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// REQUIRES: std-at-least-c++20
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 gps_clock;
18
19// static utc_time<common_type_t<_Duration, seconds>>
20// to_utc(const gps_time<_Duration>& __time) noexcept;
21
22#include <chrono>
23#include <cassert>
24#include <source_location>
25
26#include "test_macros.h"
27#include "assert_macros.h"
28#include "concat_macros.h"
29
30static void test_known_values() {
31 namespace cr = std::chrono;
32 using namespace std::literals::chrono_literals;
33
34 assert(cr::gps_clock::to_utc(cr::gps_seconds{0s}) == cr::utc_clock::from_sys(cr::sys_days{cr::January / 6 / 1980}));
35}
36
37template <class Duration>
38static void test_leap_seconds(std::chrono::gps_time<Duration> gps,
39 std::chrono::utc_time<Duration> expected,
40 std::source_location loc = std::source_location::current()) {
41 auto utc = std::chrono::gps_clock::to_utc(gps);
42 TEST_REQUIRE(utc == expected,
43 TEST_WRITE_CONCATENATED(loc, "\nExpected output ", expected, "\nActual output ", utc, '\n'));
44}
45
46// Tests set if existing database entries at the time of writing.
47static void test_transitions() {
48 using namespace std::literals::chrono_literals;
49 namespace cr = std::chrono;
50
51 // "sys" is the time of the transition to the next leap second.
52 // "elapsed" is the number of leap seconds before the transition.
53 auto test_transition = [](cr::sys_days sys, cr::seconds elapsed) {
54 constexpr auto unix_to_gps_epoch_offset =
55 cr::sys_days{cr::January / 1 / 1970} - cr::sys_days{cr::January / 6 / 1980};
56 cr::gps_seconds gps{sys.time_since_epoch() + unix_to_gps_epoch_offset + elapsed};
57
58 test_leap_seconds(gps - 1ns, cr::utc_clock::from_sys(sys - 1ns));
59 test_leap_seconds(gps + 1s, cr::utc_clock::from_sys(sys));
60 test_leap_seconds(gps + 1s + 1ns, cr::utc_clock::from_sys(sys + 1ns));
61 };
62
63 // Transitions from the start of UTC.
64 test_transition(cr::sys_days{cr::July / 1 / 1972}, -9s);
65 test_transition(cr::sys_days{cr::January / 1 / 1973}, -8s);
66 test_transition(cr::sys_days{cr::January / 1 / 1974}, -7s);
67 test_transition(cr::sys_days{cr::January / 1 / 1975}, -6s);
68 test_transition(cr::sys_days{cr::January / 1 / 1976}, -5s);
69 test_transition(cr::sys_days{cr::January / 1 / 1977}, -4s);
70 test_transition(cr::sys_days{cr::January / 1 / 1978}, -3s);
71 test_transition(cr::sys_days{cr::January / 1 / 1979}, -2s);
72 test_transition(cr::sys_days{cr::January / 1 / 1980}, -1s);
73 test_transition(cr::sys_days{cr::July / 1 / 1981}, 0s);
74 test_transition(cr::sys_days{cr::July / 1 / 1982}, 1s);
75 test_transition(cr::sys_days{cr::July / 1 / 1983}, 2s);
76 test_transition(cr::sys_days{cr::July / 1 / 1985}, 3s);
77 test_transition(cr::sys_days{cr::January / 1 / 1988}, 4s);
78 test_transition(cr::sys_days{cr::January / 1 / 1990}, 5s);
79 test_transition(cr::sys_days{cr::January / 1 / 1991}, 6s);
80 test_transition(cr::sys_days{cr::July / 1 / 1992}, 7s);
81 test_transition(cr::sys_days{cr::July / 1 / 1993}, 8s);
82 test_transition(cr::sys_days{cr::July / 1 / 1994}, 9s);
83 test_transition(cr::sys_days{cr::January / 1 / 1996}, 10s);
84 test_transition(cr::sys_days{cr::July / 1 / 1997}, 11s);
85 test_transition(cr::sys_days{cr::January / 1 / 1999}, 12s);
86 test_transition(cr::sys_days{cr::January / 1 / 2006}, 13s);
87 test_transition(cr::sys_days{cr::January / 1 / 2009}, 14s);
88 test_transition(cr::sys_days{cr::July / 1 / 2012}, 15s);
89 test_transition(cr::sys_days{cr::July / 1 / 2015}, 16s);
90 test_transition(cr::sys_days{cr::January / 1 / 2017}, 17s);
91}
92
93// Tests whether the return type is the expected type.
94static void test_return_type() {
95 using namespace std::literals::chrono_literals;
96 namespace cr = std::chrono;
97
98 {
99 [[maybe_unused]] std::same_as<cr::utc_time<cr::nanoseconds>> decltype(auto) _ =
100 cr::gps_clock::to_utc(cr::gps_time<cr::nanoseconds>{0ns});
101 }
102 {
103 [[maybe_unused]] std::same_as<cr::utc_time<cr::microseconds>> decltype(auto) _ =
104 cr::gps_clock::to_utc(cr::gps_time<cr::microseconds>{0us});
105 }
106 {
107 [[maybe_unused]] std::same_as<cr::utc_time<cr::milliseconds>> decltype(auto) _ =
108 cr::gps_clock::to_utc(cr::gps_time<cr::milliseconds>{0ms});
109 }
110
111 {
112 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
113 cr::gps_clock::to_utc(cr::gps_time<cr::seconds>{cr::seconds{0}});
114 }
115
116 {
117 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
118 cr::gps_clock::to_utc(cr::gps_time<cr::minutes>{cr::minutes{0}});
119 }
120 {
121 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
122 cr::gps_clock::to_utc(cr::gps_time<cr::hours>{cr::hours{0}});
123 }
124 {
125 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
126 cr::gps_clock::to_utc(cr::gps_time<cr::days>{cr::days{0}});
127 }
128 {
129 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
130 cr::gps_clock::to_utc(cr::gps_time<cr::weeks>{cr::weeks{0}});
131 }
132 {
133 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
134 cr::gps_clock::to_utc(cr::gps_time<cr::months>{cr::months{0}});
135 }
136 {
137 [[maybe_unused]] std::same_as<cr::utc_time<cr::seconds>> decltype(auto) _ =
138 cr::gps_clock::to_utc(cr::gps_time<cr::years>{cr::years{0}});
139 }
140}
141
142int main(int, const char**) {
143 using namespace std::literals::chrono_literals;
144
145 std::chrono::gps_seconds time = std::chrono::gps_seconds{0s};
146 static_assert(noexcept(std::chrono::gps_clock::to_utc(time)));
147
148 test_known_values();
149 test_transitions();
150 test_return_type();
151
152 return 0;
153}
154

source code of libcxx/test/std/time/time.clock/time.clock.gps/time.clock.gps.members/to_utc.pass.cpp