libstdc++
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00001 // -*- C++ -*- 00002 00003 // Copyright (C) 2005-2013 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the terms 00007 // of the GNU General Public License as published by the Free Software 00008 // Foundation; either version 3, or (at your option) any later 00009 // version. 00010 00011 // This library is distributed in the hope that it will be useful, but 00012 // WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00014 // General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. 00026 00027 // Permission to use, copy, modify, sell, and distribute this software 00028 // is hereby granted without fee, provided that the above copyright 00029 // notice appears in all copies, and that both that copyright notice 00030 // and this permission notice appear in supporting documentation. None 00031 // of the above authors, nor IBM Haifa Research Laboratories, make any 00032 // representation about the suitability of this software for any 00033 // purpose. It is provided "as is" without express or implied 00034 // warranty. 00035 00036 /** 00037 * @file lu_counter_metadata.hpp 00038 * Contains implementation of a lu counter policy's metadata. 00039 */ 00040 00041 namespace __gnu_pbds 00042 { 00043 namespace detail 00044 { 00045 template<typename Size_Type> 00046 class lu_counter_policy_base; 00047 00048 /// A list-update metadata type that moves elements to the front of 00049 /// the list based on the counter algorithm. 00050 template<typename Size_Type = std::size_t> 00051 class lu_counter_metadata 00052 { 00053 public: 00054 typedef Size_Type size_type; 00055 00056 private: 00057 lu_counter_metadata(size_type init_count) : m_count(init_count) 00058 { } 00059 00060 friend class lu_counter_policy_base<size_type>; 00061 00062 mutable size_type m_count; 00063 }; 00064 00065 /// Base class for list-update counter policy. 00066 template<typename Size_Type> 00067 class lu_counter_policy_base 00068 { 00069 protected: 00070 typedef Size_Type size_type; 00071 00072 lu_counter_metadata<size_type> 00073 operator()(size_type max_size) const 00074 { return lu_counter_metadata<Size_Type>(std::rand() % max_size); } 00075 00076 template<typename Metadata_Reference> 00077 bool 00078 operator()(Metadata_Reference r_data, size_type m_max_count) const 00079 { 00080 if (++r_data.m_count != m_max_count) 00081 return false; 00082 r_data.m_count = 0; 00083 return true; 00084 } 00085 }; 00086 } // namespace detail 00087 } // namespace __gnu_pbds