src/xercesc/validators/common/CMNode.hpp

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * $Id$
 */

#if !defined(XERCESC_INCLUDE_GUARD_CMNODE_HPP)
#define XERCESC_INCLUDE_GUARD_CMNODE_HPP

#include <limits.h>

#include <xercesc/validators/common/ContentSpecNode.hpp>
#include <xercesc/validators/common/CMStateSet.hpp>

namespace XERCES_CPP_NAMESPACE {

class CMNode : public XMemory
{
public :
    enum {
    	// Special value to indicate a nullable node
        epsilonNode = UINT_MAX - 1
    };

    // -----------------------------------------------------------------------
    //  Constructors and Destructors
    // -----------------------------------------------------------------------
    CMNode
    (
        const ContentSpecNode::NodeTypes type
        , unsigned int maxStates
        , MemoryManager* const manager = XMLPlatformUtils::fgMemoryManager
    );
    virtual ~CMNode();


    // -----------------------------------------------------------------------
    //  Virtual methods to be provided derived node classes
    // -----------------------------------------------------------------------
    virtual void orphanChild() = 0;

    // -----------------------------------------------------------------------
    //  Getter methods
    // -----------------------------------------------------------------------
    ContentSpecNode::NodeTypes getType() const;
    const CMStateSet& getFirstPos();
    const CMStateSet& getLastPos();
    bool isNullable() const;

protected :
    // -----------------------------------------------------------------------
    //  Protected, abstract methods
    // -----------------------------------------------------------------------
    virtual void calcFirstPos(CMStateSet& toUpdate) const = 0;
    virtual void calcLastPos(CMStateSet& toUpdate) const = 0;

    // -----------------------------------------------------------------------
    //  Protected data members
    //
    //  fMemoryManager
    //      Pluggable memory manager for dynamic allocation/deallocation.
    // -----------------------------------------------------------------------
    MemoryManager*             fMemoryManager;


private :
    // -----------------------------------------------------------------------
    //  Unimplemented constructors and operators
    // -----------------------------------------------------------------------
    CMNode();
    CMNode(const CMNode&);
    CMNode& operator=(const CMNode&);


    // -----------------------------------------------------------------------
    //  Private data members
    //
    //  fType
    //      The type of node. This indicates whether its a leaf or an
    //      operation.
    //
    //  fFirstPos
    //      The set of NFA states that represent the entry states of this
    //      node in the DFA.
    //
    //  fLastPos
    //      The set of NFA states that represent the final states of this
    //      node in the DFA.
    //
    //  fMaxStates
    //      The maximum number of states that the NFA has, which means the
    //      max number of NFA states that have to be traced in the state
    //      sets during the building of the DFA. Its unfortunate that it
    //      has to be stored redundantly, but we need to fault in the
    //      state set members and they have to be sized to this size.
    //
    //  fIsNullable
    //      Whether the node can be empty
    // -----------------------------------------------------------------------
    ContentSpecNode::NodeTypes fType;
    CMStateSet*                fFirstPos;
    CMStateSet*                fLastPos;
    unsigned int               fMaxStates;

protected:
    bool                       fIsNullable;
};



// ---------------------------------------------------------------------------
//  CMNode: Constructors and Destructors
// ---------------------------------------------------------------------------
inline CMNode::CMNode(const ContentSpecNode::NodeTypes type
                    , unsigned int maxStates
                    , MemoryManager* const manager) :

    fMemoryManager(manager)
    , fType(type)
    , fFirstPos(0)
    , fLastPos(0)
    , fMaxStates(maxStates)
    , fIsNullable(false)
{
}

inline CMNode::~CMNode()
{
    // Clean up any position sets that got created
    delete fFirstPos;
    delete fLastPos;
}


// ---------------------------------------------------------------------------
//  CMNode: Getter methods
// ---------------------------------------------------------------------------
inline ContentSpecNode::NodeTypes CMNode::getType() const
{
    return fType;
}

inline const CMStateSet& CMNode::getFirstPos()
{
    //
    //  Fault in the state set if needed. Since we can't use mutable members
    //  cast off the const'ness.
    //
    if (!fFirstPos)
    {
        fFirstPos = new (fMemoryManager) CMStateSet(fMaxStates, fMemoryManager);
        calcFirstPos(*fFirstPos);
    }
    return *fFirstPos;
}

inline const CMStateSet& CMNode::getLastPos()
{
    //
    //  Fault in the state set if needed. Since we can't use mutable members
    //  cast off the const'ness.
    //
    if (!fLastPos)
    {
        fLastPos = new (fMemoryManager) CMStateSet(fMaxStates, fMemoryManager);
        calcLastPos(*fLastPos);
    }
    return *fLastPos;
}

inline bool CMNode::isNullable() const
{
    return fIsNullable;
}

}

#endif