src/xmlpatterns/iterators/qrangeiterator_p.h
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
    12 ** You may use this file in accordance with the terms and conditions
       
    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
    23 **
       
    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
    27 **
       
    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    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_RangeIterator_H
       
    53 #define Patternist_RangeIterator_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 RangeIterator represents a sequence of integers between a
       
    65      * start and end value.
       
    66      *
       
    67      * The RangeIterator contains the evaluation logic for the range expression, <tt>N to M</tt>,
       
    68      * and its behavior is therefore consistent with the definition of that XPath expression.
       
    69      * Hence, the detailed behavior of the RangeIterator can be found in the XPath 2.0
       
    70      * specification.
       
    71      *
       
    72      * @see <a href="http://www.w3.org/TR/xpath20/\#doc-xpath-RangeExpr">XML Path Language
       
    73      * (XPath) 2.0, 3.3 Sequence Expressions, RangeExpr</a>
       
    74      * @see RangeExpression
       
    75      * @author Frans Englich <frans.englich@nokia.com>
       
    76      * @ingroup Patternist_iterators
       
    77      * @todo Documentation is missing
       
    78      */
       
    79     class Q_AUTOTEST_EXPORT RangeIterator : public Item::Iterator
       
    80     {
       
    81     public:
       
    82 
       
    83         /**
       
    84          * RangeIterator can iterate in both directions.
       
    85          * This enumerator exist for identifying different directions.
       
    86          */
       
    87         enum Direction
       
    88         {
       
    89             /**
       
    90              * Signifies that the QAbstractXmlForwardIterator operates in a reverse direction, where the
       
    91              * first item returned by the next() function is from the beginning of the
       
    92              * source sequence.
       
    93              */
       
    94             Backward = 0,
       
    95 
       
    96             /**
       
    97              * Signifies the forward direction. Iterators do conceptually operate
       
    98              * in the forward direction by default.
       
    99              */
       
   100             Forward = 1
       
   101         };
       
   102 
       
   103         /**
       
   104          * Creates an QAbstractXmlForwardIterator that returns integer values from consecutive sequence
       
   105          * of integers between @p start and @p end, where the step taken
       
   106          * between each integer is 1 with polarity as specified in @p direction.
       
   107          *
       
   108          * @note @p start must be smaller than @p end, not larger
       
   109          * or equal. This is not checked.
       
   110          */
       
   111         RangeIterator(const xsInteger start,
       
   112                       const Direction direction,
       
   113                       const xsInteger end);
       
   114 
       
   115         virtual Item next();
       
   116         virtual Item current() const;
       
   117         virtual xsInteger position() const;
       
   118         virtual xsInteger count();
       
   119         virtual Item::Iterator::Ptr toReversed();
       
   120         virtual Item::Iterator::Ptr copy() const;
       
   121 
       
   122     private:
       
   123         xsInteger m_start;
       
   124         xsInteger m_end;
       
   125         Item m_current;
       
   126         xsInteger m_position;
       
   127         xsInteger m_count;
       
   128         const Direction m_direction;
       
   129 
       
   130         /**
       
   131          * We only need to store -1 or 1, so save memory with a bit field.
       
   132          */
       
   133         const qint8 m_increment : 2;
       
   134     };
       
   135 }
       
   136 
       
   137 QT_END_NAMESPACE
       
   138 
       
   139 QT_END_HEADER
       
   140 
       
   141 #endif