/*

    Copyright 2005-2007 Adobe Systems Incorporated

   

    Use, modification and distribution are subject to the Boost Software License,

    Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at

    http://www.boost.org/LICENSE_1_0.txt).



    See http://opensource.adobe.com/gil for most recent version including documentation.

*/



/*************************************************************************************************/



#ifndef GIL_PIXEL_ITERATOR_ADAPTOR_H

#define GIL_PIXEL_ITERATOR_ADAPTOR_H



////////////////////////////////////////////////////////////////////////////////////////

/// \file               

/// \brief pixel step iterator, pixel image iterator and pixel dereference iterator

/// \author Lubomir Bourdev and Hailin Jin \n

///         Adobe Systems Incorporated

/// \date   2005-2007 \n Last updated on February 16, 2007

///

////////////////////////////////////////////////////////////////////////////////////////



#include <iterator>

#include <boost/iterator/iterator_facade.hpp>

#include "gil_config.hpp"

#include "gil_concept.hpp"

#include "pixel_iterator.hpp"



namespace boost { namespace gil {





/// \defgroup PixelIteratorModelDerefPtr dereference_iterator_adaptor

/// \ingroup PixelIteratorModel

/// \brief An iterator that invokes a provided function object upon dereference. Models: IteratorAdaptorConcept, PixelIteratorConcept





/// \ingroup PixelIteratorModelDerefPtr PixelBasedModel

/// \brief An adaptor over an existing iterator that provides for custom filter on dereferencing the object. Models: IteratorAdaptorConcept, PixelIteratorConcept



template <typename Iterator,    // Models Iterator

          typename DFn>  // Models Returns the result of dereferencing a given iterator of type Iterator

class dereference_iterator_adaptor : public iterator_adaptor<dereference_iterator_adaptor<Iterator,DFn>,

                                                             Iterator,

                                                             typename DFn::value_type,

                                                             use_default,

                                                             typename DFn::reference,

                                                             use_default> {

    DFn _deref_fn;

public:

    typedef iterator_adaptor<dereference_iterator_adaptor<Iterator,DFn>,

                                    Iterator,

                                    typename DFn::value_type,

                                    use_default,

                                    typename DFn::reference,

                                    use_default> parent_t;

    typedef typename DFn::result_type                         reference;

    typedef typename std::iterator_traits<Iterator>::difference_type difference_type;

    typedef DFn                                               dereference_fn;



    dereference_iterator_adaptor() {}

    template <typename Iterator1> 

    dereference_iterator_adaptor(const dereference_iterator_adaptor<Iterator1,DFn>& dit) : parent_t(dit.base()), _deref_fn(dit._deref_fn) {}

    dereference_iterator_adaptor(Iterator it, DFn deref_fn=DFn()) : parent_t(it), _deref_fn(deref_fn) {}

    template <typename Iterator1, typename DFn1> 

    dereference_iterator_adaptor(const dereference_iterator_adaptor<Iterator1,DFn1>& it) : parent_t(it.base()), _deref_fn(it._deref_fn) {}

    /// For some reason operator[] provided by iterator_facade returns a custom class that is convertible to reference

    /// We require our own reference because it is registered in iterator_traits

    reference operator[](difference_type d) const { return *(*this+d);}



    // although iterator_adaptor defines these, the default implementation computes distance and compares for zero.

    // it is often faster to just apply the relation operator to the base

    bool    operator> (const dereference_iterator_adaptor& p) const { return this->base_reference()> p.base_reference(); }

    bool    operator< (const dereference_iterator_adaptor& p) const { return this->base_reference()< p.base_reference(); }

    bool    operator>=(const dereference_iterator_adaptor& p) const { return this->base_reference()>=p.base_reference(); }

    bool    operator<=(const dereference_iterator_adaptor& p) const { return this->base_reference()<=p.base_reference(); }

    bool    operator==(const dereference_iterator_adaptor& p) const { return this->base_reference()==p.base_reference(); }

    bool    operator!=(const dereference_iterator_adaptor& p) const { return this->base_reference()!=p.base_reference(); }



    Iterator& base()              { return this->base_reference(); }

    const Iterator& base() const  { return this->base_reference(); }

    const DFn& deref_fn() const { return _deref_fn; }

private:

    template <typename Iterator1, typename DFn1> 

    friend class dereference_iterator_adaptor;

    friend class boost::iterator_core_access;



    reference dereference() const { return _deref_fn(*(this->base_reference())); }

};



template <typename I, typename DFn> 

struct const_iterator_type<dereference_iterator_adaptor<I,DFn> > { 

    typedef dereference_iterator_adaptor<typename const_iterator_type<I>::type,typename DFn::const_t> type; 

};



template <typename I, typename DFn> 

struct iterator_is_mutable<dereference_iterator_adaptor<I,DFn> > : public mpl::bool_<DFn::is_mutable> {};





template <typename I, typename DFn>

struct is_iterator_adaptor<dereference_iterator_adaptor<I,DFn> > : public mpl::true_{};



template <typename I, typename DFn>

struct iterator_adaptor_get_base<dereference_iterator_adaptor<I,DFn> > {

    typedef I type;

};



template <typename I, typename DFn, typename NewBaseIterator>

struct iterator_adaptor_rebind<dereference_iterator_adaptor<I,DFn>,NewBaseIterator> {

    typedef dereference_iterator_adaptor<NewBaseIterator,DFn> type;

};



/////////////////////////////

//  PixelBasedConcept

/////////////////////////////



template <typename I, typename DFn>

struct color_space_type<dereference_iterator_adaptor<I,DFn> > : public color_space_type<typename DFn::value_type> {};



template <typename I, typename DFn>

struct channel_mapping_type<dereference_iterator_adaptor<I,DFn> > : public channel_mapping_type<typename DFn::value_type> {};



template <typename I, typename DFn>

struct is_planar<dereference_iterator_adaptor<I,DFn> > : public is_planar<typename DFn::value_type> {};



template <typename I, typename DFn>

struct channel_type<dereference_iterator_adaptor<I,DFn> > : public channel_type<typename DFn::value_type> {};





/////////////////////////////

//  MemoryBasedIteratorConcept

/////////////////////////////



template <typename Iterator, typename DFn>

struct byte_to_memunit<dereference_iterator_adaptor<Iterator,DFn> > : public byte_to_memunit<Iterator> {};



template <typename Iterator, typename DFn>

inline typename std::iterator_traits<Iterator>::difference_type 

memunit_step(const dereference_iterator_adaptor<Iterator,DFn>& p) { 

    return memunit_step(p.base());

}



template <typename Iterator, typename DFn>

inline typename std::iterator_traits<Iterator>::difference_type 

memunit_distance(const dereference_iterator_adaptor<Iterator,DFn>& p1, 

              const dereference_iterator_adaptor<Iterator,DFn>& p2) { 

    return memunit_distance(p1.base(),p2.base()); 

}



template <typename Iterator, typename DFn>

inline void memunit_advance(dereference_iterator_adaptor<Iterator,DFn>& p, 

                         typename std::iterator_traits<Iterator>::difference_type diff) { 

    memunit_advance(p.base(), diff);

}



template <typename Iterator, typename DFn>

inline dereference_iterator_adaptor<Iterator,DFn> 

memunit_advanced(const dereference_iterator_adaptor<Iterator,DFn>& p, 

              typename std::iterator_traits<Iterator>::difference_type diff) { 

    return dereference_iterator_adaptor<Iterator,DFn>(memunit_advanced(p.base(), diff), p.deref_fn()); 

}





template <typename Iterator, typename DFn>

inline 

typename std::iterator_traits<dereference_iterator_adaptor<Iterator,DFn> >::reference 

memunit_advanced_ref(const dereference_iterator_adaptor<Iterator,DFn>& p, 

                  typename std::iterator_traits<Iterator>::difference_type diff) { 

    return *memunit_advanced(p, diff);

}



/////////////////////////////

//  HasDynamicXStepTypeConcept

/////////////////////////////



template <typename Iterator, typename DFn>

struct dynamic_x_step_type<dereference_iterator_adaptor<Iterator,DFn> > {

    typedef dereference_iterator_adaptor<typename dynamic_x_step_type<Iterator>::type,DFn> type;

};



/// \brief Returns the type (and creates an instance) of an iterator that invokes the given dereference adaptor upon dereferencing

/// \ingroup PixelIteratorModelDerefPtr

template <typename Iterator, typename Deref>

struct iterator_add_deref {

    GIL_CLASS_REQUIRE(Deref, boost::gil, PixelDereferenceAdaptorConcept)



    typedef dereference_iterator_adaptor<Iterator, Deref> type;



    static type make(const Iterator& it, const Deref& d) { return type(it,d); }

};



/// \ingroup PixelIteratorModelDerefPtr

/// \brief For dereference iterator adaptors, compose the new function object after the old one

template <typename Iterator, typename PREV_DEREF, typename Deref>

struct iterator_add_deref<dereference_iterator_adaptor<Iterator, PREV_DEREF>,Deref> {

//    GIL_CLASS_REQUIRE(Deref, boost::gil, PixelDereferenceAdaptorConcept)



    typedef dereference_iterator_adaptor<Iterator, deref_compose<Deref,PREV_DEREF> > type;



    static type make(const dereference_iterator_adaptor<Iterator, PREV_DEREF>& it, const Deref& d) { 

        return type(it.base(),deref_compose<Deref,PREV_DEREF>(d,it.deref_fn())); 

    }

};



} }  // namespace boost::gil



#endif