libcxx/test/std/containers/unord/unord.multimap/rehash.pass.cpp

   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
  28 template <class C>
  29 void rehash_postcondition(const C& c, std::size_t n)
  30 {
  31     assert(c.bucket_count() >= c.size() / c.max_load_factor() && c.bucket_count() >= n);
  32 }
  33
  34 template <class C>
  35 void test(const C& c)
  36 {
  37     assert(c.size() == 6);
  38     typedef std::pair<typename C::const_iterator, typename C::const_iterator> Eq;
  39     Eq eq = c.equal_range(1);
  40     assert(std::distance(eq.first, eq.second) == 2);
  41     typename C::const_iterator i = eq.first;
  42     {
  43         std::set<std::string> s;
  44         s.insert("one");
  45         s.insert("four");
  46         for ( int n = 0; n < 2; ++n )
  47         {
  48             assert(i->first == 1);
  49             assert(s.find(i->second) != s.end());
  50             s.erase(s.find(i->second));
  51             ++i;
  52         }
  53     }
  54     eq = c.equal_range(2);
  55     assert(std::distance(eq.first, eq.second) == 2);
  56     i = eq.first;
  57     {
  58         std::set<std::string> s;
  59         s.insert("two");
  60         s.insert("four");
  61         for ( int n = 0; n < 2; ++n )
  62         {
  63             assert(i->first == 2);
  64             assert(s.find(i->second) != s.end());
  65             s.erase(s.find(i->second));
  66             ++i;
  67         }
  68     }
  69     eq = c.equal_range(3);
  70     assert(std::distance(eq.first, eq.second) == 1);
  71     i = eq.first;
  72     assert(i->first == 3);
  73     assert(i->second == "three");
  74     eq = c.equal_range(4);
  75     assert(std::distance(eq.first, eq.second) == 1);
  76     i = eq.first;
  77     assert(i->first == 4);
  78     assert(i->second == "four");
  79     assert(static_cast<std::size_t>(std::distance(c.begin(), c.end())) == c.size());
  80     assert(static_cast<std::size_t>(std::distance(c.cbegin(), c.cend())) == c.size());
  81     assert(std::fabs(c.load_factor() - (float)c.size()/c.bucket_count()) < FLT_EPSILON);
  82 }
  83
  84 int main(int, char**)
  85 {
  86     {
  87         typedef std::unordered_multimap<int, std::string> C;
  88         typedef std::pair<int, std::string> P;
  89         P a[] =
  90         {
  91             P(1, "one"),
  92             P(2, "two"),
  93             P(3, "three"),
  94             P(4, "four"),
  95             P(1, "four"),
  96             P(2, "four"),
  97         };
  98         C c(a, a + sizeof(a)/sizeof(a[0]));
  99         test(c);
 100         assert(c.bucket_count() >= 7);
 101         c.rehash(3);
 102         rehash_postcondition(c, 3);
 103         LIBCPP_ASSERT(c.bucket_count() == 7);
 104         test(c);
 105         c.max_load_factor(2);
 106         c.rehash(3);
 107         rehash_postcondition(c, 3);
 108         LIBCPP_ASSERT(c.bucket_count() == 3);
 109         test(c);
 110         c.rehash(31);
 111         rehash_postcondition(c, 31);
 112         LIBCPP_ASSERT(c.bucket_count() == 31);
 113         test(c);
 114     }
 115 #if TEST_STD_VER >= 11
 116     {
 117         typedef std::unordered_multimap<int, std::string, std::hash<int>, std::equal_to<int>,
 118                             min_allocator<std::pair<const int, std::string>>> C;
 119         typedef std::pair<int, std::string> P;
 120         P a[] =
 121         {
 122             P(1, "one"),
 123             P(2, "two"),
 124             P(3, "three"),
 125             P(4, "four"),
 126             P(1, "four"),
 127             P(2, "four"),
 128         };
 129         C c(a, a + sizeof(a)/sizeof(a[0]));
 130         test(c);
 131         assert(c.bucket_count() >= 7);
 132         c.rehash(3);
 133         rehash_postcondition(c, 3);
 134         LIBCPP_ASSERT(c.bucket_count() == 7);
 135         test(c);
 136         c.max_load_factor(2);
 137         c.rehash(3);
 138         rehash_postcondition(c, 3);
 139         LIBCPP_ASSERT(c.bucket_count() == 3);
 140         test(c);
 141         c.rehash(31);
 142         rehash_postcondition(c, 31);
 143         LIBCPP_ASSERT(c.bucket_count() == 31);
 144         test(c);
 145     }
 146 #endif
 147
 148   return 0;
 149 }