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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
// constexpr counted_iterator& operator++();
// constexpr decltype(auto) operator++(int);
// constexpr counted_iterator operator++(int)
// requires forward_iterator<I>;
#include <iterator>
#include "test_macros.h"
#include "test_iterators.h"
#ifndef TEST_HAS_NO_EXCEPTIONS
template <class It>
class ThrowsOnInc
{
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_;}
ThrowsOnInc() = default;
explicit constexpr ThrowsOnInc(It it) : it_(it) {}
constexpr reference operator*() const {return *it_;}
constexpr ThrowsOnInc& operator++() {throw 42;}
constexpr ThrowsOnInc operator++(int) {throw 42;}
};
#endif // TEST_HAS_NO_EXCEPTIONS
struct InputOrOutputArchetype {
using difference_type = int;
int *ptr;
constexpr int operator*() const { return *ptr; }
constexpr void operator++(int) { ++ptr; }
constexpr InputOrOutputArchetype& operator++() { ++ptr; return *this; }
};
template<class Iter>
concept PlusEnabled = requires(Iter& iter) {
iter++;
++iter;
};
constexpr bool test() {
int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
{
using Counted = std::counted_iterator<InputOrOutputArchetype>;
std::counted_iterator iter(InputOrOutputArchetype{buffer}, 8);
iter++;
assert((++iter).base().ptr == buffer + 2);
ASSERT_SAME_TYPE(decltype(iter++), void);
ASSERT_SAME_TYPE(decltype(++iter), Counted&);
}
{
using Counted = std::counted_iterator<cpp20_input_iterator<int*>>;
std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);
iter++;
assert(++iter == Counted(cpp20_input_iterator<int*>{buffer + 2}, 6));
ASSERT_SAME_TYPE(decltype(iter++), void);
ASSERT_SAME_TYPE(decltype(++iter), Counted&);
}
{
using Counted = std::counted_iterator<forward_iterator<int*>>;
std::counted_iterator iter(forward_iterator<int*>{buffer}, 8);
assert(iter++ == Counted(forward_iterator<int*>{buffer}, 8));
assert(++iter == Counted(forward_iterator<int*>{buffer + 2}, 6));
ASSERT_SAME_TYPE(decltype(iter++), Counted);
ASSERT_SAME_TYPE(decltype(++iter), Counted&);
}
{
using Counted = std::counted_iterator<random_access_iterator<int*>>;
std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);
assert(iter++ == Counted(random_access_iterator<int*>{buffer}, 8));
assert(++iter == Counted(random_access_iterator<int*>{buffer + 2}, 6));
ASSERT_SAME_TYPE(decltype(iter++), Counted);
ASSERT_SAME_TYPE(decltype(++iter), Counted&);
}
{
static_assert( PlusEnabled< std::counted_iterator<random_access_iterator<int*>>>);
static_assert(!PlusEnabled<const std::counted_iterator<random_access_iterator<int*>>>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
#ifndef TEST_HAS_NO_EXCEPTIONS
int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
{
using Counted = std::counted_iterator<ThrowsOnInc<int*>>;
std::counted_iterator iter(ThrowsOnInc<int*>{buffer}, 8);
try {
(void)iter++;
assert(false);
} catch (int x) {
assert(x == 42);
assert(iter.count() == 8);
}
ASSERT_SAME_TYPE(decltype(iter++), ThrowsOnInc<int*>);
ASSERT_SAME_TYPE(decltype(++iter), Counted&);
}
#endif // TEST_HAS_NO_EXCEPTIONS
return 0;
}
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