8 #ifndef BOOST_GIL_STEP_ITERATOR_HPP 9 #define BOOST_GIL_STEP_ITERATOR_HPP 11 #include <boost/gil/dynamic_step.hpp> 12 #include <boost/gil/pixel_iterator.hpp> 13 #include <boost/gil/pixel_iterator_adaptor.hpp> 14 #include <boost/gil/utilities.hpp> 16 #include <boost/iterator/iterator_facade.hpp> 21 namespace boost {
namespace gil {
36 template <
typename Derived,
40 class step_iterator_adaptor :
public iterator_adaptor<Derived, Iterator, use_default, use_default, use_default, typename SFn::difference_type>
43 using parent_t = iterator_adaptor<Derived, Iterator, use_default, use_default, use_default, typename SFn::difference_type>;
44 using base_difference_type =
typename std::iterator_traits<Iterator>::difference_type;
45 using difference_type =
typename SFn::difference_type;
46 using reference =
typename std::iterator_traits<Iterator>::reference;
51 difference_type step()
const {
return _step_fn.step(); }
56 friend class boost::iterator_core_access;
58 void increment() { _step_fn.advance(this->base_reference(),1); }
59 void decrement() { _step_fn.advance(this->base_reference(),-1); }
60 void advance(base_difference_type d) { _step_fn.advance(this->base_reference(),d); }
61 difference_type distance_to(
const step_iterator_adaptor& it)
const {
return _step_fn.difference(this->base_reference(),it.base_reference()); }
66 template <
typename D,
typename Iterator,
typename SFn>
inline 68 return p1.step()>0 ? p1.base()> p2.base() : p1.base()< p2.base();
71 template <
typename D,
typename Iterator,
typename SFn>
inline 72 bool operator<(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
73 return p1.step()>0 ? p1.base()< p2.base() : p1.base()> p2.base();
76 template <
typename D,
typename Iterator,
typename SFn>
inline 77 bool operator>=(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
78 return p1.step()>0 ? p1.base()>=p2.base() : p1.base()<=p2.base();
81 template <
typename D,
typename Iterator,
typename SFn>
inline 82 bool operator<=(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
83 return p1.step()>0 ? p1.base()<=p2.base() : p1.base()>=p2.base();
86 template <
typename D,
typename Iterator,
typename SFn>
inline 87 bool operator==(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
88 return p1.base()==p2.base();
91 template <
typename D,
typename Iterator,
typename SFn>
inline 92 bool operator!=(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
93 return p1.base()!=p2.base();
120 template <
typename Iterator>
122 using difference_type = std::ptrdiff_t;
124 memunit_step_fn(difference_type step=memunit_step(Iterator())) : _step(step) {}
126 difference_type difference(
const Iterator& it1,
const Iterator& it2)
const {
return memunit_distance(it1,it2)/_step; }
127 void advance(Iterator& it, difference_type d)
const { memunit_advance(it,d*_step); }
128 difference_type step()
const {
return _step; }
130 void set_step(std::ptrdiff_t step) { _step=step; }
132 GIL_CLASS_REQUIRE(Iterator, boost::gil, MemoryBasedIteratorConcept)
133 difference_type _step;
136 template <
typename Iterator>
139 memunit_step_fn<Iterator>>
141 GIL_CLASS_REQUIRE(Iterator, boost::gil, MemoryBasedIteratorConcept)
146 using reference =
typename parent_t::reference;
147 using difference_type =
typename parent_t::difference_type;
148 using x_iterator = Iterator;
151 memory_based_step_iterator(Iterator it, std::ptrdiff_t memunit_step) : parent_t(it, memunit_step_fn<Iterator>(memunit_step)) {}
152 template <
typename I2>
153 memory_based_step_iterator(
const memory_based_step_iterator<I2>& it)
154 : parent_t(it.base(), memunit_step_fn<Iterator>(it.step())) {}
158 reference
operator[](difference_type d)
const {
return *(*
this+d); }
160 void set_step(std::ptrdiff_t memunit_step) { this->_step_fn.set_step(memunit_step); }
162 x_iterator& base() {
return parent_t::base_reference(); }
163 x_iterator
const& base()
const {
return parent_t::base_reference(); }
166 template <
typename Iterator>
167 struct const_iterator_type<memory_based_step_iterator<Iterator> > {
168 using type = memory_based_step_iterator<typename const_iterator_type<Iterator>::type>;
171 template <
typename Iterator>
172 struct iterator_is_mutable<memory_based_step_iterator<Iterator> > :
public iterator_is_mutable<Iterator> {};
179 template <
typename Iterator>
180 struct is_iterator_adaptor<memory_based_step_iterator<Iterator> > :
public mpl::true_{};
182 template <
typename Iterator>
183 struct iterator_adaptor_get_base<memory_based_step_iterator<Iterator> > {
184 using type = Iterator;
187 template <
typename Iterator,
typename NewBaseIterator>
188 struct iterator_adaptor_rebind<memory_based_step_iterator<Iterator>,NewBaseIterator> {
189 using type = memory_based_step_iterator<NewBaseIterator>;
196 template <
typename Iterator>
197 struct color_space_type<memory_based_step_iterator<Iterator> > :
public color_space_type<Iterator> {};
199 template <
typename Iterator>
200 struct channel_mapping_type<memory_based_step_iterator<Iterator> > :
public channel_mapping_type<Iterator> {};
202 template <
typename Iterator>
203 struct is_planar<memory_based_step_iterator<Iterator> > :
public is_planar<Iterator> {};
205 template <
typename Iterator>
206 struct channel_type<memory_based_step_iterator<Iterator> > :
public channel_type<Iterator> {};
211 template <
typename Iterator>
212 struct byte_to_memunit<memory_based_step_iterator<Iterator> > :
public byte_to_memunit<Iterator> {};
214 template <
typename Iterator>
215 inline std::ptrdiff_t memunit_step(
const memory_based_step_iterator<Iterator>& p) {
return p.step(); }
217 template <
typename Iterator>
218 inline std::ptrdiff_t memunit_distance(
const memory_based_step_iterator<Iterator>& p1,
219 const memory_based_step_iterator<Iterator>& p2) {
220 return memunit_distance(p1.base(),p2.base());
223 template <
typename Iterator>
224 inline void memunit_advance(memory_based_step_iterator<Iterator>& p,
225 std::ptrdiff_t diff) {
226 memunit_advance(p.base(), diff);
229 template <
typename Iterator>
230 inline memory_based_step_iterator<Iterator>
231 memunit_advanced(
const memory_based_step_iterator<Iterator>& p,
232 std::ptrdiff_t diff) {
233 return memory_based_step_iterator<Iterator>(memunit_advanced(p.base(), diff),p.step());
236 template <
typename Iterator>
237 inline typename std::iterator_traits<Iterator>::reference
238 memunit_advanced_ref(
const memory_based_step_iterator<Iterator>& p,
239 std::ptrdiff_t diff) {
240 return memunit_advanced_ref(p.base(), diff);
247 template <
typename Iterator>
248 struct dynamic_x_step_type<memory_based_step_iterator<Iterator> > {
249 using type = memory_based_step_iterator<Iterator>;
253 template <
typename Iterator,
typename Deref>
254 struct iterator_add_deref<memory_based_step_iterator<Iterator>,Deref> {
255 GIL_CLASS_REQUIRE(Deref, boost::gil, PixelDereferenceAdaptorConcept)
257 using type = memory_based_step_iterator<typename iterator_add_deref<Iterator, Deref>::type>;
259 static type make(
const memory_based_step_iterator<Iterator>& it,
const Deref& d) {
return type(iterator_add_deref<Iterator, Deref>::make(it.base(),d),it.step()); }
266 template <
typename I>
typename dynamic_x_step_type<I>::type make_step_iterator(
const I& it, std::ptrdiff_t step);
271 template <
typename I>
272 typename dynamic_x_step_type<I>::type make_step_iterator_impl(
const I& it, std::ptrdiff_t step, mpl::false_) {
273 return memory_based_step_iterator<I>(it, step);
277 template <
typename I>
278 typename dynamic_x_step_type<I>::type make_step_iterator_impl(
const I& it, std::ptrdiff_t step, mpl::true_) {
279 return make_step_iterator(it.base(), step);
283 template <
typename BaseIt>
284 memory_based_step_iterator<BaseIt> make_step_iterator_impl(
const memory_based_step_iterator<BaseIt>& it, std::ptrdiff_t step, mpl::true_) {
285 return memory_based_step_iterator<BaseIt>(it.base(), step);
302 template <
typename I>
303 typename dynamic_x_step_type<I>::type make_step_iterator(
const I& it, std::ptrdiff_t step) {
304 return detail::make_step_iterator_impl(it, step,
typename is_iterator_adaptor<I>::type());
reference operator[](difference_type d) const
Definition: step_iterator.hpp:158
function object that returns the memory unit distance between two iterators and advances a given iter...
Definition: step_iterator.hpp:121
An adaptor over an existing iterator that changes the step unit.
Definition: step_iterator.hpp:40
MEMORY-BASED STEP ITERATOR.
Definition: algorithm.hpp:36