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