libcxx/test/std/containers/unord/unord.map/reserve.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 reserve(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 test(const C& c)
  26 {
  27     assert(c.size() == 4);
  28     assert(c.at(1) == "one");
  29     assert(c.at(2) == "two");
  30     assert(c.at(3) == "three");
  31     assert(c.at(4) == "four");
  32 }
  33
  34 void reserve_invariant(std::size_t n) // LWG #2156
  35 {
  36     for (std::size_t i = 0; i < n; ++i)
  37     {
  38         std::unordered_map<std::size_t, size_t> c;
  39         c.reserve(n);
  40         std::size_t buckets = c.bucket_count();
  41         for (std::size_t j = 0; j < i; ++j)
  42         {
  43             c[i] = i;
  44             assert(buckets == c.bucket_count());
  45         }
  46     }
  47 }
  48
  49 int main(int, char**)
  50 {
  51     {
  52         typedef std::unordered_map<int, std::string> C;
  53         typedef std::pair<int, std::string> P;
  54         P a[] =
  55         {
  56             P(1, "one"),
  57             P(2, "two"),
  58             P(3, "three"),
  59             P(4, "four"),
  60             P(1, "four"),
  61             P(2, "four"),
  62         };
  63         C c(a, a + sizeof(a)/sizeof(a[0]));
  64         test(c);
  65         assert(c.bucket_count() >= 5);
  66         c.reserve(3);
  67         LIBCPP_ASSERT(c.bucket_count() == 5);
  68         test(c);
  69         c.max_load_factor(2);
  70         c.reserve(3);
  71         assert(c.bucket_count() >= 2);
  72         test(c);
  73         c.reserve(31);
  74         assert(c.bucket_count() >= 16);
  75         test(c);
  76     }
  77 #if TEST_STD_VER >= 11
  78     {
  79         typedef std::unordered_map<int, std::string, std::hash<int>, std::equal_to<int>,
  80                             min_allocator<std::pair<const int, std::string>>> C;
  81         typedef std::pair<int, std::string> P;
  82         P a[] =
  83         {
  84             P(1, "one"),
  85             P(2, "two"),
  86             P(3, "three"),
  87             P(4, "four"),
  88             P(1, "four"),
  89             P(2, "four"),
  90         };
  91         C c(a, a + sizeof(a)/sizeof(a[0]));
  92         test(c);
  93         assert(c.bucket_count() >= 5);
  94         c.reserve(3);
  95         LIBCPP_ASSERT(c.bucket_count() == 5);
  96         test(c);
  97         c.max_load_factor(2);
  98         c.reserve(3);
  99         assert(c.bucket_count() >= 2);
 100         test(c);
 101         c.reserve(31);
 102         assert(c.bucket_count() >= 16);
 103         test(c);
 104     }
 105 #endif
 106     reserve_invariant(20);
 107
 108   return 0;
 109 }