blob: 7bc4d2fe5f8029b1faade401faf90c689087b931 (
plain)
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
|
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** 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 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/
//
// 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_SingletonIterator_H
#define Patternist_SingletonIterator_H
#include <QtXmlPatterns/private/qabstractxmlforwarditerator_p.h>
#include <QtXmlPatterns/private/qprimitives_p.h>
QT_BEGIN_NAMESPACE
namespace QPatternist
{
/**
* @short An QAbstractXmlForwardIterator over exactly one item.
*
* SingletonIterator's constructor takes one value which is
* the item it forms an QAbstractXmlForwardIterator over. Other QAbstractXmlForwardIterator instances can
* also form an QAbstractXmlForwardIterator with one in length, but by that SingletonIterator
* has this as it only task, it means it is efficient at it.
*
* Having to represent single items in Iterators is relatively common.
*
* @author Frans Englich <frans.englich@nokia.com>
* @ingroup Patternist_iterators
*/
template<typename T>
class SingletonIterator : public QAbstractXmlForwardIterator<T>
{
public:
/**
* Creates an iterator over @p item.
*
* @note item may not be @c null. Use the EmptyIterator for
* the empty sequence
*/
SingletonIterator(const T &item) : m_item(item),
m_position(0)
{
Q_ASSERT(!qIsForwardIteratorEnd(item));
}
virtual T next()
{
switch(m_position)
{
case 0:
{
++m_position;
return m_item;
}
case 1:
{
m_position = -1;
return T();
}
default:
{
Q_ASSERT(m_position == -1);
return T();
}
}
}
virtual T current() const
{
if(m_position == 1)
return m_item;
else
return T();
}
virtual xsInteger position() const
{
return m_position;
}
/**
* @returns a copy of this instance, rewinded to the beginning.
*/
virtual typename QAbstractXmlForwardIterator<T>::Ptr toReversed()
{
return typename QAbstractXmlForwardIterator<T>::Ptr(new SingletonIterator<T>(m_item));
}
/**
* @returns always 1
*/
virtual xsInteger count()
{
return 1;
}
virtual typename QAbstractXmlForwardIterator<T>::Ptr copy() const
{
return typename QAbstractXmlForwardIterator<T>::Ptr(new SingletonIterator(m_item));
}
private:
const T m_item;
qint8 m_position;
};
/**
* @short An object generator for SingletonIterator.
*
* makeSingletonIterator() is a convenience function for avoiding specifying
* the full template instantiation for SingletonIterator. Conceptually, it
* is identical to Qt's qMakePair().
*
* @relates SingletonIterator
*/
template<typename T>
inline
typename SingletonIterator<T>::Ptr
makeSingletonIterator(const T &item)
{
return typename SingletonIterator<T>::Ptr(new SingletonIterator<T>(item));
}
}
QT_END_NAMESPACE
#endif
|
