//===----------------------------------------------------------------------===//
//
// 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>
// sys_time<common_type_t<Duration, seconds>>
// to_sys(const local_time<Duration>& tp, choose z) const;
#include <chrono>
#include <format>
#include <cassert>
#include <string_view>
#include "test_macros.h"
// Tests unique conversions. To make sure the test is does not depend on changes
// in the database it uses a time zone with a fixed offset.
static void test_unique() {
using namespace std::literals::chrono_literals;
const std::chrono::time_zone* tz = std::chrono::locate_zone("Etc/GMT+1");
assert(tz->to_sys(std::chrono::local_time<std::chrono::nanoseconds>{-1ns}, std::chrono::choose::earliest) ==
std::chrono::sys_time<std::chrono::nanoseconds>{-1ns + 1h});
assert(tz->to_sys(std::chrono::local_time<std::chrono::microseconds>{0us}, std::chrono::choose::latest) ==
std::chrono::sys_time<std::chrono::microseconds>{1h});
assert(tz->to_sys(
std::chrono::local_time<std::chrono::seconds>{
(std::chrono::sys_days{std::chrono::January / 1 / -21970}).time_since_epoch()},
std::chrono::choose::earliest) ==
std::chrono::sys_time<std::chrono::seconds>{
(std::chrono::sys_days{std::chrono::January / 1 / -21970}).time_since_epoch() + 1h});
// sys_time<common_type_t<Duration, seconds>> is seconds for the larger types
assert(tz->to_sys(
std::chrono::local_time<std::chrono::days>{
(std::chrono::sys_days{std::chrono::January / 1 / 21970}).time_since_epoch()},
std::chrono::choose::latest) ==
std::chrono::sys_time<std::chrono::seconds>{
(std::chrono::sys_days{std::chrono::January / 1 / 21970}).time_since_epoch() + 1h});
assert(tz->to_sys(std::chrono::local_time<std::chrono::weeks>{}, std::chrono::choose::earliest) ==
std::chrono::sys_time<std::chrono::seconds>{
(std::chrono::sys_days{std::chrono::January / 1 / 1970}).time_since_epoch() + 1h});
// Note months and years cannot be streamed; however these functions don't
// throw an exception and thus can be used.
assert(tz->to_sys(std::chrono::local_time<std::chrono::months>{}, std::chrono::choose::latest) ==
std::chrono::sys_time<std::chrono::seconds>{
(std::chrono::sys_days{std::chrono::January / 1 / 1970}).time_since_epoch() + 1h});
assert(tz->to_sys(std::chrono::local_time<std::chrono::years>{}, std::chrono::choose::earliest) ==
std::chrono::sys_time<std::chrono::seconds>{
(std::chrono::sys_days{std::chrono::January / 1 / 1970}).time_since_epoch() + 1h});
}
// Tests non-existant conversions.
static void test_nonexistent() {
using namespace std::literals::chrono_literals;
const std::chrono::time_zone* tz = std::chrono::locate_zone("Europe/Berlin");
// Z Europe/Berlin 0:53:28 - LMT 1893 Ap
// ...
// 1 DE CE%sT 1980
// 1 E CE%sT
//
// ...
// R E 1981 ma - Mar lastSu 1u 1 S
// R E 1996 ma - O lastSu 1u 0 -
// Pick an historic date where it's well known what the time zone rules were.
// This makes it unlikely updates to the database change these rules.
std::chrono::local_time<std::chrono::seconds> time{
(std::chrono::sys_days{std::chrono::March / 30 / 1986} + 2h + 30min).time_since_epoch()};
std::chrono::sys_seconds expected{time.time_since_epoch() - 1h};
// Validates whether the database did not change.
std::chrono::local_info info = tz->get_info(time);
assert(info.result == std::chrono::local_info::nonexistent);
assert(tz->to_sys(time + 0ns, std::chrono::choose::earliest) == expected);
assert(tz->to_sys(time + 0us, std::chrono::choose::latest) == expected);
assert(tz->to_sys(time + 0ms, std::chrono::choose::earliest) == expected);
assert(tz->to_sys(time + 0s, std::chrono::choose::latest) == expected);
}
// Tests ambiguous conversions.
static void test_ambiguous() {
using namespace std::literals::chrono_literals;
const std::chrono::time_zone* tz = std::chrono::locate_zone("Europe/Berlin");
// Z Europe/Berlin 0:53:28 - LMT 1893 Ap
// ...
// 1 DE CE%sT 1980
// 1 E CE%sT
//
// ...
// R E 1981 ma - Mar lastSu 1u 1 S
// R E 1996 ma - O lastSu 1u 0 -
// Pick an historic date where it's well known what the time zone rules were.
// This makes it unlikely updates to the database change these rules.
std::chrono::local_time<std::chrono::seconds> time{
(std::chrono::sys_days{std::chrono::September / 28 / 1986} + 2h + 30min).time_since_epoch()};
std::chrono::sys_seconds earlier{time.time_since_epoch() - 2h};
std::chrono::sys_seconds later{time.time_since_epoch() - 1h};
// Validates whether the database did not change.
std::chrono::local_info info = tz->get_info(time);
assert(info.result == std::chrono::local_info::ambiguous);
assert(tz->to_sys(time + 0ns, std::chrono::choose::earliest) == earlier);
assert(tz->to_sys(time + 0us, std::chrono::choose::latest) == later);
assert(tz->to_sys(time + 0ms, std::chrono::choose::earliest) == earlier);
assert(tz->to_sys(time + 0s, std::chrono::choose::latest) == later);
}
// This test does the basic validations of this function. The library function
// uses `local_info get_info(const local_time<Duration>& tp)` as implementation
// detail. The get_info function does extensive testing of the data.
int main(int, char**) {
test_unique();
test_nonexistent();
test_ambiguous();
return 0;
}
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