76 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// requires bidirectional_iterator<I>;13// constexpr counted_iterator operator--(int)14// requires bidirectional_iterator<I>;15 16#include <iterator>17 18#include "test_macros.h"19#include "test_iterators.h"20 21template<class Iter>22concept MinusEnabled = requires(Iter& iter) {23 iter--;24 --iter;25};26 27constexpr bool test() {28 int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};29 30 {31 using Counted = std::counted_iterator<bidirectional_iterator<int*>>;32 std::counted_iterator iter(bidirectional_iterator<int*>{buffer + 2}, 6);33 assert(iter-- == Counted(bidirectional_iterator<int*>{buffer + 2}, 6));34 assert(--iter == Counted(bidirectional_iterator<int*>{buffer}, 8));35 assert(iter.count() == 8);36 37 ASSERT_SAME_TYPE(decltype(iter--), Counted);38 ASSERT_SAME_TYPE(decltype(--iter), Counted&);39 }40 {41 using Counted = std::counted_iterator<random_access_iterator<int*>>;42 Counted iter(random_access_iterator<int*>{buffer + 2}, 6);43 assert(iter-- == Counted(random_access_iterator<int*>{buffer + 2}, 6));44 assert(--iter == Counted(random_access_iterator<int*>{buffer}, 8));45 assert(iter.count() == 8);46 47 ASSERT_SAME_TYPE(decltype(iter--), Counted);48 ASSERT_SAME_TYPE(decltype(--iter), Counted&);49 }50 {51 using Counted = std::counted_iterator<contiguous_iterator<int*>>;52 std::counted_iterator iter(contiguous_iterator<int*>{buffer + 2}, 6);53 assert(iter-- == Counted(contiguous_iterator<int*>{buffer + 2}, 6));54 assert(--iter == Counted(contiguous_iterator<int*>{buffer}, 8));55 assert(iter.count() == 8);56 57 ASSERT_SAME_TYPE(decltype(iter--), Counted);58 ASSERT_SAME_TYPE(decltype(--iter), Counted&);59 }60 61 {62 static_assert( MinusEnabled<std::counted_iterator<contiguous_iterator<int*>>>);63 static_assert(!MinusEnabled<const std::counted_iterator<contiguous_iterator<int*>>>);64 static_assert(!MinusEnabled<std::counted_iterator<forward_iterator<int*>>>);65 }66 67 return true;68}69 70int main(int, char**) {71 test();72 static_assert(test());73 74 return 0;75}76