libcxx/include/__chrono/tzdb.h

   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 !defined(_LIBCPP_HAS_NO_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 // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)
  95
  96 #endif // _LIBCPP___CHRONO_TZDB_H