libstdc++-v3/testsuite/24_iterators/reverse_iterator/dr1052.cc

   1 // Copyright (C) 2018 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++11 } }
  19
  20 // PR libstdc++/86734
  21 // LWG 1052. reverse_iterator::operator-> should also support smart pointers
  22 // LWG 2775. reverse_iterator is does not compile for fancy pointers
  23
  24 #include <iterator>
  25 #include <testsuite_hooks.h>
  26
  27 void
  28 test01()
  29 {
  30   // Example 1 from LWG 1052
  31
  32   struct X { int m; };
  33
  34   static X x;
  35
  36   struct IterX {
  37     typedef std::bidirectional_iterator_tag iterator_category;
  38     typedef X& reference;
  39     struct pointer
  40     {
  41       pointer(X& v) : value(v) {}
  42       X& value;
  43       X* operator->() const {return &value;}
  44     };
  45     typedef std::ptrdiff_t difference_type;
  46     typedef X value_type;
  47     // additional iterator requirements not important for this issue
  48
  49     reference operator*() const { return x; }
  50     pointer operator->() const { return pointer(x); }
  51     IterX& operator--() {return *this;}
  52
  53   };
  54
  55   std::reverse_iterator<IterX> ix;
  56   VERIFY( &ix->m == &(*ix).m );
  57 }
  58
  59 void
  60 test02()
  61 {
  62   // Example 2 from LWG 1052
  63
  64   struct P {
  65     P() : first(10), second(20.0) { }
  66     int first;
  67     double second;
  68   };
  69   P op;
  70   std::reverse_iterator<P*> ri(&op + 1);
  71   VERIFY( ri->first == 10 );
  72 }
  73
  74 // N.B. Example 3 from LWG 1052 isn't expected to work,
  75 // because a caching iterator like IterX is not a forward iterator.
  76
  77 int
  78 main()
  79 {
  80   test01();
  81   test02();
  82 }