1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <string_view> 11 12 // constexpr const_iterator begin() const; 13 14 #include <string_view> 15 #include <cassert> 16 17 #include "test_macros.h" 18 19 template <class S> 20 void 21 test(S s) 22 { 23 const S& cs = s; 24 typename S::iterator b = s.begin(); 25 typename S::const_iterator cb1 = cs.begin(); 26 typename S::const_iterator cb2 = s.cbegin(); 27 if (!s.empty()) 28 { 29 assert( *b == s[0]); 30 assert( &*b == &s[0]); 31 assert( *cb1 == s[0]); 32 assert(&*cb1 == &s[0]); 33 assert( *cb2 == s[0]); 34 assert(&*cb2 == &s[0]); 35 36 } 37 assert( b == cb1); 38 assert( b == cb2); 39 assert(cb1 == cb2); 40 } 41 42 43 int main() 44 { 45 typedef std::string_view string_view; 46 typedef std::u16string_view u16string_view; 47 typedef std::u32string_view u32string_view; 48 typedef std::wstring_view wstring_view; 49 50 test(string_view ()); 51 test(u16string_view()); 52 test(u32string_view()); 53 test(wstring_view ()); 54 test(string_view ( "123")); 55 test(wstring_view (L"123")); 56 #if TEST_STD_VER >= 11 57 test(u16string_view{u"123"}); 58 test(u32string_view{U"123"}); 59 #endif 60 61 #if TEST_STD_VER > 11 62 { 63 constexpr string_view sv { "123", 3 }; 64 constexpr u16string_view u16sv {u"123", 3 }; 65 constexpr u32string_view u32sv {U"123", 3 }; 66 constexpr wstring_view wsv {L"123", 3 }; 67 68 static_assert ( *sv.begin() == sv[0], "" ); 69 static_assert ( *u16sv.begin() == u16sv[0], "" ); 70 static_assert ( *u32sv.begin() == u32sv[0], "" ); 71 static_assert ( *wsv.begin() == wsv[0], "" ); 72 73 static_assert ( *sv.cbegin() == sv[0], "" ); 74 static_assert ( *u16sv.cbegin() == u16sv[0], "" ); 75 static_assert ( *u32sv.cbegin() == u32sv[0], "" ); 76 static_assert ( *wsv.cbegin() == wsv[0], "" ); 77 } 78 #endif 79 } 80