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| author | mikhnenko <mikhnenko@yandex-team.com> | 2024-03-27 10:35:27 +0300 |
|---|---|---|
| committer | mikhnenko <mikhnenko@yandex-team.com> | 2024-03-27 10:47:39 +0300 |
| commit | 9b902baa4a858f2176c82aa0b20f88232f0da0d8 (patch) | |
| tree | 7165a551c2244c4b3c28479ac3a3f6d62346ec89 /contrib/libs/cxxsupp/libcxx/src/tz.cpp | |
| parent | a1c989e67e438005fa0c34ed0e910536c8941862 (diff) | |
| download | ydb-9b902baa4a858f2176c82aa0b20f88232f0da0d8.tar.gz | |
Update libcxx to 10 Oct 2023 dc129d6f715cf83a2072fc8de8b4e4c70bca6935
97ce40d276e44357a49b7a945af841896126dca8
Diffstat (limited to 'contrib/libs/cxxsupp/libcxx/src/tz.cpp')
| -rw-r--r-- | contrib/libs/cxxsupp/libcxx/src/tz.cpp | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/contrib/libs/cxxsupp/libcxx/src/tz.cpp b/contrib/libs/cxxsupp/libcxx/src/tz.cpp new file mode 100644 index 0000000000..4425f0e6b9 --- /dev/null +++ b/contrib/libs/cxxsupp/libcxx/src/tz.cpp @@ -0,0 +1,146 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +// For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html + +#include <chrono> +#include <filesystem> +#include <fstream> +#include <stdexcept> +#include <string> + +// Contains a parser for the IANA time zone data files. +// +// These files can be found at https://data.iana.org/time-zones/ and are in the +// public domain. Information regarding the input can be found at +// https://data.iana.org/time-zones/tz-how-to.html and +// https://man7.org/linux/man-pages/man8/zic.8.html. +// +// As indicated at https://howardhinnant.github.io/date/tz.html#Installation +// For Windows another file seems to be required +// https://raw.githubusercontent.com/unicode-org/cldr/master/common/supplemental/windowsZones.xml +// This file seems to contain the mapping of Windows time zone name to IANA +// time zone names. +// +// However this article mentions another way to do the mapping on Windows +// https://devblogs.microsoft.com/oldnewthing/20210527-00/?p=105255 +// This requires Windows 10 Version 1903, which was released in May of 2019 +// and considered end of life in December 2020 +// https://learn.microsoft.com/en-us/lifecycle/announcements/windows-10-1903-end-of-servicing +// +// TODO TZDB Implement the Windows mapping in tzdb::current_zone + +_LIBCPP_BEGIN_NAMESPACE_STD + +namespace chrono { + +// This function is weak so it can be overriden in the tests. The +// declaration is in the test header test/support/test_tzdb.h +_LIBCPP_WEAK string_view __libcpp_tzdb_directory() { +#if defined(__linux__) + return "/usr/share/zoneinfo/"; +#else +# error "unknown path to the IANA Time Zone Database" +#endif +} + +[[nodiscard]] static bool __is_whitespace(int __c) { return __c == ' ' || __c == '\t'; } + +static void __skip_optional_whitespace(istream& __input) { + while (chrono::__is_whitespace(__input.peek())) + __input.get(); +} + +static void __skip_mandatory_whitespace(istream& __input) { + if (!chrono::__is_whitespace(__input.get())) + std::__throw_runtime_error("corrupt tzdb: expected whitespace"); + + chrono::__skip_optional_whitespace(__input); +} + +static void __matches(istream& __input, char __expected) { + if (std::tolower(__input.get()) != __expected) + std::__throw_runtime_error((string("corrupt tzdb: expected character '") + __expected + '\'').c_str()); +} + +static void __matches(istream& __input, string_view __expected) { + for (auto __c : __expected) + if (std::tolower(__input.get()) != __c) + std::__throw_runtime_error((string("corrupt tzdb: expected string '") + string(__expected) + '\'').c_str()); +} + +[[nodiscard]] static string __parse_string(istream& __input) { + string __result; + while (true) { + int __c = __input.get(); + switch (__c) { + case ' ': + case '\t': + case '\n': + __input.unget(); + [[fallthrough]]; + case istream::traits_type::eof(): + if (__result.empty()) + std::__throw_runtime_error("corrupt tzdb: expected a string"); + + return __result; + + default: + __result.push_back(__c); + } + } +} + +static string __parse_version(istream& __input) { + // The first line in tzdata.zi contains + // # version YYYYw + // The parser expects this pattern + // #\s*version\s*\(.*) + // This part is not documented. + chrono::__matches(__input, '#'); + chrono::__skip_optional_whitespace(__input); + chrono::__matches(__input, "version"); + chrono::__skip_mandatory_whitespace(__input); + return chrono::__parse_string(__input); +} + +static tzdb __make_tzdb() { + tzdb __result; + + filesystem::path __root = chrono::__libcpp_tzdb_directory(); + ifstream __tzdata{__root / "tzdata.zi"}; + + __result.version = chrono::__parse_version(__tzdata); + return __result; +} + +//===----------------------------------------------------------------------===// +// Public API +//===----------------------------------------------------------------------===// + +_LIBCPP_NODISCARD_EXT _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI tzdb_list& get_tzdb_list() { + static tzdb_list __result{chrono::__make_tzdb()}; + return __result; +} + +_LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI const tzdb& reload_tzdb() { + if (chrono::remote_version() == chrono::get_tzdb().version) + return chrono::get_tzdb(); + + return chrono::get_tzdb_list().__emplace_front(chrono::__make_tzdb()); +} + +_LIBCPP_NODISCARD_EXT _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI string remote_version() { + filesystem::path __root = chrono::__libcpp_tzdb_directory(); + ifstream __tzdata{__root / "tzdata.zi"}; + return chrono::__parse_version(__tzdata); +} + +} // namespace chrono + +_LIBCPP_END_NAMESPACE_STD |