third_party/llvm-project/libcxx/test/std/iterators/predef.iterators/counted.iterator/ctor.iter.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03, c++11, c++14, c++17

// constexpr counted_iterator() requires default_initializable<I> = default;
// constexpr counted_iterator(I x, iter_difference_t<I> n);
// template<class I2>
//   requires convertible_to<const I2&, I>
//     constexpr counted_iterator(const counted_iterator<I2>& x);

#include <iterator>

#include "test_macros.h"
#include "test_iterators.h"

struct InputOrOutputArchetype {
  using difference_type = int;

  int *ptr;

  constexpr int operator*() { return *ptr; }
  constexpr void operator++(int) { ++ptr; }
  constexpr InputOrOutputArchetype& operator++() { ++ptr; return *this; }
};

constexpr bool test() {
  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};

  {
    std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
    assert(base(iter.base()) == buffer);
    assert(iter.count() == 8);
  }

  {
    std::counted_iterator iter(forward_iterator<int*>{buffer}, 8);
    assert(iter.base() == forward_iterator<int*>{buffer});
    assert(iter.count() == 8);
  }

  {
    std::counted_iterator iter(contiguous_iterator<int*>{buffer}, 8);
    assert(iter.base() == contiguous_iterator<int*>{buffer});
    assert(iter.count() == 8);
  }

  {
    std::counted_iterator iter(InputOrOutputArchetype{buffer}, 8);
    assert(iter.base().ptr == buffer);
    assert(iter.count() == 8);
  }

  return true;
}

int main(int, char**) {
  test();
  static_assert(test());

  return 0;
}