Chris@16: /*
Chris@16:     Copyright 2005-2007 Adobe Systems Incorporated
Chris@16:    
Chris@16:     Use, modification and distribution are subject to the Boost Software License,
Chris@16:     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:     http://www.boost.org/LICENSE_1_0.txt).
Chris@16: 
Chris@16:     See http://opensource.adobe.com/gil for most recent version including documentation.
Chris@16: */
Chris@16: 
Chris@16: /*************************************************************************************************/
Chris@16: 
Chris@16: #ifndef GIL_PIXEL_ITERATOR_H
Chris@16: #define GIL_PIXEL_ITERATOR_H
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: /// \file               
Chris@16: /// \brief pixel iterator support
Chris@16: /// \author Lubomir Bourdev and Hailin Jin \n
Chris@16: ///         Adobe Systems Incorporated
Chris@16: /// \date   2005-2007 \n May 16, 2006
Chris@16: ///
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #include <cassert>
Chris@16: #include <iterator>
Chris@16: #include "gil_config.hpp"
Chris@16: #include "gil_concept.hpp"
Chris@16: #include "utilities.hpp"
Chris@16: #include "pixel.hpp"
Chris@16: 
Chris@16: namespace boost { namespace gil {
Chris@16: 
Chris@16: //forwarded declaration (as this file is included in step_iterator.hpp)
Chris@16: template <typename Iterator>
Chris@16: class memory_based_step_iterator;
Chris@16: 
Chris@16: template <typename Iterator> struct dynamic_x_step_type;
Chris@16: 
Chris@16: /// \brief metafunction predicate determining whether the given iterator is a plain one or an adaptor over another iterator.
Chris@16: /// Examples of adaptors are the step iterator and the dereference iterator adaptor.
Chris@16: template <typename It>
Chris@16: struct is_iterator_adaptor : public mpl::false_{};
Chris@16: 
Chris@16: /// \brief returns the base iterator for a given iterator adaptor. Provide an specialization when introducing new iterator adaptors
Chris@16: template <typename It>
Chris@16: struct iterator_adaptor_get_base;
Chris@16: 
Chris@16: /// \brief Changes the base iterator of an iterator adaptor. Provide an specialization when introducing new iterator adaptors
Chris@16: template <typename It, typename NewBaseIt>
Chris@16: struct iterator_adaptor_rebind;
Chris@16: 
Chris@16: /// \brief Returns the type of an iterator just like the input iterator, except operating over immutable values
Chris@16: template <typename It>
Chris@16: struct const_iterator_type;
Chris@16: 
Chris@16: // The default implementation when the iterator is a C pointer is to use the standard constness semantics
Chris@16: template <typename T> struct const_iterator_type<      T*> { typedef const T* type; };
Chris@16: template <typename T> struct const_iterator_type<const T*> { typedef const T* type; };
Chris@16: 
Chris@16: /// \brief Metafunction predicate returning whether the given iterator allows for changing its values
Chris@16: /// \ingroup GILIsMutable
Chris@16: template <typename It>
Chris@16: struct iterator_is_mutable{};
Chris@16: 
Chris@16: // The default implementation when the iterator is a C pointer is to use the standard constness semantics
Chris@16: template <typename T> struct iterator_is_mutable<      T*> : public mpl::true_{};
Chris@16: template <typename T> struct iterator_is_mutable<const T*> : public mpl::false_{};
Chris@16: 
Chris@16: /// \defgroup PixelIteratorModelInterleavedPtr C pointer to a pixel
Chris@16: /// \ingroup PixelIteratorModel
Chris@16: /// \brief Iterators over interleaved pixels.
Chris@16: /// A C pointer to a model of PixelValueConcept is used as an iterator over interleaved pixels. Models PixelIteratorConcept, HomogeneousPixelBasedConcept, HasDynamicXStepTypeConcept, MemoryBasedIteratorConcept
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  HasDynamicXStepTypeConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: /// \ingroup PixelIteratorModelInterleavedPtr 
Chris@16: template <typename Pixel>
Chris@16: struct dynamic_x_step_type<Pixel*> {
Chris@16:     typedef memory_based_step_iterator<Pixel*> type;
Chris@16: };
Chris@16: 
Chris@16: /// \ingroup PixelIteratorModelInterleavedPtr 
Chris@16: template <typename Pixel>
Chris@16: struct dynamic_x_step_type<const Pixel*> {
Chris@16:     typedef memory_based_step_iterator<const Pixel*> type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  PixelBasedConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename Pixel> struct color_space_type<      Pixel*> : public color_space_type<Pixel> {};
Chris@16: template <typename Pixel> struct color_space_type<const Pixel*> : public color_space_type<Pixel> {};
Chris@16: 
Chris@16: template <typename Pixel> struct channel_mapping_type<      Pixel*> : public channel_mapping_type<Pixel> {};
Chris@16: template <typename Pixel> struct channel_mapping_type<const Pixel*> : public channel_mapping_type<Pixel> {};
Chris@16: 
Chris@16: template <typename Pixel> struct is_planar<      Pixel*> : public is_planar<Pixel> {};
Chris@16: template <typename Pixel> struct is_planar<const Pixel*> : public is_planar<Pixel> {};
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  HomogeneousPixelBasedConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename Pixel> struct channel_type<Pixel*> : public channel_type<Pixel> {};
Chris@16: template <typename Pixel> struct channel_type<const Pixel*> : public channel_type<Pixel> {};
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: ///
Chris@16: /// Support for pixel iterator movement measured in memory units (bytes or bits) as opposed to pixel type. \n
Chris@16: /// Necessary to handle image row alignment and channel plane alignment.
Chris@16: ///
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  MemoryBasedIteratorConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct byte_to_memunit : public mpl::int_<1> {};
Chris@16: 
Chris@16: template <typename P>
Chris@16: inline std::ptrdiff_t memunit_step(const P*) { return sizeof(P); }
Chris@16: 
Chris@16: template <typename P>
Chris@16: inline std::ptrdiff_t memunit_distance(const P* p1, const P* p2) { 
Chris@16:     return (gil_reinterpret_cast_c<const unsigned char*>(p2)-gil_reinterpret_cast_c<const unsigned char*>(p1)); 
Chris@16: }
Chris@16: 
Chris@16: template <typename P>
Chris@16: inline void memunit_advance(P* &p, std::ptrdiff_t diff) { 
Chris@16:     p=(P*)((unsigned char*)(p)+diff);
Chris@16: }
Chris@16: 
Chris@16: template <typename P>
Chris@16: inline P* memunit_advanced(const P* p, std::ptrdiff_t diff) {
Chris@16:     return (P*)((char*)(p)+diff);
Chris@16: }
Chris@16: 
Chris@16: //  memunit_advanced_ref
Chris@16: //  (shortcut to advancing a pointer by a given number of memunits and taking the reference in case the compiler is not smart enough)
Chris@16: 
Chris@16: template <typename P>
Chris@16: inline P& memunit_advanced_ref(P* p, std::ptrdiff_t diff) {
Chris@16:     return *memunit_advanced(p,diff);
Chris@16: }
Chris@16: 
Chris@16: } }  // namespace boost::gil
Chris@16: 
Chris@16: #endif