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 // <functional>
10 
11 // template <class T>
12 // struct hash
13 //     : public unary_function<T, size_t>
14 // {
15 //     size_t operator()(T val) const;
16 // };
17 
18 // Not very portable
19 
20 #include <string_view>
21 #include <string>
22 #include <cassert>
23 #include <type_traits>
24 
25 #include "test_macros.h"
26 
27 using std::string_view;
28 
29 template <class SV>
30 void
31 test()
32 {
33     typedef std::hash<SV> H;
34     static_assert((std::is_same<typename H::argument_type, SV>::value), "" );
35     static_assert((std::is_same<typename H::result_type, std::size_t>::value), "" );
36 
37     typedef typename SV::value_type char_type;
38     typedef std::basic_string<char_type> String;
39     typedef std::hash<String> SH;
40     ASSERT_NOEXCEPT(H()(SV()));
41 
42     char_type g1 [ 10 ];
43     char_type g2 [ 10 ];
44     for ( int i = 0; i < 10; ++i )
45         g1[i] = g2[9-i] = static_cast<char_type>('0' + i);
46     H h;
47     SH sh;
48     SV s1(g1, 10);
49     String ss1(s1);
50     SV s2(g2, 10);
51     String ss2(s2);
52     assert(h(s1) == h(s1));
53     assert(h(s1) != h(s2));
54     assert(sh(ss1) == h(s1));
55     assert(sh(ss2) == h(s2));
56 }
57 
58 int main(int, char**)
59 {
60     test<std::string_view>();
61 #if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
62     test<std::u8string_view>();
63 #endif
64 #ifndef TEST_HAS_NO_UNICODE_CHARS
65     test<std::u16string_view>();
66     test<std::u32string_view>();
67 #endif
68 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
69     test<std::wstring_view>();
70 #endif
71 
72   return 0;
73 }
74