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/* -*- C++ -*-
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*
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* This file is a part of LEMON, a generic C++ optimization library
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*
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* Copyright (C) 2003-2008
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* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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* (Egervary Research Group on Combinatorial Optimization, EGRES).
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*
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* Permission to use, modify and distribute this software is granted
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* provided that this copyright notice appears in all copies. For
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* precise terms see the accompanying LICENSE file.
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*
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* This software is provided "AS IS" with no warranty of any kind,
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* express or implied, and with no claim as to its suitability for any
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* purpose.
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*
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*/
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#ifndef LEMON_BITS_INVALID_H
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#define LEMON_BITS_INVALID_H
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///\file
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///\brief Definition of INVALID.
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namespace lemon {
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/// \brief Dummy type to make it easier to create invalid iterators.
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///
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/// Dummy type to make it easier to create invalid iterators.
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/// See \ref INVALID for the usage.
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struct Invalid {
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public:
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bool operator==(Invalid) { return true; }
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bool operator!=(Invalid) { return false; }
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bool operator< (Invalid) { return false; }
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};
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/// \brief Invalid iterators.
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///
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/// \ref Invalid is a global type that converts to each iterator
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/// in such a way that the value of the target iterator will be invalid.
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//Some people didn't like this:
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//const Invalid &INVALID = *(Invalid *)0;
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#ifdef LEMON_ONLY_TEMPLATES
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const Invalid INVALID = Invalid();
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#else
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extern const Invalid INVALID;
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#endif
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} //namespace lemon
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#endif
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