tinyxml.h

这个代码用C＋＋实现了一个小型虚拟机

	in a document, or stand on its own. The type of a TiXmlNode
	can be queried, and it can be cast to its more defined type.
*/
class TiXmlNode : public TiXmlBase
{
	friend class TiXmlDocument;
	friend class TiXmlElement;

public:
	#ifdef TIXML_USE_STL	

	    /** An input stream operator, for every class. Tolerant of newlines and
		    formatting, but doesn't expect them.
	    */
	    friend std::istream& operator >> (std::istream& in, TiXmlNode& base);

	    /** An output stream operator, for every class. Note that this outputs
		    without any newlines or formatting, as opposed to Print(), which
		    includes tabs and new lines.

		    The operator<< and operator>> are not completely symmetric. Writing
		    a node to a stream is very well defined. You'll get a nice stream
		    of output, without any extra whitespace or newlines.
		    
		    But reading is not as well defined. (As it always is.) If you create
		    a TiXmlElement (for example) and read that from an input stream,
		    the text needs to define an element or junk will result. This is
		    true of all input streams, but it's worth keeping in mind.

		    A TiXmlDocument will read nodes until it reads a root element, and
			all the children of that root element.
	    */	
	    friend std::ostream& operator<< (std::ostream& out, const TiXmlNode& base);

		/// Appends the XML node or attribute to a std::string.
		friend std::string& operator<< (std::string& out, const TiXmlNode& base );

	#else
	    // Used internally, not part of the public API.
	    friend TIXML_OSTREAM& operator<< (TIXML_OSTREAM& out, const TiXmlNode& base);
	#endif

	/** The types of XML nodes supported by TinyXml. (All the
			unsupported types are picked up by UNKNOWN.)
	*/
	enum NodeType
	{
		DOCUMENT,
		ELEMENT,
		COMMENT,
		UNKNOWN,
		TEXT,
		DECLARATION,
		TYPECOUNT
	};

	virtual ~TiXmlNode();

	/** The meaning of 'value' changes for the specific type of
		TiXmlNode.
		@verbatim
		Document:	filename of the xml file
		Element:	name of the element
		Comment:	the comment text
		Unknown:	the tag contents
		Text:		the text string
		@endverbatim

		The subclasses will wrap this function.
	*/
	const char *Value() const { return value.c_str (); }

    #ifdef TIXML_USE_STL
	/** Return Value() as a std::string. If you only use STL,
	    this is more efficient than calling Value().
		Only available in STL mode.
	*/
	const std::string& ValueStr() const { return value; }
	#endif

	/** Changes the value of the node. Defined as:
		@verbatim
		Document:	filename of the xml file
		Element:	name of the element
		Comment:	the comment text
		Unknown:	the tag contents
		Text:		the text string
		@endverbatim
	*/
	void SetValue(const char * _value) { value = _value;}

    #ifdef TIXML_USE_STL
	/// STL std::string form.
	void SetValue( const std::string& _value )    
	{	  
		StringToBuffer buf( _value );
		SetValue( buf.buffer ? buf.buffer : "" );    	
	}	
	#endif

	/// Delete all the children of this node. Does not affect 'this'.
	void Clear();

	/// One step up the DOM.
	TiXmlNode* Parent()							{ return parent; }
	const TiXmlNode* Parent() const				{ return parent; }

	const TiXmlNode* FirstChild()	const	{ return firstChild; }		///< The first child of this node. Will be null if there are no children.
	TiXmlNode* FirstChild()					{ return firstChild; }
	const TiXmlNode* FirstChild( const char * value ) const;			///< The first child of this node with the matching 'value'. Will be null if none found.
	TiXmlNode* FirstChild( const char * value );						///< The first child of this node with the matching 'value'. Will be null if none found.

	const TiXmlNode* LastChild() const	{ return lastChild; }		/// The last child of this node. Will be null if there are no children.
	TiXmlNode* LastChild()	{ return lastChild; }
	const TiXmlNode* LastChild( const char * value ) const;			/// The last child of this node matching 'value'. Will be null if there are no children.
	TiXmlNode* LastChild( const char * value );	

    #ifdef TIXML_USE_STL
	const TiXmlNode* FirstChild( const std::string& _value ) const	{	return FirstChild (_value.c_str ());	}	///< STL std::string form.
	TiXmlNode* FirstChild( const std::string& _value )				{	return FirstChild (_value.c_str ());	}	///< STL std::string form.
	const TiXmlNode* LastChild( const std::string& _value ) const	{	return LastChild (_value.c_str ());	}	///< STL std::string form.
	TiXmlNode* LastChild( const std::string& _value )				{	return LastChild (_value.c_str ());	}	///< STL std::string form.
	#endif

	/** An alternate way to walk the children of a node.
		One way to iterate over nodes is:
		@verbatim
			for( child = parent->FirstChild(); child; child = child->NextSibling() )
		@endverbatim

		IterateChildren does the same thing with the syntax:
		@verbatim
			child = 0;
			while( child = parent->IterateChildren( child ) )
		@endverbatim

		IterateChildren takes the previous child as input and finds
		the next one. If the previous child is null, it returns the
		first. IterateChildren will return null when done.
	*/
	const TiXmlNode* IterateChildren( const TiXmlNode* previous ) const;
	TiXmlNode* IterateChildren( TiXmlNode* previous );

	/// This flavor of IterateChildren searches for children with a particular 'value'
	const TiXmlNode* IterateChildren( const char * value, const TiXmlNode* previous ) const;
	TiXmlNode* IterateChildren( const char * value, TiXmlNode* previous );

    #ifdef TIXML_USE_STL
	const TiXmlNode* IterateChildren( const std::string& _value, const TiXmlNode* previous ) const	{	return IterateChildren (_value.c_str (), previous);	}	///< STL std::string form.
	TiXmlNode* IterateChildren( const std::string& _value, TiXmlNode* previous ) {	return IterateChildren (_value.c_str (), previous);	}	///< STL std::string form.
	#endif

	/** Add a new node related to this. Adds a child past the LastChild.
		Returns a pointer to the new object or NULL if an error occured.
	*/
	TiXmlNode* InsertEndChild( const TiXmlNode& addThis );


	/** Add a new node related to this. Adds a child past the LastChild.

		NOTE: the node to be added is passed by pointer, and will be
		henceforth owned (and deleted) by tinyXml. This method is efficient
		and avoids an extra copy, but should be used with care as it
		uses a different memory model than the other insert functions.

		@sa InsertEndChild
	*/
	TiXmlNode* LinkEndChild( TiXmlNode* addThis );

	/** Add a new node related to this. Adds a child before the specified child.
		Returns a pointer to the new object or NULL if an error occured.
	*/
	TiXmlNode* InsertBeforeChild( TiXmlNode* beforeThis, const TiXmlNode& addThis );

	/** Add a new node related to this. Adds a child after the specified child.
		Returns a pointer to the new object or NULL if an error occured.
	*/
	TiXmlNode* InsertAfterChild(  TiXmlNode* afterThis, const TiXmlNode& addThis );

	/** Replace a child of this node.
		Returns a pointer to the new object or NULL if an error occured.
	*/
	TiXmlNode* ReplaceChild( TiXmlNode* replaceThis, const TiXmlNode& withThis );

	/// Delete a child of this node.
	bool RemoveChild( TiXmlNode* removeThis );

	/// Navigate to a sibling node.
	const TiXmlNode* PreviousSibling() const			{ return prev; }
	TiXmlNode* PreviousSibling()						{ return prev; }

	/// Navigate to a sibling node.
	const TiXmlNode* PreviousSibling( const char * ) const;
	TiXmlNode* PreviousSibling( const char * );

    #ifdef TIXML_USE_STL
	const TiXmlNode* PreviousSibling( const std::string& _value ) const	{	return PreviousSibling (_value.c_str ());	}	///< STL std::string form.
	TiXmlNode* PreviousSibling( const std::string& _value ) 			{	return PreviousSibling (_value.c_str ());	}	///< STL std::string form.
	const TiXmlNode* NextSibling( const std::string& _value) const		{	return NextSibling (_value.c_str ());	}	///< STL std::string form.
	TiXmlNode* NextSibling( const std::string& _value) 					{	return NextSibling (_value.c_str ());	}	///< STL std::string form.
	#endif

	/// Navigate to a sibling node.
	const TiXmlNode* NextSibling() const				{ return next; }
	TiXmlNode* NextSibling()							{ return next; }

	/// Navigate to a sibling node with the given 'value'.
	const TiXmlNode* NextSibling( const char * ) const;
	TiXmlNode* NextSibling( const char * );

	/** Convenience function to get through elements.
		Calls NextSibling and ToElement. Will skip all non-Element
		nodes. Returns 0 if there is not another element.
	*/
	const TiXmlElement* NextSiblingElement() const;
	TiXmlElement* NextSiblingElement();

	/** Convenience function to get through elements.
		Calls NextSibling and ToElement. Will skip all non-Element
		nodes. Returns 0 if there is not another element.
	*/
	const TiXmlElement* NextSiblingElement( const char * ) const;
	TiXmlElement* NextSiblingElement( const char * );

    #ifdef TIXML_USE_STL
	const TiXmlElement* NextSiblingElement( const std::string& _value) const	{	return NextSiblingElement (_value.c_str ());	}	///< STL std::string form.
	TiXmlElement* NextSiblingElement( const std::string& _value)				{	return NextSiblingElement (_value.c_str ());	}	///< STL std::string form.
	#endif

	/// Convenience function to get through elements.
	const TiXmlElement* FirstChildElement()	const;
	TiXmlElement* FirstChildElement();

	/// Convenience function to get through elements.
	const TiXmlElement* FirstChildElement( const char * value ) const;
	TiXmlElement* FirstChildElement( const char * value );

    #ifdef TIXML_USE_STL
	const TiXmlElement* FirstChildElement( const std::string& _value ) const	{	return FirstChildElement (_value.c_str ());	}	///< STL std::string form.
	TiXmlElement* FirstChildElement( const std::string& _value )				{	return FirstChildElement (_value.c_str ());	}	///< STL std::string form.
	#endif

	/** Query the type (as an enumerated value, above) of this node.
		The possible types are: DOCUMENT, ELEMENT, COMMENT,
								UNKNOWN, TEXT, and DECLARATION.
	*/
	int Type() const	{ return type; }

	/** Return a pointer to the Document this node lives in.
		Returns null if not in a document.
	*/
	const TiXmlDocument* GetDocument() const;
	TiXmlDocument* GetDocument();

	/// Returns true if this node has no children.
	bool NoChildren() const						{ return !firstChild; }

	const TiXmlDocument* ToDocument()	const		{ return ( this && type == DOCUMENT ) ? (const TiXmlDocument*) this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	const TiXmlElement*  ToElement() const			{ return ( this && type == ELEMENT  ) ? (const TiXmlElement*)  this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	const TiXmlComment*  ToComment() const			{ return ( this && type == COMMENT  ) ? (const TiXmlComment*)  this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	const TiXmlUnknown*  ToUnknown() const			{ return ( this && type == UNKNOWN  ) ? (const TiXmlUnknown*)  this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	const TiXmlText*	   ToText()    const		{ return ( this && type == TEXT     ) ? (const TiXmlText*)     this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	const TiXmlDeclaration* ToDeclaration() const	{ return ( this && type == DECLARATION ) ? (const TiXmlDeclaration*) this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.

	TiXmlDocument* ToDocument()			{ return ( this && type == DOCUMENT ) ? (TiXmlDocument*) this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	TiXmlElement*  ToElement()			{ return ( this && type == ELEMENT  ) ? (TiXmlElement*)  this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	TiXmlComment*  ToComment()			{ return ( this && type == COMMENT  ) ? (TiXmlComment*)  this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	TiXmlUnknown*  ToUnknown()			{ return ( this && type == UNKNOWN  ) ? (TiXmlUnknown*)  this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	TiXmlText*	   ToText()   			{ return ( this && type == TEXT     ) ? (TiXmlText*)     this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.
	TiXmlDeclaration* ToDeclaration()	{ return ( this && type == DECLARATION ) ? (TiXmlDeclaration*) this : 0; } ///< Cast to a more defined type. Will return null not of the requested type.

	/** Create an exact duplicate of this node and return it. The memory must be deleted
		by the caller. 
	*/
	virtual TiXmlNode* Clone() const = 0;

protected:
	TiXmlNode( NodeType _type );

	// Copy to the allocated object. Shared functionality between Clone, Copy constructor,
	// and the assignment operator.
	void CopyTo( TiXmlNode* target ) const;

	#ifdef TIXML_USE_STL
	    // The real work of the input operator.
	    virtual void StreamIn( TIXML_ISTREAM* in, TIXML_STRING* tag ) = 0;
	#endif

	// Figure out what is at *p, and parse it. Returns null if it is not an xml node.
	TiXmlNode* Identify( const char* start, TiXmlEncoding encoding );

	TiXmlNode*		parent;
	NodeType		type;

	TiXmlNode*		firstChild;
	TiXmlNode*		lastChild;

	TIXML_STRING	value;

	TiXmlNode*		prev;
	TiXmlNode*		next;

private:
	TiXmlNode( const TiXmlNode& );				// not implemented.
	void operator=( const TiXmlNode& base );	// not allowed.
};


/** An attribute is a name-value pair. Elements have an arbitrary
	number of attributes, each with a unique name.

	@note The attributes are not TiXmlNodes, since they are not
		  part of the tinyXML document object model. There are other
		  suggested ways to look at this problem.
*/
class TiXmlAttribute : public TiXmlBase
{
	friend class TiXmlAttributeSet;

public:
	/// Construct an empty attribute.
	TiXmlAttribute() : TiXmlBase()
	{
		document = 0;
		prev = next = 0;
	}

	#ifdef TIXML_USE_STL
	/// std::string constructor.
	TiXmlAttribute( const std::string& _name, const std::string& _value )
	{
		name = _name;
		value = _value;
		document = 0;
		prev = next = 0;
	}
	#endif

	/// Construct an attribute with a name and value.
	TiXmlAttribute( const char * _name, const char * _value )
	{
		name = _name;
		value = _value;
		document = 0;
		prev = next = 0;
	}

	const char*		Name()  const		{ return name.c_str (); }		///< Return the name of this attribute.
	const char*		Value() const		{ return value.c_str (); }		///< Return the value of this attribute.
	int				IntValue() const;									///< Return the value of this attribute, converted to an integer.
	double			DoubleValue() const;								///< Return the value of this attribute, converted to a double.

	/** QueryIntValue examines the value string. It is an alternative to the
		IntValue() method with richer error checking.
		If the value is an integer, it is stored in 'value' and 
		the call returns TIXML_SUCCESS. If it is not
		an integer, it returns TIXML_WRONG_TYPE.

		A specialized but useful call. Note that for success it returns 0,
		which is the opposite of almost all other TinyXml calls.
	*/
	int QueryIntValue( int* _value ) const;
	/// QueryDoubleValue examines the value string. See QueryIntValue().
	int QueryDoubleValue( double* _value ) const;

	void SetName( const char* _name )	{ name = _name; }				///< Set the name of this attribute.
	void SetValue( const char* _value )	{ value = _value; }				///< Set the value.

	void SetIntValue( int _value );										///< Set the value from an integer.
	void SetDoubleValue( double _value );								///< Set the value from a double.

    #ifdef TIXML_USE_STL
	/// STL std::string form.
	void SetName( const std::string& _name )	
	{	
		StringToBuffer buf( _name );
		SetName ( buf.buffer ? buf.buffer : "error" );	
	}