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

   1 // Copyright (C) 2019-2021 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 <iterator>
  22 #include <testsuite_hooks.h>
  23
  24 void
  25 test01()
  26 {
  27   using I = std::common_iterator<int*, const int*>;
  28   static_assert( std::is_default_constructible_v<I> );
  29   static_assert( std::is_copy_constructible_v<I> );
  30   static_assert( std::is_copy_assignable_v<I> );
  31   static_assert( std::is_constructible_v<I, int*> );
  32   static_assert( std::is_constructible_v<I, const int*> );
  33
  34   struct sentinel { operator int*() const { return nullptr; } };
  35   using K = std::common_iterator<int*, sentinel>;
  36   static_assert( std::is_constructible_v<I, const K&> );
  37   static_assert( std::is_assignable_v<I, const K&> );
  38
  39   struct sentinel2
  40   {
  41     const int* p;
  42     sentinel2(const int* p = 0) : p(p) { }
  43     bool operator==(const int* p) const { return p == this->p; }
  44   };
  45
  46   using J = std::common_iterator<const int*, sentinel2>;
  47   static_assert( std::is_constructible_v<J, const I&> );
  48   static_assert( std::is_convertible_v<const I&, J> );
  49 }
  50
  51 void
  52 test02()
  53 {
  54   struct sentinel { int limit; };
  55
  56   struct iterator
  57   {
  58     using iterator_category = std::input_iterator_tag;
  59     using value_type = int;
  60     using difference_type = std::ptrdiff_t;
  61     using reference = const int&;
  62
  63     const int& operator*() const { return counter; }
  64
  65     iterator& operator++() { ++counter; return *this; }
  66
  67     iterator operator++(int) { auto i = *this; ++counter; return i; }
  68
  69     bool operator==(sentinel s) const { return counter == s.limit; }
  70
  71     int counter = 0;
  72   };
  73
  74   static_assert( std::sentinel_for<sentinel, iterator> );
  75
  76   int out[5] = { };
  77   std::common_iterator<int*, const int*> obegin = std::begin(out);
  78   std::common_iterator<int*, const int*> oend = std::cend(out);
  79
  80   iterator i;
  81   sentinel s{5};
  82   std::common_iterator<iterator, sentinel> begin = i, end = s;
  83   while (begin != end)
  84     *obegin++ = *begin++;
  85
  86   VERIFY(obegin == oend);
  87   for (int& i : out)
  88     VERIFY( i == (&i - out) );
  89 }
  90
  91 void
  92 test03()
  93 {
  94   int arr[2] = { 1, 2 };
  95   std::common_iterator<int*, const int*> i = std::ranges::begin(arr);
  96   std::common_iterator<int*, const int*> end = std::ranges::cend(arr);
  97   VERIFY( i != end );
  98   VERIFY( (end - i) == 2 );
  99   VERIFY( (i - end) == -2 );
 100   auto j = i;
 101   VERIFY( j == i );
 102   VERIFY( (j - i) == 0 );
 103   j = end;
 104   VERIFY( j != i );
 105   VERIFY( j == end );
 106   j = std::ranges::next(i);
 107   VERIFY( j != i );
 108   VERIFY( j != end );
 109   VERIFY( (end - j) == 1 );
 110   VERIFY( (j - i) == 1 );
 111   VERIFY( (i - j) == -1 );
 112   ++j;
 113   VERIFY( j == end );
 114   VERIFY( (end - j) == 0 );
 115   j = i;
 116   VERIFY( j == i );
 117   VERIFY( (j - end) == -2 );
 118   VERIFY( (j - i) == 0 );
 119
 120   try
 121   {
 122     struct S { operator const int*() const { throw 1; } };
 123     i = std::common_iterator<int*, S>(S{});
 124     VERIFY( false );
 125   }
 126   catch (int)
 127   {
 128   }
 129 }
 130
 131 void
 132 test04()
 133 {
 134   struct X
 135   {
 136     X(int i) : i(i) { }
 137     X(X&& x) : i(x.i) { x.i = -1; }
 138     X& operator=(X&& x) { i = x.i; x.i = 0; return *this; }
 139     int i;
 140   };
 141
 142   X arr[] = { 1, 2 };
 143   std::common_iterator<X*, const X*> i(arr), j(arr+1);
 144   std::ranges::iter_swap(i, j);
 145   VERIFY( arr[0].i == 2 );
 146   VERIFY( arr[1].i == 1 );
 147
 148   X x = std::ranges::iter_move(i);
 149   VERIFY( arr[0].i == -1 );
 150   VERIFY( x.i == 2 );
 151 }
 152
 153 int
 154 main()
 155 {
 156   test01();
 157   test02();
 158   test03();
 159   test04();
 160 }