Add libc++ and libc++abi to third-party.

third_party/libcxx/include/chrono

+// -*- C++ -*-
+//===---------------------------- chrono ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CHRONO
+#define _LIBCPP_CHRONO
+
+/*
+    chrono synopsis
+
+namespace std
+{
+namespace chrono
+{
+
+template <class ToDuration, class Rep, class Period>
+constexpr
+ToDuration
+duration_cast(const duration<Rep, Period>& fd);
+
+template <class Rep> struct treat_as_floating_point : is_floating_point<Rep> {};
+
+template <class Rep>
+struct duration_values
+{
+public:
+    static constexpr Rep zero();
+    static constexpr Rep max();
+    static constexpr Rep min();
+};
+
+// duration
+
+template <class Rep, class Period = ratio<1>>
+class duration
+{
+    static_assert(!__is_duration<Rep>::value, "A duration representation can not be a duration");
+    static_assert(__is_ratio<Period>::value, "Second template parameter of duration must be a std::ratio");
+    static_assert(Period::num > 0, "duration period must be positive");
+public:
+    typedef Rep rep;
+    typedef Period period;
+
+    constexpr duration() = default;
+    template <class Rep2>
+        constexpr explicit duration(const Rep2& r,
+            typename enable_if
+            <
+               is_convertible<Rep2, rep>::value &&
+               (treat_as_floating_point<rep>::value ||
+               !treat_as_floating_point<rep>::value && !treat_as_floating_point<Rep2>::value)
+            >::type* = 0);
+
+    // conversions
+    template <class Rep2, class Period2>
+        constexpr duration(const duration<Rep2, Period2>& d,
+            typename enable_if
+            <
+                treat_as_floating_point<rep>::value ||
+                ratio_divide<Period2, period>::type::den == 1
+            >::type* = 0);
+
+    // observer
+
+    constexpr rep count() const;
+
+    // arithmetic
+
+    constexpr duration  operator+() const;
+    constexpr duration  operator-() const;
+    duration& operator++();
+    duration  operator++(int);
+    duration& operator--();
+    duration  operator--(int);
+
+    duration& operator+=(const duration& d);
+    duration& operator-=(const duration& d);
+
+    duration& operator*=(const rep& rhs);
+    duration& operator/=(const rep& rhs);
+
+    // special values
+
+    static constexpr duration zero();
+    static constexpr duration min();
+    static constexpr duration max();
+};
+
+typedef duration<long long,         nano> nanoseconds;
+typedef duration<long long,        micro> microseconds;
+typedef duration<long long,        milli> milliseconds;
+typedef duration<long long              > seconds;
+typedef duration<     long, ratio<  60> > minutes;
+typedef duration<     long, ratio<3600> > hours;
+
+template <class Clock, class Duration = typename Clock::duration>
+class time_point
+{
+public:
+    typedef Clock                     clock;
+    typedef Duration                  duration;
+    typedef typename duration::rep    rep;
+    typedef typename duration::period period;
+private:
+    duration d_;  // exposition only
+
+public:
+    time_point();  // has value "epoch" // constexpr in C++14
+    explicit time_point(const duration& d);  // same as time_point() + d // constexpr in C++14
+
+    // conversions
+    template <class Duration2>
+       time_point(const time_point<clock, Duration2>& t); // constexpr in C++14
+
+    // observer
+
+    duration time_since_epoch() const; // constexpr in C++14
+
+    // arithmetic
+
+    time_point& operator+=(const duration& d);
+    time_point& operator-=(const duration& d);
+
+    // special values
+
+    static constexpr time_point min();
+    static constexpr time_point max();
+};
+
+} // chrono
+
+// common_type traits
+template <class Rep1, class Period1, class Rep2, class Period2>
+  struct common_type<chrono::duration<Rep1, Period1>, chrono::duration<Rep2, Period2>>;
+
+template <class Clock, class Duration1, class Duration2>
+  struct common_type<chrono::time_point<Clock, Duration1>, chrono::time_point<Clock, Duration2>>;
+
+namespace chrono {
+
+// duration arithmetic
+template <class Rep1, class Period1, class Rep2, class Period2>
+  constexpr
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator+(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+  constexpr
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator-(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period, class Rep2>
+  constexpr
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator*(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period, class Rep2>
+  constexpr
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator*(const Rep1& s, const duration<Rep2, Period>& d);
+template <class Rep1, class Period, class Rep2>
+  constexpr
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator/(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period1, class Rep2, class Period2>
+  constexpr
+  typename common_type<Rep1, Rep2>::type
+  operator/(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
+// duration comparisons
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator==(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator!=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator< (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator<=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator> (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator>=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
+// duration_cast
+template <class ToDuration, class Rep, class Period>
+  ToDuration duration_cast(const duration<Rep, Period>& d);
+
+// time_point arithmetic (all constexpr in C++14)
+template <class Clock, class Duration1, class Rep2, class Period2>
+  time_point<Clock, typename common_type<Duration1, duration<Rep2, Period2>>::type>
+  operator+(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Clock, class Duration2>
+  time_point<Clock, typename common_type<duration<Rep1, Period1>, Duration2>::type>
+  operator+(const duration<Rep1, Period1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Rep2, class Period2>
+  time_point<Clock, typename common_type<Duration1, duration<Rep2, Period2>>::type>
+  operator-(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+  typename common_type<Duration1, Duration2>::type
+  operator-(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+
+// time_point comparisons (all constexpr in C++14)
+template <class Clock, class Duration1, class Duration2>
+   bool operator==(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator!=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator< (const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator<=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator> (const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator>=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+
+// time_point_cast (constexpr in C++14)
+
+template <class ToDuration, class Clock, class Duration>
+  time_point<Clock, ToDuration> time_point_cast(const time_point<Clock, Duration>& t);
+
+// Clocks
+
+class system_clock
+{
+public:
+    typedef microseconds                     duration;
+    typedef duration::rep                    rep;
+    typedef duration::period                 period;
+    typedef chrono::time_point<system_clock> time_point;
+    static const bool is_steady =            false; // constexpr in C++14
+
+    static time_point now() noexcept;
+    static time_t     to_time_t  (const time_point& __t) noexcept;
+    static time_point from_time_t(time_t __t) noexcept;
+};
+
+class steady_clock
+{
+public:
+    typedef nanoseconds                                   duration;
+    typedef duration::rep                                 rep;
+    typedef duration::period                              period;
+    typedef chrono::time_point<steady_clock, duration>    time_point;
+    static const bool is_steady =                         true; // constexpr in C++14
+
+    static time_point now() noexcept;
+};
+
+typedef steady_clock high_resolution_clock;
+
+}  // chrono
+
+constexpr chrono::hours                                 operator "" h(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , ratio<3600,1>> operator "" h(long double); // C++14
+constexpr chrono::minutes                               operator "" min(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , ratio<60,1>>   operator "" min(long double); // C++14
+constexpr chrono::seconds                               operator "" s(unsigned long long); // C++14
+constexpr chrono::duration<unspecified >                operator "" s(long double); // C++14
+constexpr chrono::milliseconds                          operator "" ms(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , milli>         operator "" ms(long double); // C++14
+constexpr chrono::microseconds                          operator "" us(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , micro>         operator "" us(long double); // C++14
+constexpr chrono::nanoseconds                           operator "" ns(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , nano>          operator "" ns(long double); // C++14
+
+}  // std
+*/
+
+#include <__config>
+#include <ctime>
+#include <type_traits>
+#include <ratio>
+#include <limits>
+
+#include <__undef_min_max>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace chrono
+{
+
+template <class _Rep, class _Period = ratio<1> > class _LIBCPP_TYPE_VIS_ONLY duration;
+
+template <class _Tp>
+struct __is_duration : false_type {};
+
+template <class _Rep, class _Period>
+struct __is_duration<duration<_Rep, _Period> > : true_type  {};
+
+template <class _Rep, class _Period>
+struct __is_duration<const duration<_Rep, _Period> > : true_type  {};
+
+template <class _Rep, class _Period>
+struct __is_duration<volatile duration<_Rep, _Period> > : true_type  {};
+
+template <class _Rep, class _Period>
+struct __is_duration<const volatile duration<_Rep, _Period> > : true_type  {};
+
+} // chrono
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+struct _LIBCPP_TYPE_VIS_ONLY common_type<chrono::duration<_Rep1, _Period1>,
+                                         chrono::duration<_Rep2, _Period2> >
+{
+    typedef chrono::duration<typename common_type<_Rep1, _Rep2>::type,
+                             typename __ratio_gcd<_Period1, _Period2>::type> type;
+};
+
+namespace chrono {
+
+// duration_cast
+
+template <class _FromDuration, class _ToDuration,
+          class _Period = typename ratio_divide<typename _FromDuration::period, typename _ToDuration::period>::type,
+          bool = _Period::num == 1,
+          bool = _Period::den == 1>
+struct __duration_cast;
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, true, true>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        return _ToDuration(static_cast<typename _ToDuration::rep>(__fd.count()));
+    }
+};
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, true, false>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        typedef typename common_type<typename _ToDuration::rep, typename _FromDuration::rep, intmax_t>::type _Ct;
+        return _ToDuration(static_cast<typename _ToDuration::rep>(
+                           static_cast<_Ct>(__fd.count()) / static_cast<_Ct>(_Period::den)));
+    }
+};
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, false, true>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        typedef typename common_type<typename _ToDuration::rep, typename _FromDuration::rep, intmax_t>::type _Ct;
+        return _ToDuration(static_cast<typename _ToDuration::rep>(
+                           static_cast<_Ct>(__fd.count()) * static_cast<_Ct>(_Period::num)));
+    }
+};
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, false, false>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        typedef typename common_type<typename _ToDuration::rep, typename _FromDuration::rep, intmax_t>::type _Ct;
+        return _ToDuration(static_cast<typename _ToDuration::rep>(
+                           static_cast<_Ct>(__fd.count()) * static_cast<_Ct>(_Period::num)
+                                                          / static_cast<_Ct>(_Period::den)));
+    }
+};
+
+template <class _ToDuration, class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    _ToDuration
+>::type
+duration_cast(const duration<_Rep, _Period>& __fd)
+{
+    return __duration_cast<duration<_Rep, _Period>, _ToDuration>()(__fd);
+}
+
+template <class _Rep>
+struct _LIBCPP_TYPE_VIS_ONLY treat_as_floating_point : is_floating_point<_Rep> {};
+
+template <class _Rep>
+struct _LIBCPP_TYPE_VIS_ONLY duration_values
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR _Rep zero() {return _Rep(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR _Rep max()  {return numeric_limits<_Rep>::max();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR _Rep min()  {return numeric_limits<_Rep>::lowest();}
+};
+
+// duration
+
+template <class _Rep, class _Period>
+class _LIBCPP_TYPE_VIS_ONLY duration
+{
+    static_assert(!__is_duration<_Rep>::value, "A duration representation can not be a duration");
+    static_assert(__is_ratio<_Period>::value, "Second template parameter of duration must be a std::ratio");
+    static_assert(_Period::num > 0, "duration period must be positive");
+
+    template <class _R1, class _R2>
+    struct __no_overflow
+    {
+    private:
+        static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
+        static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
+        static const intmax_t __n1 = _R1::num / __gcd_n1_n2;
+        static const intmax_t __d1 = _R1::den / __gcd_d1_d2;
+        static const intmax_t __n2 = _R2::num / __gcd_n1_n2;
+        static const intmax_t __d2 = _R2::den / __gcd_d1_d2;
+        static const intmax_t max = -((intmax_t(1) << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1);
+
+        template <intmax_t _Xp, intmax_t _Yp, bool __overflow>
+        struct __mul    // __overflow == false
+        {
+            static const intmax_t value = _Xp * _Yp;
+        };
+
+        template <intmax_t _Xp, intmax_t _Yp>
+        struct __mul<_Xp, _Yp, true>
+        {
+            static const intmax_t value = 1;
+        };
+
+    public:
+        static const bool value = (__n1 <= max / __d2) && (__n2 <= max / __d1);
+        typedef ratio<__mul<__n1, __d2, !value>::value,
+                      __mul<__n2, __d1, !value>::value> type;
+    };
+    
+public:
+    typedef _Rep rep;
+    typedef _Period period;
+private:
+    rep __rep_;
+public:
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+        duration() = default;
+#else
+        duration() {}
+#endif
+
+    template <class _Rep2>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+        explicit duration(const _Rep2& __r,
+            typename enable_if
+            <
+               is_convertible<_Rep2, rep>::value &&
+               (treat_as_floating_point<rep>::value ||
+               !treat_as_floating_point<_Rep2>::value)
+            >::type* = 0)
+                : __rep_(__r) {}
+
+    // conversions
+    template <class _Rep2, class _Period2>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+        duration(const duration<_Rep2, _Period2>& __d,
+            typename enable_if
+            <
+                __no_overflow<_Period2, period>::value && (
+                treat_as_floating_point<rep>::value ||
+                (__no_overflow<_Period2, period>::type::den == 1 &&
+                 !treat_as_floating_point<_Rep2>::value))
+            >::type* = 0)
+                : __rep_(_VSTD::chrono::duration_cast<duration>(__d).count()) {}
+
+    // observer
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR rep count() const {return __rep_;}
+
+    // arithmetic
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR duration  operator+() const {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR duration  operator-() const {return duration(-__rep_);}
+    _LIBCPP_INLINE_VISIBILITY duration& operator++()      {++__rep_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY duration  operator++(int)   {return duration(__rep_++);}
+    _LIBCPP_INLINE_VISIBILITY duration& operator--()      {--__rep_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY duration  operator--(int)   {return duration(__rep_--);}
+
+    _LIBCPP_INLINE_VISIBILITY duration& operator+=(const duration& __d) {__rep_ += __d.count(); return *this;}
+    _LIBCPP_INLINE_VISIBILITY duration& operator-=(const duration& __d) {__rep_ -= __d.count(); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY duration& operator*=(const rep& rhs) {__rep_ *= rhs; return *this;}
+    _LIBCPP_INLINE_VISIBILITY duration& operator/=(const rep& rhs) {__rep_ /= rhs; return *this;}
+    _LIBCPP_INLINE_VISIBILITY duration& operator%=(const rep& rhs) {__rep_ %= rhs; return *this;}
+    _LIBCPP_INLINE_VISIBILITY duration& operator%=(const duration& rhs) {__rep_ %= rhs.count(); return *this;}
+
+    // special values
+
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR duration zero() {return duration(duration_values<rep>::zero());}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR duration min()  {return duration(duration_values<rep>::min());}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR duration max()  {return duration(duration_values<rep>::max());}
+};
+
+typedef duration<long long,         nano> nanoseconds;
+typedef duration<long long,        micro> microseconds;
+typedef duration<long long,        milli> milliseconds;
+typedef duration<long long              > seconds;
+typedef duration<     long, ratio<  60> > minutes;
+typedef duration<     long, ratio<3600> > hours;
+
+// Duration ==
+
+template <class _LhsDuration, class _RhsDuration>
+struct __duration_eq
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _RhsDuration& __rhs) const
+        {
+            typedef typename common_type<_LhsDuration, _RhsDuration>::type _Ct;
+            return _Ct(__lhs).count() == _Ct(__rhs).count();
+        }
+};
+
+template <class _LhsDuration>
+struct __duration_eq<_LhsDuration, _LhsDuration>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _LhsDuration& __rhs) const
+        {return __lhs.count() == __rhs.count();}
+};
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator==(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __duration_eq<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >()(__lhs, __rhs);
+}
+
+// Duration !=
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator!=(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return !(__lhs == __rhs);
+}
+
+// Duration <
+
+template <class _LhsDuration, class _RhsDuration>
+struct __duration_lt
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _RhsDuration& __rhs) const
+        {
+            typedef typename common_type<_LhsDuration, _RhsDuration>::type _Ct;
+            return _Ct(__lhs).count() < _Ct(__rhs).count();
+        }
+};
+
+template <class _LhsDuration>
+struct __duration_lt<_LhsDuration, _LhsDuration>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _LhsDuration& __rhs) const
+        {return __lhs.count() < __rhs.count();}
+};
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator< (const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __duration_lt<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >()(__lhs, __rhs);
+}
+
+// Duration >
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator> (const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __rhs < __lhs;
+}
+
+// Duration <=
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator<=(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return !(__rhs < __lhs);
+}
+
+// Duration >=
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator>=(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return !(__lhs < __rhs);
+}
+
+// Duration +
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type
+operator+(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Cd;
+    return _Cd(_Cd(__lhs).count() + _Cd(__rhs).count());
+}
+
+// Duration -
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type
+operator-(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Cd;
+    return _Cd(_Cd(__lhs).count() - _Cd(__rhs).count());
+}
+
+// Duration *
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    is_convertible<_Rep2, typename common_type<_Rep1, _Rep2>::type>::value,
+    duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+>::type
+operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef duration<_Cr, _Period> _Cd;
+    return _Cd(_Cd(__d).count() * static_cast<_Cr>(__s));
+}
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    is_convertible<_Rep1, typename common_type<_Rep1, _Rep2>::type>::value,
+    duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+>::type
+operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
+{
+    return __d * __s;
+}
+
+// Duration /
+
+template <class _Duration, class _Rep, bool = __is_duration<_Rep>::value>
+struct __duration_divide_result
+{
+};
+
+template <class _Duration, class _Rep2,
+    bool = is_convertible<_Rep2,
+                          typename common_type<typename _Duration::rep, _Rep2>::type>::value>
+struct __duration_divide_imp
+{
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+struct __duration_divide_imp<duration<_Rep1, _Period>, _Rep2, true>
+{
+    typedef duration<typename common_type<_Rep1, _Rep2>::type, _Period> type;
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+struct __duration_divide_result<duration<_Rep1, _Period>, _Rep2, false>
+    : __duration_divide_imp<duration<_Rep1, _Period>, _Rep2>
+{
+};
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename __duration_divide_result<duration<_Rep1, _Period>, _Rep2>::type
+operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef duration<_Cr, _Period> _Cd;
+    return _Cd(_Cd(__d).count() / static_cast<_Cr>(__s));
+}
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<_Rep1, _Rep2>::type
+operator/(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Ct;
+    return _Ct(__lhs).count() / _Ct(__rhs).count();
+}
+
+// Duration %
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename __duration_divide_result<duration<_Rep1, _Period>, _Rep2>::type
+operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef duration<_Cr, _Period> _Cd;
+    return _Cd(_Cd(__d).count() % static_cast<_Cr>(__s));
+}
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type
+operator%(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Cd;
+    return _Cd(static_cast<_Cr>(_Cd(__lhs).count()) % static_cast<_Cr>(_Cd(__rhs).count()));
+}
+
+//////////////////////////////////////////////////////////
+///////////////////// time_point /////////////////////////
+//////////////////////////////////////////////////////////
+
+template <class _Clock, class _Duration = typename _Clock::duration>
+class _LIBCPP_TYPE_VIS_ONLY time_point
+{
+    static_assert(__is_duration<_Duration>::value,
+                  "Second template parameter of time_point must be a std::chrono::duration");
+public:
+    typedef _Clock                    clock;
+    typedef _Duration                 duration;
+    typedef typename duration::rep    rep;
+    typedef typename duration::period period;
+private:
+    duration __d_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 time_point() : __d_(duration::zero()) {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 explicit time_point(const duration& __d) : __d_(__d) {}
+
+    // conversions
+    template <class _Duration2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    time_point(const time_point<clock, _Duration2>& t,
+        typename enable_if
+        <
+            is_convertible<_Duration2, duration>::value
+        >::type* = 0)
+            : __d_(t.time_since_epoch()) {}
+
+    // observer
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 duration time_since_epoch() const {return __d_;}
+
+    // arithmetic
+
+    _LIBCPP_INLINE_VISIBILITY time_point& operator+=(const duration& __d) {__d_ += __d; return *this;}
+    _LIBCPP_INLINE_VISIBILITY time_point& operator-=(const duration& __d) {__d_ -= __d; return *this;}
+
+    // special values
+
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR time_point min() {return time_point(duration::min());}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR time_point max() {return time_point(duration::max());}
+};
+
+} // chrono
+
+template <class _Clock, class _Duration1, class _Duration2>
+struct _LIBCPP_TYPE_VIS_ONLY common_type<chrono::time_point<_Clock, _Duration1>,
+                                         chrono::time_point<_Clock, _Duration2> >
+{
+    typedef chrono::time_point<_Clock, typename common_type<_Duration1, _Duration2>::type> type;
+};
+
+namespace chrono {
+
+template <class _ToDuration, class _Clock, class _Duration>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, _ToDuration>
+time_point_cast(const time_point<_Clock, _Duration>& __t)
+{
+    return time_point<_Clock, _ToDuration>(_VSTD::chrono::duration_cast<_ToDuration>(__t.time_since_epoch()));
+}
+
+// time_point ==
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __lhs.time_since_epoch() == __rhs.time_since_epoch();
+}
+
+// time_point !=
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return !(__lhs == __rhs);
+}
+
+// time_point <
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __lhs.time_since_epoch() < __rhs.time_since_epoch();
+}
+
+// time_point >
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __rhs < __lhs;
+}
+
+// time_point <=
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<=(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return !(__rhs < __lhs);
+}
+
+// time_point >=
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>=(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return !(__lhs < __rhs);
+}
+
+// time_point operator+(time_point x, duration y);
+
+template <class _Clock, class _Duration1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type>
+operator+(const time_point<_Clock, _Duration1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type> _Tr;
+    return _Tr (__lhs.time_since_epoch() + __rhs);
+}
+
+// time_point operator+(duration x, time_point y);
+
+template <class _Rep1, class _Period1, class _Clock, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, typename common_type<duration<_Rep1, _Period1>, _Duration2>::type>
+operator+(const duration<_Rep1, _Period1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __rhs + __lhs;
+}
+
+// time_point operator-(time_point x, duration y);
+
+template <class _Clock, class _Duration1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type>
+operator-(const time_point<_Clock, _Duration1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __lhs + (-__rhs);
+}
+
+// duration operator-(time_point x, time_point y);
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename common_type<_Duration1, _Duration2>::type
+operator-(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __lhs.time_since_epoch() - __rhs.time_since_epoch();
+}
+
+//////////////////////////////////////////////////////////
+/////////////////////// clocks ///////////////////////////
+//////////////////////////////////////////////////////////
+
+class _LIBCPP_TYPE_VIS system_clock
+{
+public:
+    typedef microseconds                     duration;
+    typedef duration::rep                    rep;
+    typedef duration::period                 period;
+    typedef chrono::time_point<system_clock> time_point;
+    static _LIBCPP_CONSTEXPR_AFTER_CXX11 const bool is_steady = false;
+
+    static time_point now() _NOEXCEPT;
+    static time_t     to_time_t  (const time_point& __t) _NOEXCEPT;
+    static time_point from_time_t(time_t __t) _NOEXCEPT;
+};
+
+class _LIBCPP_TYPE_VIS steady_clock
+{
+public:
+    typedef nanoseconds                                   duration;
+    typedef duration::rep                                 rep;
+    typedef duration::period                              period;
+    typedef chrono::time_point<steady_clock, duration>    time_point;
+    static _LIBCPP_CONSTEXPR_AFTER_CXX11 const bool is_steady = true;
+
+    static time_point now() _NOEXCEPT;
+};
+
+typedef steady_clock high_resolution_clock;
+
+} // chrono
+
+#if _LIBCPP_STD_VER > 11
+// Suffixes for duration literals [time.duration.literals]
+inline namespace literals
+{ 
+  inline namespace chrono_literals
+  {
+
+    constexpr chrono::hours operator"" h(unsigned long long __h)
+    {
+        return chrono::hours(static_cast<chrono::hours::rep>(__h));
+    }
+
+    constexpr chrono::duration<long double, ratio<3600,1>> operator"" h(long double __h)
+    {
+        return chrono::duration<long double, ratio<3600,1>>(__h);
+    }
+
+
+    constexpr chrono::minutes operator"" min(unsigned long long __m)
+    {
+        return chrono::minutes(static_cast<chrono::minutes::rep>(__m));
+    }
+
+    constexpr chrono::duration<long double, ratio<60,1>> operator"" min(long double __m)
+    {
+        return chrono::duration<long double, ratio<60,1>> (__m);
+    }
+
+
+    constexpr chrono::seconds operator"" s(unsigned long long __s)
+    {
+        return chrono::seconds(static_cast<chrono::seconds::rep>(__s));
+    }
+
+    constexpr chrono::duration<long double> operator"" s(long double __s)
+    {
+        return chrono::duration<long double> (__s);
+    }
+
+
+    constexpr chrono::milliseconds operator"" ms(unsigned long long __ms)
+    {
+        return chrono::milliseconds(static_cast<chrono::milliseconds::rep>(__ms));
+    }
+
+    constexpr chrono::duration<long double, milli> operator"" ms(long double __ms)
+    {
+        return chrono::duration<long double, milli>(__ms);
+    }
+
+
+    constexpr chrono::microseconds operator"" us(unsigned long long __us)
+    {
+        return chrono::microseconds(static_cast<chrono::microseconds::rep>(__us));
+    }
+
+    constexpr chrono::duration<long double, micro> operator"" us(long double __us)
+    {
+        return chrono::duration<long double, micro> (__us);
+    }
+    
+
+    constexpr chrono::nanoseconds operator"" ns(unsigned long long __ns)
+    {
+        return chrono::nanoseconds(static_cast<chrono::nanoseconds::rep>(__ns));
+    }
+
+    constexpr chrono::duration<long double, nano> operator"" ns(long double __ns)
+    {
+        return chrono::duration<long double, nano> (__ns);
+    }
+
+}}
+
+namespace chrono { // hoist the literals into namespace std::chrono
+   using namespace literals::chrono_literals;
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif  // _LIBCPP_CHRONO