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 = hash<Key>, class Pred = equal_to<Key>,
12// class Alloc = allocator<pair<const Key, T>>>
13// class unordered_multimap
14
15// void rehash(size_type n);
16
17#include <unordered_map>
18#include <string>
19#include <set>
20#include <cassert>
21#include <cfloat>
22#include <cmath>
23#include <cstddef>
24
25#include "test_macros.h"
26#include "min_allocator.h"
27
28template <class C>
29void rehash_postcondition(const C& c, std::size_t n) {
30 assert(c.bucket_count() >= c.size() / c.max_load_factor() && c.bucket_count() >= n);
31}
32
33template <class C>
34void test(const C& c) {
35 assert(c.size() == 6);
36 typedef std::pair<typename C::const_iterator, typename C::const_iterator> Eq;
37 Eq eq = c.equal_range(1);
38 assert(std::distance(eq.first, eq.second) == 2);
39 typename C::const_iterator i = eq.first;
40 {
41 std::set<std::string> s;
42 s.insert(x: "one");
43 s.insert(x: "four");
44 for (int n = 0; n < 2; ++n) {
45 assert(i->first == 1);
46 assert(s.find(i->second) != s.end());
47 s.erase(s.find(i->second));
48 ++i;
49 }
50 }
51 eq = c.equal_range(2);
52 assert(std::distance(eq.first, eq.second) == 2);
53 i = eq.first;
54 {
55 std::set<std::string> s;
56 s.insert(x: "two");
57 s.insert(x: "four");
58 for (int n = 0; n < 2; ++n) {
59 assert(i->first == 2);
60 assert(s.find(i->second) != s.end());
61 s.erase(s.find(i->second));
62 ++i;
63 }
64 }
65 eq = c.equal_range(3);
66 assert(std::distance(eq.first, eq.second) == 1);
67 i = eq.first;
68 assert(i->first == 3);
69 assert(i->second == "three");
70 eq = c.equal_range(4);
71 assert(std::distance(eq.first, eq.second) == 1);
72 i = eq.first;
73 assert(i->first == 4);
74 assert(i->second == "four");
75 assert(static_cast<std::size_t>(std::distance(c.begin(), c.end())) == c.size());
76 assert(static_cast<std::size_t>(std::distance(c.cbegin(), c.cend())) == c.size());
77 assert(std::fabs(c.load_factor() - (float)c.size() / c.bucket_count()) < FLT_EPSILON);
78}
79
80int main(int, char**) {
81 {
82 typedef std::unordered_multimap<int, std::string> C;
83 typedef std::pair<int, std::string> P;
84 P a[] = {
85 P(1, "one"),
86 P(2, "two"),
87 P(3, "three"),
88 P(4, "four"),
89 P(1, "four"),
90 P(2, "four"),
91 };
92 C c(a, a + sizeof(a) / sizeof(a[0]));
93 test(c);
94 assert(c.bucket_count() >= 7);
95 c.rehash(n: 3);
96 rehash_postcondition(c, n: 3);
97 LIBCPP_ASSERT(c.bucket_count() == 7);
98 test(c);
99 c.max_load_factor(z: 2);
100 c.rehash(n: 3);
101 rehash_postcondition(c, n: 3);
102 LIBCPP_ASSERT(c.bucket_count() == 3);
103 test(c);
104 c.rehash(n: 31);
105 rehash_postcondition(c, n: 31);
106 LIBCPP_ASSERT(c.bucket_count() == 31);
107 test(c);
108 }
109#if TEST_STD_VER >= 11
110 {
111 typedef std::unordered_multimap<int,
112 std::string,
113 std::hash<int>,
114 std::equal_to<int>,
115 min_allocator<std::pair<const int, std::string>>>
116 C;
117 typedef std::pair<int, std::string> P;
118 P a[] = {
119 P(1, "one"),
120 P(2, "two"),
121 P(3, "three"),
122 P(4, "four"),
123 P(1, "four"),
124 P(2, "four"),
125 };
126 C c(a, a + sizeof(a) / sizeof(a[0]));
127 test(c);
128 assert(c.bucket_count() >= 7);
129 c.rehash(3);
130 rehash_postcondition(c, 3);
131 LIBCPP_ASSERT(c.bucket_count() == 7);
132 test(c);
133 c.max_load_factor(2);
134 c.rehash(3);
135 rehash_postcondition(c, 3);
136 LIBCPP_ASSERT(c.bucket_count() == 3);
137 test(c);
138 c.rehash(31);
139 rehash_postcondition(c, 31);
140 LIBCPP_ASSERT(c.bucket_count() == 31);
141 test(c);
142 }
143#endif
144
145 return 0;
146}
147

source code of libcxx/test/std/containers/unord/unord.multimap/rehash.pass.cpp