xref: /llvm-project/libcxx/test/std/time/time.clock/time.clock.utc/get_leap_second_info.pass.cpp (revision 0cd794d4860e376698bb4da24bcdf8cbf331835c)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: c++03, c++11, c++14, c++17
10 // UNSUPPORTED: no-filesystem, no-localization, no-tzdb
11 
12 // XFAIL: libcpp-has-no-experimental-tzdb
13 // XFAIL: availability-tzdb-missing
14 
15 // <chrono>
16 //
17 // class utc_clock;
18 
19 // template<class Duration>
20 // leap_second_info get_leap_second_info(const utc_time<Duration>& ut);
21 
22 #include <chrono>
23 #include <cassert>
24 
25 #include "test_macros.h"
26 #include "assert_macros.h"
27 #include "concat_macros.h"
28 
29 template <class Duration>
30 static void test_leap_second_info(
31     std::chrono::time_point<std::chrono::utc_clock, Duration> time, bool is_leap_second, std::chrono::seconds elapsed) {
32   std::chrono::leap_second_info result = std::chrono::get_leap_second_info(time);
33   TEST_REQUIRE(
34       result.is_leap_second == is_leap_second && result.elapsed == elapsed,
35       TEST_WRITE_CONCATENATED(
36           "\nExpected output [",
37           is_leap_second,
38           ", ",
39           elapsed,
40           "]\nActual output   [",
41           result.is_leap_second,
42           ", ",
43           result.elapsed,
44           "]\n"));
45 }
46 
47 static std::chrono::utc_seconds get_utc_time(long long seconds_since_1900) {
48   // The file leap-seconds.list stores dates since 1 January 1900, 00:00:00, we want
49   // seconds since 1 January 1970.
50   constexpr auto offset =
51       std::chrono::sys_days{std::chrono::January / 1 / 1970} - std::chrono::sys_days{std::chrono::January / 1 / 1900};
52   return std::chrono::utc_seconds{std::chrono::seconds{seconds_since_1900} - offset};
53 }
54 
55 // Tests set of existing database entries at the time of writing.
56 int main(int, const char**) {
57   using namespace std::literals::chrono_literals;
58 
59   test_leap_second_info(std::chrono::utc_seconds::min(), false, 0s);
60 
61   // Epoch transition no transitions.
62   test_leap_second_info(std::chrono::utc_seconds{-1s}, false, 0s);
63   test_leap_second_info(std::chrono::utc_seconds{0s}, false, 0s);
64   test_leap_second_info(std::chrono::utc_seconds{1s}, false, 0s);
65 
66   // Transitions from the start of UTC.
67   auto test_transition = [](std::chrono::utc_seconds time, std::chrono::seconds elapsed, bool positive) {
68     // Note at the time of writing all leap seconds are positive so the else
69     // branch is never executed. The private test for this function tests
70     // negative leap seconds and uses the else branch.
71 
72     if (positive) {
73       // Every transition has the following tests
74       // - 1ns before the start of the transition is_leap_second -> false, elapsed -> elapsed
75       // -         at the start of the transition is_leap_second -> true,  elapsed -> elapsed + 1
76       // - 1ns after  the start of the transition is_leap_second -> true,  elapsed -> elapsed + 1
77       // - 1ns before the end   of the transition is_leap_second -> true,  elapsed -> elapsed + 1
78       // -         at the end   of the transition is_leap_second -> false, elapsed -> elapsed + 1
79 
80       test_leap_second_info(time - 1ns, false, elapsed);
81       test_leap_second_info(time, true, elapsed + 1s);
82       test_leap_second_info(time + 1ns, true, elapsed + 1s);
83       test_leap_second_info(time + 1s - 1ns, true, elapsed + 1s);
84       test_leap_second_info(time + 1s, false, elapsed + 1s);
85     } else {
86       // Every transition has the following tests
87       // - 1ns before the transition is_leap_second -> false, elapsed -> elapsed
88       // -         at the transition is_leap_second -> false  elapsed -> elapsed - 1
89       // - 1ns after  the transition is_leap_second -> false, elapsed -> elapsed - 1
90       test_leap_second_info(time - 1ns, false, elapsed);
91       test_leap_second_info(time, false, elapsed - 1s);
92       test_leap_second_info(time + 1ns, false, elapsed - 1s);
93     }
94   };
95 
96   // The timestamps are from leap-seconds.list in the IANA database.
97   // Note the times stamps are timestamps without leap seconds so the number
98   // here are incremented by x "leap seconds".
99   test_transition(get_utc_time(2287785600 + 0), 0s, true);   // 1 Jul 1972
100   test_transition(get_utc_time(2303683200 + 1), 1s, true);   // 1 Jan 1973
101   test_transition(get_utc_time(2335219200 + 2), 2s, true);   // 1 Jan 1974
102   test_transition(get_utc_time(2366755200 + 3), 3s, true);   // 1 Jan 1975
103   test_transition(get_utc_time(2398291200 + 4), 4s, true);   // 1 Jan 1976
104   test_transition(get_utc_time(2429913600 + 5), 5s, true);   // 1 Jan 1977
105   test_transition(get_utc_time(2461449600 + 6), 6s, true);   // 1 Jan 1978
106   test_transition(get_utc_time(2492985600 + 7), 7s, true);   // 1 Jan 1979
107   test_transition(get_utc_time(2524521600 + 8), 8s, true);   // 1 Jan 1980
108   test_transition(get_utc_time(2571782400 + 9), 9s, true);   // 1 Jul 1981
109   test_transition(get_utc_time(2603318400 + 10), 10s, true); // 1 Jul 1982
110   test_transition(get_utc_time(2634854400 + 11), 11s, true); // 1 Jul 1983
111   test_transition(get_utc_time(2698012800 + 12), 12s, true); // 1 Jul 1985
112   test_transition(get_utc_time(2776982400 + 13), 13s, true); // 1 Jan 1988
113   test_transition(get_utc_time(2840140800 + 14), 14s, true); // 1 Jan 1990
114   test_transition(get_utc_time(2871676800 + 15), 15s, true); // 1 Jan 1991
115   test_transition(get_utc_time(2918937600 + 16), 16s, true); // 1 Jul 1992
116   test_transition(get_utc_time(2950473600 + 17), 17s, true); // 1 Jul 1993
117   test_transition(get_utc_time(2982009600 + 18), 18s, true); // 1 Jul 1994
118   test_transition(get_utc_time(3029443200 + 19), 19s, true); // 1 Jan 1996
119   test_transition(get_utc_time(3076704000 + 20), 20s, true); // 1 Jul 1997
120   test_transition(get_utc_time(3124137600 + 21), 21s, true); // 1 Jan 1999
121   test_transition(get_utc_time(3345062400 + 22), 22s, true); // 1 Jan 2006
122   test_transition(get_utc_time(3439756800 + 23), 23s, true); // 1 Jan 2009
123   test_transition(get_utc_time(3550089600 + 24), 24s, true); // 1 Jul 2012
124   test_transition(get_utc_time(3644697600 + 25), 25s, true); // 1 Jul 2015
125   test_transition(get_utc_time(3692217600 + 26), 26s, true); // 1 Jan 2017
126 
127   return 0;
128 }
129