124 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 iterator& operator+=(difference_type n)12// requires random_access_range<Base>;13//14// constexpr iterator& operator-=(difference_type n)15// requires random_access_range<Base>;16//17// friend constexpr iterator operator+(const iterator& x, difference_type y)18// requires random_access_range<Base>;19//20// friend constexpr iterator operator+(difference_type x, const iterator& y)21// requires random_access_range<Base>;22//23// friend constexpr iterator operator-(const iterator& x, difference_type y)24// requires random_access_range<Base>;25//26// friend constexpr difference_type operator-(const iterator& x, const iterator& y)27// requires sized_sentinel_for<iterator_t<Base>, iterator_t<Base>>;28 29#include <ranges>30 31#include <tuple>32 33#include "test_iterators.h"34 35template <class T, class U>36concept CanPlus = requires(T t, U u) { t + u; };37 38template <class T, class U>39concept CanPlusEqual = requires(T t, U u) { t += u; };40 41template <class T, class U>42concept CanMinus = requires(T t, U u) { t - u; };43 44template <class T, class U>45concept CanMinusEqual = requires(T t, U u) { t -= u; };46 47template <class BaseRange>48using ElemIter = std::ranges::iterator_t<std::ranges::elements_view<BaseRange, 0>>;49 50using RandomAccessRange = std::ranges::subrange<std::tuple<int>*>;51static_assert(std::ranges::random_access_range<RandomAccessRange>);52static_assert(std::sized_sentinel_for<std::ranges::iterator_t<RandomAccessRange>, //53 std::ranges::iterator_t<RandomAccessRange>>);54 55static_assert(CanPlus<ElemIter<RandomAccessRange>, int>);56static_assert(CanPlus<int, ElemIter<RandomAccessRange>>);57static_assert(CanPlusEqual<ElemIter<RandomAccessRange>, int>);58static_assert(CanMinus<ElemIter<RandomAccessRange>, int>);59static_assert(CanMinus<ElemIter<RandomAccessRange>, ElemIter<RandomAccessRange>>);60static_assert(CanMinusEqual<ElemIter<RandomAccessRange>, int>);61 62using BidiRange = std::ranges::subrange<bidirectional_iterator<std::tuple<int>*>>;63static_assert(!std::ranges::random_access_range<BidiRange>);64static_assert(!std::sized_sentinel_for<std::ranges::iterator_t<BidiRange>, //65 std::ranges::iterator_t<BidiRange>>);66 67static_assert(!CanPlus<ElemIter<BidiRange>, int>);68static_assert(!CanPlus<int, ElemIter<BidiRange>>);69static_assert(!CanPlusEqual<ElemIter<BidiRange>, int>);70static_assert(!CanMinus<ElemIter<BidiRange>, int>);71static_assert(!CanMinus<ElemIter<BidiRange>, ElemIter<BidiRange>>);72static_assert(!CanMinusEqual<ElemIter<BidiRange>, int>);73 74constexpr bool test() {75 std::tuple<int> ts[] = {{1}, {2}, {3}, {4}};76 77 RandomAccessRange r{&ts[0], &ts[0] + 4};78 auto ev = r | std::views::elements<0>;79 {80 // operator+(x, n) operator+(n,x) and operator+=81 auto it1 = ev.begin();82 83 auto it2 = it1 + 3;84 assert(it2.base() == &ts[3]);85 86 auto it3 = 3 + it1;87 assert(it3.base() == &ts[3]);88 89 it1 += 3;90 assert(it1 == it2);91 assert(it1.base() == &ts[3]);92 }93 94 {95 // operator-(x, n) and operator-=96 auto it1 = ev.end();97 98 auto it2 = it1 - 3;99 assert(it2.base() == &ts[1]);100 101 it1 -= 3;102 assert(it1 == it2);103 assert(it1.base() == &ts[1]);104 }105 106 {107 // operator-(x, y)108 assert((ev.end() - ev.begin()) == 4);109 110 auto it1 = ev.begin() + 2;111 auto it2 = ev.end() - 1;112 assert((it1 - it2) == -1);113 }114 115 return true;116}117 118int main(int, char**) {119 test();120 static_assert(test());121 122 return 0;123}124