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     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

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     7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit.

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    41 

    42 //

    43 //  W A R N I N G

    44 //  -------------

    45 //

    46 // This file is not part of the Qt API.  It exists purely as an

    47 // implementation detail.  This header file may change from version to

    48 // version without notice, or even be removed.

    49 //

    50 // We mean it.

    51 

    52 #ifndef Patternist_SubsequenceIterator_H

    53 #define Patternist_SubsequenceIterator_H

    54 

    55 #include "qitem_p.h"

    56 

    57 QT_BEGIN_HEADER

    58 

    59 QT_BEGIN_NAMESPACE

    60 

    61 namespace QPatternist

    62 {

    63     /**

    64      * @short Picks out a slice from another QAbstractXmlForwardIterator, specified by a start and end position.

    65      *

    66      * SubsequenceIterator allows a "slice", a subsequence, from an QAbstractXmlForwardIterator to

    67      * be extracted. The SubsequenceIterator's constructor takes a source QAbstractXmlForwardIterator,

    68      * a start position, and the length of the subsequence to be extracted.

    69      *

    70      * SubsequenceIterator contains the central business logic to implement

    71      * the <tt>fn:subsequence()</tt> function. The detailed behavior, such as how it behaves

    72      * if the source QAbstractXmlForwardIterator is empty or if the specified subsequence stretches

    73      * beyond the source QAbstractXmlForwardIterator, is therefore consistent with the definition of

    74      * the <tt>fn:subsequence()</tt> function.

    75      *

    76      * @see <a href="http://www.w3.org/TR/xpath-functions/#func-subsequence">XQuery 1.0

    77      * and XPath 2.0 Functions and Operators, 15.1.10 fn:subsequence</a>

    78      * @author Frans Englich <frans.englich@nokia.com>

    79      * @ingroup Patternist_iterators

    80      */

    81     class SubsequenceIterator : public Item::Iterator

    82     {

    83     public:

    84         /**

    85          * Creates a SubsequenceIterator that extracts a subsequence from the sequence

    86          * in @p iterator, as specified by the @p start position and @p length parameter.

    87          *

    88          * @param iterator the iterator which the subsequence should

    89          * be extracted from

    90          * @param start the start position of extraction. Must be 1 or larger.

    91          * @param length the length of the subsequence to extract. If it is

    92          * -1, to the end is returned. The value must be -1 or 1 or larger.

    93          */

    94         SubsequenceIterator(const Item::Iterator::Ptr &iterator,

    95                             const xsInteger start,

    96                             const xsInteger length);

    97 

    98         virtual Item next();

    99         virtual Item current() const;

   100         virtual xsInteger position() const;

   101         virtual Item::Iterator::Ptr copy() const;

   102 

   103     private:

   104         xsInteger m_position;

   105         Item m_current;

   106         const Item::Iterator::Ptr m_it;

   107         xsInteger m_counter;

   108         const xsInteger m_start;

   109         const xsInteger m_len;

   110         const xsInteger m_stop;

   111     };

   112 }

   113 

   114 QT_END_NAMESPACE

   115 

   116 QT_END_HEADER

   117 

   118 #endif