cf50936b23
Completes: - LWG3359 <chrono> leap second support should allow for negative leap seconds - P1361R2 Integration of chrono with text formatting Implements parts of: - P0355 Extending <chrono> to Calendars and Time Zones Fixes: #100432 Fixes: #100014
91 lines
3.2 KiB
C++
91 lines
3.2 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___CHRONO_GPS_CLOCK_H
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#define _LIBCPP___CHRONO_GPS_CLOCK_H
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#include <version>
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// Enable the contents of the header only when libc++ was built with experimental features enabled.
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#if _LIBCPP_HAS_EXPERIMENTAL_TZDB
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# include <__assert>
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# include <__chrono/duration.h>
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# include <__chrono/time_point.h>
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# include <__chrono/utc_clock.h>
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# include <__config>
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# include <__type_traits/common_type.h>
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# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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# endif
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_LIBCPP_PUSH_MACROS
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# include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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# if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION
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namespace chrono {
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class gps_clock;
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template <class _Duration>
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using gps_time = time_point<gps_clock, _Duration>;
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using gps_seconds = gps_time<seconds>;
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class gps_clock {
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public:
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using rep = utc_clock::rep;
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using period = utc_clock::period;
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using duration = chrono::duration<rep, period>;
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using time_point = chrono::time_point<gps_clock>;
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static constexpr bool is_steady = false; // The utc_clock is not steady.
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// The static difference between UTC and GPS time as specified in the Standard.
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static constexpr chrono::seconds __offset{315964809};
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static time_point now() { return from_utc(utc_clock::now()); }
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template <class _Duration>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static utc_time<common_type_t<_Duration, seconds>>
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to_utc(const gps_time<_Duration>& __time) noexcept {
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using _Rp = common_type_t<_Duration, seconds>;
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_Duration __time_since_epoch = __time.time_since_epoch();
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_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(__time_since_epoch >= utc_time<_Rp>::min().time_since_epoch() + __offset,
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"the GPS to UTC conversion would underflow");
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return utc_time<_Rp>{__time_since_epoch + __offset};
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}
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template <class _Duration>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI static gps_time<common_type_t<_Duration, seconds>>
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from_utc(const utc_time<_Duration>& __time) noexcept {
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using _Rp = common_type_t<_Duration, seconds>;
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_Duration __time_since_epoch = __time.time_since_epoch();
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_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(__time_since_epoch <= utc_time<_Rp>::max().time_since_epoch() - __offset,
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"the UTC to GPS conversion would overflow");
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return gps_time<_Rp>{__time_since_epoch - __offset};
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}
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};
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} // namespace chrono
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# endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM &&
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// _LIBCPP_HAS_LOCALIZATION
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB
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#endif // _LIBCPP___CHRONO_GPS_CLOCK_H
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