DOMCasts.hpp

#ifndef DOMCasts_HEADER_GUARD_
#define DOMCasts_HEADER_GUARD_

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001-2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
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 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
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 * 5. Products derived from this software may not be called "Apache",
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 *
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 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation, and was
 * originally based on software copyright (c) 2001, International
 * Business Machines, Inc., http://www.ibm.com .  For more information
 * on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
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/*
 * $Id$
 */

//
//  This file is part of the internal implementation of the C++ XML DOM.
//  It should NOT be included or used directly by application programs.
//
//  Applications should include the file <xercesc/dom/DOM.hpp> for the entire
//  DOM API, or xercesc/dom/DOM*.hpp for individual DOM classes, where the class
//  name is substituded for the *.
//

//
//  Define inline casting functions to convert from
//    (DOMNode *) to DOMParentNode or DOMChildNode *.
//
//  This requires knowledge of the structure of the fields of
//   for all node types.  There are three categories -
//
//  Nodetypes that can have children and can be a child themselves.
//    e.g.  Elements
//
//       Object
//           DOMNodeImpl     fNode;
//           DOMParentNode   fParent;
//           DOMChildNode    fChild;
//             ...            // other fields, depending on node type.
//
//  Nodetypes that can not have children, e.g. TEXT
//
//       Object
//           DOMNodeImpl     fNode;
//           DOMChildNode    fChild;
//              ...            // other fields, depending on node type
//
//  Nodetypes that can not be a child of other nodes, but that can
//  have children (are a parent)  e.g. ATTR
//       Object
//           DOMNodeImpl     fNode;
//           DOMParentNode   fParent
//               ...           // other fields, depending on node type
//
//   The casting functions make these assumptions:
//      1.  The cast is possible.  Using code will not attempt to
//          cast to something that does not exist, such as the child
//          part of an ATTR
//
//      2.  The nodes belong to this implementation.
//
//    Some of the casts use the LEAFNODE flag in the common fNode part to
//    determine whether an fParent field exists, and thus the
//    position of the fChild part within the node.
//
//  These functions also cast off const.  It was either do that, or make
//  a second overloaded set that took and returned const arguements.
//

#include "DOMElementImpl.hpp"
#include "DOMTextImpl.hpp"

XERCES_CPP_NAMESPACE_BEGIN


static inline DOMNodeImpl *castToNodeImpl(const DOMNode *p)
{
    DOMElementImpl *pE = (DOMElementImpl *)p;
    return &(pE->fNode);
}


static inline DOMParentNode *castToParentImpl(const DOMNode *p) {
    DOMElementImpl *pE = (DOMElementImpl *)p;
    return &(pE->fParent);
}


static inline DOMChildNode *castToChildImpl(const DOMNode *p) {
    DOMElementImpl *pE = (DOMElementImpl *)p;
    if (pE->fNode.isLeafNode())  {
        DOMTextImpl *pT = (DOMTextImpl *)p;
        return &(pT->fChild);
    }
    return &(pE->fChild);
}


static inline DOMNode *castToNode(const DOMParentNode *p ) {
    int parentOffset = (char *)&(((DOMElementImpl *)0)->fParent) - (char *)0;
    char *retPtr = (char *)p - parentOffset;
    return (DOMNode *)retPtr;
}

static inline DOMNode *castToNode(const DOMNodeImpl *p) {
    int nodeImplOffset = (char *)&(((DOMElementImpl *)0)->fNode) - (char *)0;
    char *retPtr = (char *)p - nodeImplOffset;
    return (DOMNode *)retPtr;
}


static inline DOMNodeImpl *castToNodeImpl(const DOMParentNode *p)
{
    int nodeImplOffset = (char *)&(((DOMElementImpl *)0)->fNode) - (char *)0;
    int parentOffset = (char *)&(((DOMElementImpl *)0)->fParent) - (char *)0;
    char *retPtr = (char *)p - parentOffset + nodeImplOffset;
    return (DOMNodeImpl *)retPtr;
}

XERCES_CPP_NAMESPACE_END

#endif