1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
// Boost.Geometry (aka GGL, Generic Geometry Library)
// Copyright (c) 2014-2021, Oracle and/or its affiliates.
// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
// Licensed under the Boost Software License version 1.0.
// http://www.boost.org/users/license.html
#ifndef BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
#define BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
#include <type_traits>
#include <boost/iterator/iterator_facade.hpp>
#include <boost/iterator/iterator_categories.hpp>
#include <boost/geometry/core/assert.hpp>
namespace boost { namespace geometry
{
template
<
typename OuterIterator,
typename InnerIterator,
typename Value,
typename AccessInnerBegin,
typename AccessInnerEnd,
typename Reference = Value&
>
class flatten_iterator
: public boost::iterator_facade
<
flatten_iterator
<
OuterIterator,
InnerIterator,
Value,
AccessInnerBegin,
AccessInnerEnd,
Reference
>,
Value,
boost::bidirectional_traversal_tag,
Reference
>
{
private:
OuterIterator m_outer_it, m_outer_end;
InnerIterator m_inner_it;
public:
typedef OuterIterator outer_iterator_type;
typedef InnerIterator inner_iterator_type;
// default constructor
flatten_iterator() = default;
// for begin
flatten_iterator(OuterIterator outer_it, OuterIterator outer_end)
: m_outer_it(outer_it), m_outer_end(outer_end)
{
advance_through_empty();
}
// for end
flatten_iterator(OuterIterator outer_end)
: m_outer_it(outer_end), m_outer_end(outer_end)
{}
template
<
typename OtherOuterIterator, typename OtherInnerIterator,
typename OtherValue,
typename OtherAccessInnerBegin, typename OtherAccessInnerEnd,
typename OtherReference,
std::enable_if_t
<
std::is_convertible<OtherOuterIterator, OuterIterator>::value
&& std::is_convertible<OtherInnerIterator, InnerIterator>::value,
int
> = 0
>
flatten_iterator(flatten_iterator
<
OtherOuterIterator,
OtherInnerIterator,
OtherValue,
OtherAccessInnerBegin,
OtherAccessInnerEnd,
OtherReference
> const& other)
: m_outer_it(other.m_outer_it),
m_outer_end(other.m_outer_end),
m_inner_it(other.m_inner_it)
{}
flatten_iterator(flatten_iterator const& other) = default;
flatten_iterator& operator=(flatten_iterator const& other)
{
m_outer_it = other.m_outer_it;
m_outer_end = other.m_outer_end;
// avoid assigning an iterator having singular value
if ( other.m_outer_it != other.m_outer_end )
{
m_inner_it = other.m_inner_it;
}
return *this;
}
private:
friend class boost::iterator_core_access;
template
<
typename Outer,
typename Inner,
typename V,
typename InnerBegin,
typename InnerEnd,
typename R
>
friend class flatten_iterator;
static inline bool empty(OuterIterator outer_it)
{
return AccessInnerBegin::apply(*outer_it)
== AccessInnerEnd::apply(*outer_it);
}
inline void advance_through_empty()
{
while ( m_outer_it != m_outer_end && empty(m_outer_it) )
{
++m_outer_it;
}
if ( m_outer_it != m_outer_end )
{
m_inner_it = AccessInnerBegin::apply(*m_outer_it);
}
}
inline Reference dereference() const
{
BOOST_GEOMETRY_ASSERT( m_outer_it != m_outer_end );
BOOST_GEOMETRY_ASSERT( m_inner_it != AccessInnerEnd::apply(*m_outer_it) );
return *m_inner_it;
}
template
<
typename OtherOuterIterator,
typename OtherInnerIterator,
typename OtherValue,
typename OtherAccessInnerBegin,
typename OtherAccessInnerEnd,
typename OtherReference
>
inline bool equal(flatten_iterator
<
OtherOuterIterator,
OtherInnerIterator,
OtherValue,
OtherAccessInnerBegin,
OtherAccessInnerEnd,
OtherReference
> const& other) const
{
if ( m_outer_it != other.m_outer_it )
{
return false;
}
if ( m_outer_it == m_outer_end )
{
return true;
}
return m_inner_it == other.m_inner_it;
}
inline void increment()
{
BOOST_GEOMETRY_ASSERT( m_outer_it != m_outer_end );
BOOST_GEOMETRY_ASSERT( m_inner_it != AccessInnerEnd::apply(*m_outer_it) );
++m_inner_it;
if ( m_inner_it == AccessInnerEnd::apply(*m_outer_it) )
{
++m_outer_it;
advance_through_empty();
}
}
inline void decrement()
{
if ( m_outer_it == m_outer_end
|| m_inner_it == AccessInnerBegin::apply(*m_outer_it) )
{
do
{
--m_outer_it;
}
while ( empty(m_outer_it) );
m_inner_it = AccessInnerEnd::apply(*m_outer_it);
}
--m_inner_it;
}
};
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_ITERATORS_FLATTEN_ITERATOR_HPP
|
