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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qbuiltintypes_p.h"
#include "qcommonsequencetypes_p.h"
#include "qcommonvalues_p.h"
#include "qgenericsequencetype_p.h"
#include "qinteger_p.h"
#include "qliteral_p.h"
#include "qrangeiterator_p.h"
#include "qrangeexpression_p.h"
QT_BEGIN_NAMESPACE
using namespace QPatternist;
RangeExpression::RangeExpression(const Expression::Ptr &operand1,
const Expression::Ptr &operand2) : PairContainer(operand1, operand2)
{
}
Item::Iterator::Ptr RangeExpression::evaluateSequence(const DynamicContext::Ptr &context) const
{
const Item s(m_operand1->evaluateSingleton(context));
if(!s)
return CommonValues::emptyIterator;
const Item e(m_operand2->evaluateSingleton(context));
if(!e)
return CommonValues::emptyIterator;
const xsInteger start = s.as<Numeric>()->toInteger();
const xsInteger end = e.as<Numeric>()->toInteger();
if(start > end)
return CommonValues::emptyIterator;
else if(start == end)
return makeSingletonIterator(s);
else
return Item::Iterator::Ptr(new RangeIterator(start, RangeIterator::Forward, end));
}
Item RangeExpression::evaluateSingleton(const DynamicContext::Ptr &context) const
{
return m_operand1->evaluateSingleton(context);
}
SequenceType::List RangeExpression::expectedOperandTypes() const
{
SequenceType::List result;
result.append(CommonSequenceTypes::ZeroOrOneInteger);
result.append(CommonSequenceTypes::ZeroOrOneInteger);
return result;
}
SequenceType::Ptr RangeExpression::staticType() const
{
/* This logic makes the Cardinality more specific. */
Cardinality::Count from;
bool hasFrom;
if(m_operand1->is(IDIntegerValue))
{
from = m_operand1->as<Literal>()->item().as<Integer>()->toInteger();
hasFrom = true;
}
else
{
hasFrom = false;
from = 0;
}
/* We can't check whether to is -1 since maybe the user wrote -1. Hence
* hasTo is required. */
bool hasTo;
Cardinality::Count to;
if(m_operand2->is(IDIntegerValue))
{
const xsInteger asInt = m_operand2->as<Literal>()->item().as<Integer>()->toInteger();
to = asInt;
if(to == asInt)
hasTo = true;
else
{
/* Cardinality::Count is not the same as type xsInteger. We had overflow. */
to = -1;
hasTo = false;
}
}
else
{
to = -1;
hasTo = false;
}
if(hasTo && hasFrom)
{
if(from > to)
{
/* The query is incorrectly written, we'll evaluate to the empty sequence.
* Just return what's correct. */
return CommonSequenceTypes::ZeroOrMoreIntegers;
}
else
{
Cardinality::Count count = (to - from) + 1; /* + 1, since it's inclusive. */
return makeGenericSequenceType(BuiltinTypes::xsInteger, Cardinality::fromExact(count));
}
}
else
{
/* We can't do fromExact(from, -1) since the latter can evaluate to a value that actually is
* lower than from, although that unfortunately is very unlikely. */
return CommonSequenceTypes::ZeroOrMoreIntegers;
}
}
Expression::Properties RangeExpression::properties() const
{
return Expression::DisableElimination;
}
ExpressionVisitorResult::Ptr RangeExpression::accept(const ExpressionVisitor::Ptr &visitor) const
{
return visitor->visit(this);
}
QT_END_NAMESPACE
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