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 // template<class charT, class traits>
14 //   constexpr bool operator<=(basic_string_view<charT, traits> lhs, basic_string_view<charT, traits> rhs);
15 // (plus "sufficient additional overloads" to make implicit conversions work as intended)
16 
17 #include <string_view>
18 #include <cassert>
19 #include <string>
20 
21 #include "test_macros.h"
22 #include "constexpr_char_traits.h"
23 #include "make_string.h"
24 
25 template<class T>
26 struct ConvertibleTo {
27     T t_;
28     TEST_CONSTEXPR explicit ConvertibleTo(T t) : t_(t) {}
29     TEST_CONSTEXPR operator T() const {
30         return t_;
31     }
32 };
33 
34 template<class SV>
35 TEST_CONSTEXPR_CXX14 bool test()
36 {
37     typedef typename SV::value_type CharT;
38     typedef typename SV::traits_type Traits;
39 
40     // Test the behavior of the operator, both with and without implicit conversions.
41     SV v[] = {
42         SV(MAKE_CSTRING(CharT, "")),
43         SV(MAKE_CSTRING(CharT, "abc")),
44         SV(MAKE_CSTRING(CharT, "abcdef")),
45         SV(MAKE_CSTRING(CharT, "acb")),
46     };
47     for (int i = 0; i < 4; ++i) {
48         for (int j = 0; j < 4; ++j) {
49             // See http://eel.is/c++draft/string.view#tab:string.view.comparison.overloads
50             bool expected = (i <= j);
51             assert((v[i] <= v[j]) == expected);
52             assert((v[i].data() <= v[j]) == expected);
53             assert((v[i] <= v[j].data()) == expected);
54             assert((ConvertibleTo<SV>(v[i]) <= v[j]) == expected);
55             assert((v[i] <= ConvertibleTo<SV>(v[j])) == expected);
56 
57             if (!TEST_IS_CONSTANT_EVALUATED || TEST_STD_VER >= 20) {
58                 assert((std::basic_string<CharT, Traits>(v[i]) <= v[j]) == expected);
59                 assert((v[i] <= std::basic_string<CharT, Traits>(v[j])) == expected);
60             }
61         }
62     }
63 
64     // Test its behavior with embedded null bytes.
65     SV abc = SV(MAKE_CSTRING(CharT, "abc"));
66     SV abc0def = SV(MAKE_CSTRING(CharT, "abc\0def"), 7);
67     SV abcdef = SV(MAKE_CSTRING(CharT, "abcdef"));
68     assert((abc <= abc0def) == true);
69     assert((abc <= abcdef) == true);
70     assert((abc0def <= abc) == false);
71     assert((abc0def <= abcdef) == true);
72     assert((abcdef <= abc) == false);
73     assert((abcdef <= abc0def) == false);
74 
75     assert((abc.data() <= abc0def) == true);
76     assert((abc0def <= abc.data()) == false);
77 
78     if (!TEST_IS_CONSTANT_EVALUATED || TEST_STD_VER >= 20) {
79         assert((std::basic_string<CharT, Traits>(abc) <= abc0def) == true);
80         assert((abc0def <= std::basic_string<CharT, Traits>(abc)) == false);
81     }
82 
83     return true;
84 }
85 
86 int main(int, char**)
87 {
88     test<std::string_view>();
89 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
90     test<std::wstring_view>();
91 #endif
92 #if TEST_STD_VER >= 11
93     test<std::u16string_view>();
94     test<std::u32string_view>();
95 #endif
96 #if TEST_STD_VER > 14
97     static_assert(test<std::string_view>(), "");
98 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
99     static_assert(test<std::wstring_view>(), "");
100 #endif
101     static_assert(test<std::u16string_view>(), "");
102     static_assert(test<std::u32string_view>(), "");
103 #endif
104 
105 #if TEST_STD_VER > 11
106     test<std::basic_string_view<char, constexpr_char_traits<char>>>();
107     static_assert(test<std::basic_string_view<char, constexpr_char_traits<char>>>(), "");
108 #endif
109 
110 #if TEST_STD_VER > 17
111     test<std::u8string_view>();
112     static_assert(test<std::u8string_view>());
113 #endif
114 
115     return 0;
116 }
117