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 // NOTE: Older versions of clang have a bug where they fail to evalute
11 // string_view::at as a constant expression.
12 // XFAIL: clang-3.4, clang-3.3
13
14 // <string_view>
15
16 // constexpr const _CharT& at(size_type _pos) const;
17
18 #include <experimental/string_view>
19 #include <cassert>
20
21 template <typename CharT>
test(const CharT * s,size_t len)22 void test ( const CharT *s, size_t len ) {
23 std::experimental::basic_string_view<CharT> sv ( s, len );
24 assert ( sv.length() == len );
25 for ( size_t i = 0; i < len; ++i ) {
26 assert ( sv.at(i) == s[i] );
27 assert ( &sv.at(i) == s + i );
28 }
29
30 try { sv.at(len); } catch ( const std::out_of_range & ) { return ; }
31 assert ( false );
32 }
33
main()34 int main () {
35 test ( "ABCDE", 5 );
36 test ( "a", 1 );
37
38 test ( L"ABCDE", 5 );
39 test ( L"a", 1 );
40
41 #if __cplusplus >= 201103L
42 test ( u"ABCDE", 5 );
43 test ( u"a", 1 );
44
45 test ( U"ABCDE", 5 );
46 test ( U"a", 1 );
47 #endif
48
49 #if __cplusplus >= 201103L
50 {
51 constexpr std::experimental::basic_string_view<char> sv ( "ABC", 2 );
52 static_assert ( sv.length() == 2, "" );
53 static_assert ( sv.at(0) == 'A', "" );
54 static_assert ( sv.at(1) == 'B', "" );
55 }
56 #endif
57 }
58