libstdc++-v3/testsuite/std/ranges/access/end.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 <ranges>
  22 #include <utility> // as_const
  23 #include <testsuite_hooks.h>
  24 #include <testsuite_iterators.h>
  25
  26 static_assert(__gnu_test::is_customization_point_object(std::ranges::end));
  27
  28 using std::same_as;
  29
  30 void
  31 test01()
  32 {
  33   int a[2] = {};
  34
  35   // t + extent_v<T> if E is of array type T.
  36
  37   static_assert(same_as<decltype(std::ranges::end(a)), decltype(a + 2)>);
  38   static_assert(noexcept(std::ranges::end(a)));
  39   VERIFY( std::ranges::end(a) == (a + 2) );
  40 }
  41
  42 void
  43 test02()
  44 {
  45   using __gnu_test::test_range;
  46   using __gnu_test::random_access_iterator_wrapper;
  47   using __gnu_test::input_iterator_wrapper;
  48   using __gnu_test::output_iterator_wrapper;
  49
  50   int a[] = { 0, 1 };
  51
  52   // Otherwise, decay-copy(t.end()) if it is a valid expression
  53   // and its type S models sentinel_for<decltype(ranges::begin(E))>.
  54
  55   test_range<int, random_access_iterator_wrapper> r(a);
  56   static_assert(same_as<decltype(std::ranges::end(r)), decltype(r.end())>);
  57   VERIFY( std::ranges::end(r) == std::ranges::next(r.begin(), 2) );
  58
  59   test_range<int, input_iterator_wrapper> i(a);
  60   static_assert(same_as<decltype(std::ranges::end(i)), decltype(i.end())>);
  61   VERIFY( std::ranges::end(i) == std::ranges::next(i.begin(), 2) );
  62
  63   test_range<int, output_iterator_wrapper> o(a);
  64   static_assert(same_as<decltype(std::ranges::end(o)), decltype(o.end())>);
  65   VERIFY( std::ranges::end(o) == std::ranges::next(o.begin(), 2) );
  66 }
  67
  68 struct R
  69 {
  70   int a[4] = { 0, 1, 2, 3 };
  71
  72   const int* begin() const;
  73   friend int* begin(R&&) noexcept;
  74   friend const int* begin(const R&&) noexcept;
  75
  76   // Should be ignored because it doesn't return a sentinel for int*
  77   const long* end() const;
  78
  79   friend int* end(R& r) { return r.a + 0; }
  80   friend int* end(R&& r) { return r.a + 1; }
  81   friend const int* end(const R& r) noexcept { return r.a + 2; }
  82   friend const int* end(const R&& r) noexcept { return r.a + 3; }
  83 };
  84
  85 struct RV // view on an R
  86 {
  87   R& r;
  88
  89   const int* begin() const;
  90
  91   friend int* end(RV& v) noexcept { return end(v.r); }
  92   friend const int* end(const RV& v) { return end(std::as_const(v.r)); }
  93 };
  94
  95 // Allow ranges::begin to work with RV&&
  96 template<> constexpr bool std::ranges::enable_borrowed_range<RV> = true;
  97
  98 void
  99 test03()
 100 {
 101   R r;
 102   const R& c = r;
 103
 104   // Otherwise, decay-copy(end(t)) if it is a valid expression
 105   // and its type S models sentinel_for<decltype(ranges::begin(E))>.
 106
 107   static_assert(same_as<decltype(std::ranges::end(r)), decltype(end(r))>);
 108   static_assert(!noexcept(std::ranges::end(r)));
 109   VERIFY( std::ranges::end(r) == end(r) );
 110
 111   static_assert(same_as<decltype(std::ranges::end(c)), decltype(end(c))>);
 112   static_assert(noexcept(std::ranges::end(c)));
 113   VERIFY( std::ranges::end(c) == end(c) );
 114
 115   RV v{r};
 116   static_assert(same_as<decltype(std::ranges::end(std::move(v))),
 117                 decltype(end(r))>);
 118   static_assert(noexcept(std::ranges::end(std::move(v))));
 119   VERIFY( std::ranges::end(std::move(v)) == end(r) );
 120
 121   const RV cv{r};
 122   static_assert(same_as<decltype(std::ranges::end(std::move(cv))),
 123                 decltype(end(c))>);
 124   static_assert(!noexcept(std::ranges::end(std::move(cv))));
 125   VERIFY( std::ranges::end(std::move(cv)) == end(c) );
 126 }
 127
 128 struct RR
 129 {
 130   short s = 0;
 131   long l = 0;
 132   int a[4] = { 0, 1, 2, 3 };
 133
 134   const void* begin() const; // return type not an iterator
 135
 136   friend const short* begin(RR&) noexcept;
 137   short* end() noexcept { return &s; }
 138
 139   friend const long* begin(const RR&) noexcept;
 140   const long* end() const { return &l; }
 141
 142   friend const int* begin(RR&&) noexcept;
 143   friend int* end(RR&) { throw 1; } // not valid for rvalues
 144   friend int* end(RR&& r) { return r.a + 1; }
 145
 146   friend const int* begin(const RR&&) noexcept;
 147   friend const int* end(const RR&) { throw 1; } // not valid for rvalues
 148   friend const int* end(const RR&& r) noexcept { return r.a + 3; }
 149 };
 150
 151 // N.B. this is a lie, end on an RR rvalue will return a dangling pointer.
 152 template<> constexpr bool std::ranges::enable_borrowed_range<RR> = true;
 153
 154 void
 155 test04()
 156 {
 157   RR r;
 158   const RR& c = r;
 159   VERIFY( std::ranges::end(r) == &r.s );
 160   static_assert(noexcept(std::ranges::end(r)));
 161
 162   VERIFY( std::ranges::end(std::move(r)) == &r.s );
 163   static_assert(noexcept(std::ranges::end(std::move(r))));
 164
 165   VERIFY( std::ranges::end(c) == &r.l );
 166   static_assert(!noexcept(std::ranges::end(c)));
 167
 168   VERIFY( std::ranges::end(std::move(c)) == &r.l );
 169   static_assert(!noexcept(std::ranges::end(std::move(c))));
 170 }
 171
 172 int
 173 main()
 174 {
 175   test01();
 176   test02();
 177   test03();
 178   test04();
 179 }