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//===----------------------------------------------------------------------===//
//
// 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
// UNSUPPORTED: libcpp-no-concepts
// UNSUPPORTED: gcc-10
// template<common_with<I> I2>
// friend constexpr iter_difference_t<I2> operator-(
// const counted_iterator& x, const counted_iterator<I2>& y);
#include <iterator>
#include "test_macros.h"
#include "test_iterators.h"
// This iterator is common_with forward_iterator but NOT comparable with it.
template <class It>
class CommonWithForwardIter
{
It it_;
public:
typedef std::input_iterator_tag iterator_category;
typedef typename std::iterator_traits<It>::value_type value_type;
typedef typename std::iterator_traits<It>::difference_type difference_type;
typedef It pointer;
typedef typename std::iterator_traits<It>::reference reference;
constexpr It base() const {return it_;}
CommonWithForwardIter() = default;
explicit constexpr CommonWithForwardIter(It it) : it_(it) {}
constexpr CommonWithForwardIter(const forward_iterator<It>& it) : it_(it.base()) {}
constexpr reference operator*() const {return *it_;}
constexpr CommonWithForwardIter& operator++() {++it_; return *this;}
constexpr CommonWithForwardIter operator++(int)
{CommonWithForwardIter tmp(*this); ++(*this); return tmp;}
};
constexpr bool test() {
int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
{
std::counted_iterator iter1(random_access_iterator<int*>{buffer}, 8);
std::counted_iterator iter2(random_access_iterator<int*>{buffer + 4}, 4);
assert(iter1 - iter2 == -4);
assert(iter2 - iter1 == 4);
assert(iter1.count() == 8);
assert(iter2.count() == 4);
ASSERT_SAME_TYPE(decltype(iter1 - iter2), std::iter_difference_t<int*>);
}
{
const std::counted_iterator iter1(random_access_iterator<int*>{buffer}, 8);
const std::counted_iterator iter2(random_access_iterator<int*>{buffer + 4}, 4);
assert(iter1 - iter2 == -4);
assert(iter2 - iter1 == 4);
assert(iter1.count() == 8);
assert(iter2.count() == 4);
ASSERT_SAME_TYPE(decltype(iter1 - iter2), std::iter_difference_t<int*>);
}
{
std::counted_iterator iter1(contiguous_iterator<int*>{buffer}, 8);
std::counted_iterator iter2(contiguous_iterator<int*>{buffer + 2}, 6);
assert(iter1 - iter2 == -2);
assert(iter2 - iter1 == 2);
assert(iter1.count() == 8);
assert(iter2.count() == 6);
ASSERT_SAME_TYPE(decltype(iter1 - iter2), std::iter_difference_t<int*>);
}
{
const std::counted_iterator iter1(contiguous_iterator<int*>{buffer}, 8);
const std::counted_iterator iter2(contiguous_iterator<int*>{buffer + 2}, 6);
assert(iter1 - iter2 == -2);
assert(iter2 - iter1 == 2);
assert(iter1.count() == 8);
assert(iter2.count() == 6);
ASSERT_SAME_TYPE(decltype(iter1 - iter2), std::iter_difference_t<int*>);
}
// The minus operator works even if Iter is not a random_access_iterator because
// counted_iterator is able to implement it by subtracting the counts rather than
// the underlying iterators.
{
std::counted_iterator iter1(CommonWithForwardIter<int*>{buffer}, 8);
std::counted_iterator iter2(forward_iterator<int*>{buffer + 2}, 6);
assert(iter1 - iter2 == -2);
assert(iter2 - iter1 == 2);
assert(iter1.count() == 8);
assert(iter2.count() == 6);
ASSERT_SAME_TYPE(decltype(iter1 - iter2), std::iter_difference_t<int*>);
}
{
const std::counted_iterator iter1(CommonWithForwardIter<int*>{buffer}, 8);
const std::counted_iterator iter2(forward_iterator<int*>{buffer + 2}, 6);
assert(iter1 - iter2 == -2);
assert(iter2 - iter1 == 2);
assert(iter1.count() == 8);
assert(iter2.count() == 6);
ASSERT_SAME_TYPE(decltype(iter1 - iter2), std::iter_difference_t<int*>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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