libstdc++-v3/testsuite/std/ranges/access/begin.cc

   1 // Copyright (C) 2019 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> // N.B. should be <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   static_assert(same_as<decltype(std::ranges::begin(a)), decltype(a + 0)>);
  33   static_assert(noexcept(std::ranges::begin(a)));
  34   VERIFY( std::ranges::begin(a) == (a + 0) );
  35
  36   constexpr long b[2] = { };
  37   static_assert( std::ranges::begin(b) == (b + 0) );
  38
  39   struct Incomplete;
  40   using A = Incomplete[]; // unbounded array of incomplete type
  41   extern A& f();
  42   static_assert( same_as<decltype(std::ranges::begin(f())), Incomplete*> );
  43 }
  44
  45 void
  46 test02()
  47 {
  48   using __gnu_test::test_range;
  49   using __gnu_test::random_access_iterator_wrapper;
  50   using __gnu_test::input_iterator_wrapper;
  51   using __gnu_test::output_iterator_wrapper;
  52
  53   int a[] = { 0, 1 };
  54
  55   test_range<int, random_access_iterator_wrapper> r(a);
  56   static_assert(same_as<decltype(std::ranges::begin(r)), decltype(r.begin())>);
  57   VERIFY( std::ranges::begin(r) == r.begin() );
  58
  59   test_range<int, input_iterator_wrapper> i(a);
  60   static_assert(same_as<decltype(std::ranges::begin(i)), decltype(i.begin())>);
  61   VERIFY( std::ranges::begin(i) == i.begin() );
  62
  63   test_range<int, output_iterator_wrapper> o(a);
  64   static_assert(same_as<decltype(std::ranges::begin(o)), decltype(o.begin())>);
  65   *std::ranges::begin(o) = 99;
  66   VERIFY( a[0] == 99 );
  67 }
  68
  69 struct R
  70 {
  71   int a[4] = { 0, 1, 2, 3 };
  72
  73   friend int* begin(R& r) { return r.a + 0; }
  74   friend int* begin(R&& r) { return r.a + 1; }
  75   friend const int* begin(const R& r) noexcept { return r.a + 2; }
  76   friend const int* begin(const R&& r) noexcept { return r.a + 3; }
  77 };
  78
  79 void
  80 test03()
  81 {
  82   R r;
  83   const R& c = r;
  84
  85   static_assert(same_as<decltype(std::ranges::begin(r)), decltype(begin(r))>);
  86   static_assert(!noexcept(std::ranges::begin(r)));
  87   VERIFY( std::ranges::begin(r) == begin(r) );
  88
  89   static_assert(same_as<decltype(std::ranges::begin(std::move(r))),
  90                 decltype(begin(std::move(r)))>);
  91   static_assert(!noexcept(std::ranges::begin(std::move(r))));
  92   VERIFY( std::ranges::begin(std::move(r)) == begin(std::move(r)) );
  93
  94
  95   static_assert(same_as<decltype(std::ranges::begin(c)), decltype(begin(c))>);
  96   static_assert(noexcept(std::ranges::begin(c)));
  97   VERIFY( std::ranges::begin(c) == begin(c) );
  98
  99   static_assert(same_as<decltype(std::ranges::begin(std::move(c))),
 100                 decltype(begin(std::move(c)))>);
 101   static_assert(noexcept(std::ranges::begin(std::move(c))));
 102   VERIFY( std::ranges::begin(std::move(c)) == begin(std::move(c)) );
 103 }
 104
 105 struct RR
 106 {
 107   short s = 0;
 108   long l = 0;
 109   int a[4] = { 0, 1, 2, 3 };
 110
 111   short* begin() noexcept { return &s; }
 112   const long* begin() const { return &l; }
 113
 114   friend int* begin(RR& r) { return r.a + 0; }
 115   friend int* begin(RR&& r) { return r.a + 1; }
 116   friend const int* begin(const RR& r) { return r.a + 2; }
 117   friend const int* begin(const RR&& r) noexcept { return r.a + 3; }
 118 };
 119
 120 void
 121 test04()
 122 {
 123   RR r;
 124   const RR& c = r;
 125   VERIFY( std::ranges::begin(r) == &r.s );
 126   static_assert(noexcept(std::ranges::begin(r)));
 127
 128   VERIFY( std::ranges::begin(std::move(r)) == r.a + 1 );
 129   static_assert(!noexcept(std::ranges::begin(std::move(r))));
 130
 131   VERIFY( std::ranges::begin(c) == &r.l );
 132   static_assert(!noexcept(std::ranges::begin(c)));
 133
 134   VERIFY( std::ranges::begin(std::move(c)) == r.a + 3 );
 135   static_assert(noexcept(std::ranges::begin(std::move(c))));
 136 }
 137
 138 int
 139 main()
 140 {
 141   test01();
 142   test02();
 143   test03();
 144   test04();
 145 }