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_set>
10
11// template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
12// class Alloc = allocator<Value>>
13// class unordered_multiset
14
15// void rehash(size_type n);
16
17#include <unordered_set>
18#include <cassert>
19
20#include "test_macros.h"
21#include "min_allocator.h"
22
23template <class C>
24void rehash_postcondition(const C& c, std::size_t n) {
25 assert(c.bucket_count() >= c.size() / c.max_load_factor() && c.bucket_count() >= n);
26}
27
28template <class C>
29void test(const C& c) {
30 assert(c.size() == 6);
31 assert(c.count(1) == 2);
32 assert(c.count(2) == 2);
33 assert(c.count(3) == 1);
34 assert(c.count(4) == 1);
35}
36
37int main(int, char**) {
38 {
39 typedef std::unordered_multiset<int> C;
40 typedef int P;
41 P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
42 C c(a, a + sizeof(a) / sizeof(a[0]));
43 test(c);
44 assert(c.bucket_count() >= 7);
45 c.rehash(n: 3);
46 rehash_postcondition(c, n: 3);
47 LIBCPP_ASSERT(c.bucket_count() == 7);
48 test(c);
49 c.max_load_factor(z: 2);
50 c.rehash(n: 3);
51 rehash_postcondition(c, n: 3);
52 LIBCPP_ASSERT(c.bucket_count() == 3);
53 test(c);
54 c.rehash(n: 31);
55 rehash_postcondition(c, n: 31);
56 LIBCPP_ASSERT(c.bucket_count() == 31);
57 test(c);
58 }
59#if TEST_STD_VER >= 11
60 {
61 typedef std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> C;
62 typedef int P;
63 P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
64 C c(a, a + sizeof(a) / sizeof(a[0]));
65 test(c);
66 assert(c.bucket_count() >= 7);
67 c.rehash(3);
68 rehash_postcondition(c, 3);
69 LIBCPP_ASSERT(c.bucket_count() == 7);
70 test(c);
71 c.max_load_factor(2);
72 c.rehash(3);
73 rehash_postcondition(c, 3);
74 LIBCPP_ASSERT(c.bucket_count() == 3);
75 test(c);
76 c.rehash(31);
77 rehash_postcondition(c, 31);
78 LIBCPP_ASSERT(c.bucket_count() == 31);
79 test(c);
80 }
81#endif
82
83 return 0;
84}
85

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