text: // -*- C++ -*-
  
  // Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.
  //
  // This file is part of the GNU ISO C++ Library.  This library is free
  // software; you can redistribute it and/or modify it under the terms
  // of the GNU General Public License as published by the Free Software
  // Foundation; either version 3, or (at your option) any later
  // version.
  
  // This library is distributed in the hope that it will be useful, but
  // WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // General Public License for more details.
  
  // Under Section 7 of GPL version 3, you are granted additional
  // permissions described in the GCC Runtime Library Exception, version
  // 3.1, as published by the Free Software Foundation.
  
  // You should have received a copy of the GNU General Public License and
  // a copy of the GCC Runtime Library Exception along with this program;
  // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  // <http://www.gnu.org/licenses/>.
  
  // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  
  // Permission to use, copy, modify, sell, and distribute this software
  // is hereby granted without fee, provided that the above copyright
  // notice appears in all copies, and that both that copyright notice
  // and this permission notice appear in supporting documentation. None
  // of the above authors, nor IBM Haifa Research Laboratories, make any
  // representation about the suitability of this software for any
  // purpose. It is provided "as is" without express or implied
  // warranty.
  
  /**
   * @file mask_based_range_hashing.hpp
   * Contains a range hashing policy base.
   */
  
  #ifndef PB_DS_MASK_BASED_RANGE_HASHING_HPP
  #define PB_DS_MASK_BASED_RANGE_HASHING_HPP
  
  namespace __gnu_pbds
  {
    namespace detail
    {
  #define PB_DS_CLASS_T_DEC template<typename Size_Type>
  #define PB_DS_CLASS_C_DEC mask_based_range_hashing<Size_Type>
  
      template<typename Size_Type>
      class mask_based_range_hashing
      {
      protected:
        typedef Size_Type size_type;
  
        void
        swap(mask_based_range_hashing& other)
        { std::swap(m_mask, other.m_mask); }
  
        void
        notify_resized(size_type size);
  
        inline size_type
        range_hash(size_type hash) const
        { return size_type(hash & m_mask); }
  
      private:
        size_type 		m_mask;
        const static size_type 	s_num_bits_in_size_type;
        const static size_type 	s_highest_bit_1;
      };
  
      PB_DS_CLASS_T_DEC
      const typename PB_DS_CLASS_C_DEC::size_type
      PB_DS_CLASS_C_DEC::s_num_bits_in_size_type =
        sizeof(typename PB_DS_CLASS_C_DEC::size_type) << 3;
  
      PB_DS_CLASS_T_DEC
      const typename PB_DS_CLASS_C_DEC::size_type PB_DS_CLASS_C_DEC::s_highest_bit_1 = static_cast<typename PB_DS_CLASS_C_DEC::size_type>(1) << (s_num_bits_in_size_type - 1);
  
   
      PB_DS_CLASS_T_DEC
      void
      PB_DS_CLASS_C_DEC::
      notify_resized(size_type size)
      {
        size_type i = 0;
        while (size ^ s_highest_bit_1)
  	{
  	  size <<= 1;
  	  ++i;
  	}
  
        m_mask = 1;
        i += 2;
        while (i++ < s_num_bits_in_size_type)
          m_mask = (m_mask << 1) ^ 1;
      }
  
  #undef PB_DS_CLASS_T_DEC
  #undef PB_DS_CLASS_C_DEC
  
    } // namespace detail
  } // namespace __gnu_pbds
  
  #endif
  