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