src/xmlpatterns/iterators/qsubsequenceiterator.cpp
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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 #include "qxpathhelper_p.h"
       
    43 
       
    44 #include "qsubsequenceiterator_p.h"
       
    45 
       
    46 QT_BEGIN_NAMESPACE
       
    47 
       
    48 using namespace QPatternist;
       
    49 
       
    50 SubsequenceIterator::SubsequenceIterator(const Item::Iterator::Ptr &iterator,
       
    51                                          const xsInteger start,
       
    52                                          const xsInteger len)
       
    53                                          : m_position(0),
       
    54                                            m_it(iterator),
       
    55                                            m_counter(start),
       
    56                                            m_start(start),
       
    57                                            m_len(len),
       
    58                                            m_stop(m_start + m_len)
       
    59 {
       
    60     Q_ASSERT(iterator);
       
    61     Q_ASSERT(start >= 1);
       
    62     Q_ASSERT(len == -1 || len >= 1);
       
    63 
       
    64     /* Note, "The first item of a sequence is located at position 1, not position 0." */
       
    65     for(xsInteger i = 1; i != m_start; ++i)
       
    66         m_it->next();
       
    67 }
       
    68 
       
    69 Item SubsequenceIterator::next()
       
    70 {
       
    71     if(m_position == -1)
       
    72         return Item();
       
    73 
       
    74     m_current = m_it->next();
       
    75     ++m_position;
       
    76 
       
    77     if(m_len == -1)
       
    78     {
       
    79         if(!m_current)
       
    80             m_position = -1;
       
    81 
       
    82         return m_current;
       
    83     }
       
    84 
       
    85     ++m_counter;
       
    86 
       
    87     if(!(m_counter > m_stop) && m_current)
       
    88         return m_current;
       
    89 
       
    90     m_position = -1;
       
    91     m_current.reset();
       
    92     return Item();
       
    93 }
       
    94 
       
    95 Item SubsequenceIterator::current() const
       
    96 {
       
    97     return m_current;
       
    98 }
       
    99 
       
   100 xsInteger SubsequenceIterator::position() const
       
   101 {
       
   102     return m_position;
       
   103 }
       
   104 
       
   105 Item::Iterator::Ptr SubsequenceIterator::copy() const
       
   106 {
       
   107     return Item::Iterator::Ptr(new SubsequenceIterator(m_it->copy(), m_start, m_len));
       
   108 }
       
   109 
       
   110 QT_END_NAMESPACE