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

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#include "qitem_p.h"

#include "qboolean_p.h"

#include "qbuiltintypes_p.h"

#include "qcommonsequencetypes_p.h"

#include "qemptysequence_p.h"

#include "qoptimizationpasses_p.h"

#include "qvaluecomparison_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

ValueComparison::ValueComparison(const Expression::Ptr &op1,

                                 const AtomicComparator::Operator op,

                                 const Expression::Ptr &op2) : PairContainer(op1, op2),

                                                               m_operator(op)

{

}

Item ValueComparison::evaluateSingleton(const DynamicContext::Ptr &context) const

{

    const Item it1(m_operand1->evaluateSingleton(context));

    if(!it1)

        return Item();

    const Item it2(m_operand2->evaluateSingleton(context));

    if(!it2)

        return Item();

    return Boolean::fromValue(flexibleCompare(it1, it2, context));

}

Expression::Ptr ValueComparison::typeCheck(const StaticContext::Ptr &context,

                                           const SequenceType::Ptr &reqType)

{

    const Expression::Ptr me(PairContainer::typeCheck(context, reqType));

    const ItemType::Ptr t1(m_operand1->staticType()->itemType());

    const ItemType::Ptr t2(m_operand2->staticType()->itemType());

    Q_ASSERT(t1);

    Q_ASSERT(t2);

    if(*CommonSequenceTypes::Empty == *t1 ||

       *CommonSequenceTypes::Empty == *t2)

    {

        return EmptySequence::create(this, context);

    }

    else

    {

        prepareComparison(fetchComparator(t1, t2, context));

        return me;

    }

}

Expression::Ptr ValueComparison::compress(const StaticContext::Ptr &context)

{

    const Expression::Ptr me(PairContainer::compress(context));

    if(me != this)

        return me;

    if(isCaseInsensitiveCompare(m_operand1, m_operand2))

        useCaseInsensitiveComparator();

    return me;

}

bool ValueComparison::isCaseInsensitiveCompare(Expression::Ptr &op1, Expression::Ptr &op2)

{

    Q_ASSERT(op1);

    Q_ASSERT(op2);

    const ID iD = op1->id();

    if((iD == IDLowerCaseFN || iD == IDUpperCaseFN) && iD == op2->id())

    {

        /* Both are either fn:lower-case() or fn:upper-case(). */

        /* Replace the calls to the functions with its operands. */

        op1 = op1->operands().first();

        op2 = op2->operands().first();

        return true;

    }

    else

        return false;

}

OptimizationPass::List ValueComparison::optimizationPasses() const

{

    return OptimizationPasses::comparisonPasses;

}

SequenceType::List ValueComparison::expectedOperandTypes() const

{

    SequenceType::List result;

    result.append(CommonSequenceTypes::ZeroOrOneAtomicType);

    result.append(CommonSequenceTypes::ZeroOrOneAtomicType);

    return result;

}

SequenceType::Ptr ValueComparison::staticType() const

{

    if(m_operand1->staticType()->cardinality().allowsEmpty() ||

       m_operand2->staticType()->cardinality().allowsEmpty())

        return CommonSequenceTypes::ZeroOrOneBoolean;

    else

        return CommonSequenceTypes::ExactlyOneBoolean;

}

ExpressionVisitorResult::Ptr ValueComparison::accept(const ExpressionVisitor::Ptr &visitor) const

{

    return visitor->visit(this);

}

Expression::ID ValueComparison::id() const

{

    return IDValueComparison;

}

QT_END_NAMESPACE