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

   1 // Copyright (C) 2011-2016 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8 //
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17 //
  18 // { dg-options "-std=gnu++11" }
  19
  20 #include <unordered_set>
  21 #include <testsuite_hooks.h>
  22
  23 void test01()
  24 {
  25   bool test __attribute__((unused)) = true;
  26   std::unordered_set<int> us;
  27   typedef typename std::unordered_set<int>::size_type size_type;
  28   bool rehashed = false;
  29   for (int i = 0; i != 100000; ++i)
  30   {
  31     size_type bkt_count = us.bucket_count();
  32     us.insert(i);
  33     if (bkt_count != us.bucket_count())
  34       {
  35         // Container has been rehashed, lets check that it won't be rehash again
  36         // if we remove and restore the last 2 inserted elements:
  37         rehashed = true;
  38         bkt_count = us.bucket_count();
  39         VERIFY( us.erase(i) == 1 );
  40         VERIFY( bkt_count == us.bucket_count() );
  41         if (i > 0)
  42           {
  43             VERIFY( us.erase(i - 1) == 1 );
  44             VERIFY( bkt_count == us.bucket_count() );
  45
  46             VERIFY( us.insert(i - 1).second );
  47             VERIFY( bkt_count == us.bucket_count() );
  48           }
  49         VERIFY( us.insert(i).second );
  50         VERIFY( bkt_count == us.bucket_count() );
  51       }
  52   }
  53
  54   // At lest we check a rehash once:
  55   VERIFY( rehashed );
  56 }
  57
  58 int main()
  59 {
  60   test01();
  61   return 0;
  62 }