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// UNSUPPORTED: c++03, c++11, c++14, c++17
9// <chrono>
10
11// template <class Duration>
12// class hh_mm_ss
13// {
14// public:
15// static unsigned constexpr fractional_width = see below;
16// using precision = see below;
17//
18// precision is duration<common_type_t<Duration::rep, seconds::rep>,
19// ratio<1, 10^^fractional_width>>
20
21#include <chrono>
22#include <cassert>
23#include <ratio>
24#include <type_traits>
25
26#include "test_macros.h"
27
28constexpr unsigned long long powers[] = {
29 1ULL,
30 10ULL,
31 100ULL,
32 1000ULL,
33 10000ULL,
34 100000ULL,
35 1000000ULL,
36 10000000ULL,
37 100000000ULL,
38 1000000000ULL,
39 10000000000ULL,
40 100000000000ULL,
41 1000000000000ULL,
42 10000000000000ULL,
43 100000000000000ULL,
44 1000000000000000ULL,
45 10000000000000000ULL,
46 100000000000000000ULL,
47 1000000000000000000ULL,
48 10000000000000000000ULL
49};
50
51template <typename Duration, unsigned width>
52constexpr bool check_precision()
53{
54 using HMS = std::chrono::hh_mm_ss<Duration>;
55 using CT = std::common_type_t<typename Duration::rep, std::chrono::seconds::rep>;
56 using Pre = std::chrono::duration<CT, std::ratio<1, powers[width]>>;
57 return std::is_same_v<typename HMS::precision, Pre>;
58}
59
60int main(int, char**)
61{
62 using microfortnights = std::chrono::duration<int, std::ratio<756, 625>>;
63
64 static_assert( check_precision<std::chrono::hours, 0>(), "");
65 static_assert( check_precision<std::chrono::minutes, 0>(), "");
66 static_assert( check_precision<std::chrono::seconds, 0>(), "");
67 static_assert( check_precision<std::chrono::milliseconds, 3>(), "");
68 static_assert( check_precision<std::chrono::microseconds, 6>(), "");
69 static_assert( check_precision<std::chrono::nanoseconds, 9>(), "");
70 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 2>>, 1>(), "");
71 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 3>>, 6>(), "");
72 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 4>>, 2>(), "");
73 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 5>>, 1>(), "");
74 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 6>>, 6>(), "");
75 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 7>>, 6>(), "");
76 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 8>>, 3>(), "");
77 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 9>>, 6>(), "");
78 static_assert( check_precision<std::chrono::duration<int, std::ratio< 1, 10>>, 1>(), "");
79 static_assert( check_precision<microfortnights, 4>(), "");
80
81 return 0;
82}
83

source code of libcxx/test/std/time/time.hms/time.hms.members/precision.pass.cpp