libstdc++-v3/testsuite/std/ranges/adaptors/all.cc

   1 // Copyright (C) 2020-2022 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 <algorithm>
  22 #include <ranges>
  23 #include <testsuite_hooks.h>
  24 #include <testsuite_iterators.h>
  25
  26 namespace ranges = std::ranges;
  27 namespace views = std::ranges::views;
  28
  29 void
  30 test01()
  31 {
  32   int x[] = {1,2,3,4,5};
  33   auto v = views::all(x);
  34
  35   static_assert(ranges::view<decltype(v)>);
  36   static_assert(ranges::random_access_range<decltype(v)>);
  37
  38   VERIFY( ranges::size(v) == 5 );
  39   VERIFY( ranges::size(x | views::all) == 5 );
  40   VERIFY( ranges::size(v | views::all | views::all) == 5 );
  41   VERIFY( ranges::size(v | (views::all | views::all)) == 5 );
  42
  43   ranges::reverse(v);
  44   VERIFY( ranges::equal(v, (int[]){5,4,3,2,1}) );
  45 }
  46
  47 void
  48 test02()
  49 {
  50   int x[5] = { 0 };
  51   int k = 0;
  52   for (auto&& i : ranges::ref_view{x})
  53     i += ++k;
  54   VERIFY( ranges::equal(x, (int[]){1,2,3,4,5}) );
  55 }
  56
  57 constexpr bool
  58 test03()
  59 {
  60   std::array ints{0,1,2,3,4,5};
  61   auto even = [] (int i) { return i%2==0; };
  62   auto odd = [] (int i) { return i%2==1; };
  63   auto square = [] (int i) { return i*i; };
  64   int sum = 0;
  65   for (auto v : (ints
  66                  | (views::all
  67                     | (views::filter(even)
  68                     | (views::filter(odd) | views::all)))
  69                  | views::transform(square)))
  70     sum += v;
  71   return sum == 0;
  72 }
  73
  74 constexpr bool
  75 test04()
  76 {
  77   auto odd = [] (int i) { return i%2==1; };
  78   auto square = [] (int i) { return i*i; };
  79   auto increment = [] (int i) { return i+1; };
  80   auto small = [] (int i) { return i<30; };
  81   auto non_negative = [] (int i) { return i>=0; };
  82   auto negative = [] (int i) { return i<0; };
  83   return ranges::equal(views::iota(-5)
  84                        | views::drop_while(negative)
  85                        | views::take_while(non_negative)
  86                        | views::transform(increment)
  87                        | views::filter(odd)
  88                        | views::take(3)
  89                        | views::all
  90                        | views::transform(square),
  91                        views::iota(-5)
  92                        | views::drop_while(negative)
  93                        | views::drop(1)
  94                        | views::filter(odd)
  95                        | views::transform(square)
  96                        | views::take_while(small)
  97                        | views::take_while(small));
  98 }
  99
 100 static_assert(std::is_empty_v<decltype(views::common
 101                                        | views::join
 102                                        | views::all
 103                                        | views::common
 104                                        | views::keys
 105                                        | views::reverse)>);
 106 #if 0
 107 // Adding empty range adaptor closure objects to a pipeline used to not
 108 // increase the size of the pipeline, but now that our range adaptor closure
 109 // objects derive from a common empty base class, [[no_unique_address]] can no
 110 // longer make two empty adjacent range adaptor closure objects occupy the same
 111 // data member address.
 112 static_assert(sizeof(decltype(views::take(5) | views::drop(5)))
 113               == sizeof(decltype(views::take(5)
 114                                  | views::join
 115                                  | views::common
 116                                  | views::all
 117                                  | views::keys
 118                                  | views::drop(5)
 119                                  | views::reverse)));
 120 #endif
 121
 122 template<auto all = views::all>
 123 void
 124 test05()
 125 {
 126   // Verify SFINAE behavior.
 127   static_assert(!requires { all(); });
 128   static_assert(!requires { all(0, 0); });
 129   static_assert(!requires { all(0); });
 130   static_assert(!requires { 0 | all; });
 131 }
 132
 133 template<bool B1, bool B2>
 134 struct BorrowedRange
 135 {
 136   int* ptr = nullptr;
 137
 138   BorrowedRange(int (&arr)[3]) noexcept : ptr(arr) { }
 139
 140   int* begin() const noexcept(B1) { return ptr; }
 141   int* end() const noexcept(B2) { return ptr + 3; }
 142 };
 143
 144 template<bool B1, bool B2>
 145 const bool std::ranges::enable_borrowed_range<BorrowedRange<B1, B2>> = true;
 146
 147 void
 148 test06()
 149 {
 150   int x[] { 1, 2, 3 };
 151
 152   // Using ref_view:
 153   static_assert(noexcept(views::all(x)));
 154
 155   // Using subrange:
 156   static_assert(noexcept(views::all(BorrowedRange<true, true>(x))));
 157   static_assert(!noexcept(views::all(BorrowedRange<true, false>(x))));
 158   static_assert(!noexcept(views::all(BorrowedRange<false, true>(x))));
 159   static_assert(!noexcept(views::all(BorrowedRange<false, false>(x))));
 160 }
 161
 162 void
 163 test07()
 164 {
 165   // LWG 3481
 166   struct view_t : ranges::empty_view<int> { // move-only view
 167     view_t(const view_t&) = delete;
 168     view_t(view_t&&) = default;
 169     view_t& operator=(const view_t&) = delete;
 170     view_t& operator=(view_t&&) = default;
 171   };
 172   static_assert(std::movable<view_t> && !std::copyable<view_t>);
 173   static_assert(!ranges::viewable_range<view_t&>);
 174 }
 175
 176 int
 177 main()
 178 {
 179   test01();
 180   test02();
 181   static_assert(test03());
 182   static_assert(test04());
 183   test05();
 184   test06();
 185   test07();
 186 }