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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___CHRONO_GPS_CLOCK_H
#define _LIBCPP___CHRONO_GPS_CLOCK_H
#include <version>
// Enable the contents of the header only when libc++ was built with experimental features enabled.
#if _LIBCPP_HAS_EXPERIMENTAL_TZDB
# include <__assert>
# include <__chrono/duration.h>
# include <__chrono/time_point.h>
# include <__chrono/utc_clock.h>
# include <__config>
# include <__type_traits/common_type.h>
# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
# endif
_LIBCPP_PUSH_MACROS
# include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
# if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION
namespace chrono {
class gps_clock;
template <class _Duration>
using gps_time = time_point<gps_clock, _Duration>;
using gps_seconds = gps_time<seconds>;
class gps_clock {
public:
using rep = utc_clock::rep;
using period = utc_clock::period;
using duration = chrono::duration<rep, period>;
using time_point = chrono::time_point<gps_clock>;
static constexpr bool is_steady = false; // The utc_clock is not steady.
// The static difference between UTC and GPS time as specified in the Standard.
static constexpr chrono::seconds __offset{315964809};
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static time_point now() { return from_utc(utc_clock::now()); }
template <class _Duration>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static utc_time<common_type_t<_Duration, seconds>>
to_utc(const gps_time<_Duration>& __time) noexcept {
using _Rp = common_type_t<_Duration, seconds>;
_Duration __time_since_epoch = __time.time_since_epoch();
_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(__time_since_epoch >= utc_time<_Rp>::min().time_since_epoch() + __offset,
"the GPS to UTC conversion would underflow");
return utc_time<_Rp>{__time_since_epoch + __offset};
}
template <class _Duration>
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static gps_time<common_type_t<_Duration, seconds>>
from_utc(const utc_time<_Duration>& __time) noexcept {
using _Rp = common_type_t<_Duration, seconds>;
_Duration __time_since_epoch = __time.time_since_epoch();
_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(__time_since_epoch <= utc_time<_Rp>::max().time_since_epoch() - __offset,
"the UTC to GPS conversion would overflow");
return gps_time<_Rp>{__time_since_epoch - __offset};
}
};
} // namespace chrono
# endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM &&
// _LIBCPP_HAS_LOCALIZATION
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB
#endif // _LIBCPP___CHRONO_GPS_CLOCK_H
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