1// -*- C++ -*- 2 3// Copyright (C) 2005, 2006 Free Software Foundation, Inc. 4// 5// This file is part of the GNU ISO C++ Library. This library is free 6// software; you can redistribute it and/or modify it under the terms 7// of the GNU General Public License as published by the Free Software 8// Foundation; either version 2, or (at your option) any later 9// version. 10 11// This library is distributed in the hope that it will be useful, but 12// WITHOUT ANY WARRANTY; without even the implied warranty of 13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14// General Public License for more details. 15 16// You should have received a copy of the GNU General Public License 17// along with this library; see the file COPYING. If not, write to 18// the Free Software Foundation, 59 Temple Place - Suite 330, Boston, 19// MA 02111-1307, USA. 20 21// As a special exception, you may use this file as part of a free 22// software library without restriction. Specifically, if other files 23// instantiate templates or use macros or inline functions from this 24// file, or you compile this file and link it with other files to 25// produce an executable, this file does not by itself cause the 26// resulting executable to be covered by the GNU General Public 27// License. This exception does not however invalidate any other 28// reasons why the executable file might be covered by the GNU General 29// Public License. 30 31// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. 32 33// Permission to use, copy, modify, sell, and distribute this software 34// is hereby granted without fee, provided that the above copyright 35// notice appears in all copies, and that both that copyright notice 36// and this permission notice appear in supporting documentation. None 37// of the above authors, nor IBM Haifa Research Laboratories, make any 38// representation about the suitability of this software for any 39// purpose. It is provided "as is" without express or implied 40// warranty. 41 42/** 43 * @file counter_lu_metadata.hpp 44 * Contains implementation of a lu counter policy's metadata. 45 */ 46 47namespace pb_ds 48{ 49 namespace detail 50 { 51 template<typename Size_Type> 52 class counter_lu_policy_base; 53 54 // A list-update metadata type that moves elements to the front of 55 // the list based on the counter algorithm. 56 template<typename Size_Type = size_t> 57 class counter_lu_metadata 58 { 59 public: 60 typedef Size_Type size_type; 61 62 private: 63 counter_lu_metadata(size_type init_count) : m_count(init_count) 64 { } 65 66 friend class counter_lu_policy_base<size_type>; 67 68 mutable size_type m_count; 69 }; 70 71 template<typename Size_Type> 72 class counter_lu_policy_base 73 { 74 protected: 75 typedef Size_Type size_type; 76 77 counter_lu_metadata<size_type> 78 operator()(size_type max_size) const 79 { return counter_lu_metadata<Size_Type>(rand() % max_size); } 80 81 template<typename Metadata_Reference> 82 bool 83 operator()(Metadata_Reference r_data, size_type m_max_count) const 84 { 85 if (++r_data.m_count != m_max_count) 86 return false; 87 r_data.m_count = 0; 88 return true; 89 } 90 }; 91 } // namespace detail 92} // namespace pb_ds 93