xref: /llvm-project/libcxx/test/std/time/time.hms/time.hms.members/precision.pass.cpp (revision 355e0ce3c5366bd0b564a25e4b6675353da3c53e)
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 
28 constexpr 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 
51 template <typename Duration, unsigned width>
check_precision()52 constexpr 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 
main(int,char **)60 int 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