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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_UnlimitedContainer_H

#define Patternist_UnlimitedContainer_H

#include <QList>

#include "qexpression_p.h"

#include "qgenericsequencetype_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Base class for expressions that has any amount of operands.

     *

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

     * @ingroup Patternist_expressions

     */

    class UnlimitedContainer : public Expression

    {

    public:

        /**

         * Creates an UnlimitedContainer containing the operands @p operands. @p operands

         * may be empty.

         */

        UnlimitedContainer(const Expression::List &operands = Expression::List());

        virtual void setOperands(const Expression::List &list);

        virtual Expression::List operands() const;

        /**

         * @note This function cannot be called before setOperands is called.

         */

        virtual bool compressOperands(const StaticContext::Ptr &);

        /**

         * Tells how operandsUnionType() should compute the cardinality of

         * its children.

         *

         * This type is public because of a bug in the HP-UX aCC compiler.

         */

        enum CardinalityComputation

        {

            ProductOfCardinality,

            UnionOfCardinality

        };

    protected:

        /**

         * Computes and returns the union type of all the Expression instances

         * in this Expression's operands.

         *

         * This implementation is placed inside because CardinalityComputation

         * can't be referenced from the outside(in conforming compilers).

         */

        template<CardinalityComputation suppliedCard>

        inline

        SequenceType::Ptr operandsUnionType() const

        {

            Q_ASSERT(suppliedCard ==  ProductOfCardinality || suppliedCard == UnionOfCardinality);

            const Expression::List::const_iterator end(m_operands.constEnd());

            Expression::List::const_iterator it(m_operands.constBegin());

            /* Load the first one, and jump over it in the loop. */

            SequenceType::Ptr t(m_operands.first()->staticType());

            ItemType::Ptr type(t->itemType());

            Cardinality card(t->cardinality());

            ++it;

            for(; it != end; ++it)

            {

                t = (*it)->staticType();

                type |= t->itemType();

                /* Since this function is a template function, it doesn't

                 * hurt performance that this test is inside the loop. */

                if(suppliedCard == ProductOfCardinality)

                    card += t->cardinality();

                else

                    card |= t->cardinality();

            }

            return makeGenericSequenceType(type, card);

        }

        Expression::List m_operands;

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif