libstdc++
sample_update_policy.hpp
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00001 // -*- C++ -*-
00002 
00003 // Copyright (C) 2005, 2006, 2009 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 sample_update_policy.hpp
00038  * Contains a sample policy for list update containers.
00039  */
00040 
00041 #ifndef PB_DS_SAMPLE_UPDATE_POLICY_HPP
00042 #define PB_DS_SAMPLE_UPDATE_POLICY_HPP
00043 
00044 namespace __gnu_pbds
00045 {
00046   /// A sample list-update policy.
00047   struct sample_update_policy
00048   {
00049     /// Default constructor.
00050     sample_update_policy();
00051 
00052     /// Copy constructor.
00053     sample_update_policy(const sample_update_policy&);
00054 
00055     /// Swaps content.
00056     inline void
00057     swap(sample_update_policy& other);
00058 
00059   protected:
00060     /// Metadata on which this functor operates.
00061     typedef some_metadata_type metadata_type;
00062 
00063     /// Creates a metadata object.
00064     metadata_type
00065     operator()() const;
00066 
00067     /// Decides whether a metadata object should be moved to the front
00068     /// of the list. A list-update based containers object will call
00069     /// this method to decide whether to move a node to the front of
00070     /// the list. The method shoule return true if the node should be
00071     /// moved to the front of the list.
00072     bool
00073     operator()(metadata_reference) const;
00074   };
00075 }
00076 #endif