boost/gil/planar_pixel_iterator.hpp
/*
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
