__cxx03/__chrono/tzdb.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 // For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html
0011
0012 #ifndef _LIBCPP___CXX03___CHRONO_TZDB_H
0013 #define _LIBCPP___CXX03___CHRONO_TZDB_H
0014
0015 #include <__cxx03/version>
0016 // Enable the contents of the header only when libc++ was built with experimental features enabled.
0017 #if !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
0018
0019 #  include <__cxx03/__algorithm/ranges_lower_bound.h>
0020 #  include <__cxx03/__chrono/leap_second.h>
0021 #  include <__cxx03/__chrono/time_zone.h>
0022 #  include <__cxx03/__chrono/time_zone_link.h>
0023 #  include <__cxx03/__config>
0024 #  include <__cxx03/string>
0025 #  include <__cxx03/vector>
0026
0027 #  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0028 #    pragma GCC system_header
0029 #  endif
0030
0031 _LIBCPP_PUSH_MACROS
0032 #  include <__cxx03/__undef_macros>
0033
0034 _LIBCPP_BEGIN_NAMESPACE_STD
0035
0036 #  if _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM) &&   \
0037       !defined(_LIBCPP_HAS_NO_LOCALIZATION)
0038
0039 namespace chrono {
0040
0041 struct tzdb {
0042   string version;
0043   vector<time_zone> zones;
0044   vector<time_zone_link> links;
0045
0046   vector<leap_second> leap_seconds;
0047
0048   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI const time_zone* __locate_zone(string_view __name) const {
0049     if (const time_zone* __result = __find_in_zone(__name))
0050       return __result;
0051
0052     if (auto __it = ranges::lower_bound(links, __name, {}, &time_zone_link::name);
0053         __it != links.end() && __it->name() == __name)
0054       if (const time_zone* __result = __find_in_zone(__it->target()))
0055         return __result;
0056
0057     return nullptr;
0058   }
0059
0060   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI const time_zone* locate_zone(string_view __name) const {
0061     if (const time_zone* __result = __locate_zone(__name))
0062       return __result;
0063
0064     std::__throw_runtime_error("tzdb: requested time zone not found");
0065   }
0066
0067   [[nodiscard]] _LIBCPP_AVAILABILITY_TZDB _LIBCPP_HIDE_FROM_ABI const time_zone* current_zone() const {
0068     return __current_zone();
0069   }
0070
0071 private:
0072   _LIBCPP_HIDE_FROM_ABI const time_zone* __find_in_zone(string_view __name) const noexcept {
0073     if (auto __it = ranges::lower_bound(zones, __name, {}, &time_zone::name);
0074         __it != zones.end() && __it->name() == __name)
0075       return std::addressof(*__it);
0076
0077     return nullptr;
0078   }
0079
0080   [[nodiscard]] _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI const time_zone* __current_zone() const;
0081 };
0082
0083 } // namespace chrono
0084
0085 #  endif // _LIBCPP_STD_VER >= 20 && !defined(_LIBCPP_HAS_NO_TIME_ZONE_DATABASE) && !defined(_LIBCPP_HAS_NO_FILESYSTEM)
0086          // && !defined(_LIBCPP_HAS_NO_LOCALIZATION)
0087
0088 _LIBCPP_END_NAMESPACE_STD
0089
0090 _LIBCPP_POP_MACROS
0091
0092 #endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
0093
0094 #endif // _LIBCPP___CXX03___CHRONO_TZDB_H