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