[llvm-branch-commits] [libcxx] [libc++][TZDB] Implements time_zone::to_local. (PR #91003)

[Louis Dionne via llvm-branch-commits]

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@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: no-filesystem, no-localization, no-tzdb
+
+// XFAIL: libcpp-has-no-experimental-tzdb
+// XFAIL: availability-tzdb-missing
+
+// <chrono>
+
+// class time_zone;
+
+// template <class _Duration>
+// local_time<common_type_t<Duration, seconds>>
+//   to_local(const sys_time<Duration>& tp) const;
+
+#include <chrono>
+#include <format>
+#include <cassert>
+#include <string_view>
+
+#include "test_macros.h"
+#include "assert_macros.h"
+#include "concat_macros.h"
+
+int main(int, char**) {
+  // To make sure the test does not depend on changes in the database it uses a
+  // time zone with a fixed offset.
+  using namespace std::literals::chrono_literals;
+
+  const std::chrono::time_zone* tz = std::chrono::locate_zone("Etc/GMT+1");
+
+  assert(tz->to_local(std::chrono::sys_time<std::chrono::nanoseconds>{-1ns}) ==
+         std::chrono::local_time<std::chrono::nanoseconds>{-1ns - 1h});
+
+  assert(tz->to_local(std::chrono::sys_time<std::chrono::microseconds>{0us}) ==
+         std::chrono::local_time<std::chrono::microseconds>{0us - 1h});
+
+  assert(tz->to_local(
+             std::chrono::sys_time<std::chrono::seconds>{std::chrono::sys_days{std::chrono::January / 1 / -21970}}) ==
+         std::chrono::local_time<std::chrono::seconds>{
+             (std::chrono::sys_days{std::chrono::January / 1 / -21970}).time_since_epoch() - 1h});
+
+  assert(
+      tz->to_local(std::chrono::sys_time<std::chrono::days>{std::chrono::sys_days{std::chrono::January / 1 / 21970}}) ==
+      std::chrono::local_time<std::chrono::seconds>{
+          (std::chrono::sys_days{std::chrono::January / 1 / 21970}).time_since_epoch() - 1h});
+
+  assert(tz->to_local(std::chrono::sys_time<std::chrono::weeks>{}) ==
+         std::chrono::local_time<std::chrono::seconds>{
+             (std::chrono::sys_days{std::chrono::January / 1 / 1970}).time_since_epoch() - 1h});
+
+  assert(tz->to_local(std::chrono::sys_time<std::chrono::months>{}) ==
+         std::chrono::local_time<std::chrono::seconds>{
+             (std::chrono::sys_days{std::chrono::January / 1 / 1970}).time_since_epoch() - 1h});
+
+  assert(tz->to_local(std::chrono::sys_time<std::chrono::years>{}) ==
+         std::chrono::local_time<std::chrono::seconds>{
+             (std::chrono::sys_days{std::chrono::January / 1 / 1970}).time_since_epoch() - 1h});
+}
----------------
ldionne wrote:

`return 0;`

https://github.com/llvm/llvm-project/pull/91003