libstdc++-v3/testsuite/25_algorithms/minmax/constrained.cc

   1 // Copyright (C) 2020-2024 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-do run { target c++20 } }
  19
  20 #include <algorithm>
  21 #include <string>
  22 #include <utility>
  23 #include <vector>
  24 #include <testsuite_hooks.h>
  25 #include <testsuite_iterators.h>
  26
  27 using __gnu_test::test_container;
  28 using __gnu_test::test_range;
  29 using __gnu_test::input_iterator_wrapper;
  30
  31 namespace ranges = std::ranges;
  32
  33 template<typename T1, typename T2>
  34 constexpr bool
  35 operator==(const ranges::minmax_result<T1>& lhs,
  36            const ranges::minmax_result<T2>& rhs)
  37 {
  38   return (lhs.min == rhs.min
  39           && rhs.max == rhs.max);
  40 }
  41
  42
  43 struct X
  44 {
  45   int i, j;
  46 };
  47
  48 using res_t = ranges::minmax_result<int>;
  49
  50 void
  51 test01()
  52 {
  53   VERIFY( ranges::minmax(1, 2) == res_t(1,2) );
  54   VERIFY( ranges::minmax(2, 1) == res_t(1,2) );
  55   VERIFY( ranges::minmax(1, 2, ranges::greater{}) == res_t(2,1) );
  56   VERIFY( ranges::minmax(1, 2, ranges::greater{}, std::negate<>{}) == res_t(1,2) );
  57   VERIFY( ranges::minmax(1, 2, {}, std::negate<>{}) == res_t(2,1) );
  58   VERIFY( ranges::minmax(X{1,2}, X{1,3}, {}, &X::i).min.j == 2 );
  59   VERIFY( ranges::minmax(X{1,2}, X{1,3}, {}, &X::i).max.j == 3 );
  60 }
  61
  62 void
  63 test02()
  64 {
  65   int x[] = {1,2,3,4};
  66   do
  67     {
  68       test_range<int, input_iterator_wrapper> cx(x);
  69       VERIFY( ranges::minmax(cx) == res_t(1,4) );
  70       cx.bounds.first = x;
  71       VERIFY( ranges::minmax(cx, ranges::greater{}) == res_t(4,1) );
  72       cx.bounds.first = x;
  73       VERIFY( ranges::minmax(cx, {}, std::negate<>{}) == res_t(4,1));
  74       cx.bounds.first = x;
  75       VERIFY( ranges::minmax(cx, ranges::greater{}, std::negate<>{})
  76               == res_t(1,4) );
  77     } while (ranges::next_permutation(x).found);
  78
  79   constexpr X y[] = {{1,5},{1,2},{1,3}};
  80   static_assert(ranges::minmax(y, {}, &X::i).min.j == 5);
  81   static_assert(ranges::minmax(y, {}, &X::i).max.j == 3);
  82 }
  83
  84 void
  85 test03()
  86 {
  87   VERIFY( ranges::minmax({2,3,1,4}) == res_t(1,4) );
  88   VERIFY( ranges::minmax({2,3,1,4}, ranges::greater{}) == res_t(4,1) );
  89   VERIFY( ranges::minmax({2,3,1,4}, {}, std::negate<>{}) == res_t(4,1) );
  90   VERIFY( ranges::minmax({2,3,1,4}, ranges::greater{}, std::negate<>{})
  91           == res_t(1,4) );
  92 }
  93
  94 void
  95 test04()
  96 {
  97   // Verify we perform at most 3*N/2 applications of the comparison predicate.
  98   static int counter;
  99   struct counted_less
 100   { bool operator()(int a, int b) { ++counter; return a < b; } };
 101
 102   ranges::minmax({1,2}, counted_less{});
 103   VERIFY( counter == 1 );
 104
 105   counter = 0;
 106   ranges::minmax({1,2,3}, counted_less{});
 107   VERIFY( counter == 3 );
 108
 109   counter = 0;
 110   ranges::minmax({1,2,3,4,5,6,7,8,9,10}, counted_less{});
 111   VERIFY( counter <= 15 );
 112
 113   counter = 0;
 114   ranges::minmax({10,9,8,7,6,5,4,3,2,1}, counted_less{});
 115   VERIFY( counter <= 15 );
 116 }
 117
 118 void
 119 test05()
 120 {
 121   // PR libstdc++/100387
 122   using namespace std::literals::string_literals;
 123   auto comp = [](const auto& a, const auto& b) {
 124     return a.size() == b.size() ? a.front() < b.front() : a.size() > b.size();
 125   };
 126   auto result = ranges::minmax({"b"s, "a"s}, comp);
 127   VERIFY( result.min == "a"s && result.max == "b"s );
 128   result = ranges::minmax({"c"s, "b"s, "a"s}, comp);
 129   VERIFY( result.min == "a"s && result.max == "c"s );
 130 }
 131
 132 struct A {
 133   A() = delete;
 134   A(int i) : i(i) { }
 135   A(const A&) = default;
 136   A(A&& other) : A(std::as_const(other)) { ++move_count; }
 137   A& operator=(const A&) = default;
 138   A& operator=(A&& other) {
 139     ++move_count;
 140     return *this = std::as_const(other);
 141   };
 142   friend auto operator<=>(const A&, const A&) = default;
 143   static inline int move_count = 0;
 144   int i;
 145 };
 146
 147 void
 148 test06()
 149 {
 150   // PR libstdc++/104858
 151   // Verify ranges::minmax doesn't dereference the iterator for the first
 152   // element in the range twice.
 153   A a(42);
 154   ranges::subrange r = {std::move_iterator(&a), std::move_sentinel(&a + 1)};
 155   auto result = ranges::minmax(r);
 156   VERIFY( A::move_count == 1 );
 157   VERIFY( result.min.i == 42 && result.max.i == 42 );
 158 }
 159
 160 int
 161 main()
 162 {
 163   test01();
 164   test02();
 165   test03();
 166   test04();
 167   test05();
 168   test06();
 169 }