libcxx/test/std/iterators/predef.iterators/counted.iterator/deref.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17
  10
  11 // constexpr decltype(auto) operator*();
  12 // constexpr decltype(auto) operator*() const
  13 //   requires dereferenceable<const I>;
  14
  15 #include <iterator>
  16
  17 #include "test_macros.h"
  18 #include "test_iterators.h"
  19
  20 struct InputOrOutputArchetype {
  21   using difference_type = int;
  22
  23   int *ptr;
  24
  25   constexpr int operator*() const { return *ptr; }
  26   constexpr void operator++(int) { ++ptr; }
  27   constexpr InputOrOutputArchetype& operator++() { ++ptr; return *this; }
  28 };
  29
  30 struct NonConstDeref {
  31   using difference_type = int;
  32
  33   int *ptr;
  34
  35   constexpr int operator*() { return *ptr; }
  36   constexpr void operator++(int) { ++ptr; }
  37   constexpr NonConstDeref& operator++() { ++ptr; return *this; }
  38 };
  39
  40 template<class T>
  41 concept IsDereferenceable = requires(T& i) {
  42   *i;
  43 };
  44
  45 constexpr bool test() {
  46   int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
  47
  48   {
  49     static_assert( IsDereferenceable<std::counted_iterator<InputOrOutputArchetype>>);
  50     static_assert( IsDereferenceable<const std::counted_iterator<InputOrOutputArchetype>>);
  51     static_assert( IsDereferenceable<std::counted_iterator<NonConstDeref>>);
  52     static_assert(!IsDereferenceable<const std::counted_iterator<NonConstDeref>>);
  53   }
  54
  55   {
  56     std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
  57     for (int i = 1; i < 9; ++i, ++iter)
  58       assert(*iter == i);
  59   }
  60
  61   {
  62     std::counted_iterator iter(forward_iterator<int*>{buffer}, 8);
  63     for (int i = 1; i < 9; ++i, ++iter)
  64       assert(*iter == i);
  65   }
  66
  67   {
  68     std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
  69     for (int i = 1; i < 9; ++i, ++iter)
  70       assert(*iter == i);
  71   }
  72
  73   {
  74     std::counted_iterator iter(InputOrOutputArchetype{buffer}, 8);
  75     for (int i = 1; i < 9; ++i, ++iter)
  76       assert(*iter == i);
  77   }
  78
  79   {
  80     const std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
  81     assert(*iter == 1);
  82   }
  83
  84   {
  85     const std::counted_iterator iter(forward_iterator<int*>{buffer + 1}, 7);
  86     assert(*iter == 2);
  87   }
  88
  89   {
  90     const std::counted_iterator iter(contiguous_iterator<int*>{buffer + 2}, 6);
  91     assert(*iter == 3);
  92   }
  93
  94   {
  95     const std::counted_iterator iter(InputOrOutputArchetype{buffer + 2}, 6);
  96     assert(*iter == 3);
  97   }
  98
  99   return true;
 100 }
 101
 102 int main(int, char**) {
 103   test();
 104   static_assert(test());
 105
 106   return 0;
 107 }