/****************************************************************************

**

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

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** Contact: Nokia Corporation (qt-info@nokia.com)

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

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** No Commercial Usage

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** this package.

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** GNU Lesser General Public License Usage

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//

//  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_AccelIterators_H

#define Patternist_AccelIterators_H

#include "qacceltree_p.h"

#include "qitem_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Abstract base class for Iterators for the AccelTree, that

     * contains common functions and members.

     *

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

     */

    class AccelIterator : public QXmlNodeModelIndex::Iterator

    {

    public:

        virtual xsInteger position() const;

        virtual QXmlNodeModelIndex current() const;

    protected:

        inline AccelIterator(const AccelTree *const doc,

                             const AccelTree::PreNumber pre,

                             const AccelTree::PreNumber currentPre) : m_document(doc)

                                                                    , m_preNumber(pre)

                                                                    , m_currentPre(currentPre)

                                                                    , m_position(0)

        {

            Q_ASSERT(m_document);

            Q_ASSERT(m_preNumber >= 0);

        }

        inline QXmlNodeModelIndex closedExit()

        {

            m_position = -1;

            m_current.reset();

            return QXmlNodeModelIndex();

        }

        /**

         * We do not own it.

         */

        const AccelTree *const      m_document;

        /**

         * The pre number of the node that should be navigated from.

         */

        const AccelTree::PreNumber  m_preNumber;

        AccelTree::PreNumber        m_currentPre;

        xsInteger                   m_position;

        QXmlNodeModelIndex          m_current;

    };

    /**

     * @short Iterates along the @c ancestor or @c ancestor-or-self axis in an AccelTree.

     *

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

     */

    template<const bool IncludeSelf>

    class AncestorIterator : public AccelIterator

    {

    public:

        /**

         * @p pre is the node from which iteration starts

         * from. In the @c ancestor axis it is excluded,

         * while in @c ancestor-or-self it is included. @p pre

         * must have at least one ancestor.

         */

        inline AncestorIterator(const AccelTree *const doc,

                                const AccelTree::PreNumber pre) : AccelIterator(doc, pre, IncludeSelf ? pre : doc->basicData.at(pre).parent())

        {

            Q_ASSERT(IncludeSelf || m_document->hasParent(pre));

        }

        virtual QXmlNodeModelIndex next()

        {

            if(m_currentPre == -1)

                return closedExit();

            else

            {

                ++m_position;

                m_current = m_document->createIndex(m_currentPre);

                m_currentPre = m_document->basicData.at(m_currentPre).parent();

                return m_current;

            }

        }

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const

        {

            return QXmlNodeModelIndex::Iterator::Ptr(new AncestorIterator<IncludeSelf>(m_document, m_preNumber));

        }

    };

    /**

     * @short Iterates along the @c child axis in an AccelTree.

     *

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

     */

    class ChildIterator : public AccelIterator

    {

    public:

        /**

         * @p pre must have at least one child.

         */

        inline ChildIterator(const AccelTree *const doc,

                             const AccelTree::PreNumber pre) : AccelIterator(doc, pre, pre + 1),

                                                               m_depth(m_document->depth(m_currentPre))

        {

            Q_ASSERT(m_document->hasChildren(pre));

            /* Skip the attributes, that are children in the pre/post plane, of

             * the node we're applying the child axis to. */

            while(m_document->kind(m_currentPre) == QXmlNodeModelIndex::Attribute)

            {

                ++m_currentPre;

                /* We check the depth here because we would otherwise include

                 * following siblings. */

                if(m_currentPre > m_document->maximumPreNumber() || m_document->depth(m_currentPre) != m_depth)

                {

                    m_currentPre = -1;

                    break;

                }

            }

        }

        virtual QXmlNodeModelIndex next();

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const;

    private:

        const AccelTree::Depth m_depth;

    };

    /**

     * @short Iterates along the sibling axes in an AccelTree.

     *

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

     */

    template<const bool IsFollowing>

    class SiblingIterator : public AccelIterator

    {

    public:

        inline SiblingIterator(const AccelTree *const doc,

                               const AccelTree::PreNumber pre) : AccelIterator(doc, pre, pre + (IsFollowing ? 0 : -1)),

                                                                 m_depth(doc->depth(pre))

        {

            Q_ASSERT_X(IsFollowing || pre != 0, "",

                       "When being preceding-sibling, the context node cannot be the first node in the document.");

            Q_ASSERT_X(!IsFollowing || pre != m_document->maximumPreNumber(), "",

                       "When being following-sibling, the context node cannot be the last node in the document.");

        }

        virtual QXmlNodeModelIndex next()

        {

            if(m_currentPre == -1)

                return QXmlNodeModelIndex();

            if(IsFollowing)

            {

                /* Skip the descendants, and jump to the next node. */

                m_currentPre += m_document->size(m_currentPre) + 1;

                if(m_currentPre > m_document->maximumPreNumber() || m_document->depth(m_currentPre) != m_depth)

                    return closedExit();

                else

                {

                    ++m_position;

                    m_current = m_document->createIndex(m_currentPre);

                    return m_current;

                }

            }

            else

            {

                while(m_document->depth(m_currentPre) > m_depth)

                    --m_currentPre;

                while(m_document->kind(m_currentPre) == QXmlNodeModelIndex::Attribute)

                    --m_currentPre;

                if(m_document->depth(m_currentPre) == m_depth &&

                   m_document->kind(m_currentPre) != QXmlNodeModelIndex::Attribute)

                {

                    m_current = m_document->createIndex(m_currentPre);

                    ++m_position;

                    --m_currentPre;

                    return m_current;

                }

                else

                {

                    m_currentPre = -1;

                    return closedExit();

                }

            }

        }

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const

        {

            return QXmlNodeModelIndex::Iterator::Ptr(new SiblingIterator<IsFollowing>(m_document, m_preNumber));

        }

    private:

        const AccelTree::Depth m_depth;

    };

    /**

     * @short Implements axis @c descendant and @c descendant-or-self for the

     * AccelTree.

     *

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

     */

    template<const bool IncludeSelf>

    class DescendantIterator : public AccelIterator

    {

    public:

        /**

         * @p pre must have at least one child.

         */

        inline DescendantIterator(const AccelTree *const doc,

                                  const AccelTree::PreNumber pre) : AccelIterator(doc, pre, pre + (IncludeSelf ? 0 : 1)),

                                                                    m_postNumber(doc->postNumber(pre))

        {

            Q_ASSERT(IncludeSelf || m_document->hasChildren(pre));

            /* Make sure that m_currentPre is the first node part of this axis.

             * Since we're not including ourself, advance to the node after our

             * attributes, if any. */

            if(!IncludeSelf)

            {

                while(m_document->kind(m_currentPre) == QXmlNodeModelIndex::Attribute)

                {

                    ++m_currentPre;

                    /* We check the depth here because we would otherwise include

                     * following siblings. */

                    if(m_currentPre > m_document->maximumPreNumber() || m_document->postNumber(m_currentPre) > m_postNumber)

                    {

                        m_currentPre = -1;

                        break;

                    }

                }

            }

        }

        virtual QXmlNodeModelIndex next()

        {

            if(m_currentPre == -1)

                return closedExit();

            ++m_position;

            m_current = m_document->createIndex(m_currentPre);

            ++m_currentPre;

            if(m_currentPre > m_document->maximumPreNumber())

            {

                m_currentPre = -1;

                return m_current;

            }

            if(m_document->postNumber(m_currentPre) < m_postNumber)

            {

                while(m_document->kind(m_currentPre) == QXmlNodeModelIndex::Attribute)

                {

                    ++m_currentPre;

                    if(m_currentPre > m_document->maximumPreNumber())

                    {

                        m_currentPre = -1;

                        break;

                    }

                }

            }

            else

                m_currentPre = -1;

            return m_current;

        }

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const

        {

            return QXmlNodeModelIndex::Iterator::Ptr(new DescendantIterator<IncludeSelf>(m_document, m_preNumber));

        }

    private:

        const AccelTree::PreNumber m_postNumber;

    };

    /**

     * @short Implements axis @c following for the AccelTree.

     *

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

     */

    class FollowingIterator : public AccelIterator

    {

    public:

        /**

         * @ pre must have at least one child.

         */

        inline FollowingIterator(const AccelTree *const doc,

                                 const AccelTree::PreNumber pre) : AccelIterator(doc, pre, pre)

        {

        }

        virtual QXmlNodeModelIndex next();

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const;

    };

    /**

     * @short Implements axis @c preceding for the AccelTree.

     *

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

     */

    class PrecedingIterator : public AccelIterator

    {

    public:

        /**

         * @ pre must have at least one child.

         */

        inline PrecedingIterator(const AccelTree *const doc,

                                 const AccelTree::PreNumber pre) : AccelIterator(doc, pre,

                                                                                 pre - 1 /* currentPre */)

                                                                 , m_postNumber(m_document->postNumber(m_preNumber))

        {

        }

        virtual QXmlNodeModelIndex next();

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const;

    private:

        const AccelTree::PreNumber  m_postNumber;

    };

    /**

     * @short Implements axis @c attribute for the AccelTree.

     *

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

     */

    class AttributeIterator : public AccelIterator

    {

    public:

        /**

         * @p pre must have at least one child.

         */

        inline AttributeIterator(const AccelTree *const doc, const AccelTree::PreNumber pre) : AccelIterator(doc, pre, pre + 1)

        {

            Q_ASSERT(m_document->hasChildren(pre));

            Q_ASSERT(m_document->kind(m_currentPre) == QXmlNodeModelIndex::Attribute);

        }

        virtual QXmlNodeModelIndex next();

        virtual QXmlNodeModelIndex::Iterator::Ptr copy() const;

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif