libstdc++-v3/testsuite/23_containers/unordered_set/hash_policy/26132.cc

   1 // { dg-do run { target c++11 } }
   2
   3 // 2010-08-13  Paolo Carlini  <paolo.carlini@oracle.com>
   4 //
   5 // Copyright (C) 2010-2019 Free Software Foundation, Inc.
   6 //
   7 // This file is part of the GNU ISO C++ Library.  This library is free
   8 // software; you can redistribute it and/or modify it under the
   9 // terms of the GNU General Public License as published by the
  10 // Free Software Foundation; either version 3, or (at your option)
  11 // any later version.
  12 //
  13 // This library is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17 //
  18 // You should have received a copy of the GNU General Public License along
  19 // with this library; see the file COPYING3.  If not see
  20 // <http://www.gnu.org/licenses/>.
  21
  22 #include <unordered_set>
  23 #include <testsuite_hooks.h>
  24
  25 // libstdc++/26132
  26 template<typename _USet>
  27   void test()
  28   {
  29     for (float lf = 1.0; lf < 101.0; lf *= 10.0)
  30       for (int size = 1; size <= 6561; size *= 3)
  31         {
  32           _USet us1;
  33           typedef typename _USet::size_type size_type;
  34
  35           us1.max_load_factor(10.0);
  36
  37           for (int i = 0; i < size; ++i)
  38             us1.insert(i);
  39
  40           us1.max_load_factor(lf);
  41
  42           for (int i = 1; i <= 6561; i *= 81)
  43             {
  44               const size_type n = size * 81 / i;
  45               us1.rehash(n);
  46               VERIFY( us1.bucket_count() > us1.size() / us1.max_load_factor() );
  47               VERIFY( us1.bucket_count() >= n );
  48             }
  49         }
  50   }
  51
  52 template<typename _Value>
  53   using unordered_set_power2_rehash =
  54   std::_Hashtable<_Value, _Value, std::allocator<_Value>,
  55                   std::__detail::_Identity,
  56                   std::equal_to<_Value>,
  57                   std::hash<_Value>,
  58                   std::__detail::_Mask_range_hashing,
  59                   std::__detail::_Default_ranged_hash,
  60                   std::__detail::_Power2_rehash_policy,
  61                   std::__detail::_Hashtable_traits<false, true, true>>;
  62
  63 int main()
  64 {
  65   test<std::unordered_set<int>>();
  66   test<unordered_set_power2_rehash<int>>();
  67   return 0;
  68 }