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 
10 // <chrono>
11 // class year_month_weekday_last;
12 
13 // constexpr year_month_weekday_last operator-(const year_month_weekday_last& ymwdl, const months& dm) noexcept;
14 //   Returns: ymwdl + (-dm).
15 //
16 // constexpr year_month_weekday_last operator-(const year_month_weekday_last& ymwdl, const years& dy) noexcept;
17 //   Returns: ymwdl + (-dy).
18 
19 #include <chrono>
20 #include <type_traits>
21 #include <cassert>
22 
23 #include "test_macros.h"
24 
25 
testConstexprYears(std::chrono::year_month_weekday_last ym)26 constexpr bool testConstexprYears(std::chrono::year_month_weekday_last ym)
27 {
28     std::chrono::years offset{14};
29     if (static_cast<int>((ym         ).year()) != 66) return false;
30     if (static_cast<int>((ym - offset).year()) != 52) return false;
31     return true;
32 }
33 
testConstexprMonths(std::chrono::year_month_weekday_last ym)34 constexpr bool testConstexprMonths(std::chrono::year_month_weekday_last ym)
35 {
36     std::chrono::months offset{6};
37     if (static_cast<unsigned>((ym         ).month()) != 10) return false;
38     if (static_cast<unsigned>((ym - offset).month()) !=  4) return false;
39     return true;
40 }
41 
main(int,char **)42 int main(int, char**)
43 {
44     using year                    = std::chrono::year;
45     using month                   = std::chrono::month;
46     using weekday                 = std::chrono::weekday;
47     using weekday_last            = std::chrono::weekday_last;
48     using year_month_weekday_last = std::chrono::year_month_weekday_last;
49     using years                   = std::chrono::years;
50     using months                  = std::chrono::months;
51 
52     constexpr month October = std::chrono::October;
53     constexpr weekday Tuesday = std::chrono::Tuesday;
54 
55     { // year_month_weekday_last - years
56 
57     ASSERT_NOEXCEPT(                                   std::declval<year_month_weekday_last>() - std::declval<years>());
58     ASSERT_SAME_TYPE(year_month_weekday_last, decltype(std::declval<year_month_weekday_last>() - std::declval<years>()));
59 
60     static_assert(testConstexprYears(year_month_weekday_last{year{66}, October, weekday_last{Tuesday}}), "");
61 
62     year_month_weekday_last ym{year{1234}, October, weekday_last{Tuesday}};
63     for (int i = 0; i <= 10; ++i)
64     {
65         year_month_weekday_last ym1 = ym - years{i};
66         assert(ym1.year()         == year{1234 - i});
67         assert(ym1.month()        == October);
68         assert(ym1.weekday()      == Tuesday);
69         assert(ym1.weekday_last() == weekday_last{Tuesday});
70     }
71     }
72 
73     { // year_month_weekday_last - months
74 
75     ASSERT_NOEXCEPT(                                   std::declval<year_month_weekday_last>() - std::declval<months>());
76     ASSERT_SAME_TYPE(year_month_weekday_last, decltype(std::declval<year_month_weekday_last>() - std::declval<months>()));
77 
78     static_assert(testConstexprMonths(year_month_weekday_last{year{66}, October, weekday_last{Tuesday}}), "");
79 
80     year_month_weekday_last ym{year{1234}, October, weekday_last{Tuesday}};
81     for (unsigned i = 0; i < 10; ++i)
82     {
83         year_month_weekday_last ym1 = ym - months{i};
84         assert(ym1.year()         == year{1234});
85         assert(ym1.month()        == month{10 - i});
86         assert(ym1.weekday()      == Tuesday);
87         assert(ym1.weekday_last() == weekday_last{Tuesday});
88     }
89     }
90 
91 
92   return 0;
93 }
94