1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 // For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html 11 12 #ifndef _LIBCPP___CHRONO_TZDB_H 13 #define _LIBCPP___CHRONO_TZDB_H 14 15 #include <version> 16 // Enable the contents of the header only when libc++ was built with experimental features enabled. 17 #if _LIBCPP_HAS_EXPERIMENTAL_TZDB 18 19 # include <__algorithm/ranges_lower_bound.h> 20 # include <__chrono/leap_second.h> 21 # include <__chrono/time_zone.h> 22 # include <__chrono/time_zone_link.h> 23 # include <__config> 24 # include <__memory/addressof.h> 25 # include <__vector/vector.h> 26 # include <stdexcept> 27 # include <string> 28 # include <string_view> 29 30 # if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 31 # pragma GCC system_header 32 # endif 33 34 _LIBCPP_PUSH_MACROS 35 # include <__undef_macros> 36 37 _LIBCPP_BEGIN_NAMESPACE_STD 38 39 # if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION 40 41 namespace chrono { 42 43 struct tzdb { 44 string version; 45 vector<time_zone> zones; 46 vector<time_zone_link> links; 47 48 vector<leap_second> leap_seconds; 49 50 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI const time_zone* __locate_zone(string_view __name) const { 51 if (const time_zone* __result = __find_in_zone(__name)) 52 return __result; 53 54 if (auto __it = ranges::lower_bound(links, __name, {}, &time_zone_link::name); 55 __it != links.end() && __it->name() == __name) 56 if (const time_zone* __result = __find_in_zone(__it->target())) 57 return __result; 58 59 return nullptr; 60 } 61 62 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI const time_zone* locate_zone(string_view __name) const { 63 if (const time_zone* __result = __locate_zone(__name)) 64 return __result; 65 66 std::__throw_runtime_error("tzdb: requested time zone not found"); 67 } 68 69 [[nodiscard]] _LIBCPP_AVAILABILITY_TZDB _LIBCPP_HIDE_FROM_ABI const time_zone* current_zone() const { 70 return __current_zone(); 71 } 72 73 private: 74 _LIBCPP_HIDE_FROM_ABI const time_zone* __find_in_zone(string_view __name) const noexcept { 75 if (auto __it = ranges::lower_bound(zones, __name, {}, &time_zone::name); 76 __it != zones.end() && __it->name() == __name) 77 return std::addressof(*__it); 78 79 return nullptr; 80 } 81 82 [[nodiscard]] _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI const time_zone* __current_zone() const; 83 }; 84 85 } // namespace chrono 86 87 # endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && 88 // _LIBCPP_HAS_LOCALIZATION 89 90 _LIBCPP_END_NAMESPACE_STD 91 92 _LIBCPP_POP_MACROS 93 94 #endif // _LIBCPP_HAS_EXPERIMENTAL_TZDB 95 96 #endif // _LIBCPP___CHRONO_TZDB_H 97