libstdc++-v3/testsuite/24_iterators/common_iterator/1.cc

   1 // Copyright (C) 2019-2024 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 <iterator>
  21 #include <testsuite_hooks.h>
  22
  23 void
  24 test01()
  25 {
  26   using I = std::common_iterator<int*, const int*>;
  27   static_assert( std::is_default_constructible_v<I> );
  28   static_assert( std::is_copy_constructible_v<I> );
  29   static_assert( std::is_move_constructible_v<I> );
  30   static_assert( std::is_copy_assignable_v<I> );
  31   static_assert( std::is_move_assignable_v<I> );
  32   static_assert( std::is_constructible_v<I, int*> );
  33   static_assert( std::is_constructible_v<I, const int*> );
  34
  35   static_assert( std::is_nothrow_copy_constructible_v<I> ); // GCC extension
  36   static_assert( std::is_nothrow_move_constructible_v<I> ); // GCC extension
  37   static_assert( std::is_nothrow_copy_assignable_v<I> ); // GCC extension
  38   static_assert( std::is_nothrow_move_assignable_v<I> ); // GCC extension
  39
  40   struct sentinel { operator int*() const noexcept { return nullptr; } };
  41   using K = std::common_iterator<int*, sentinel>;
  42   static_assert( std::is_constructible_v<I, const K&> );
  43   static_assert( std::is_assignable_v<I, const K&> );
  44
  45   static_assert( std::is_nothrow_assignable_v<I&, const K&> ); // GCC extension
  46
  47   struct sentinel_throwing { operator int*() const { return nullptr; } };
  48   using K_throwing = std::common_iterator<int*, sentinel_throwing>;
  49   // Conversion is noexcept(false)
  50   static_assert( ! std::is_nothrow_assignable_v<I&, const K_throwing&> );
  51
  52
  53   struct sentinel2
  54   {
  55     const int* p;
  56     sentinel2(const int* p = 0) : p(p) { }
  57     bool operator==(const int* p) const { return p == this->p; }
  58   };
  59
  60   using J = std::common_iterator<const int*, sentinel2>;
  61   static_assert( std::is_constructible_v<J, const I&> );
  62   static_assert( std::is_convertible_v<const I&, J> );
  63
  64   static_assert( std::is_constructible_v<J, I> );
  65   static_assert( std::is_convertible_v<I, J> );
  66
  67   // Constructor is noexcept(false)
  68   static_assert( ! std::is_nothrow_constructible_v<J, I> );
  69 }
  70
  71 void
  72 test02()
  73 {
  74   struct sentinel { int limit; };
  75
  76   struct iterator
  77   {
  78     using iterator_category = std::input_iterator_tag;
  79     using value_type = int;
  80     using difference_type = std::ptrdiff_t;
  81     using reference = const int&;
  82
  83     const int& operator*() const { return counter; }
  84
  85     iterator& operator++() { ++counter; return *this; }
  86
  87     iterator operator++(int) { auto i = *this; ++counter; return i; }
  88
  89     bool operator==(sentinel s) const { return counter == s.limit; }
  90
  91     int counter = 0;
  92   };
  93
  94   static_assert( std::sentinel_for<sentinel, iterator> );
  95
  96   int out[5] = { };
  97   std::common_iterator<int*, const int*> obegin = std::begin(out);
  98   std::common_iterator<int*, const int*> oend = std::cend(out);
  99
 100   iterator i;
 101   sentinel s{5};
 102   std::common_iterator<iterator, sentinel> begin = i, end = s;
 103   while (begin != end)
 104     *obegin++ = *begin++;
 105
 106   VERIFY(obegin == oend);
 107   for (int& i : out)
 108     VERIFY( i == (&i - out) );
 109 }
 110
 111 constexpr bool
 112 test03()
 113 {
 114   int arr[2] = { 1, 2 };
 115   std::common_iterator<int*, const int*> i = std::ranges::begin(arr);
 116   std::common_iterator<int*, const int*> end = std::ranges::cend(arr);
 117   VERIFY( i != end );
 118   VERIFY( (end - i) == 2 );
 119   VERIFY( (i - end) == -2 );
 120   auto j = i;
 121   VERIFY( j == i );
 122   VERIFY( (j - i) == 0 );
 123   j = end;
 124   VERIFY( j != i );
 125   VERIFY( j == end );
 126   j = std::ranges::next(i);
 127   VERIFY( j != i );
 128   VERIFY( j != end );
 129   VERIFY( (end - j) == 1 );
 130   VERIFY( (j - i) == 1 );
 131   VERIFY( (i - j) == -1 );
 132   ++j;
 133   VERIFY( j == end );
 134   VERIFY( (end - j) == 0 );
 135   j = i;
 136   VERIFY( j == i );
 137   VERIFY( (j - end) == -2 );
 138   VERIFY( (j - i) == 0 );
 139
 140   if (std::is_constant_evaluated())
 141     return true;
 142
 143   try
 144   {
 145     struct S { operator const int*() const { throw 1; } };
 146     i = std::common_iterator<int*, S>(S{});
 147     VERIFY( false );
 148   }
 149   catch (int)
 150   {
 151   }
 152
 153   return true;
 154 }
 155
 156 static_assert( test03() );
 157
 158 void
 159 test04()
 160 {
 161   struct X
 162   {
 163     X(int i) : i(i) { }
 164     X(X&& x) : i(x.i) { x.i = -1; }
 165     X& operator=(X&& x) { i = x.i; x.i = 0; return *this; }
 166     int i;
 167   };
 168
 169   X arr[] = { 1, 2 };
 170   std::common_iterator<X*, const X*> i(arr), j(arr+1);
 171   std::ranges::iter_swap(i, j);
 172   VERIFY( arr[0].i == 2 );
 173   VERIFY( arr[1].i == 1 );
 174
 175   X x = std::ranges::iter_move(i);
 176   VERIFY( arr[0].i == -1 );
 177   VERIFY( x.i == 2 );
 178 }
 179
 180 constexpr bool
 181 test_pr103992()
 182 {
 183   using C1 = std::common_iterator<std::reverse_iterator<int*>,
 184                                   std::unreachable_sentinel_t>;
 185   using C2 = std::common_iterator<std::reverse_iterator<const int*>,
 186                                   std::unreachable_sentinel_t>;
 187   C1 c1;
 188   C2 c2 = c1;
 189   C1 c3 = c1;
 190
 191   return true;
 192 }
 193
 194 static_assert( test_pr103992() );
 195
 196 int
 197 main()
 198 {
 199   test01();
 200   test02();
 201   test03();
 202   test04();
 203 }