138 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// constexpr counted_iterator& operator++();12// constexpr decltype(auto) operator++(int);13// constexpr counted_iterator operator++(int)14// requires forward_iterator<I>;15 16#include <iterator>17 18#include "test_macros.h"19#include "test_iterators.h"20 21#ifndef TEST_HAS_NO_EXCEPTIONS22template <class It>23class ThrowsOnInc24{25 It it_;26 27public:28 typedef std::input_iterator_tag iterator_category;29 typedef typename std::iterator_traits<It>::value_type value_type;30 typedef typename std::iterator_traits<It>::difference_type difference_type;31 typedef It pointer;32 typedef typename std::iterator_traits<It>::reference reference;33 34 constexpr It base() const {return it_;}35 36 ThrowsOnInc() = default;37 explicit constexpr ThrowsOnInc(It it) : it_(it) {}38 39 constexpr reference operator*() const {return *it_;}40 41 constexpr ThrowsOnInc& operator++() {throw 42;}42 constexpr ThrowsOnInc operator++(int) {throw 42;}43};44#endif // TEST_HAS_NO_EXCEPTIONS45 46struct InputOrOutputArchetype {47 using difference_type = int;48 49 int *ptr;50 51 constexpr int operator*() const { return *ptr; }52 constexpr void operator++(int) { ++ptr; }53 constexpr InputOrOutputArchetype& operator++() { ++ptr; return *this; }54};55 56template<class Iter>57concept PlusEnabled = requires(Iter& iter) {58 iter++;59 ++iter;60};61 62constexpr bool test() {63 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};64 65 {66 using Counted = std::counted_iterator<InputOrOutputArchetype>;67 std::counted_iterator iter(InputOrOutputArchetype{buffer}, 8);68 69 iter++;70 assert((++iter).base().ptr == buffer + 2);71 72 ASSERT_SAME_TYPE(decltype(iter++), void);73 ASSERT_SAME_TYPE(decltype(++iter), Counted&);74 }75 {76 using Counted = std::counted_iterator<cpp20_input_iterator<int*>>;77 std::counted_iterator iter(cpp20_input_iterator<int*>{buffer}, 8);78 79 iter++;80 assert(++iter == Counted(cpp20_input_iterator<int*>{buffer + 2}, 6));81 82 ASSERT_SAME_TYPE(decltype(iter++), void);83 ASSERT_SAME_TYPE(decltype(++iter), Counted&);84 }85 {86 using Counted = std::counted_iterator<forward_iterator<int*>>;87 std::counted_iterator iter(forward_iterator<int*>{buffer}, 8);88 89 assert(iter++ == Counted(forward_iterator<int*>{buffer}, 8));90 assert(++iter == Counted(forward_iterator<int*>{buffer + 2}, 6));91 92 ASSERT_SAME_TYPE(decltype(iter++), Counted);93 ASSERT_SAME_TYPE(decltype(++iter), Counted&);94 }95 {96 using Counted = std::counted_iterator<random_access_iterator<int*>>;97 std::counted_iterator iter(random_access_iterator<int*>{buffer}, 8);98 99 assert(iter++ == Counted(random_access_iterator<int*>{buffer}, 8));100 assert(++iter == Counted(random_access_iterator<int*>{buffer + 2}, 6));101 102 ASSERT_SAME_TYPE(decltype(iter++), Counted);103 ASSERT_SAME_TYPE(decltype(++iter), Counted&);104 }105 106 {107 static_assert( PlusEnabled< std::counted_iterator<random_access_iterator<int*>>>);108 static_assert(!PlusEnabled<const std::counted_iterator<random_access_iterator<int*>>>);109 }110 111 return true;112}113 114int main(int, char**) {115 test();116 static_assert(test());117 118#ifndef TEST_HAS_NO_EXCEPTIONS119 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};120 {121 using Counted = std::counted_iterator<ThrowsOnInc<int*>>;122 std::counted_iterator iter(ThrowsOnInc<int*>{buffer}, 8);123 try {124 (void)iter++;125 assert(false);126 } catch (int x) {127 assert(x == 42);128 assert(iter.count() == 8);129 }130 131 ASSERT_SAME_TYPE(decltype(iter++), ThrowsOnInc<int*>);132 ASSERT_SAME_TYPE(decltype(++iter), Counted&);133 }134#endif // TEST_HAS_NO_EXCEPTIONS135 136 return 0;137}138