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#include "qinteger_p.h"

#include "qrangeiterator_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

RangeIterator::RangeIterator(const xsInteger start,

                             const Direction direction,

                             const xsInteger end)

                             : m_start(start),

                               m_end(end),

                               m_position(0),

                               m_count(start),

                               m_direction(direction),

                               m_increment(m_direction == Forward ? 1 : -1)

{

    Q_ASSERT(m_start < m_end);

    Q_ASSERT(m_direction == Backward || m_direction == Forward);

    if(m_direction == Backward)

    {

        qSwap(m_start, m_end);

        m_count = m_start;

    }

}

Item RangeIterator::next()

{

    if(m_position == -1)

        return Item();

    else if((m_direction == Forward && m_count > m_end) ||

            (m_direction == Backward && m_count < m_end))

    {

        m_position = -1;

        m_current.reset();

        return Item();

    }

    else

    {

        m_current = Integer::fromValue(m_count);

        m_count += m_increment;

        ++m_position;

        return m_current;

    }

}

xsInteger RangeIterator::count()

{

    /* This complication is for handling that m_start & m_end may be reversed. */

    xsInteger ret;

    if(m_start < m_end)

        ret = m_end - m_start;

    else

        ret = m_start - m_end;

    return ret + 1;

}

Item::Iterator::Ptr RangeIterator::toReversed()

{

    return Item::Iterator::Ptr(new RangeIterator(m_start, Backward, m_end));

}

Item RangeIterator::current() const

{

    return m_current;

}

xsInteger RangeIterator::position() const

{

    return m_position;

}

Item::Iterator::Ptr RangeIterator::copy() const

{

    if(m_direction == Backward)

        return Item::Iterator::Ptr(new RangeIterator(m_end, Backward, m_start));

    else

        return Item::Iterator::Ptr(new RangeIterator(m_start, Forward, m_end));

}

QT_END_NAMESPACE