libstdc++-v3/testsuite/18_support/comparisons/algorithms/weak_order.cc

   1 // Copyright (C) 2019 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++2a" }
  19 // { dg-do run { target c++2a } }
  20
  21 #include <compare>
  22 #include <limits>
  23 #include <testsuite_hooks.h>
  24
  25 using std::weak_order;
  26 using std::weak_ordering;
  27
  28 void
  29 test01()
  30 {
  31   int one = 1, two = 2;
  32
  33   VERIFY( weak_order(one, two) == weak_ordering::less );
  34   VERIFY( weak_order(one, one) == weak_ordering::equivalent );
  35   VERIFY( weak_order(two, one) == weak_ordering::greater );
  36   static_assert( noexcept(weak_order(1, 1)) );
  37 }
  38
  39 constexpr weak_ordering different_cv_quals(int i, const int j)
  40 {
  41   return weak_order(i, j);
  42 }
  43
  44 void
  45 test02()
  46 {
  47   int fortytwo = 42, nines = 999, lots = 1000;
  48
  49   VERIFY( different_cv_quals(fortytwo, nines) == weak_ordering::less );
  50   VERIFY( different_cv_quals(-nines, -nines) == weak_ordering::equivalent );
  51   VERIFY( different_cv_quals(-nines, -lots) == weak_ordering::greater );
  52 }
  53
  54 void
  55 test03()
  56 {
  57   double zero = 0.0;
  58   VERIFY( weak_order(zero, zero) == weak_ordering::equivalent );
  59   VERIFY( weak_order(-zero, -zero) == weak_ordering::equivalent );
  60   VERIFY( weak_order(-zero, zero) == weak_ordering::equivalent );
  61   VERIFY( weak_order(zero, -zero) == weak_ordering::equivalent );
  62
  63   double min = std::numeric_limits<double>::lowest();
  64   double max = std::numeric_limits<double>::max();
  65   double nan = std::numeric_limits<double>::quiet_NaN();
  66   double inf = std::numeric_limits<double>::infinity();
  67   double denorm = std::numeric_limits<double>::denorm_min();
  68   double smallest = std::numeric_limits<double>::min();
  69   double epsilon = std::numeric_limits<double>::epsilon();
  70   VERIFY( weak_order(denorm, smallest) == weak_ordering::less );
  71   VERIFY( weak_order(denorm, 0.0) == weak_ordering::greater );
  72   VERIFY( weak_order(0.0, nan) == weak_ordering::less );
  73   VERIFY( weak_order(nan, nan) == weak_ordering::equivalent );
  74   VERIFY( weak_order(nan, -nan) == weak_ordering::greater );
  75   VERIFY( weak_order(-nan, nan) == weak_ordering::less );
  76   VERIFY( weak_order(nan, 0.0) == weak_ordering::greater );
  77   VERIFY( weak_order(-nan, 0.0) == weak_ordering::less );
  78   VERIFY( weak_order(-nan, min) == weak_ordering::less );
  79   VERIFY( weak_order(-inf, min) == weak_ordering::less );
  80   VERIFY( weak_order(-nan, -inf) == weak_ordering::less );
  81   VERIFY( weak_order(-inf, -nan) == weak_ordering::greater );
  82   VERIFY( weak_order(max, inf) == weak_ordering::less );
  83   VERIFY( weak_order(inf, max) == weak_ordering::greater );
  84   VERIFY( weak_order(inf, nan) == weak_ordering::less );
  85   VERIFY( weak_order(1.0, 1.0+epsilon) == weak_ordering::less );
  86 }
  87
  88 namespace N
  89 {
  90   struct X { int i; };
  91
  92   constexpr weak_ordering operator<=>(X l, X r)
  93   {
  94     if (l.i < 0 && r.i < 0)
  95       return weak_ordering::equivalent;
  96     return r.i <=> l.i;
  97   }
  98 }
  99
 100 void
 101 test04()
 102 {
 103   using N::X;
 104   X one{1};
 105   X negone{-1};
 106
 107   VERIFY( weak_order(one, X{1}) == weak_ordering::equivalent );
 108   VERIFY( weak_order(negone, X{-2}) == weak_ordering::equivalent );
 109   VERIFY( weak_order(one, X{2}) == weak_ordering::greater );
 110   static_assert( !noexcept(weak_order(X{1}, X{2})) );
 111 }
 112
 113 int main()
 114 {
 115   test01();
 116   test02();
 117   test03();
 118   test04();
 119 }