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 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20 10 11 // <string> 12 13 // constexpr basic_string substr(size_type pos = 0, size_type n = npos) &&; 14 15 #include <algorithm> 16 #include <string> 17 18 #include "constexpr_char_traits.h" 19 #include "make_string.h" 20 #include "min_allocator.h" 21 #include "test_allocator.h" 22 23 #define STR(string) MAKE_CSTRING(typename S::value_type, string) 24 25 constexpr struct should_throw_exception_t { 26 } should_throw_exception; 27 28 template <class S> 29 constexpr void test(S orig, size_t pos, ptrdiff_t n, S expected) { 30 S str = std::move(orig).substr(pos, n); 31 LIBCPP_ASSERT(orig.__invariants()); 32 LIBCPP_ASSERT(str.__invariants()); 33 assert(str == expected); 34 } 35 36 template <class S> 37 constexpr void test(S orig, size_t pos, ptrdiff_t n, should_throw_exception_t) { 38 #ifndef TEST_HAS_NO_EXCEPTIONS 39 if (!std::is_constant_evaluated()) { 40 try { 41 S str = std::move(orig).substr(pos, n); 42 assert(false); 43 } catch (const std::out_of_range&) { 44 } 45 } 46 #else 47 (void)orig; 48 (void)pos; 49 (void)n; 50 #endif 51 } 52 53 template <class S> 54 constexpr void test_string() { 55 test<S>(STR(""), 0, 0, STR("")); 56 test<S>(STR(""), 0, 1, STR("")); 57 test<S>(STR(""), 1, 0, should_throw_exception); 58 test<S>(STR(""), 1, 1, should_throw_exception); 59 test<S>(STR("short string"), 0, 1, STR("s")); 60 test<S>(STR("short string"), 5, 5, STR(" stri")); 61 test<S>(STR("short string"), 12, 5, STR("")); 62 test<S>(STR("short string"), 13, 5, should_throw_exception); 63 test<S>(STR("long long string so no SSO"), 0, 0, STR("")); 64 test<S>(STR("long long string so no SSO"), 0, 10, STR("long long ")); 65 test<S>(STR("long long string so no SSO"), 10, 10, STR("string so ")); 66 test<S>(STR("long long string so no SSO"), 20, 10, STR("no SSO")); 67 test<S>(STR("long long string so no SSO"), 26, 10, STR("")); 68 test<S>(STR("long long string so no SSO"), 27, 0, should_throw_exception); 69 } 70 71 template <class CharT, class CharTraits> 72 constexpr void test_allocators() { 73 test_string<std::basic_string<CharT, CharTraits, std::allocator<CharT>>>(); 74 test_string<std::basic_string<CharT, CharTraits, min_allocator<CharT>>>(); 75 test_string<std::basic_string<CharT, CharTraits, test_allocator<CharT>>>(); 76 } 77 78 template <class CharT> 79 constexpr void test_char_traits() { 80 test_allocators<CharT, std::char_traits<CharT>>(); 81 test_allocators<CharT, constexpr_char_traits<CharT>>(); 82 } 83 84 constexpr bool test() { 85 test_char_traits<char>(); 86 test_char_traits<char16_t>(); 87 test_char_traits<char32_t>(); 88 #ifndef TEST_HAS_NO_WIDE_CHARACTERS 89 test_char_traits<wchar_t>(); 90 #endif 91 #ifndef TEST_HAS_NO_CHAR8_T 92 test_char_traits<char8_t>(); 93 #endif 94 95 return true; 96 } 97 98 int main(int, char**) { 99 test(); 100 static_assert(test()); 101 102 return 0; 103 } 104