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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // <iterator> 10 11 // All of these became constexpr in C++17 12 // 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 removing 27 // <TODO:Remove brackets> below 28 29 // Make sure we catch forced conversions to the difference_type if they happen. 30 // ADDITIONAL_COMPILE_FLAGS<TODO:Remove brackets>: -Wsign-conversion 31 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 40 template <class Distance, class It> 41 TEST_CONSTEXPR_CXX17 42 void 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 49 TEST_CONSTEXPR_CXX17 bool tests() 50 { 51 const char* s = "1234567890"; 52 53 // Check with iterator_traits::difference_type 54 { 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 types 67 { 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 issues 76 { 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 87 int main(int, char**) 88 { 89 tests(); 90 #if TEST_STD_VER >= 17 91 static_assert(tests(), ""); 92 #endif 93 return 0; 94 } 95