src/xmlpatterns/expr/qunlimitedcontainer_p.h
changeset 0 1918ee327afb
child 4 3b1da2848fc7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/expr/qunlimitedcontainer_p.h	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,149 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** 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 Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+//  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