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