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 gps_time<common_type_t<_Duration, seconds>>
20// from_utc(const utc<_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 // [time.clock.gps.overview]/1
35 // The clock gps_clock measures seconds since the first Sunday of January,
36 // 1980 00:00:00 UTC.
37 // The first Sunday is 1980-1-6 (so January sixth)
38 // ... 1980-01-06 00:00:00 GPS is equivalent to 1980-01-06 00:00:00 UTC
39
40 assert(cr::gps_clock::from_utc(cr::utc_clock::from_sys(cr::sys_days{cr::January / 6 / 1980})) == cr::gps_seconds{0s});
41}
42
43template <class Duration>
44static void test_leap_seconds(std::chrono::utc_time<Duration> utc,
45 std::chrono::gps_time<Duration> expected,
46 std::source_location loc = std::source_location::current()) {
47 auto gps = std::chrono::gps_clock::from_utc(utc);
48 TEST_REQUIRE(gps == expected,
49 TEST_WRITE_CONCATENATED(loc, "\nExpected output ", expected, "\nActual output ", gps, '\n'));
50}
51
52// Tests set if existing database entries at the time of writing.
53static void test_transitions() {
54 using namespace std::literals::chrono_literals;
55 namespace cr = std::chrono;
56
57 // "sys" is the time of the transition to the next leap second.
58 // "elapsed" is the number of leap seconds before the transition.
59 auto test_transition = [](cr::sys_days sys, cr::seconds elapsed) {
60 constexpr auto unix_to_gps_epoch_offset =
61 cr::sys_days{cr::January / 1 / 1970} - cr::sys_days{cr::January / 6 / 1980};
62 cr::gps_seconds gps{sys.time_since_epoch() + unix_to_gps_epoch_offset + elapsed};
63
64 test_leap_seconds(cr::utc_clock::from_sys(sys - 1ns), gps - 1ns);
65 test_leap_seconds(cr::utc_clock::from_sys(sys), gps + 1s);
66 test_leap_seconds(cr::utc_clock::from_sys(sys) + 1ns, gps + 1s + 1ns);
67 };
68
69 // Transitions from the start of UTC.
70 test_transition(cr::sys_days{cr::July / 1 / 1972}, -9s);
71 test_transition(cr::sys_days{cr::January / 1 / 1973}, -8s);
72 test_transition(cr::sys_days{cr::January / 1 / 1974}, -7s);
73 test_transition(cr::sys_days{cr::January / 1 / 1975}, -6s);
74 test_transition(cr::sys_days{cr::January / 1 / 1976}, -5s);
75 test_transition(cr::sys_days{cr::January / 1 / 1977}, -4s);
76 test_transition(cr::sys_days{cr::January / 1 / 1978}, -3s);
77 test_transition(cr::sys_days{cr::January / 1 / 1979}, -2s);
78 test_transition(cr::sys_days{cr::January / 1 / 1980}, -1s);
79 test_transition(cr::sys_days{cr::July / 1 / 1981}, 0s);
80 test_transition(cr::sys_days{cr::July / 1 / 1982}, 1s);
81 test_transition(cr::sys_days{cr::July / 1 / 1983}, 2s);
82 test_transition(cr::sys_days{cr::July / 1 / 1985}, 3s);
83 test_transition(cr::sys_days{cr::January / 1 / 1988}, 4s);
84 test_transition(cr::sys_days{cr::January / 1 / 1990}, 5s);
85 test_transition(cr::sys_days{cr::January / 1 / 1991}, 6s);
86 test_transition(cr::sys_days{cr::July / 1 / 1992}, 7s);
87 test_transition(cr::sys_days{cr::July / 1 / 1993}, 8s);
88 test_transition(cr::sys_days{cr::July / 1 / 1994}, 9s);
89 test_transition(cr::sys_days{cr::January / 1 / 1996}, 10s);
90 test_transition(cr::sys_days{cr::July / 1 / 1997}, 11s);
91 test_transition(cr::sys_days{cr::January / 1 / 1999}, 12s);
92 test_transition(cr::sys_days{cr::January / 1 / 2006}, 13s);
93 test_transition(cr::sys_days{cr::January / 1 / 2009}, 14s);
94 test_transition(cr::sys_days{cr::July / 1 / 2012}, 15s);
95 test_transition(cr::sys_days{cr::July / 1 / 2015}, 16s);
96 test_transition(cr::sys_days{cr::January / 1 / 2017}, 17s);
97}
98
99// Tests whether the return type is the expected type.
100static void test_return_type() {
101 using namespace std::literals::chrono_literals;
102 namespace cr = std::chrono;
103
104 {
105 [[maybe_unused]] std::same_as<cr::gps_time<cr::nanoseconds>> decltype(auto) _ =
106 cr::gps_clock::from_utc(cr::utc_time<cr::nanoseconds>{0ns});
107 }
108 {
109 [[maybe_unused]] std::same_as<cr::gps_time<cr::microseconds>> decltype(auto) _ =
110 cr::gps_clock::from_utc(cr::utc_time<cr::microseconds>{0us});
111 }
112 {
113 [[maybe_unused]] std::same_as<cr::gps_time<cr::milliseconds>> decltype(auto) _ =
114 cr::gps_clock::from_utc(cr::utc_time<cr::milliseconds>{0ms});
115 }
116
117 {
118 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
119 cr::gps_clock::from_utc(cr::utc_time<cr::seconds>{cr::seconds{0}});
120 }
121
122 {
123 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
124 cr::gps_clock::from_utc(cr::utc_time<cr::minutes>{cr::minutes{0}});
125 }
126 {
127 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
128 cr::gps_clock::from_utc(cr::utc_time<cr::hours>{cr::hours{0}});
129 }
130 {
131 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
132 cr::gps_clock::from_utc(cr::utc_time<cr::days>{cr::days{0}});
133 }
134 {
135 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
136 cr::gps_clock::from_utc(cr::utc_time<cr::weeks>{cr::weeks{0}});
137 }
138 {
139 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
140 cr::gps_clock::from_utc(cr::utc_time<cr::months>{cr::months{0}});
141 }
142 {
143 [[maybe_unused]] std::same_as<cr::gps_time<cr::seconds>> decltype(auto) _ =
144 cr::gps_clock::from_utc(cr::utc_time<cr::years>{cr::years{0}});
145 }
146}
147
148int main(int, const char**) {
149 using namespace std::literals::chrono_literals;
150 std::chrono::utc_seconds time = std::chrono::utc_seconds{0s};
151 static_assert(noexcept(std::chrono::gps_clock::from_utc(time)));
152
153 test_known_values();
154 test_transitions();
155 test_return_type();
156
157 return 0;
158}
159

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