libstdc++-v3/testsuite/23_containers/vector/element_access/constexpr.cc

   1 // { dg-do compile { target c++20 } }
   2
   3 #include <vector>
   4 #include <testsuite_hooks.h>
   5
   6 constexpr bool
   7 test_iterators()
   8 {
   9   std::vector<int> v;
  10   VERIFY( v.begin() == v.end() );
  11   v.reserve(1);
  12   VERIFY( v.begin() == v.end() );
  13   v.resize(2);
  14   VERIFY( v.begin() != v.end() );
  15   VERIFY( v.cbegin() == v.begin() );
  16   VERIFY( v.crbegin() == v.rbegin() );
  17   VERIFY( v.cend() == v.end() );
  18   VERIFY( v.crend() == v.rend() );
  19
  20   auto it = v.begin();
  21   VERIFY( it[0] == 0 );
  22   VERIFY( &*it == &v.front() );
  23   VERIFY( &it[1] == &v[1] );
  24   VERIFY( it++ == v.begin() );
  25   VERIFY( ++it == v.end() );
  26   VERIFY( (it - 2) == v.begin() );
  27   VERIFY( (it - v.begin()) == 2 );
  28   it -= 2;
  29   it += 1;
  30   VERIFY( (it + 1) == v.end() );
  31   VERIFY( (1 + it) == v.end() );
  32   it = it + 1;
  33   auto it2 = v.begin();
  34   std::swap(it, it2);
  35   VERIFY( it == v.begin() );
  36   VERIFY( it2 == v.end() );
  37
  38   auto rit = v.rbegin();
  39   VERIFY( rit[0] == 0 );
  40   VERIFY( &*rit == &v.back() );
  41   VERIFY( &rit[1] == &v[0] );
  42   VERIFY( rit++ == v.rbegin() );
  43   VERIFY( ++rit == v.rend() );
  44   VERIFY( (rit - 2) == v.rbegin() );
  45   VERIFY( (rit - v.rbegin()) == 2 );
  46   rit -= 2;
  47   rit += 1;
  48   VERIFY( (rit + 1) == v.rend() );
  49   VERIFY( (1 + rit) == v.rend() );
  50   rit = rit + 1;
  51   auto rit2 = v.rbegin();
  52   std::swap(rit, rit2);
  53   VERIFY( rit == v.rbegin() );
  54   VERIFY( rit2 == v.rend() );
  55
  56   return true;
  57 }
  58
  59 static_assert(test_iterators());
  60
  61 constexpr bool
  62 test_access()
  63 {
  64   std::vector<int> v{1, 2, 3};
  65   VERIFY( v.at(1) == 2 );
  66   VERIFY( v[2] == 3 );
  67   VERIFY( &v[2] == &v.at(2) );
  68   VERIFY( &v.front() == &v[0] );
  69   VERIFY( &v.back() == &v[2] );
  70
  71   const auto& vc = v;
  72   VERIFY( vc.at(1) == 2 );
  73   VERIFY( &vc.at(1) == &v.at(1) );
  74   VERIFY( &vc.at(1) == &vc[1] );
  75   VERIFY( &vc.front() == &vc[0] );
  76   VERIFY( &vc.back() == &vc[2] );
  77
  78   return true;
  79 }
  80
  81 static_assert(test_access());
  82
  83 template<typename T = int>
  84   constexpr std::false_type
  85   access_empty() { return {}; }
  86
  87 template<typename T = int>
  88   requires (std::bool_constant<&std::vector<T>().at(0) != nullptr>::value)
  89   constexpr std::true_type
  90   access_empty() { return {}; }
  91
  92 template<typename T = int>
  93   requires (std::bool_constant<&std::vector<T>()[0] != nullptr>::value)
  94   constexpr std::true_type
  95   access_empty() { return {}; }
  96
  97 template<typename T = int>
  98   requires (std::bool_constant<&std::vector<T>().front() != nullptr>::value)
  99   constexpr std::true_type
 100   access_empty() { return {}; }
 101
 102 template<typename T = int>
 103   requires (std::bool_constant<&std::vector<T>().back() != nullptr>::value)
 104   constexpr std::true_type
 105   access_empty() { return {}; }
 106
 107 static_assert( ! access_empty() );
 108
 109 template<typename T = int>
 110   constexpr std::false_type
 111   access_past_the_end() { return {}; }
 112
 113 template<typename T = int>
 114   requires (std::bool_constant<&std::vector<T>(3).at(3) != nullptr>::value)
 115   constexpr std::true_type
 116   access_past_the_end() { return {}; }
 117
 118 template<typename T = int>
 119   requires (std::bool_constant<&std::vector<T>(3)[3] != nullptr>::value)
 120   constexpr std::true_type
 121   access_past_the_end() { return {}; }
 122
 123 static_assert( ! access_past_the_end() );