#ifndef DATE_ITERATOR_HPP___

#define DATE_ITERATOR_HPP___

/* Copyright (c) 2002,2003 CrystalClear Software, Inc.

 * Use, modification and distribution is subject to the 

 * Boost Software License, Version 1.0. (See accompanying

 * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)

 * Author: Jeff Garland, Bart Garst

 * $Date: 2008-02-27 15:00:24 -0500 (Wed, 27 Feb 2008) $

 */

#include <iterator>

namespace boost {

namespace date_time {

  //! An iterator over dates with varying resolution (day, week, month, year, etc)

  enum date_resolutions {day, week, months, year, decade, century, NumDateResolutions};

  //! Base date iterator type

  /*! This class provides the skeleton for the creation of iterators.

   *  New and interesting interators can be created by plugging in a new

   *  function that derives the next value from the current state.

   *  generation of various types of -based information.

   *

   *  <b>Template Parameters</b>

   *

   *  <b>date_type</b>

   *

   *  The date_type is a concrete date_type. The date_type must

   *  define a duration_type and a calendar_type.

   */

  template<class date_type>

  class date_itr_base {

  // works, but benefit unclear at the moment

  //   class date_itr_base : public std::iterator<std::input_iterator_tag, 

  //                                             date_type, void, void, void>{

  public:

    typedef typename date_type::duration_type duration_type;

    typedef date_type value_type;

    typedef std::input_iterator_tag iterator_category;

    date_itr_base(date_type d) : current_(d) {}

    virtual ~date_itr_base() {};

    date_itr_base& operator++() 

    {

      current_ = current_ + get_offset(current_);

      return *this;

    }

    date_itr_base& operator--() 

    {

      current_ = current_ + get_neg_offset(current_);

      return *this;

    }

    virtual duration_type get_offset(const date_type& current) const=0;

    virtual duration_type get_neg_offset(const date_type& current) const=0;

    date_type operator*() {return current_;};

    date_type* operator->() {return &current_;};

    bool operator<  (const date_type& d) {return current_ < d;}

    bool operator<= (const date_type& d) {return current_ <= d;}

    bool operator>  (const date_type& d) {return current_ > d;}

    bool operator>= (const date_type& d) {return current_ >= d;}

    bool operator== (const date_type& d) {return current_ == d;}

    bool operator!= (const date_type& d) {return current_ != d;}    

  private:

    date_type current_;

  };

  //! Overrides the base date iterator providing hook for functors

  /*

   *  <b>offset_functor</b>

   *

   *  The offset functor must define a get_offset function that takes the

   *  current point in time and calculates and offset.

   *

   */

  template<class offset_functor, class date_type>

  class date_itr : public date_itr_base<date_type> {

  public:

    typedef typename date_type::duration_type duration_type;

    date_itr(date_type d, int factor=1) : 

      date_itr_base<date_type>(d), 

      of_(factor) 

    {}

  private:

    virtual duration_type get_offset(const date_type& current) const

    {

      return of_.get_offset(current);

    }

    virtual duration_type get_neg_offset(const date_type& current) const

    {

      return of_.get_neg_offset(current);

    }

    offset_functor of_;

  };

} } //namespace date_time

#endif