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

   1 // Copyright (C) 2016-2019 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-do run { target c++11 } }
  19
  20 #include <limits>
  21 #include <unordered_set>
  22
  23 #include <testsuite_hooks.h>
  24
  25 void test01()
  26 {
  27   std::__detail::_Prime_rehash_policy policy;
  28
  29   // Starts at 4 because 2 & 3 are two consecutives primes that make this test
  30   // fail.
  31   for (std::size_t i = 4;;)
  32     {
  33       auto nxt = policy._M_next_bkt(i);
  34
  35       if (nxt <= i)
  36         {
  37           // Lower or equals only when reaching max prime.
  38           constexpr auto mx = std::numeric_limits<std::size_t>::max();
  39           VERIFY( nxt == policy._M_next_bkt(mx) );
  40           break;
  41         }
  42
  43       VERIFY( nxt > i );
  44       i = nxt + 1;
  45     }
  46 }
  47
  48 int main()
  49 {
  50   test01();
  51   return 0;
  52 }