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_view> 10 11 // constexpr const_iterator begin() const; 12 13 #include <string_view> 14 #include <cassert> 15 16 #include "test_macros.h" 17 18 template <class S> 19 void 20 test(S s) 21 { 22 const S& cs = s; 23 typename S::iterator b = s.begin(); 24 typename S::const_iterator cb1 = cs.begin(); 25 typename S::const_iterator cb2 = s.cbegin(); 26 if (!s.empty()) 27 { 28 assert( *b == s[0]); 29 assert( &*b == &s[0]); 30 assert( *cb1 == s[0]); 31 assert(&*cb1 == &s[0]); 32 assert( *cb2 == s[0]); 33 assert(&*cb2 == &s[0]); 34 35 } 36 assert( b == cb1); 37 assert( b == cb2); 38 assert(cb1 == cb2); 39 } 40 41 42 int main(int, char**) 43 { 44 typedef std::string_view string_view; 45 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L 46 typedef std::u8string_view u8string_view; 47 #endif 48 typedef std::u16string_view u16string_view; 49 typedef std::u32string_view u32string_view; 50 51 test(string_view ()); 52 test(u16string_view()); 53 test(u32string_view()); 54 test(string_view ( "123")); 55 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L 56 test(u8string_view{u8"123"}); 57 #endif 58 #if TEST_STD_VER >= 11 59 test(u16string_view{u"123"}); 60 test(u32string_view{U"123"}); 61 #endif 62 63 #ifndef TEST_HAS_NO_WIDE_CHARACTERS 64 typedef std::wstring_view wstring_view; 65 test(wstring_view ()); 66 test(wstring_view (L"123")); 67 #endif 68 69 #if TEST_STD_VER > 11 70 { 71 constexpr string_view sv { "123", 3 }; 72 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L 73 constexpr u8string_view u8sv {u8"123", 3 }; 74 #endif 75 constexpr u16string_view u16sv {u"123", 3 }; 76 constexpr u32string_view u32sv {U"123", 3 }; 77 78 static_assert ( *sv.begin() == sv[0], "" ); 79 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L 80 static_assert ( *u8sv.begin() == u8sv[0], "" ); 81 #endif 82 static_assert ( *u16sv.begin() == u16sv[0], "" ); 83 static_assert ( *u32sv.begin() == u32sv[0], "" ); 84 85 static_assert ( *sv.cbegin() == sv[0], "" ); 86 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L 87 static_assert ( *u8sv.cbegin() == u8sv[0], "" ); 88 #endif 89 static_assert ( *u16sv.cbegin() == u16sv[0], "" ); 90 static_assert ( *u32sv.cbegin() == u32sv[0], "" ); 91 92 #ifndef TEST_HAS_NO_WIDE_CHARACTERS 93 { 94 constexpr wstring_view wsv {L"123", 3 }; 95 static_assert ( *wsv.begin() == wsv[0], "" ); 96 static_assert ( *wsv.cbegin() == wsv[0], "" ); 97 } 98 #endif 99 } 100 #endif // TEST_STD_VER > 11 101 102 return 0; 103 } 104