95 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// <iterator>10 11// All of these became constexpr in C++1712//13// template <InputIterator Iter, class Distance>14// constexpr void advance(Iter& i, Distance n);15//16// template <BidirectionalIterator Iter, class Distance>17// constexpr void advance(Iter& i, Distance n);18//19// template <RandomAccessIterator Iter, class Distance>20// constexpr void advance(Iter& i, Distance n);21 22 23// TODO: test_iterators.h includes <ranges>, and <ranges> includes <chrono> and <atomic>.24// Lots of implementation headers under <__chrono/> and <atomic> has signed to unsigned conversion,25// which will trigger the -Wsign-conversion warning.26// Once those headers are fixed, enable the -Wsign-conversion for this test by removing27// <TODO:Remove brackets> below28 29// Make sure we catch forced conversions to the difference_type if they happen.30// ADDITIONAL_COMPILE_FLAGS<TODO:Remove brackets>(gcc-style-warnings): -Wsign-conversion31 32#include <iterator>33#include <cassert>34#include <cstddef>35#include <type_traits>36 37#include "test_macros.h"38#include "test_iterators.h"39 40template <class Distance, class It>41TEST_CONSTEXPR_CXX1742void check_advance(It it, Distance n, It result)43{44 static_assert(std::is_same<decltype(std::advance(it, n)), void>::value, "");45 std::advance(it, n);46 assert(it == result);47}48 49TEST_CONSTEXPR_CXX17 bool tests()50{51 const char* s = "1234567890";52 53 // Check with iterator_traits::difference_type54 {55 typedef std::iterator_traits<const char*>::difference_type Distance;56 check_advance<Distance>(cpp17_input_iterator<const char*>(s), 10, cpp17_input_iterator<const char*>(s+10));57 check_advance<Distance>(forward_iterator<const char*>(s), 10, forward_iterator<const char*>(s+10));58 check_advance<Distance>(bidirectional_iterator<const char*>(s+5), 5, bidirectional_iterator<const char*>(s+10));59 check_advance<Distance>(bidirectional_iterator<const char*>(s+5), -5, bidirectional_iterator<const char*>(s));60 check_advance<Distance>(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));61 check_advance<Distance>(random_access_iterator<const char*>(s+5), -5, random_access_iterator<const char*>(s));62 check_advance<Distance>(s+5, 5, s+10);63 check_advance<Distance>(s+5, -5, s);64 }65 66 // Also check with other distance types67 {68 typedef int Distance;69 check_advance<Distance>(cpp17_input_iterator<const char*>(s), 10, cpp17_input_iterator<const char*>(s+10));70 check_advance<Distance>(forward_iterator<const char*>(s), 10, forward_iterator<const char*>(s+10));71 check_advance<Distance>(bidirectional_iterator<const char*>(s), 10, bidirectional_iterator<const char*>(s+10));72 check_advance<Distance>(random_access_iterator<const char*>(s), 10, random_access_iterator<const char*>(s+10));73 }74 75 // Check with unsigned distance types to catch signedness-change issues76 {77 typedef std::size_t Distance;78 check_advance<Distance>(cpp17_input_iterator<const char*>(s), 10u, cpp17_input_iterator<const char*>(s+10));79 check_advance<Distance>(forward_iterator<const char*>(s), 10u, forward_iterator<const char*>(s+10));80 check_advance<Distance>(bidirectional_iterator<const char*>(s), 10u, bidirectional_iterator<const char*>(s+10));81 check_advance<Distance>(random_access_iterator<const char*>(s), 10u, random_access_iterator<const char*>(s+10));82 }83 84 return true;85}86 87int main(int, char**)88{89 tests();90#if TEST_STD_VER >= 1791 static_assert(tests(), "");92#endif93 return 0;94}95