SPAR/AIModule/BWTA/vendors/CGAL/CGAL/Flattening_iterator.h

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// Copyright (c) 2001-2007 Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.5-branch/STL_Extension/include/CGAL/Flattening_iterator.h $
// $Id: Flattening_iterator.h 37883 2007-04-03 16:07:32Z ameyer $
//
// Author(s)     : Arno Eigenwillig <arno@mpi-inf.mpg.de>

#ifndef CGAL_FLATTENING_ITERATOR_H
#define CGAL_FLATTENING_ITERATOR_H 1

#include <CGAL/basic.h>
#include <CGAL/Nested_iterator.h>

#include <iterator>
#include <functional>

// LiS2CGAL check whether Nested_iterator in CGAL works in STL_extensions

CGAL_BEGIN_NAMESPACE

template <int level_, class InputIterator>
class Recursive_const_flattening;

template <class InputIterator>
class Recursive_const_flattening<0, InputIterator> {
public:
    typedef Recursive_const_flattening Self;
    static const int level = 0;
    typedef InputIterator  Input_iterator;

    typedef Input_iterator Recursive_flattening_iterator;

    struct Flatten {
        typedef Recursive_flattening_iterator result_type;
        typedef Input_iterator argument_type;

        Recursive_flattening_iterator
        operator () (Input_iterator /*end*/, Input_iterator it) {
            return it;
        }
    };
};

template <class InputIterator>
class Recursive_const_flattening<1, InputIterator> {
public:
    typedef Recursive_const_flattening Self;
    static const int level = 1;
    typedef InputIterator Input_iterator;

private:
    struct Nested_iterator_traits
    {
      typedef Input_iterator Base_iterator;
      typedef typename std::iterator_traits<Input_iterator>::value_type::const_iterator
              Iterator;

      Iterator begin(Input_iterator it) const { return it->begin(); }
      Iterator end  (Input_iterator it) const { return it->end();   }
    };

public:

    typedef CGAL::Nested_iterator< Input_iterator, Nested_iterator_traits >
            Recursive_flattening_iterator;

    struct Flatten {
        typedef Recursive_flattening_iterator result_type;
        typedef Input_iterator                argument_type;

        Recursive_flattening_iterator
        operator () (Input_iterator end, Input_iterator it) {
            return Recursive_flattening_iterator(end,it);
        }
    };
};

template< int level_, class InputIterator >
class Recursive_const_flattening {
public:
    typedef Recursive_const_flattening Self;
    static const int level = level_;
    typedef InputIterator Input_iterator;

    typedef Recursive_const_flattening<
            level-1,
            typename std::iterator_traits<Input_iterator>::value_type::const_iterator
        > Nested_self;

private:
    struct Nested_iterator_traits
    {
      typedef Input_iterator
              Base_iterator;
      typedef typename Nested_self::Recursive_flattening_iterator
              Iterator;

      Iterator begin(Input_iterator it) const { return typename Nested_self::Flatten()(it->end(),it->begin()); }
      Iterator end  (Input_iterator it) const { return typename Nested_self::Flatten()(it->end(),it->end());   }
    };

public:
    typedef CGAL::Nested_iterator< Input_iterator, Nested_iterator_traits >
            Recursive_flattening_iterator;

    struct Flatten {
        typedef Recursive_flattening_iterator result_type;
        typedef Input_iterator                argument_type;

        Recursive_flattening_iterator
        operator () (Input_iterator end,Input_iterator it) {
            return Recursive_flattening_iterator(end,it);
        }
    };
};

#ifdef DOXYGEN_RUNNING

template <int level_, class InputIterator>
class Recursive_flattening { };
#endif // DOXYGEN_RUNNING

/*
 * Part 2: Helper functions
 */

template <int level, class InputIterator> inline
typename Recursive_const_flattening<level, InputIterator>
    ::Recursive_flattening_iterator
recursive_const_flattener(InputIterator end,InputIterator it) {
    return typename Recursive_const_flattening<level, InputIterator>::Flatten()(end,it);
}

template <class InputIterator> inline
typename Recursive_const_flattening<1, InputIterator>
    ::Recursive_flattening_iterator
const_flattener(InputIterator end,InputIterator it) {
    return typename Recursive_const_flattening<1, InputIterator>::Flatten()(end,it);
}

#ifdef DOXYGEN_RUNNING

template <int level, class InputIterator> inline
typename Recursive_flattening<level, InputIterator>
    ::Recursive_flattening_iterator
recursive_flattener(InputIterator it);

template <class InputIterator> inline
typename Recursive_flattening<1, InputIterator>
    ::Recursive_flattening_iterator
flattener(InputIterator it);
#endif // DOXYGEN_RUNNING


CGAL_END_NAMESPACE

#endif // LiS_FLATTENING_ITERATOR_H