libcxx/test/std/containers/unord/unord.set/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_set>
  10
  11 // template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
  12 //           class Alloc = allocator<Value>>
  13 // class unordered_set
  14
  15 // void reserve(size_type n);
  16
  17 #include <unordered_set>
  18 #include <cassert>
  19
  20 #include "test_macros.h"
  21 #include "min_allocator.h"
  22
  23 template <class C>
  24 void test(const C& c)
  25 {
  26     assert(c.size() == 4);
  27     assert(c.count(1) == 1);
  28     assert(c.count(2) == 1);
  29     assert(c.count(3) == 1);
  30     assert(c.count(4) == 1);
  31 }
  32
  33 void reserve_invariant(size_t n) // LWG #2156
  34 {
  35     for (size_t i = 0; i < n; ++i)
  36     {
  37         std::unordered_set<size_t> c;
  38         c.reserve(n);
  39         size_t buckets = c.bucket_count();
  40         for (size_t j = 0; j < i; ++j)
  41         {
  42             c.insert(i);
  43             assert(buckets == c.bucket_count());
  44         }
  45     }
  46 }
  47
  48 int main(int, char**)
  49 {
  50     {
  51         typedef std::unordered_set<int> C;
  52         typedef int P;
  53         P a[] =
  54         {
  55             P(1),
  56             P(2),
  57             P(3),
  58             P(4),
  59             P(1),
  60             P(2)
  61         };
  62         C c(a, a + sizeof(a)/sizeof(a[0]));
  63         test(c);
  64         assert(c.bucket_count() >= 5);
  65         c.reserve(3);
  66         LIBCPP_ASSERT(c.bucket_count() == 5);
  67         test(c);
  68         c.max_load_factor(2);
  69         c.reserve(3);
  70         assert(c.bucket_count() >= 2);
  71         test(c);
  72         c.reserve(31);
  73         assert(c.bucket_count() >= 16);
  74         test(c);
  75     }
  76 #if TEST_STD_VER >= 11
  77     {
  78         typedef std::unordered_set<int, std::hash<int>,
  79                                       std::equal_to<int>, min_allocator<int>> C;
  80         typedef int P;
  81         P a[] =
  82         {
  83             P(1),
  84             P(2),
  85             P(3),
  86             P(4),
  87             P(1),
  88             P(2)
  89         };
  90         C c(a, a + sizeof(a)/sizeof(a[0]));
  91         test(c);
  92         assert(c.bucket_count() >= 5);
  93         c.reserve(3);
  94         LIBCPP_ASSERT(c.bucket_count() == 5);
  95         test(c);
  96         c.max_load_factor(2);
  97         c.reserve(3);
  98         assert(c.bucket_count() >= 2);
  99         test(c);
 100         c.reserve(31);
 101         assert(c.bucket_count() >= 16);
 102         test(c);
 103     }
 104 #endif
 105     reserve_invariant(20);
 106
 107   return 0;
 108 }