libstdc++-v3/testsuite/23_containers/unordered_set/max_load_factor/robustness.cc

   1 // { dg-do run { target c++11 } }
   2
   3 // Copyright (C) 2011-2022 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10 //
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20 #include <unordered_set>
  21 #include <limits>
  22 #include <ext/throw_allocator.h>
  23 #include <testsuite_hooks.h>
  24
  25 template<template<typename _Value, typename _Hash,
  26                   typename _Pred, typename _Alloc>
  27            typename _USet>
  28   void test()
  29   {
  30     typedef std::numeric_limits<std::size_t> nl_size_t;
  31     _USet<int, std::hash<int>, std::equal_to<int>,
  32           __gnu_cxx::throw_allocator_limit<int> > us;
  33     int val = 0;
  34     for (; val != 100; ++val)
  35       {
  36         VERIFY( us.insert(val).second );
  37         VERIFY( us.load_factor() <= us.max_load_factor() );
  38       }
  39
  40     float cur_max_load_factor = us.max_load_factor();
  41     int counter = 0;
  42     std::size_t thrown_exceptions = 0;
  43
  44     // Reduce max load factor.
  45     us.max_load_factor(us.max_load_factor() / 4);
  46
  47     // At this point load factor is higher than max_load_factor because we can't
  48     // rehash in max_load_factor call.
  49     VERIFY( us.load_factor() > us.max_load_factor() );
  50
  51     while (true)
  52       {
  53         __gnu_cxx::limit_condition::limit_adjustor adjustor(counter++);
  54         bool do_break = false;
  55         try
  56           {
  57             size_t nbkts = us.bucket_count();
  58             // Check that unordered_set will still be correctly resized when
  59             // needed.
  60             VERIFY( us.insert(val++).second );
  61             VERIFY( us.bucket_count() != nbkts );
  62             VERIFY( us.load_factor() <= us.max_load_factor() );
  63             do_break = true;
  64           }
  65         catch (const __gnu_cxx::forced_error&)
  66           {
  67             // max load factor doesn't change.
  68             VERIFY( us.max_load_factor() == .25f );
  69             ++thrown_exceptions;
  70           }
  71
  72         if (do_break)
  73           break;
  74       }
  75
  76     VERIFY( thrown_exceptions > 0 );
  77   }
  78
  79
  80 template<typename _Value, typename _Hash,
  81          typename _Pred, typename _Alloc>
  82   using unordered_set_power2_rehash =
  83   std::_Hashtable<_Value, _Value, _Alloc,
  84                   std::__detail::_Identity,
  85                   _Pred,
  86                   _Hash,
  87                   std::__detail::_Mask_range_hashing,
  88                   std::__detail::_Default_ranged_hash,
  89                   std::__detail::_Power2_rehash_policy,
  90                   std::__detail::_Hashtable_traits<false, true, true>>;
  91
  92 int main()
  93 {
  94   test<std::unordered_set>();
  95   test<unordered_set_power2_rehash>();
  96   return 0;
  97 }