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