200 lines
8.9 KiB
C++
200 lines
8.9 KiB
C++
//
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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_ADAPTOR_HPP
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#define BOOST_GIL_PIXEL_ITERATOR_ADAPTOR_HPP
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#include <boost/gil/concepts.hpp>
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#include <boost/gil/pixel_iterator.hpp>
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#include <boost/iterator/iterator_facade.hpp>
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#include <iterator>
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namespace boost { namespace gil {
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/// \defgroup PixelIteratorModelDerefPtr dereference_iterator_adaptor
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/// \ingroup PixelIteratorModel
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/// \brief An iterator that invokes a provided function object upon dereference. Models: IteratorAdaptorConcept, PixelIteratorConcept
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/// \ingroup PixelIteratorModelDerefPtr PixelBasedModel
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/// \brief An adaptor over an existing iterator that provides for custom filter on dereferencing the object. Models: IteratorAdaptorConcept, PixelIteratorConcept
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template <typename Iterator, // Models Iterator
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typename DFn> // Models Returns the result of dereferencing a given iterator of type Iterator
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class dereference_iterator_adaptor : public iterator_adaptor<dereference_iterator_adaptor<Iterator,DFn>,
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Iterator,
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typename DFn::value_type,
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typename std::iterator_traits<Iterator>::iterator_category,
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typename DFn::reference,
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use_default> {
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DFn _deref_fn;
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public:
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using parent_t = iterator_adaptor<dereference_iterator_adaptor<Iterator,DFn>,
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Iterator,
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typename DFn::value_type,
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typename std::iterator_traits<Iterator>::iterator_category,
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typename DFn::reference,
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use_default>;
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using reference = typename DFn::result_type;
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using difference_type = typename std::iterator_traits<Iterator>::difference_type;
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using dereference_fn = DFn;
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dereference_iterator_adaptor() {}
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template <typename Iterator1>
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dereference_iterator_adaptor(const dereference_iterator_adaptor<Iterator1,DFn>& dit) : parent_t(dit.base()), _deref_fn(dit._deref_fn) {}
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dereference_iterator_adaptor(Iterator it, DFn deref_fn=DFn()) : parent_t(it), _deref_fn(deref_fn) {}
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template <typename Iterator1, typename DFn1>
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dereference_iterator_adaptor(const dereference_iterator_adaptor<Iterator1,DFn1>& it) : parent_t(it.base()), _deref_fn(it._deref_fn) {}
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/// For some reason operator[] provided by iterator_facade returns a custom class that is convertible to reference
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/// We require our own reference because it is registered in iterator_traits
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reference operator[](difference_type d) const { return *(*this+d);}
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// although iterator_adaptor defines these, the default implementation computes distance and compares for zero.
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// it is often faster to just apply the relation operator to the base
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bool operator> (const dereference_iterator_adaptor& p) const { return this->base_reference()> p.base_reference(); }
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bool operator< (const dereference_iterator_adaptor& p) const { return this->base_reference()< p.base_reference(); }
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bool operator>=(const dereference_iterator_adaptor& p) const { return this->base_reference()>=p.base_reference(); }
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bool operator<=(const dereference_iterator_adaptor& p) const { return this->base_reference()<=p.base_reference(); }
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bool operator==(const dereference_iterator_adaptor& p) const { return this->base_reference()==p.base_reference(); }
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bool operator!=(const dereference_iterator_adaptor& p) const { return this->base_reference()!=p.base_reference(); }
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Iterator& base() { return this->base_reference(); }
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const Iterator& base() const { return this->base_reference(); }
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const DFn& deref_fn() const { return _deref_fn; }
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private:
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template <typename Iterator1, typename DFn1>
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friend class dereference_iterator_adaptor;
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friend class boost::iterator_core_access;
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reference dereference() const { return _deref_fn(*(this->base_reference())); }
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};
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template <typename I, typename DFn>
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struct const_iterator_type<dereference_iterator_adaptor<I,DFn> > {
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using type = dereference_iterator_adaptor<typename const_iterator_type<I>::type,typename DFn::const_t>;
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};
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template <typename I, typename DFn>
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struct iterator_is_mutable<dereference_iterator_adaptor<I, DFn>>
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: std::integral_constant<bool, DFn::is_mutable>
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{};
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template <typename I, typename DFn>
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struct is_iterator_adaptor<dereference_iterator_adaptor<I, DFn>> : std::true_type {};
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template <typename I, typename DFn>
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struct iterator_adaptor_get_base<dereference_iterator_adaptor<I, DFn>>
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{
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using type = I;
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};
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template <typename I, typename DFn, typename NewBaseIterator>
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struct iterator_adaptor_rebind<dereference_iterator_adaptor<I,DFn>,NewBaseIterator> {
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using type = dereference_iterator_adaptor<NewBaseIterator,DFn>;
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};
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/////////////////////////////
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// PixelBasedConcept
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/////////////////////////////
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template <typename I, typename DFn>
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struct color_space_type<dereference_iterator_adaptor<I,DFn> > : public color_space_type<typename DFn::value_type> {};
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template <typename I, typename DFn>
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struct channel_mapping_type<dereference_iterator_adaptor<I,DFn> > : public channel_mapping_type<typename DFn::value_type> {};
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template <typename I, typename DFn>
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struct is_planar<dereference_iterator_adaptor<I,DFn> > : public is_planar<typename DFn::value_type> {};
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template <typename I, typename DFn>
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struct channel_type<dereference_iterator_adaptor<I,DFn> > : public channel_type<typename DFn::value_type> {};
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/////////////////////////////
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// MemoryBasedIteratorConcept
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/////////////////////////////
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template <typename Iterator, typename DFn>
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struct byte_to_memunit<dereference_iterator_adaptor<Iterator,DFn>> : public byte_to_memunit<Iterator> {};
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template <typename Iterator, typename DFn>
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inline auto memunit_step(dereference_iterator_adaptor<Iterator,DFn> const& p)
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-> typename std::iterator_traits<Iterator>::difference_type
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{
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return memunit_step(p.base());
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}
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template <typename Iterator, typename DFn>
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inline auto memunit_distance(dereference_iterator_adaptor<Iterator,DFn> const& p1,
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dereference_iterator_adaptor<Iterator,DFn> const& p2)
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-> typename std::iterator_traits<Iterator>::difference_type
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{
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return memunit_distance(p1.base(),p2.base());
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}
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template <typename Iterator, typename DFn>
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inline void memunit_advance(dereference_iterator_adaptor<Iterator,DFn>& p,
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typename std::iterator_traits<Iterator>::difference_type diff) {
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memunit_advance(p.base(), diff);
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}
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template <typename Iterator, typename DFn>
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inline auto memunit_advanced(dereference_iterator_adaptor<Iterator,DFn> const& p,
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typename std::iterator_traits<Iterator>::difference_type diff)
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-> dereference_iterator_adaptor<Iterator,DFn>
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{
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return dereference_iterator_adaptor<Iterator,DFn>(memunit_advanced(p.base(), diff), p.deref_fn());
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}
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template <typename Iterator, typename DFn>
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inline auto memunit_advanced_ref(dereference_iterator_adaptor<Iterator,DFn> const& p,
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typename std::iterator_traits<Iterator>::difference_type diff)
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-> typename std::iterator_traits<dereference_iterator_adaptor<Iterator,DFn> >::reference
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{
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return *memunit_advanced(p, diff);
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}
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/////////////////////////////
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// HasDynamicXStepTypeConcept
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/////////////////////////////
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template <typename Iterator, typename DFn>
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struct dynamic_x_step_type<dereference_iterator_adaptor<Iterator,DFn> > {
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using type = dereference_iterator_adaptor<typename dynamic_x_step_type<Iterator>::type,DFn>;
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};
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/// \brief Returns the type (and creates an instance) of an iterator that invokes the given dereference adaptor upon dereferencing
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/// \ingroup PixelIteratorModelDerefPtr
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template <typename Iterator, typename Deref>
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struct iterator_add_deref {
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BOOST_GIL_CLASS_REQUIRE(Deref, boost::gil, PixelDereferenceAdaptorConcept)
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using type = dereference_iterator_adaptor<Iterator, Deref>;
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static type make(const Iterator& it, const Deref& d) { return type(it,d); }
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};
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/// \ingroup PixelIteratorModelDerefPtr
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/// \brief For dereference iterator adaptors, compose the new function object after the old one
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template <typename Iterator, typename PREV_DEREF, typename Deref>
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struct iterator_add_deref<dereference_iterator_adaptor<Iterator, PREV_DEREF>,Deref> {
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// BOOST_GIL_CLASS_REQUIRE(Deref, boost::gil, PixelDereferenceAdaptorConcept)
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using type = dereference_iterator_adaptor<Iterator, deref_compose<Deref,PREV_DEREF>>;
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static type make(const dereference_iterator_adaptor<Iterator, PREV_DEREF>& it, const Deref& d) {
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return type(it.base(),deref_compose<Deref,PREV_DEREF>(d,it.deref_fn()));
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}
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};
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}} // namespace boost::gil
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#endif
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