1 // -*- C++ -*- 2 3 // Copyright (C) 2005, 2006, 2007, 2009, 2010 4 // Free Software Foundation, Inc. 5 // 6 // This file is part of the GNU ISO C++ Library. This library is free 7 // software; you can redistribute it and/or modify it under the terms 8 // of the GNU General Public License as published by the Free Software 9 // Foundation; either version 3, or (at your option) any later 10 // version. 11 12 // This library is distributed in the hope that it will be useful, but 13 // WITHOUT ANY WARRANTY; without even the implied warranty of 14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 // General Public License for more details. 16 17 // Under Section 7 of GPL version 3, you are granted additional 18 // permissions described in the GCC Runtime Library Exception, version 19 // 3.1, as published by the Free Software Foundation. 20 21 // You should have received a copy of the GNU General Public License and 22 // a copy of the GCC Runtime Library Exception along with this program; 23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 // <http://www.gnu.org/licenses/>. 25 26 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. 27 28 // Permission to use, copy, modify, sell, and distribute this software 29 // is hereby granted without fee, provided that the above copyright 30 // notice appears in all copies, and that both that copyright notice 31 // and this permission notice appear in supporting documentation. None 32 // of the above authors, nor IBM Haifa Research Laboratories, make any 33 // representation about the suitability of this software for any 34 // purpose. It is provided "as is" without express or implied 35 // warranty. 36 37 /** 38 * @file list_update_policy.hpp 39 * Contains policies for list update containers. 40 */ 41 42 #ifndef PB_DS_LU_POLICY_HPP 43 #define PB_DS_LU_POLICY_HPP 44 45 #include <bits/c++config.h> 46 #include <cstdlib> 47 #include <ext/pb_ds/detail/list_update_policy/counter_lu_metadata.hpp> 48 49 namespace __gnu_pbds 50 { 51 // A null type that means that each link in a list-based container 52 // does not actually need metadata. 53 struct null_lu_metadata 54 { }; 55 56 #define PB_DS_CLASS_T_DEC template<typename Allocator> 57 #define PB_DS_CLASS_C_DEC move_to_front_lu_policy<Allocator> 58 59 // A list-update policy that unconditionally moves elements to the 60 // front of the list. 61 template<typename Allocator = std::allocator<char> > 62 class move_to_front_lu_policy 63 { 64 public: 65 typedef Allocator allocator_type; 66 67 // Metadata on which this functor operates. 68 typedef null_lu_metadata metadata_type; 69 70 // Reference to metadata on which this functor operates. 71 typedef typename allocator_type::template rebind<metadata_type>::other metadata_rebind; 72 typedef typename metadata_rebind::reference metadata_reference; 73 74 // Creates a metadata object. 75 metadata_type 76 operator()() const; 77 78 // Decides whether a metadata object should be moved to the front 79 // of the list. 80 inline bool 81 operator()(metadata_reference r_metadata) const; 82 83 private: 84 static null_lu_metadata s_metadata; 85 }; 86 87 #include <ext/pb_ds/detail/list_update_policy/mtf_lu_policy_imp.hpp> 88 89 #undef PB_DS_CLASS_T_DEC 90 #undef PB_DS_CLASS_C_DEC 91 92 #define PB_DS_CLASS_T_DEC template<std::size_t Max_Count, class Allocator> 93 #define PB_DS_CLASS_C_DEC counter_lu_policy<Max_Count, Allocator> 94 95 // A list-update policy that moves elements to the front of the list 96 // based on the counter algorithm. 97 template<std::size_t Max_Count = 5, 98 typename Allocator = std::allocator<char> > 99 class counter_lu_policy 100 : private detail::counter_lu_policy_base<typename Allocator::size_type> 101 { 102 public: 103 typedef Allocator allocator_type; 104 105 enum 106 { 107 max_count = Max_Count 108 }; 109 110 typedef typename allocator_type::size_type size_type; 111 112 // Metadata on which this functor operates. 113 typedef detail::counter_lu_metadata<size_type> metadata_type; 114 115 // Reference to metadata on which this functor operates. 116 typedef typename Allocator::template rebind<metadata_type>::other metadata_rebind; 117 typedef typename metadata_rebind::reference metadata_reference; 118 119 // Creates a metadata object. 120 metadata_type 121 operator()() const; 122 123 // Decides whether a metadata object should be moved to the front 124 // of the list. 125 bool 126 operator()(metadata_reference r_metadata) const; 127 128 private: 129 typedef detail::counter_lu_policy_base<typename Allocator::size_type> base_type; 130 }; 131 132 #include <ext/pb_ds/detail/list_update_policy/counter_lu_policy_imp.hpp> 133 134 #undef PB_DS_CLASS_T_DEC 135 #undef PB_DS_CLASS_C_DEC 136 137 } // namespace __gnu_pbds 138 139 #endif 140
