructible<value_type>::value)
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: __engaged_(__x.__engaged_)
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{
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if (__engaged_)
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::new(std::addressof(__val_)) value_type(std::move(__x.__val_));
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}
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constexpr __optional_storage(const value_type& __v)
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: __val_(__v),
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__engaged_(true) {}
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constexpr __optional_storage(value_type&& __v)
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: __val_(std::move(__v)),
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__engaged_(true) {}
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template <class... _Args>
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constexpr
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explicit __optional_storage(in_place_t, _Args&&... __args)
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: __val_(std::forward<_Args>(__args)...),
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__engaged_(true) {}
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};
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template <class _Tp>
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class optional
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: private __optional_storage<_Tp>
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{
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typedef __optional_storage<_Tp> __base;
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public:
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typedef _Tp value_type;
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static_assert(!std::is_reference<value_type>::value,
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"Instantiation of optional with a reference type is ill-formed.");
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static_assert(!std::is_same<typename std::remove_cv<value_type>::type, in_place_t>::value,
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"Instantiation of optional with a in_place_t type is ill-formed.");
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static_assert(!std::is_same<typename std::remove_cv<value_type>::type, nullopt_t>::value,
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"Instantiation of optional with a nullopt_t type is ill-formed.");
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static_assert(std::is_object<value_type>::value,
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"Instantiation of optional with a non-object type is undefined behavior.");
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static_assert(std::is_nothrow_destructible<value_type>::value,
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"Instantiation of optional with an object type that is not noexcept destructible is undefined behavior.");
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constexpr optional() noexcept {}
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optional(const optional&) = default;
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optional(optional&&) = default;
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~optional() = default;
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constexpr optional(nullopt_t) noexcept {}
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constexpr optional(const value_type& __v)
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: __base(__v) {}
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constexpr optional(value_type&& __v)
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: __base(std::move(__v)) {}
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template <class... _Args,
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class = typename std::enable_if
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<
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std::is_constructible<value_type, _Args...>::value
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>::type
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>
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constexpr
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explicit optional(in_place_t, _Args&&... __args)
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: __base(in_place, std::forward<_Args>(__args)...) {}
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template <class _Up, class... _Args,
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class = typename std::enable_if
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<
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std::is_constructible<value_type, std::initializer_list<_Up>&, _Args...>::value
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>::type
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>
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constexpr
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explicit optional(in_place_t, std::initializer_list<_Up> __il, _Args&&... __args)
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: __base(in_place, __il, std::forward<_Args>(__args)...) {}
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optional& operator=(nullopt_t) noexcept
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{
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if (this->__engaged_)
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{
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this->__val_.~value_type();
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this->__engaged_ = false;
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}
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return *this;
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}
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optional&
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operator=(const optional& __opt)
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{
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if (this->__engaged_ == __opt.__engaged_)
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{
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if (this->__engaged_)
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this->__val_ = __opt.__val_;
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}
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else
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{
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if (this->__engaged_)
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this->__val_.~value_type();
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else
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::new(std::addressof(this->__val_)) value_type(__opt.__val_);
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this->__engaged_ = __opt.__engaged_;
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}
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return *this;
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}
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optional&
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operator=(optional&& __opt)
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noexcept(std::is_nothrow_move_assignable<value_type>::value &&
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std::is_nothrow_move_constructible<value_type>::value)
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{
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if (this->__engaged_ == __opt.__engaged_)
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{
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if (this->__engaged_)
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this->__val_ = std::move(__opt.__val_);
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}
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else
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{
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if (this->__engaged_)
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this->__val_.~value_type();
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else
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::new(std::addressof(this->__val_)) value_type(std::move(__opt.__val_));
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this->__engaged_ = __opt.__engaged_;
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}
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return *this;
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}
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template <class _Up,
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class = typename std::enable_if
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<
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std::is_same<typename std::remove_reference<_Up>::type, value_type>::value &&
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std::is_constructible<value_type, _Up>::value &&
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std::is_assignable<value_type&, _Up>::value
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>::type
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>
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optional&
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operator=(_Up&& __v)
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{
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if (this->__engaged_)
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this->__val_ = std::forward<_Up>(__v);
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else
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{
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::new(std::addressof(this->__val_)) value_type(std::forward<_Up>(__v));
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this->__engaged_ = true;
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}
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return *this;
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}
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template <class... _Args,
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class = typename std::enable_if
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<
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std::is_constructible<value_type, _Args...>::value
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>::type
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>
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void
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emplace(_Args&&... __args)
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{
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*this = nullopt;
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::new(std::addressof(this->__val_)) value_type(std::forward<_Args>(__args)...);
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this->__engaged_ = true;
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}
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template <class _Up, class... _Args,
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class = typename std::enable_if
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<
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std::is_constructible<value_type, std::initializer_list<_Up>&, _Args...>::value
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>::type
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>
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void
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emplace(std::initializer_list<_Up> __il, _Args&&... __args)
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{
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*this = nullopt;
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::new(std::addressof(this->__val_)) value_type(__il, std::forward<_Args>(__args)...);
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this->__engaged_ = true;
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}
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void
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swap(optional& __opt)
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noexcept(std::is_nothrow_move_constructible<value_type>::value &&
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noexcept(std::swap(std::declval<_Tp&>(), std::declval<_Tp&>())))
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{
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using std::swap;
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if (this->__engaged_ == __opt.__engaged_)
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{
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if (this->__engaged_)
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swap(this->__val_, __opt.__val_);
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}
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else
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{
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if (this->__engaged_)
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{
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::new(std::addressof(__opt.__val_)) value_type(std::move(this->__val_));
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this->__val_.~value_type();
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}
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else
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{
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::new(std::addressof(this->__val_)) value_type(std::move(__opt.__val_));
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__opt.__val_.~value_type();
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}
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swap(this->__engaged_, __opt.__engaged_);
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}
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}
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value_type const*
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operator->() const
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{
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assert(this->__engaged_); // "optional operator-> called for disengaged value");
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return std::addressof(this->__val_);
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}
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value_type*
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operator->()
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{
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assert(this->__engaged_); // "optional operator-> called for disengaged value");
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return std::addressof(this->__val_);
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}
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const value_type&
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operator*() const
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{
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assert(this->__engaged_); // "optional operator* called for disengaged value");
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return this->__val_;
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}
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value_type&
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operator*()
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{
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assert(this->__engaged_); // "optional operator* called for disengaged value");
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return this->__val_;
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}
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constexpr explicit operator bool() const noexcept {return this->__engaged_;}
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value_type const& value() const
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{
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if (!this->__engaged_)
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throw bad_optional_access("optional<T>::value: not engaged");
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return this->__val_;
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}
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value_type& value()
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{
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if (!this->__engaged_)
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throw bad_optional_access("optional<T>::value: not engaged");
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return this->__val_;
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}
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template <class _Up>
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constexpr value_type value_or(_Up&& __v) const&
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{
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static_assert(std::is_copy_constructible<value_type>::value,
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"optional<T>::value_or: T must be copy constructible");
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static_assert(std::is_convertible<_Up, value_type>::value,
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"optional<T>::value_or: U must be convertible to T");
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return this->__engaged_ ? this->__val_ :
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static_cast<value_type>(std::forward<_Up>(__v));
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}
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template <class _Up>
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value_type value_or(_Up&& __v) &&
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{
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static_assert(std::is_move_constructible<value_type>::value,
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"optional<T>::value_or: T must be move constructible");
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static_assert(std::is_convertible<_Up, value_type>::value,
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"optional<T>::value_or: U must be convertible to T");
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return this->__engaged_ ? std::move(this->__val_) :
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static_cast<value_type>(std::forward<_Up>(__v));
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}
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};
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template <class _Tp>
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inline
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bool
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operator==(const optional<_Tp>& __x, const optional<_Tp>& __y)
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{
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if (static_cast<bool>(__x) != static_cast<bool>(__y))
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return false;
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if (!static_cast<bool>(__x))
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return true;
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return *__x == *__y;
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}
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template <class _Tp>
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inline
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bool
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operator<(const optional<_Tp>& __x, const optional<_Tp>& __y)
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{
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if (!static_cast<bool>(__y))
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return false;
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if (!static_cast<bool>(__x))
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return true;
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return std::less<_Tp>{}(*__x, *__y);
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator==(const optional<_Tp>& __x, nullopt_t) noexcept
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{
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return !static_cast<bool>(__x);
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator==(nullopt_t, const optional<_Tp>& __x) noexcept
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{
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return !static_cast<bool>(__x);
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator<(const optional<_Tp>&, nullopt_t) noexcept
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{
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return false;
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator<(nullopt_t, const optional<_Tp>& __x) noexcept
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{
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return static_cast<bool>(__x);
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator==(const optional<_Tp>& __x, const _Tp& __v)
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{
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return static_cast<bool>(__x) ? *__x == __v : false;
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator==(const _Tp& __v, const optional<_Tp>& __x)
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{
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return static_cast<bool>(__x) ? *__x == __v : false;
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator<(const optional<_Tp>& __x, const _Tp& __v)
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{
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return static_cast<bool>(__x) ? std::less<_Tp>{}(*__x, __v) : true;
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}
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template <class _Tp>
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inline
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constexpr
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bool
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operator<(const _Tp& __v, const optional<_Tp>& __x)
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{
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return static_cast<bool>(__x) ? std::less<_Tp>{}(__v, *__x) : false;
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}
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template <class _Tp>
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inline
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void
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swap(optional<_Tp>& __x, optional<_Tp>& __y) noexcept(noexcept(__x.swap(__y)))
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{
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__x.swap(__y);
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}
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template <class _Tp>
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inline
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constexpr
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optional<typename std::decay<_Tp>::type>
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make_optional(_Tp&& __v)
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{
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return optional<typename std::decay<_Tp>::type>(std::forward<_Tp>(__v));
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}
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} // namespace sdl2pp_libcpp_optional
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namespace std {
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template <class _Tp>
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struct hash<sdl2pp_libcpp_optional::optional<_Tp> >
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{
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typedef sdl2pp_libcpp_optional::optional<_Tp> argument_type;
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typedef size_t result_type;
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result_type operator()(const argument_type& __opt) const noexcept
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{
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return static_cast<bool>(__opt) ? std::hash<_Tp>()(*__opt) : 0;
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}
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};
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}
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#endif // SDL2PP_LIBCPP_OPTIONAL
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