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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 // |
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43 // W A R N I N G |
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44 // ------------- |
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45 // |
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46 // This file is not part of the Qt API. It exists purely as an |
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47 // implementation detail. This header file may change from version to |
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48 // version without notice, or even be removed. |
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49 // |
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50 // We mean it. |
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51 |
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52 #ifndef Patternist_DistinctIterator_H |
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53 #define Patternist_DistinctIterator_H |
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54 |
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55 #include <QList> |
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56 |
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57 #include "qexpression_p.h" |
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58 #include "qitem_p.h" |
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59 #include "qatomiccomparator_p.h" |
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60 #include "qcomparisonplatform_p.h" |
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61 #include "qsourcelocationreflection_p.h" |
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62 |
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63 QT_BEGIN_HEADER |
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64 |
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65 QT_BEGIN_NAMESPACE |
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66 |
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67 namespace QPatternist |
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68 { |
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69 |
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70 /** |
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71 * @short Filters another sequence by removing duplicates such that the items are unique. |
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72 * |
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73 * DistinctIterator takes an input sequence, and returns a sequence where each |
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74 * item is unique. Thus, DistinctIterator removes the duplicates of items |
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75 * in a sequence. DistinctIterator is central in the implementation of the |
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76 * <tt>fn:distinct-values()</tt> function. |
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77 * |
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78 * @see <a href="http://www.w3.org/TR/xpath-functions/#func-distinct-values">XQuery 1.0 |
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79 * and XPath 2.0 Functions and Operators, 15.1.6 fn:distinct-values</a> |
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80 * @author Frans Englich <frans.englich@nokia.com> |
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81 * @ingroup Patternist_iterators |
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82 */ |
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83 class DistinctIterator : public Item::Iterator |
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84 , public ComparisonPlatform<DistinctIterator, false> |
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85 , public SourceLocationReflection |
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86 { |
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87 public: |
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88 /** |
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89 * Creates a DistinctIterator. |
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90 * @param comp the AtomicComparator to be used for comparing values. This may be @c null, |
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91 * meaning the IndexOfIterator iterator will dynamically determine what comparator to use |
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92 * @param seq the sequence whose duplicates should be filtered out |
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93 * @param context the usual context, used for error reporting and by AtomicComparators. |
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94 * @param expression the Expression that this DistinctIterator is |
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95 * evaluating for. It is used for error reporting, via |
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96 * actualReflection(). |
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97 */ |
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98 DistinctIterator(const Item::Iterator::Ptr &seq, |
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99 const AtomicComparator::Ptr &comp, |
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100 const Expression::ConstPtr &expression, |
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101 const DynamicContext::Ptr &context); |
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102 |
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103 virtual Item next(); |
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104 virtual Item current() const; |
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105 virtual xsInteger position() const; |
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106 virtual Item::Iterator::Ptr copy() const; |
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107 virtual const SourceLocationReflection *actualReflection() const; |
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108 |
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109 inline AtomicComparator::Operator operatorID() const |
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110 { |
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111 return AtomicComparator::OperatorEqual; |
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112 } |
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113 |
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114 private: |
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115 const Item::Iterator::Ptr m_seq; |
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116 const DynamicContext::Ptr m_context; |
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117 const Expression::ConstPtr m_expr; |
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118 Item m_current; |
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119 xsInteger m_position; |
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120 Item::List m_processed; |
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121 }; |
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122 } |
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123 |
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124 QT_END_NAMESPACE |
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125 |
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126 QT_END_HEADER |
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127 |
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128 #endif |