libstdc++-v3/testsuite/std/time/weekday/1.cc

   1 // { dg-do compile { target c++20 } }
   2
   3 // Copyright (C) 2020-2024 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 // Class template day [time.cal.weekday]
  21
  22 #include <chrono>
  23 #include <limits>
  24
  25 constexpr void
  26 constexpr_weekday()
  27 {
  28   using namespace std::chrono;
  29
  30   weekday dwd{};
  31   ++dwd;
  32   dwd++;
  33   --dwd;
  34   dwd--;
  35   dwd += days{3};
  36   dwd -= days{3};
  37
  38   static_assert(weekday{3}[2].weekday() == weekday{3});
  39   static_assert(weekday{3}[last].weekday() == weekday{3});
  40
  41   // Test for UB (overflow).
  42   {
  43     using rep = days::rep;
  44     using std::numeric_limits;
  45
  46     auto constexpr days_min = days{numeric_limits<rep>::min()};
  47     auto constexpr weekday_from_sysdays_min   = weekday{sys_days{days_min}};
  48     auto constexpr weekday_000_plus_days_min  = weekday{ 0 } + days_min;
  49     auto constexpr weekday_255_plus_days_min  = weekday{255} + days_min;
  50     auto constexpr weekday_000_minus_days_min = weekday{ 0 } - days_min;
  51     auto constexpr weekday_255_minus_days_min = weekday{255} - days_min;
  52
  53     auto constexpr days_max = days{numeric_limits<rep>::max()};
  54     auto constexpr weekday_from_sysdays_max   = weekday{sys_days{days_max}};
  55     auto constexpr weekday_000_plus_days_max  = weekday{ 0 } + days_max;
  56     auto constexpr weekday_255_plus_days_max  = weekday{255} + days_max;
  57     auto constexpr weekday_000_minus_days_max = weekday{ 0 } - days_max;
  58     auto constexpr weekday_255_minus_days_max = weekday{255} - days_max;
  59   }
  60
  61   static_assert(weekday{sys_days{1900y/January/1}} == Monday);
  62   static_assert(weekday{sys_days{1970y/January/1}} == Thursday);
  63   static_assert(weekday{sys_days{2020y/August/21}} == Friday);
  64
  65   static_assert(weekday{local_days{1900y/January/1}} == Monday);
  66   static_assert(weekday{local_days{1970y/January/1}} == Thursday);
  67   static_assert(weekday{local_days{2020y/August/21}} == Friday);
  68
  69   static_assert(++weekday{3} == weekday{4});
  70   static_assert(weekday{3}++ == weekday{3});
  71   static_assert(--weekday{3} == weekday{2});
  72   static_assert(weekday{3}-- == weekday{3});
  73   static_assert((weekday{3} += days{3}) == weekday{6});
  74   static_assert((weekday{3} -= days{3}) == weekday{0});
  75
  76   static_assert(Monday + days{7000} == Monday);
  77   static_assert(Monday + days{-7000} == Monday);
  78   static_assert(days{7001} + Monday == Tuesday);
  79   static_assert(days{-7001} + Monday == Sunday);
  80   static_assert(Monday - days{7000} == Monday);
  81   static_assert(Monday - days{-7000} == Monday);
  82   static_assert(Monday - days{7001} == Sunday);
  83
  84   static_assert([] {
  85     constexpr unsigned diff_tbl[7][7]
  86       = { { 0, 6, 5, 4, 3, 2, 1},
  87           { 1, 0, 6, 5, 4, 3, 2},
  88           { 2, 1, 0, 6, 5, 4, 3},
  89           { 3, 2, 1, 0, 6, 5, 4},
  90           { 4, 3, 2, 1, 0, 6, 5},
  91           { 5, 4, 3, 2, 1, 0, 6},
  92           { 6, 5, 4, 3, 2, 1, 0} };
  93     for (unsigned x = 0; x < 7; x++)
  94       for (unsigned y = 0; y < 7; y++)
  95         {
  96           if (weekday{x} - weekday{y} != days{diff_tbl[x][y]})
  97             return false;
  98           if (weekday{x} - days{diff_tbl[x][y]} != weekday{y})
  99             return false;
 100           if (weekday{x} != weekday{y} + days{diff_tbl[x][y]})
 101             return false;
 102           if (weekday{x} != days{diff_tbl[x][y]} + weekday{y})
 103             return false;
 104         }
 105     return true;
 106   }());
 107
 108   static_assert(Sunday.c_encoding() == 0);
 109   static_assert(Sunday.iso_encoding() == 7);
 110   static_assert(Monday.c_encoding() == 1);
 111   static_assert(Monday.iso_encoding() == 1);
 112
 113   static_assert(!weekday{127}.ok());
 114   static_assert(weekday{0}.ok());
 115   static_assert(weekday{6}.ok());
 116   static_assert(weekday{7}.ok()); // Ctor wraps 7 to 0.
 117   static_assert(!weekday{8}.ok());
 118
 119   static_assert(weekday{7} == weekday{0});
 120   static_assert(!(weekday{0} == weekday{1}));
 121   static_assert( (weekday{0} != weekday{2}));
 122 }