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 // <unordered_map>
10
11 // template <class Key, class T, class Hash, class Pred, class Alloc>
12 // bool
13 // operator==(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
14 // const unordered_map<Key, T, Hash, Pred, Alloc>& y);
15 //
16 // template <class Key, class T, class Hash, class Pred, class Alloc>
17 // bool
18 // operator!=(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
19 // const unordered_map<Key, T, Hash, Pred, Alloc>& y);
20
21 // Implements paper: http://wg21.link/p0809
22
23 #include <unordered_map>
24 #include <cstddef>
25 #include <limits>
26 #include <cassert>
27 #include <functional>
28
29 template <class T>
hash_identity(T val)30 std::size_t hash_identity(T val) {
31 return val;
32 }
33 template <class T>
hash_neg(T val)34 std::size_t hash_neg(T val) {
35 return std::numeric_limits<T>::max() - val;
36 }
37 template <class T>
hash_scale(T val)38 std::size_t hash_scale(T val) {
39 return static_cast<std::size_t>(val << 1);
40 }
41 template <class T>
hash_even(T val)42 std::size_t hash_even(T val) {
43 return val & 1 ? 1 : 0;
44 }
45 template <class T>
hash_same(T)46 std::size_t hash_same(T /*val*/) {
47 return 1;
48 }
49
50 template <class T>
hash_identity(T * val)51 std::size_t hash_identity(T* val) {
52 return *val;
53 }
54 template <class T>
hash_neg(T * val)55 std::size_t hash_neg(T* val) {
56 return std::numeric_limits<T>::max() - *val;
57 }
58 template <class T>
hash_scale(T * val)59 std::size_t hash_scale(T* val) {
60 return static_cast<std::size_t>(*val << 1);
61 }
62 template <class T>
hash_even(T * val)63 std::size_t hash_even(T* val) {
64 return *val & 1 ? 1 : 0;
65 }
66
67 template <class Map, class Ittr>
populate(Map & m,Ittr start,Ittr end)68 void populate(Map& m, Ittr start, Ittr end) {
69 for (auto *p1 = start, *p2 = end - 1; p1 != end; ++p1, --p2) {
70 m.insert(std::make_pair(*p1, *p2));
71 }
72 }
73
74 template <class T, std::size_t N>
test(T (& vals)[N])75 void test(T (&vals)[N]) {
76 using Hash = std::size_t (*)(T);
77 using C = std::unordered_map<T, T, Hash, std::equal_to<T> >;
78
79 C c1(0, hash_identity);
80 C c2(0, hash_neg);
81 C c3(0, hash_scale);
82 C c4(0, hash_even);
83 C c5(0, hash_same);
84
85 populate(c1, std::begin(vals), std::end(vals));
86 populate(c2, std::begin(vals), std::end(vals));
87 populate(c3, std::begin(vals), std::end(vals));
88 populate(c4, std::begin(vals), std::end(vals));
89 populate(c5, std::begin(vals), std::end(vals));
90
91 assert(c1 == c1);
92 assert(c1 == c2);
93 assert(c1 == c3);
94 assert(c1 == c4);
95 assert(c1 == c5);
96
97 assert(c2 == c1);
98 assert(c2 == c2);
99 assert(c2 == c3);
100 assert(c2 == c4);
101 assert(c2 == c5);
102
103 assert(c3 == c1);
104 assert(c3 == c2);
105 assert(c3 == c3);
106 assert(c3 == c4);
107 assert(c3 == c5);
108
109 assert(c4 == c1);
110 assert(c4 == c2);
111 assert(c4 == c3);
112 assert(c4 == c4);
113 assert(c4 == c5);
114
115 assert(c5 == c1);
116 assert(c5 == c2);
117 assert(c5 == c3);
118 assert(c5 == c4);
119 assert(c5 == c5);
120 }
121
main(int,char **)122 int main(int, char**) {
123 {
124 std::size_t vals[] = {
125 // clang-format off
126 1,
127 2, 2,
128 3, 3, 3,
129 4, 4, 4, 4,
130 5, 5, 5, 5, 5,
131 6, 6, 6, 6, 6, 6,
132 7, 7, 7, 7, 7, 7, 7,
133 8, 8, 8, 8, 8, 8, 8, 8,
134 9, 9, 9, 9, 9, 9, 9, 9, 9,
135 10
136 // clang-format on
137 };
138 test(vals);
139 }
140
141 {
142 bool vals[] = {true, false};
143 test(vals);
144 }
145
146 {
147 char* vals[] = {(char*)("a"), (char*)("b"), (char*)("cde")};
148 test(vals);
149 }
150
151 return 0;
152 }
153