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 	try {
26 		std::basic_string_view<CharT> sv1 = sv.substr(pos, n);
27         const size_t rlen = std::min(n, sv.size() - pos);
28         assert (sv1.size() == rlen);
29         for (size_t i = 0; i <= rlen; ++i)
30             assert(sv[pos+i] == sv1[i]);
31 	}
32 	catch (const std::out_of_range&) {
33 		assert(pos > sv.size());
34 	}
35 }
36 
37 
38 template<typename CharT>
39 void test ( const CharT *s ) {
40     typedef std::basic_string_view<CharT> string_view_t;
41 
42     string_view_t sv1 ( s );
43 
44     test1(sv1,  0, 0);
45     test1(sv1,  1, 0);
46     test1(sv1, 20, 0);
47     test1(sv1, sv1.size(), 0);
48 
49     test1(sv1,   0, 3);
50     test1(sv1,   2, 3);
51     test1(sv1, 100, 3);
52 
53     test1(sv1, 0, string_view_t::npos);
54     test1(sv1, 2, string_view_t::npos);
55     test1(sv1, sv1.size(), string_view_t::npos);
56 
57     test1(sv1, sv1.size() + 1, 0);
58     test1(sv1, sv1.size() + 1, 1);
59     test1(sv1, sv1.size() + 1, string_view_t::npos);
60 }
61 
62 int main () {
63     test ( "ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
64     test ( "ABCDE");
65     test ( "a" );
66     test ( "" );
67 
68     test ( L"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
69     test ( L"ABCDE" );
70     test ( L"a" );
71     test ( L"" );
72 
73 #if TEST_STD_VER >= 11
74     test ( u"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
75     test ( u"ABCDE" );
76     test ( u"a" );
77     test ( u"" );
78 
79     test ( U"ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDE" );
80     test ( U"ABCDE" );
81     test ( U"a" );
82     test ( U"" );
83 #endif
84 
85 #if TEST_STD_VER > 11
86     {
87     constexpr std::string_view sv1 { "ABCDE", 5 };
88 
89     {
90     constexpr std::string_view sv2 = sv1.substr ( 0, 3 );
91     static_assert ( sv2.size() == 3, "" );
92     static_assert ( sv2[0] == 'A', "" );
93     static_assert ( sv2[1] == 'B', "" );
94     static_assert ( sv2[2] == 'C', "" );
95     }
96 
97     {
98     constexpr std::string_view sv2 = sv1.substr ( 3, 0 );
99     static_assert ( sv2.size() == 0, "" );
100     }
101 
102     {
103     constexpr std::string_view sv2 = sv1.substr ( 3, 3 );
104     static_assert ( sv2.size() == 2, "" );
105     static_assert ( sv2[0] == 'D', "" );
106     static_assert ( sv2[1] == 'E', "" );
107     }
108     }
109 #endif
110 }
111