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 // <string> 10 11 // const_reference at(size_type pos) const; // constexpr since C++20 12 // reference at(size_type pos); // constexpr since C++20 13 14 #include <string> 15 #include <stdexcept> 16 #include <cassert> 17 18 #include "min_allocator.h" 19 20 #include "test_macros.h" 21 22 template <class S> 23 TEST_CONSTEXPR_CXX20 void 24 test(S s, typename S::size_type pos) 25 { 26 const S& cs = s; 27 if (pos < s.size()) 28 { 29 assert(s.at(pos) == s[pos]); 30 assert(cs.at(pos) == cs[pos]); 31 } 32 #ifndef TEST_HAS_NO_EXCEPTIONS 33 else if (!TEST_IS_CONSTANT_EVALUATED) 34 { 35 try 36 { 37 TEST_IGNORE_NODISCARD s.at(pos); 38 assert(false); 39 } 40 catch (std::out_of_range&) 41 { 42 assert(pos >= s.size()); 43 } 44 try 45 { 46 TEST_IGNORE_NODISCARD cs.at(pos); 47 assert(false); 48 } 49 catch (std::out_of_range&) 50 { 51 assert(pos >= s.size()); 52 } 53 } 54 #endif 55 } 56 57 TEST_CONSTEXPR_CXX20 bool test() { 58 { 59 typedef std::string S; 60 test(S(), 0); 61 test(S("123"), 0); 62 test(S("123"), 1); 63 test(S("123"), 2); 64 test(S("123"), 3); 65 } 66 #if TEST_STD_VER >= 11 67 { 68 typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S; 69 test(S(), 0); 70 test(S("123"), 0); 71 test(S("123"), 1); 72 test(S("123"), 2); 73 test(S("123"), 3); 74 } 75 #endif 76 77 return true; 78 } 79 80 int main(int, char**) 81 { 82 test(); 83 #if TEST_STD_VER > 17 84 static_assert(test()); 85 #endif 86 87 return 0; 88 } 89