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: !stdlib=libc++ && (c++03 || c++11 || c++14)
10 
11 // <string_view>
12 
13 // constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
14 
15 // Throws: out_of_range if pos > size().
16 // Effects: Determines the effective length rlen of the string to reference as the smaller of n and size() - pos.
17 // Returns: basic_string_view(data()+pos, rlen).
18 
19 #include <string_view>
20 #include <algorithm>
21 #include <stdexcept>
22 #include <cassert>
23 
24 #include "test_macros.h"
25 
26 template<typename CharT>
27 void test1(std::basic_string_view<CharT> sv, size_t n, size_t pos) {
28     std::basic_string_view<CharT> sv1;
29 #ifdef TEST_HAS_NO_EXCEPTIONS
30     if (pos > sv.size())
31         return ;  // would throw if exceptions were enabled
32     sv1 = sv.substr(pos, n);
33 #else
34     try {
35         sv1 = sv.substr(pos, n);
36         assert(pos <= sv.size());
37     }
38     catch (const std::out_of_range&) {
39         assert(pos > sv.size());
40         return ;
41     }
42 #endif
43     const size_t rlen = std::min(n, sv.size() - pos);
44     assert (sv1.size() == rlen);
45     for (size_t i = 0; i < rlen; ++i)
46         assert(sv[pos+i] == sv1[i]);
47 }
48 
49 
50 template<typename CharT>
51 void test ( const CharT *s ) {
52     typedef std::basic_string_view<CharT> string_view_t;
53 
54     string_view_t sv1 ( s );
55 
56     test1(sv1,  0, 0);
57     test1(sv1,  1, 0);
58     test1(sv1, 20, 0);
59     test1(sv1, sv1.size(), 0);
60 
61     test1(sv1,   0, 3);
62     test1(sv1,   2, 3);
63     test1(sv1, 100, 3);
64 
65     test1(sv1, 0, string_view_t::npos);
66     test1(sv1, 2, string_view_t::npos);
67     test1(sv1, sv1.size(), string_view_t::npos);
68 
69     test1(sv1, sv1.size() + 1, 0);
70     test1(sv1, sv1.size() + 1, 1);
71     test1(sv1, sv1.size() + 1, string_view_t::npos);
72 }
73 
74 int main(int, char**) {
75     test ( "ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
76     test ( "ABCDE");
77     test ( "a" );
78     test ( "" );
79 
80     test ( L"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
81     test ( L"ABCDE" );
82     test ( L"a" );
83     test ( L"" );
84 
85 #if TEST_STD_VER >= 11
86     test ( u"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
87     test ( u"ABCDE" );
88     test ( u"a" );
89     test ( u"" );
90 
91     test ( U"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
92     test ( U"ABCDE" );
93     test ( U"a" );
94     test ( U"" );
95 #endif
96 
97 #if TEST_STD_VER > 11
98     {
99     constexpr std::string_view sv1 { "ABCDE", 5 };
100 
101     {
102     constexpr std::string_view sv2 = sv1.substr ( 0, 3 );
103     static_assert ( sv2.size() == 3, "" );
104     static_assert ( sv2[0] == 'A', "" );
105     static_assert ( sv2[1] == 'B', "" );
106     static_assert ( sv2[2] == 'C', "" );
107     }
108 
109     {
110     constexpr std::string_view sv2 = sv1.substr ( 3, 0 );
111     static_assert ( sv2.size() == 0, "" );
112     }
113 
114     {
115     constexpr std::string_view sv2 = sv1.substr ( 3, 3 );
116     static_assert ( sv2.size() == 2, "" );
117     static_assert ( sv2[0] == 'D', "" );
118     static_assert ( sv2[1] == 'E', "" );
119     }
120     }
121 #endif
122 
123   return 0;
124 }
125