72 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// template<class I, sentinel_for<I> S>12// requires (!sized_sentinel_for<S, I>)13// constexpr iter_difference_t<I> ranges::distance(I first, S last);14//15// template<class I, sized_sentinel_for<decay_t<I>> S>16// constexpr iter_difference_t<I> ranges::distance(const I& first, S last);17 18#include <iterator>19#include <cassert>20 21#include "test_iterators.h"22 23template<class It>24struct EvilSentinel {25 It p_;26 friend constexpr bool operator==(EvilSentinel s, It p) { return s.p_ == p; }27 friend constexpr auto operator-(EvilSentinel s, It p) { return s.p_ - p; }28 friend constexpr auto operator-(It p, EvilSentinel s) { return p - s.p_; }29 friend constexpr void operator-(EvilSentinel s, int(&)[3]) = delete;30 friend constexpr void operator-(EvilSentinel s, int(&&)[3]) = delete;31 friend constexpr void operator-(EvilSentinel s, const int(&)[3]) = delete;32 friend constexpr void operator-(EvilSentinel s, const int(&&)[3]) = delete;33};34static_assert( std::sized_sentinel_for<EvilSentinel<int*>, int*>);35static_assert(!std::sized_sentinel_for<EvilSentinel<int*>, const int*>);36static_assert( std::sized_sentinel_for<EvilSentinel<const int*>, int*>);37static_assert( std::sized_sentinel_for<EvilSentinel<const int*>, const int*>);38 39constexpr bool test() {40 {41 int a[] = {1, 2, 3};42 assert(std::ranges::distance(a, a + 3) == 3);43 assert(std::ranges::distance(a, a) == 0);44 assert(std::ranges::distance(a + 3, a) == -3);45 }46 {47 int a[] = {1, 2, 3};48 assert(std::ranges::distance(a, EvilSentinel<int*>{a+3}) == 3);49 assert(std::ranges::distance(a, EvilSentinel<int*>{a}) == 0);50 assert(std::ranges::distance(a+3, EvilSentinel<int*>{a}) == -3);51 assert(std::ranges::distance(std::move(a), EvilSentinel<int*>{a+3}) == 3);52 }53 {54 const int a[] = {1, 2, 3};55 assert(std::ranges::distance(a, EvilSentinel<const int*>{a+3}) == 3);56 assert(std::ranges::distance(a, EvilSentinel<const int*>{a}) == 0);57 assert(std::ranges::distance(a+3, EvilSentinel<const int*>{a}) == -3);58 assert(std::ranges::distance(std::move(a), EvilSentinel<const int*>{a+3}) == 3);59 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const int(&)[3], EvilSentinel<int*>>);60 static_assert(!std::is_invocable_v<decltype(std::ranges::distance), const int(&&)[3], EvilSentinel<int*>>);61 }62 63 return true;64}65 66int main(int, char**) {67 test();68 static_assert(test());69 70 return 0;71}72