libcxx/test/std/containers/unord/unord.map/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_map
  14
  15 // void rehash(size_type n);
  16
  17 #include <unordered_map>
  18 #include <string>
  19 #include <cassert>
  20
  21 #include "test_macros.h"
  22 #include "min_allocator.h"
  23
  24 template <class C>
  25 void rehash_postcondition(const C& c, std::size_t n)
  26 {
  27     assert(c.bucket_count() >= c.size() / c.max_load_factor() && c.bucket_count() >= n);
  28 }
  29
  30 template <class C>
  31 void test(const C& c)
  32 {
  33     assert(c.size() == 4);
  34     assert(c.at(1) == "one");
  35     assert(c.at(2) == "two");
  36     assert(c.at(3) == "three");
  37     assert(c.at(4) == "four");
  38 }
  39
  40 int main(int, char**)
  41 {
  42     {
  43         typedef std::unordered_map<int, std::string> C;
  44         typedef std::pair<int, std::string> P;
  45         P a[] =
  46         {
  47             P(1, "one"),
  48             P(2, "two"),
  49             P(3, "three"),
  50             P(4, "four"),
  51             P(1, "four"),
  52             P(2, "four"),
  53         };
  54         C c(a, a + sizeof(a)/sizeof(a[0]));
  55         test(c);
  56         assert(c.bucket_count() >= 5);
  57         c.rehash(3);
  58         rehash_postcondition(c, 3);
  59         LIBCPP_ASSERT(c.bucket_count() == 5);
  60         test(c);
  61         c.max_load_factor(2);
  62         c.rehash(3);
  63         rehash_postcondition(c, 3);
  64         LIBCPP_ASSERT(c.bucket_count() == 3);
  65         test(c);
  66         c.rehash(31);
  67         rehash_postcondition(c, 31);
  68         LIBCPP_ASSERT(c.bucket_count() == 31);
  69         test(c);
  70     }
  71 #if TEST_STD_VER >= 11
  72     {
  73         typedef std::unordered_map<int, std::string, std::hash<int>, std::equal_to<int>,
  74                             min_allocator<std::pair<const int, std::string>>> C;
  75         typedef std::pair<int, std::string> P;
  76         P a[] =
  77         {
  78             P(1, "one"),
  79             P(2, "two"),
  80             P(3, "three"),
  81             P(4, "four"),
  82             P(1, "four"),
  83             P(2, "four"),
  84         };
  85         C c(a, a + sizeof(a)/sizeof(a[0]));
  86         test(c);
  87         assert(c.bucket_count() >= 5);
  88         c.rehash(3);
  89         rehash_postcondition(c, 3);
  90         LIBCPP_ASSERT(c.bucket_count() == 5);
  91         test(c);
  92         c.max_load_factor(2);
  93         c.rehash(3);
  94         rehash_postcondition(c, 3);
  95         LIBCPP_ASSERT(c.bucket_count() == 3);
  96         test(c);
  97         c.rehash(31);
  98         rehash_postcondition(c, 31);
  99         LIBCPP_ASSERT(c.bucket_count() == 31);
 100         test(c);
 101     }
 102 #endif
 103
 104   return 0;
 105 }