8 #ifndef BOOST_GIL_STEP_ITERATOR_HPP
9 #define BOOST_GIL_STEP_ITERATOR_HPP
11 #include <boost/gil/pixel_iterator.hpp>
12 #include <boost/gil/pixel_iterator_adaptor.hpp>
13 #include <boost/gil/utilities.hpp>
15 #include <boost/iterator/iterator_facade.hpp>
20 namespace boost {
namespace gil {
35 template <
typename Derived,
39 class step_iterator_adaptor :
public iterator_adaptor<Derived, Iterator, use_default, use_default, use_default, typename SFn::difference_type> {
41 typedef iterator_adaptor<Derived, Iterator, use_default, use_default, use_default, typename SFn::difference_type> parent_t;
42 typedef typename std::iterator_traits<Iterator>::difference_type base_difference_type;
43 typedef typename SFn::difference_type difference_type;
44 typedef typename std::iterator_traits<Iterator>::reference reference;
49 difference_type step()
const {
return _step_fn.step(); }
54 friend class boost::iterator_core_access;
56 void increment() { _step_fn.advance(this->base_reference(),1); }
57 void decrement() { _step_fn.advance(this->base_reference(),-1); }
58 void advance(base_difference_type d) { _step_fn.advance(this->base_reference(),d); }
59 difference_type distance_to(
const step_iterator_adaptor& it)
const {
return _step_fn.difference(this->base_reference(),it.base_reference()); }
64 template <
typename D,
typename Iterator,
typename SFn>
inline
66 return p1.step()>0 ? p1.base()> p2.base() : p1.base()< p2.base();
69 template <
typename D,
typename Iterator,
typename SFn>
inline
70 bool operator<(const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
71 return p1.step()>0 ? p1.base()< p2.base() : p1.base()> p2.base();
74 template <
typename D,
typename Iterator,
typename SFn>
inline
75 bool operator>=(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
76 return p1.step()>0 ? p1.base()>=p2.base() : p1.base()<=p2.base();
79 template <
typename D,
typename Iterator,
typename SFn>
inline
80 bool operator<=(const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
81 return p1.step()>0 ? p1.base()<=p2.base() : p1.base()>=p2.base();
84 template <
typename D,
typename Iterator,
typename SFn>
inline
85 bool operator==(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
86 return p1.base()==p2.base();
89 template <
typename D,
typename Iterator,
typename SFn>
inline
90 bool operator!=(
const step_iterator_adaptor<D,Iterator,SFn>& p1,
const step_iterator_adaptor<D,Iterator,SFn>& p2) {
91 return p1.base()!=p2.base();
118 template <
typename Iterator>
120 typedef std::ptrdiff_t difference_type;
122 memunit_step_fn(difference_type step=memunit_step(Iterator())) : _step(step) {}
124 difference_type difference(
const Iterator& it1,
const Iterator& it2)
const {
return memunit_distance(it1,it2)/_step; }
125 void advance(Iterator& it, difference_type d)
const { memunit_advance(it,d*_step); }
126 difference_type step()
const {
return _step; }
128 void set_step(std::ptrdiff_t step) { _step=step; }
131 difference_type _step;
134 template <
typename Iterator>
137 memunit_step_fn<Iterator> > {
143 typedef typename parent_t::reference reference;
144 typedef typename parent_t::difference_type difference_type;
145 typedef Iterator x_iterator;
148 memory_based_step_iterator(Iterator it, std::ptrdiff_t memunit_step) : parent_t(it, memunit_step_fn<Iterator>(memunit_step)) {}
149 template <
typename I2>
150 memory_based_step_iterator(
const memory_based_step_iterator<I2>& it)
151 : parent_t(it.base(), memunit_step_fn<Iterator>(it.step())) {}
155 reference
operator[](difference_type d)
const {
return *(*
this+d); }
157 void set_step(std::ptrdiff_t memunit_step) { this->_step_fn.set_step(memunit_step); }
159 x_iterator& base() {
return parent_t::base_reference(); }
160 x_iterator
const& base()
const {
return parent_t::base_reference(); }
163 template <
typename Iterator>
164 struct const_iterator_type<memory_based_step_iterator<Iterator> > {
165 typedef memory_based_step_iterator<typename const_iterator_type<Iterator>::type> type;
168 template <
typename Iterator>
169 struct iterator_is_mutable<memory_based_step_iterator<Iterator> > :
public iterator_is_mutable<Iterator> {};
176 template <
typename Iterator>
177 struct is_iterator_adaptor<memory_based_step_iterator<Iterator> > :
public mpl::true_{};
179 template <
typename Iterator>
180 struct iterator_adaptor_get_base<memory_based_step_iterator<Iterator> > {
181 typedef Iterator type;
184 template <
typename Iterator,
typename NewBaseIterator>
185 struct iterator_adaptor_rebind<memory_based_step_iterator<Iterator>,NewBaseIterator> {
186 typedef memory_based_step_iterator<NewBaseIterator> type;
193 template <
typename Iterator>
194 struct color_space_type<memory_based_step_iterator<Iterator> > :
public color_space_type<Iterator> {};
196 template <
typename Iterator>
197 struct channel_mapping_type<memory_based_step_iterator<Iterator> > :
public channel_mapping_type<Iterator> {};
199 template <
typename Iterator>
200 struct is_planar<memory_based_step_iterator<Iterator> > :
public is_planar<Iterator> {};
202 template <
typename Iterator>
203 struct channel_type<memory_based_step_iterator<Iterator> > :
public channel_type<Iterator> {};
208 template <
typename Iterator>
209 struct byte_to_memunit<memory_based_step_iterator<Iterator> > :
public byte_to_memunit<Iterator> {};
211 template <
typename Iterator>
212 inline std::ptrdiff_t memunit_step(
const memory_based_step_iterator<Iterator>& p) {
return p.step(); }
214 template <
typename Iterator>
215 inline std::ptrdiff_t memunit_distance(
const memory_based_step_iterator<Iterator>& p1,
216 const memory_based_step_iterator<Iterator>& p2) {
217 return memunit_distance(p1.base(),p2.base());
220 template <
typename Iterator>
221 inline void memunit_advance(memory_based_step_iterator<Iterator>& p,
222 std::ptrdiff_t diff) {
223 memunit_advance(p.base(), diff);
226 template <
typename Iterator>
227 inline memory_based_step_iterator<Iterator>
228 memunit_advanced(
const memory_based_step_iterator<Iterator>& p,
229 std::ptrdiff_t diff) {
230 return memory_based_step_iterator<Iterator>(memunit_advanced(p.base(), diff),p.step());
233 template <
typename Iterator>
234 inline typename std::iterator_traits<Iterator>::reference
235 memunit_advanced_ref(
const memory_based_step_iterator<Iterator>& p,
236 std::ptrdiff_t diff) {
237 return memunit_advanced_ref(p.base(), diff);
244 template <
typename Iterator>
245 struct dynamic_x_step_type<memory_based_step_iterator<Iterator> > {
246 typedef memory_based_step_iterator<Iterator> type;
250 template <
typename Iterator,
typename Deref>
251 struct iterator_add_deref<memory_based_step_iterator<Iterator>,Deref> {
252 GIL_CLASS_REQUIRE(Deref, boost::gil, PixelDereferenceAdaptorConcept)
254 typedef memory_based_step_iterator<typename iterator_add_deref<Iterator, Deref>::type> type;
256 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()); }
263 template <
typename I>
typename dynamic_x_step_type<I>::type make_step_iterator(
const I& it, std::ptrdiff_t step);
268 template <
typename I>
269 typename dynamic_x_step_type<I>::type make_step_iterator_impl(
const I& it, std::ptrdiff_t step, mpl::false_) {
270 return memory_based_step_iterator<I>(it, step);
274 template <
typename I>
275 typename dynamic_x_step_type<I>::type make_step_iterator_impl(
const I& it, std::ptrdiff_t step, mpl::true_) {
276 return make_step_iterator(it.base(), step);
280 template <
typename BaseIt>
281 memory_based_step_iterator<BaseIt> make_step_iterator_impl(
const memory_based_step_iterator<BaseIt>& it, std::ptrdiff_t step, mpl::true_) {
282 return memory_based_step_iterator<BaseIt>(it.base(), step);
299 template <
typename I>
300 typename dynamic_x_step_type<I>::type make_step_iterator(
const I& it, std::ptrdiff_t step) {
301 return detail::make_step_iterator_impl(it, step,
typename is_iterator_adaptor<I>::type());
Concept of a random-access iterator that can be advanced in memory units (bytes or bits) ...
Definition: concepts.hpp:1284
reference operator[](difference_type d) const
Definition: step_iterator.hpp:155
function object that returns the memory unit distance between two iterators and advances a given iter...
Definition: step_iterator.hpp:119
An adaptor over an existing iterator that changes the step unit.
Definition: step_iterator.hpp:39
MEMORY-BASED STEP ITERATOR.
Definition: algorithm.hpp:36