libcxx/test/std/time/time.hms/time.hms.members/precision.pass.cpp

   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>
  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
  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 }