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
225
226
227
228
229
230
231
232
233
234
235
236
237
|
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
#ifndef Patternist_SequenceMappingIterator_H
#define Patternist_SequenceMappingIterator_H
#include "qabstractxmlforwarditerator_p.h"
#include "qdynamiccontext_p.h"
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
namespace QPatternist
{
/**
* @short Proxies another QAbstractXmlForwardIterator, and for each item, returns the
* Sequence returned from a mapping function.
*
* ItemMappingIterator is practical when the items in an QAbstractXmlForwardIterator needs to
* be translated to another sequence, while still doing it in a pipe-lined
* fashion. In contrast to ItemMappingIterator, SequenceMappingIterator maps
* each item into another QAbstractXmlForwardIterator, and where the SequenceMappingIterator's own
* result is the concatenation of all those Iterators. Hence, while ItemMappingIterator
* is better tailored for one-to-one or one-to-zero conversion, SequenceMappingIterator
* is more suitable for one-to-many conversion.
*
* This is achieved by that SequenceMappingIterator's constructor takes
* an instance of a class, that must have the following member:
*
* @code
* QAbstractXmlForwardIterator<TResult>::Ptr mapToSequence(const TSource::Ptr &item,
* const DynamicContext::Ptr &context) const;
* @endcode
*
* @author Frans Englich <frans.englich@nokia.com>
* @see ItemMappingIterator
* @ingroup Patternist_iterators
*/
template<typename TResult, typename TSource, typename TMapper>
class SequenceMappingIterator : public QAbstractXmlForwardIterator<TResult>
{
public:
/**
* Constructs a SequenceMappingIterator.
*
* @param mapper the object that has the mapToItem() sequence.
* @param sourceIterator the QAbstractXmlForwardIterator whose items should be mapped.
* @param context the DynamicContext that will be passed to the map function.
* May be null.
*/
SequenceMappingIterator(const TMapper &mapper,
const typename QAbstractXmlForwardIterator<TSource>::Ptr &sourceIterator,
const DynamicContext::Ptr &context);
virtual TResult next();
virtual xsInteger count();
virtual TResult current() const;
virtual xsInteger position() const;
/**
* The reason the implementation is placed in line here, is due to a bug
* in MSVC-2005 version 14.00.50727.762. Note that it works with version 14.00.50727.42.
*/
virtual typename QAbstractXmlForwardIterator<TResult>::Ptr copy() const
{
return typename QAbstractXmlForwardIterator<TResult>::Ptr
(new SequenceMappingIterator<TResult, TSource, TMapper>(m_mapper,
m_mainIterator->copy(),
m_context));
}
private:
xsInteger m_position;
TResult m_current;
typename QAbstractXmlForwardIterator<TSource>::Ptr m_mainIterator;
typename QAbstractXmlForwardIterator<TResult>::Ptr m_currentIterator;
const typename DynamicContext::Ptr m_context;
const TMapper m_mapper;
};
template<typename TResult, typename TSource, typename TMapper>
SequenceMappingIterator<TResult, TSource, TMapper>::SequenceMappingIterator(
const TMapper &mapper,
const typename QAbstractXmlForwardIterator<TSource>::Ptr &iterator,
const DynamicContext::Ptr &context)
: m_position(0),
m_mainIterator(iterator),
m_context(context),
m_mapper(mapper)
{
Q_ASSERT(mapper);
Q_ASSERT(iterator);
}
template<typename TResult, typename TSource, typename TMapper>
TResult SequenceMappingIterator<TResult, TSource, TMapper>::next()
{
/* This was once implemented with a recursive function, but the stack
* got blown for some inputs by that approach. */
while(true)
{
while(!m_currentIterator)
{
const TSource mainItem(m_mainIterator->next());
if(qIsForwardIteratorEnd(mainItem)) /* We've reached the very end. */
{
m_position = -1;
m_current = TResult();
return TResult();
}
else
m_currentIterator = m_mapper->mapToSequence(mainItem, m_context);
}
m_current = m_currentIterator->next();
if(qIsForwardIteratorEnd(m_current))
{
m_currentIterator.reset();
continue;
}
else
{
++m_position;
return m_current;
}
}
}
template<typename TResult, typename TSource, typename TMapper>
xsInteger SequenceMappingIterator<TResult, TSource, TMapper>::count()
{
TSource unit(m_mainIterator->next());
xsInteger c = 0;
while(!qIsForwardIteratorEnd(unit))
{
const typename QAbstractXmlForwardIterator<TResult>::Ptr sit(m_mapper->mapToSequence(unit, m_context));
c += sit->count();
unit = m_mainIterator->next();
}
return c;
}
template<typename TResult, typename TSource, typename TMapper>
TResult SequenceMappingIterator<TResult, TSource, TMapper>::current() const
{
return m_current;
}
template<typename TResult, typename TSource, typename TMapper>
xsInteger SequenceMappingIterator<TResult, TSource, TMapper>::position() const
{
return m_position;
}
/**
* @short An object generator for SequenceMappingIterator.
*
* makeSequenceMappingIterator() is a convenience function for avoiding specifying
* the full template instantiation for SequenceMappingIterator. Conceptually, it
* is identical to Qt's qMakePair().
*
* @returns a SequenceMappingIterator wrapped in a smart pointer, that has been
* passed the constructor arguments @p mapper, @p source, and @p context.
* @see makeMappingCallbackPtr()
* @relates QAbstractXmlForwardIterator
*/
template<typename TResult, typename TSource, typename TMapper>
static inline
typename QAbstractXmlForwardIterator<TResult>::Ptr
makeSequenceMappingIterator(const TMapper &mapper,
const QExplicitlySharedDataPointer<QAbstractXmlForwardIterator<TSource> > &source,
const DynamicContext::Ptr &context)
{
return typename QAbstractXmlForwardIterator<TResult>::Ptr
(new SequenceMappingIterator<TResult, TSource, TMapper>(mapper, source, context));
}
}
QT_END_NAMESPACE
QT_END_HEADER
#endif
|
