1169691Skan// -*- C++ -*- 2169691Skan 3169691Skan// Copyright (C) 2005, 2006 Free Software Foundation, Inc. 4169691Skan// 5169691Skan// This file is part of the GNU ISO C++ Library. This library is free 6169691Skan// software; you can redistribute it and/or modify it under the terms 7169691Skan// of the GNU General Public License as published by the Free Software 8169691Skan// Foundation; either version 2, or (at your option) any later 9169691Skan// version. 10169691Skan 11169691Skan// This library is distributed in the hope that it will be useful, but 12169691Skan// WITHOUT ANY WARRANTY; without even the implied warranty of 13169691Skan// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14169691Skan// General Public License for more details. 15169691Skan 16169691Skan// You should have received a copy of the GNU General Public License 17169691Skan// along with this library; see the file COPYING. If not, write to 18169691Skan// the Free Software Foundation, 59 Temple Place - Suite 330, Boston, 19169691Skan// MA 02111-1307, USA. 20169691Skan 21169691Skan// As a special exception, you may use this file as part of a free 22169691Skan// software library without restriction. Specifically, if other files 23169691Skan// instantiate templates or use macros or inline functions from this 24169691Skan// file, or you compile this file and link it with other files to 25169691Skan// produce an executable, this file does not by itself cause the 26169691Skan// resulting executable to be covered by the GNU General Public 27169691Skan// License. This exception does not however invalidate any other 28169691Skan// reasons why the executable file might be covered by the GNU General 29169691Skan// Public License. 30169691Skan 31169691Skan// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. 32169691Skan 33169691Skan// Permission to use, copy, modify, sell, and distribute this software 34169691Skan// is hereby granted without fee, provided that the above copyright 35169691Skan// notice appears in all copies, and that both that copyright notice 36169691Skan// and this permission notice appear in supporting documentation. None 37169691Skan// of the above authors, nor IBM Haifa Research Laboratories, make any 38169691Skan// representation about the suitability of this software for any 39169691Skan// purpose. It is provided "as is" without express or implied 40169691Skan// warranty. 41169691Skan 42169691Skan/** 43169691Skan * @file mask_based_range_hashing.hpp 44169691Skan * Contains a range hashing policy base. 45169691Skan */ 46169691Skan 47169691Skan#ifndef PB_DS_MASK_BASED_RANGE_HASHING_HPP 48169691Skan#define PB_DS_MASK_BASED_RANGE_HASHING_HPP 49169691Skan 50169691Skannamespace pb_ds 51169691Skan{ 52169691Skan namespace detail 53169691Skan { 54169691Skan#define PB_DS_CLASS_T_DEC template<typename Size_Type> 55169691Skan#define PB_DS_CLASS_C_DEC mask_based_range_hashing<Size_Type> 56169691Skan 57169691Skan template<typename Size_Type> 58169691Skan class mask_based_range_hashing 59169691Skan { 60169691Skan protected: 61169691Skan typedef Size_Type size_type; 62169691Skan 63169691Skan void 64169691Skan swap(mask_based_range_hashing& other) 65169691Skan { std::swap(m_mask, other.m_mask); } 66169691Skan 67169691Skan void 68169691Skan notify_resized(size_type size); 69169691Skan 70169691Skan inline size_type 71169691Skan range_hash(size_type hash) const 72169691Skan { return size_type(hash & m_mask); } 73169691Skan 74169691Skan private: 75169691Skan size_type m_mask; 76169691Skan const static size_type s_num_bits_in_size_type; 77169691Skan const static size_type s_highest_bit_1; 78169691Skan }; 79169691Skan 80169691Skan PB_DS_CLASS_T_DEC 81169691Skan const typename PB_DS_CLASS_C_DEC::size_type 82169691Skan PB_DS_CLASS_C_DEC::s_num_bits_in_size_type = 83169691Skan sizeof(typename PB_DS_CLASS_C_DEC::size_type) << 3; 84169691Skan 85169691Skan PB_DS_CLASS_T_DEC 86169691Skan 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); 87169691Skan 88169691Skan 89169691Skan PB_DS_CLASS_T_DEC 90169691Skan void 91169691Skan PB_DS_CLASS_C_DEC:: 92169691Skan notify_resized(size_type size) 93169691Skan { 94169691Skan size_type i = 0; 95169691Skan while (size ^ s_highest_bit_1) 96169691Skan { 97169691Skan size <<= 1; 98169691Skan ++i; 99169691Skan } 100169691Skan 101169691Skan m_mask = 1; 102169691Skan i += 2; 103169691Skan while (i++ < s_num_bits_in_size_type) 104169691Skan m_mask = (m_mask << 1) ^ 1; 105169691Skan } 106169691Skan 107169691Skan#undef PB_DS_CLASS_T_DEC 108169691Skan#undef PB_DS_CLASS_C_DEC 109169691Skan 110169691Skan } // namespace detail 111169691Skan} // namespace pb_ds 112169691Skan 113169691Skan#endif 114