// -*- C++ -*-
//===--------------------------- future -----------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_FUTURE
#define _LIBCPP_FUTURE

/*
    future synopsis

namespace std
{

enum class future_errc
{
    broken_promise,
    future_already_retrieved,
    promise_already_satisfied,
    no_state
};

enum class launch
{
    any,
    async,
    sync
};

enum class future_status
{
    ready,
    timeout,
    deferred
};

template <> struct is_error_code_enum<future_errc> : public true_type { };
error_code make_error_code(future_errc e);
error_condition make_error_condition(future_errc e);

const error_category& future_category();

class future_error
    : public logic_error
{
public:
    future_error(error_code ec);  // exposition only

    const error_code& code() const throw();
    const char*       what() const throw();
};

template <class R>
class promise
{
public:
    promise();
    template <class Allocator>
        promise(allocator_arg_t, const Allocator& a);
    promise(promise&& rhs);
    promise(const promise& rhs) = delete;
    ~promise();

    // assignment
    promise& operator=(promise&& rhs);
    promise& operator=(const promise& rhs) = delete;
    void swap(promise& other);

    // retrieving the result
    future<R> get_future();

    // setting the result
    void set_value(const R& r);
    void set_value(R&& r);
    void set_exception(exception_ptr p);

    // setting the result with deferred notification
    void set_value_at_thread_exit(const R& r);
    void set_value_at_thread_exit(R&& r);
    void set_exception_at_thread_exit(exception_ptr p);
};

template <class R>
class promise<R&>
{
public:
    promise();
    template <class Allocator>
        promise(allocator_arg_t, const Allocator& a);
    promise(promise&& rhs);
    promise(const promise& rhs) = delete;
    ~promise();

    // assignment
    promise& operator=(promise&& rhs);
    promise& operator=(const promise& rhs) = delete;
    void swap(promise& other);

    // retrieving the result
    future<R> get_future();

    // setting the result
    void set_value(R& r);
    void set_exception(exception_ptr p);

    // setting the result with deferred notification
    void set_value_at_thread_exit(R&);
    void set_exception_at_thread_exit(exception_ptr p);
};

template <>
class promise<void>
{
public:
    promise();
    template <class Allocator>
        promise(allocator_arg_t, const Allocator& a);
    promise(promise&& rhs);
    promise(const promise& rhs) = delete;
    ~promise();

    // assignment
    promise& operator=(promise&& rhs);
    promise& operator=(const promise& rhs) = delete;
    void swap(promise& other);

    // retrieving the result
    future<R> get_future();

    // setting the result
    void set_value();
    void set_exception(exception_ptr p);

    // setting the result with deferred notification
    void set_value_at_thread_exit();
    void set_exception_at_thread_exit(exception_ptr p);
};

template <class R> void swap(promise<R>& x, promise<R>& y);

template <class R, class Alloc>
    struct uses_allocator<promise<R>, Alloc> : public true_type {};

template <class R>
class future
{
public:
    future();
    future(future&&);
    future(const future& rhs) = delete;
    ~future();
    future& operator=(const future& rhs) = delete;
    future& operator=(future&&);

    // retrieving the value
    R get();

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <class R>
class future<R&>
{
public:
    future();
    future(future&&);
    future(const future& rhs) = delete;
    ~future();
    future& operator=(const future& rhs) = delete;
    future& operator=(future&&);

    // retrieving the value
    R& get();

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <>
class future<void>
{
public:
    future();
    future(future&&);
    future(const future& rhs) = delete;
    ~future();
    future& operator=(const future& rhs) = delete;
    future& operator=(future&&);

    // retrieving the value
    void get();

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <class R>
class shared_future
{
public:
    shared_future();
    shared_future(const shared_future& rhs);
    shared_future(future<R>&&);
    shared_future(shared_future&& rhs);
    ~shared_future();
    shared_future& operator=(const shared_future& rhs);
    shared_future& operator=(shared_future&& rhs);

    // retrieving the value
    const R& get() const;

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <class R>
class shared_future<R&>
{
public:
    shared_future();
    shared_future(const shared_future& rhs);
    shared_future(future<R>&&);
    shared_future(shared_future&& rhs);
    ~shared_future();
    shared_future& operator=(const shared_future& rhs);
    shared_future& operator=(shared_future&& rhs);

    // retrieving the value
    R& get() const;

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <>
class shared_future<void>
{
public:
    shared_future();
    shared_future(const shared_future& rhs);
    shared_future(future<R>&&);
    shared_future(shared_future&& rhs);
    ~shared_future();
    shared_future& operator=(const shared_future& rhs);
    shared_future& operator=(shared_future&& rhs);

    // retrieving the value
    void get() const;

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <class R>
class atomic_future
{
public:
    atomic_future();
    atomic_future(const atomic_future& rhs);
    atomic_future(future<R>&&);
    ~atomic_future();
    atomic_future& operator=(const atomic_future& rhs);

    // retrieving the value
    const R& get() const;

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <class R>
class atomic_future<R&>
{
public:
    atomic_future();
    atomic_future(const atomic_future& rhs);
    atomic_future(future<R>&&);
    ~atomic_future();
    atomic_future& operator=(const atomic_future& rhs);

    // retrieving the value
    R& get() const;

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <>
class atomic_future<void>
{
public:
    atomic_future();
    atomic_future(const atomic_future& rhs);
    atomic_future(future<R>&&);
    ~atomic_future();
    atomic_future& operator=(const atomic_future& rhs);

    // retrieving the value
    void get() const;

    // functions to check state
    bool valid() const;

    void wait() const;
    template <class Rep, class Period>
        future_status
        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
    template <class Clock, class Duration>
        future_status
        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
};

template <class F, class... Args>
  future<typename result_of<F(Args...)>::type>
  async(F&& f, Args&&... args);

template <class F, class... Args>
  future<typename result_of<F(Args...)>::type>
  async(launch policy, F&& f, Args&&... args);

template <class> class packaged_task; // undefined

template <class R, class... ArgTypes>
class packaged_task<R(ArgTypes...)>
{
public:
    typedef R result_type;

    // construction and destruction
    packaged_task();
    template <class F>
        explicit packaged_task(F f);
    template <class F, class Allocator>
        explicit packaged_task(allocator_arg_t, const Allocator& a, F f);
    explicit packaged_task(R(*f)(ArgTypes...));
    template <class F>
        explicit packaged_task(F&& f);
    template <class F, class Allocator>
        explicit packaged_task(allocator_arg_t, const Allocator& a, F&& f);
    ~packaged_task();

    // no copy
    packaged_task(packaged_task&) = delete;
    packaged_task& operator=(packaged_task&) = delete;

    // move support
    packaged_task(packaged_task&& other);
    packaged_task& operator=(packaged_task&& other);
    void swap(packaged_task& other);

    explicit operator bool() const;

    // result retrieval
    future<R> get_future();

    // execution
    void operator()(ArgTypes... );
    void make_ready_at_thread_exit(ArgTypes...);

    void reset();
};

template <class R>
  void swap(packaged_task<R(ArgTypes...)&, packaged_task<R(ArgTypes...)>&);

template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;

}  // std

*/

#include <__config>
#include <system_error>

#pragma GCC system_header

_LIBCPP_BEGIN_NAMESPACE_STD

//enum class future_errc
struct future_errc
{
enum _ {
    broken_promise,
    future_already_retrieved,
    promise_already_satisfied,
    no_state
};

    _ __v_;

    future_errc(_ __v) : __v_(__v) {}
    operator int() const {return __v_;}

};

//enum class launch
struct launch
{
enum _ {
    any,
    async,
    sync
};

    _ __v_;

    launch(_ __v) : __v_(__v) {}
    operator int() const {return __v_;}

};

//enum class future_status
struct future_status
{
enum _ {
    ready,
    timeout,
    deferred
};

    _ __v_;

    future_status(_ __v) : __v_(__v) {}
    operator int() const {return __v_;}

};

_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP_FUTURE