source: trunk/yat/utility/WeightIterator.h @ 1486

#ifndef _theplu_yat_utility_weight_iterator_
#define _theplu_yat_utility_weight_iterator_

// $Id: WeightIterator.h 1486 2008-09-09 21:17:19Z jari $

/*
  Copyright (C) 2008 Peter Johansson

  This file is part of the yat library, http://dev.thep.lu.se/yat

  The yat library is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 3 of the
  License, or (at your option) any later version.

  The yat library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/

#include <boost/iterator/iterator_adaptor.hpp>
#include <boost/type_traits/remove_reference.hpp>

namespace theplu {
namespace yat {
namespace utility {

  /**
     @brief WeightIterator
  */
  template<typename Base>
  class WeightIterator
    : public boost::iterator_adaptor<
    WeightIterator<Base>               // Derived
    , Base                          // Base
    , typename boost::remove_reference<typename iterator_traits<Base>::weight_reference>::type 
    , boost::forward_traversal_tag    // CategoryOrTraversal
    , typename iterator_traits<Base>::weight_reference // Reference
    >

  {
  public:
    /**
       \brief Constructor from \a Base iterator
     */
    explicit WeightIterator(Base b)
      : WeightIterator::iterator_adaptor_(b) {}

    /**
       \brief Conversion constructor. 

       Create a WeightIterator<Base> from a
       WeightIterator<B2>. Possible if B2 is convertible to a
       Base. Constructor allows implicit conversions such as iterator
       to const_iterator.
     */
    template<typename B2>
    WeightIterator(WeightIterator<B2> other,
                   typename boost::enable_if_convertible<B2, Base>::type* = 0 )
      : WeightIterator::iterator_adaptor_(other.base()) {}

    /**
       using iterator_traits::data on Base iterator

       \return data
     */
    typename iterator_traits<Base>::weight_reference operator*(void) const
    { return iterator_traits<Base>().weight(this->base()); }

  private:
  };

  /**
     \brief convenient function to create WeightIterator

     Convenient function in same fashion as std::make_pair.
   */
  template<typename Base>
  WeightIterator<Base> weight_iterator(Base base)
  {
    return WeightIterator<Base>(base);
  }
  


}}} // of namespace utility, yat, and theplu

#endif