75 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// <string>10 11// const_reference operator[](size_type pos) const; // constexpr since C++2012// reference operator[](size_type pos); // constexpr since C++2013 14#include <string>15#include <cassert>16 17#include "test_macros.h"18#include "min_allocator.h"19 20template <class S>21TEST_CONSTEXPR_CXX20 void test_string() {22 S s("0123456789");23 const S& cs = s;24 ASSERT_SAME_TYPE(decltype(s[0]), typename S::reference);25 ASSERT_SAME_TYPE(decltype(cs[0]), typename S::const_reference);26 LIBCPP_ASSERT_NOEXCEPT(s[0]);27 LIBCPP_ASSERT_NOEXCEPT(cs[0]);28 for (typename S::size_type i = 0; i < cs.size(); ++i) {29 assert(s[i] == static_cast<char>('0' + i));30 assert(cs[i] == s[i]);31 }32 assert(cs[cs.size()] == '\0');33 const S s2 = S();34 assert(s2[0] == '\0');35}36 37// Same, but for the string that doesn't fit into SSO.38template <class S>39TEST_CONSTEXPR_CXX20 void test_string_long() {40 S s("0123456789012345678901234567890123456789");41 const S& cs = s;42 ASSERT_SAME_TYPE(decltype(s[0]), typename S::reference);43 ASSERT_SAME_TYPE(decltype(cs[0]), typename S::const_reference);44 LIBCPP_ASSERT_NOEXCEPT(s[0]);45 LIBCPP_ASSERT_NOEXCEPT(cs[0]);46 for (typename S::size_type i = 0; i < cs.size(); ++i) {47 assert(s[i] == static_cast<char>('0' + (i % 10)));48 assert(cs[i] == s[i]);49 }50 assert(s[33] == static_cast<char>('0' + (33 % 10)));51 assert(cs[34] == s[34]);52 assert(cs[cs.size()] == '\0');53 const S s2 = S();54 assert(s2[0] == '\0');55}56 57TEST_CONSTEXPR_CXX20 bool test() {58 test_string<std::string>();59#if TEST_STD_VER >= 1160 test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>();61 test_string_long<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>();62#endif63 64 return true;65}66 67int main(int, char**) {68 test();69#if TEST_STD_VER > 1770 static_assert(test());71#endif72 73 return 0;74}75