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 // Make sure we catch forced conversions to the difference_type if they happen. 23 // ADDITIONAL_COMPILER_FLAGS: -Wsign-conversion 24 25 #include <iterator> 26 #include <cassert> 27 #include <cstddef> 28 #include <type_traits> 29 30 #include "test_macros.h" 31 #include "test_iterators.h" 32 33 template <class Distance, class It> 34 TEST_CONSTEXPR_CXX17 35 void check_advance(It it, Distance n, It result) 36 { 37 static_assert(std::is_same<decltype(std::advance(it, n)), void>::value, ""); 38 std::advance(it, n); 39 assert(it == result); 40 } 41 42 TEST_CONSTEXPR_CXX17 bool tests() 43 { 44 const char* s = "1234567890"; 45 typedef std::iterator_traits<const char*>::difference_type Distance; 46 check_advance<Distance>(input_iterator<const char*>(s), 10, input_iterator<const char*>(s+10)); 47 check_advance<Distance>(forward_iterator<const char*>(s), 10, forward_iterator<const char*>(s+10)); 48 check_advance<Distance>(bidirectional_iterator<const char*>(s+5), 5, bidirectional_iterator<const char*>(s+10)); 49 check_advance<Distance>(bidirectional_iterator<const char*>(s+5), -5, bidirectional_iterator<const char*>(s)); 50 check_advance<Distance>(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10)); 51 check_advance<Distance>(random_access_iterator<const char*>(s+5), -5, random_access_iterator<const char*>(s)); 52 check_advance<Distance>(s+5, 5, s+10); 53 check_advance<Distance>(s+5, -5, s); 54 55 // Also check with other distance types 56 check_advance<std::size_t>(input_iterator<const char*>(s), 10u, input_iterator<const char*>(s+10)); 57 check_advance<std::size_t>(forward_iterator<const char*>(s), 10u, forward_iterator<const char*>(s+10)); 58 check_advance<std::size_t>(bidirectional_iterator<const char*>(s), 10u, bidirectional_iterator<const char*>(s+10)); 59 check_advance<std::size_t>(random_access_iterator<const char*>(s), 10u, random_access_iterator<const char*>(s+10)); 60 61 return true; 62 } 63 64 int main(int, char**) 65 { 66 tests(); 67 #if TEST_STD_VER >= 17 68 static_assert(tests(), ""); 69 #endif 70 return 0; 71 } 72