libstdc++-v3/testsuite/std/time/year_month_day/4.cc

   1 // { dg-do run { target c++20 } }
   2
   3 // Copyright (C) 2021-2024 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 year_month_day [time.cal.year_month_day]
  21
  22 #include <chrono>
  23 #include <testsuite_hooks.h>
  24
  25 // Slow but very clear way of advancing one day.
  26 constexpr void
  27 advance(std::chrono::year_month_day& ymd) noexcept {
  28
  29   using namespace std::chrono;
  30
  31   auto y = ymd.year();
  32   auto m = ymd.month();
  33   auto d = ymd.day();
  34
  35   if (d != year_month_day_last{year{y}, month_day_last{m}}.day())
  36     ++d;
  37   else {
  38     d = day{1};
  39     if (m != December)
  40       ++m;
  41     else {
  42       m = January;
  43       ++y;
  44     }
  45   }
  46   ymd = year_month_day{y, m, d};
  47 }
  48
  49 void test01()
  50 {
  51   using namespace std::chrono;
  52
  53   // [-32767y/January/1d, 32767y/December/31d] maps to [-12687428, 11248737]
  54
  55   auto n   = days{-12687428};
  56   auto ymd = -32767y/January/1d;
  57   while (ymd < 32767y/December/31d) {
  58     VERIFY( static_cast<sys_days>(ymd) == sys_days{n} );
  59     ++n;
  60     advance(ymd);
  61   }
  62   // One more for ymd = 32767y/December/31d and n = 11248737.
  63   VERIFY( sys_days{days{11248737}} == static_cast<sys_days>(32767y/December/31d) );
  64 }
  65
  66 int main()
  67 {
  68   test01();
  69   return 0;
  70 }