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[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc3/] [libstdc++-v3/] [include/] [ext/] [pb_ds/] [detail/] [hash_fn/] [mask_based_range_hashing.hpp] - Rev 516
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// -*- 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