/*

    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_PLANAR_PTR_H

#define GIL_PLANAR_PTR_H



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

/// \file               

/// \brief planar pixel pointer class

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

///         Adobe Systems Incorporated

/// \date   2005-2007 \n Last updated on February 12, 2007

///

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



#include <cassert>

#include <iterator>

#include <boost/iterator/iterator_facade.hpp>

#include "gil_config.hpp"

#include "pixel.hpp"

#include "step_iterator.hpp"



namespace boost { namespace gil {



//forward declaration (as this file is included in planar_pixel_reference.hpp)

template <typename ChannelReference, typename ColorSpace> 

struct planar_pixel_reference;



/// \defgroup ColorBaseModelPlanarPtr planar_pixel_iterator 

/// \ingroup ColorBaseModel

/// \brief A homogeneous color base whose element is a channel iterator. Models HomogeneousColorBaseValueConcept

/// This class is used as an iterator to a planar pixel.



/// \defgroup PixelIteratorModelPlanarPtr planar_pixel_iterator

/// \ingroup PixelIteratorModel

/// \brief An iterator over planar pixels. Models PixelIteratorConcept, HomogeneousPixelBasedConcept, MemoryBasedIteratorConcept, HasDynamicXStepTypeConcept



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

/// \brief An iterator over planar pixels. Models HomogeneousColorBaseConcept, PixelIteratorConcept, HomogeneousPixelBasedConcept, MemoryBasedIteratorConcept, HasDynamicXStepTypeConcept

///

/// Planar pixels have channel data that is not consecutive in memory.

/// To abstract this we use classes to represent references and pointers to planar pixels.

/// 

/// \ingroup PixelIteratorModelPlanarPtr ColorBaseModelPlanarPtr PixelBasedModel

template <typename ChannelPtr, typename ColorSpace>

struct planar_pixel_iterator : public iterator_facade<planar_pixel_iterator<ChannelPtr,ColorSpace>,

                                                      pixel<typename std::iterator_traits<ChannelPtr>::value_type,layout<ColorSpace> >,

                                                      random_access_traversal_tag,

                                                      const planar_pixel_reference<typename std::iterator_traits<ChannelPtr>::reference,ColorSpace> >,

                               public detail::homogeneous_color_base<ChannelPtr,layout<ColorSpace>,mpl::size<ColorSpace>::value > {

private:

    typedef iterator_facade<planar_pixel_iterator<ChannelPtr,ColorSpace>,

                            pixel<typename std::iterator_traits<ChannelPtr>::value_type,layout<ColorSpace> >,

                            random_access_traversal_tag,

                            const planar_pixel_reference<typename std::iterator_traits<ChannelPtr>::reference,ColorSpace> > parent_t;

    typedef detail::homogeneous_color_base<ChannelPtr,layout<ColorSpace>,mpl::size<ColorSpace>::value> color_base_parent_t;

    typedef typename std::iterator_traits<ChannelPtr>::value_type channel_t;

public:

    typedef typename parent_t::value_type                 value_type;

    typedef typename parent_t::reference                  reference;

    typedef typename parent_t::difference_type            difference_type;



    planar_pixel_iterator() : color_base_parent_t(0) {} 

    planar_pixel_iterator(bool) {}        // constructor that does not fill with zero (for performance)



    planar_pixel_iterator(const ChannelPtr& v0, const ChannelPtr& v1) : color_base_parent_t(v0,v1) {}

    planar_pixel_iterator(const ChannelPtr& v0, const ChannelPtr& v1, const ChannelPtr& v2) : color_base_parent_t(v0,v1,v2) {}

    planar_pixel_iterator(const ChannelPtr& v0, const ChannelPtr& v1, const ChannelPtr& v2, const ChannelPtr& v3) : color_base_parent_t(v0,v1,v2,v3) {}

    planar_pixel_iterator(const ChannelPtr& v0, const ChannelPtr& v1, const ChannelPtr& v2, const ChannelPtr& v3, const ChannelPtr& v4) : color_base_parent_t(v0,v1,v2,v3,v4) {}



    template <typename IC1,typename C1> 

    planar_pixel_iterator(const planar_pixel_iterator<IC1,C1>& ptr) : color_base_parent_t(ptr) {}





    /// Copy constructor and operator= from pointers to compatible planar pixels or planar pixel references.

    /// That allow constructs like pointer = &value or pointer = &reference

    /// Since we should not override operator& that's the best we can do.

    template <typename P> 

    planar_pixel_iterator(P* pix) : color_base_parent_t(pix, true) {

        function_requires<PixelsCompatibleConcept<P,value_type> >();

    }



    struct address_of { template <typename T> T* operator()(T& t) { return &t; } };

    template <typename P> 

    planar_pixel_iterator& operator=(P* pix) {

        function_requires<PixelsCompatibleConcept<P,value_type> >();

        static_transform(*pix,*this, address_of());



        // PERFORMANCE_CHECK: Compare to this:

        //this->template semantic_at_c<0>()=&pix->template semantic_at_c<0>();

        //this->template semantic_at_c<1>()=&pix->template semantic_at_c<1>();

        //this->template semantic_at_c<2>()=&pix->template semantic_at_c<2>();

        return *this;

    }



    /// 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 memunit_advanced_ref(*this,d*sizeof(channel_t));}



    reference operator->()                        const { return **this; }



    // PERFORMANCE_CHECK: Remove?

    bool operator< (const planar_pixel_iterator& ptr)   const { return at_c<0>(*this)< at_c<0>(ptr); }

    bool operator!=(const planar_pixel_iterator& ptr)   const { return at_c<0>(*this)!=at_c<0>(ptr); }

private:

    friend class boost::iterator_core_access;



    void increment()            { static_transform(*this,*this,detail::inc<ChannelPtr>()); }

    void decrement()            { static_transform(*this,*this,detail::dec<ChannelPtr>()); }

    void advance(ptrdiff_t d)   { static_transform(*this,*this,std::bind2nd(detail::plus_asymmetric<ChannelPtr,ptrdiff_t>(),d)); }

    reference dereference() const { return this->template deref<reference>(); }



    ptrdiff_t distance_to(const planar_pixel_iterator& it) const { return at_c<0>(it)-at_c<0>(*this); }

    bool equal(const planar_pixel_iterator& it) const { return at_c<0>(*this)==at_c<0>(it); }

};



namespace detail {

    template <typename IC> struct channel_iterator_is_mutable : public mpl::true_ {};

    template <typename T>  struct channel_iterator_is_mutable<const T*> : public mpl::false_ {};

}



template <typename IC, typename C> 

struct const_iterator_type<planar_pixel_iterator<IC,C> > { 

private:

    typedef typename std::iterator_traits<IC>::value_type channel_t;

public:

    typedef planar_pixel_iterator<typename channel_traits<channel_t>::const_pointer,C> type; 

};



// The default implementation when the iterator is a C pointer is to use the standard constness semantics

template <typename IC, typename C> 

struct iterator_is_mutable<planar_pixel_iterator<IC,C> > : public detail::channel_iterator_is_mutable<IC> {};



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

//  ColorBasedConcept

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



template <typename IC, typename C, int K>  

struct kth_element_type<planar_pixel_iterator<IC,C>, K> {

    typedef IC type;

};



template <typename IC, typename C, int K>  

struct kth_element_reference_type<planar_pixel_iterator<IC,C>, K> : public add_reference<IC> {};



template <typename IC, typename C, int K>  

struct kth_element_const_reference_type<planar_pixel_iterator<IC,C>, K> : public add_reference<typename add_const<IC>::type> {};



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

//  HomogeneousPixelBasedConcept

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



template <typename IC, typename C>

struct color_space_type<planar_pixel_iterator<IC,C> > {

    typedef C type;

};



template <typename IC, typename C>

struct channel_mapping_type<planar_pixel_iterator<IC,C> > : public channel_mapping_type<typename planar_pixel_iterator<IC,C>::value_type> {};



template <typename IC, typename C>

struct is_planar<planar_pixel_iterator<IC,C> > : public mpl::true_ {};



template <typename IC, typename C>

struct channel_type<planar_pixel_iterator<IC,C> > {

    typedef typename std::iterator_traits<IC>::value_type type;

};



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

//  MemoryBasedIteratorConcept

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



template <typename IC, typename C>

inline std::ptrdiff_t memunit_step(const planar_pixel_iterator<IC,C>&) { return sizeof(typename std::iterator_traits<IC>::value_type); }



template <typename IC, typename C>

inline std::ptrdiff_t memunit_distance(const planar_pixel_iterator<IC,C>& p1, const planar_pixel_iterator<IC,C>& p2) { 

    return memunit_distance(at_c<0>(p1),at_c<0>(p2)); 

}



template <typename IC>

struct memunit_advance_fn {

    memunit_advance_fn(std::ptrdiff_t diff) : _diff(diff) {}

    IC operator()(const IC& p) const { return memunit_advanced(p,_diff); }



    std::ptrdiff_t _diff;

};



template <typename IC, typename C>

inline void memunit_advance(planar_pixel_iterator<IC,C>& p, std::ptrdiff_t diff) { 

    static_transform(p, p, memunit_advance_fn<IC>(diff));

}



template <typename IC, typename C>

inline planar_pixel_iterator<IC,C> memunit_advanced(const planar_pixel_iterator<IC,C>& p, std::ptrdiff_t diff) {

    planar_pixel_iterator<IC,C> ret=p;

    memunit_advance(ret, diff);

    return ret;

}



template <typename ChannelPtr, typename ColorSpace>

inline planar_pixel_reference<typename std::iterator_traits<ChannelPtr>::reference,ColorSpace> 

    memunit_advanced_ref(const planar_pixel_iterator<ChannelPtr,ColorSpace>& ptr, std::ptrdiff_t diff) {

    return planar_pixel_reference<typename std::iterator_traits<ChannelPtr>::reference,ColorSpace>(ptr, diff);

}



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

//  HasDynamicXStepTypeConcept

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



template <typename IC, typename C>

struct dynamic_x_step_type<planar_pixel_iterator<IC,C> > {

    typedef memory_based_step_iterator<planar_pixel_iterator<IC,C> > type;

};



} }  // namespace boost::gil



#endif

