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/*
 * XSEC
 *
 * XSECCanon := Base (abstract) class for canonicalisation objects
 *
 *
 * Author(s): Berin Lautenbach
 *
 * $ID$
 *
 * $LOG$
 */

// XSEC includes
#include <xsec/framework/XSECDefs.hpp>
#include <xsec/utils/XSECSafeBuffer.hpp>

XSEC_DECLARE_XERCES_CLASS(DOMNode);
XSEC_DECLARE_XERCES_CLASS(DOMDocument);

// --------------------------------------------------------------------------------
//           Defines
// --------------------------------------------------------------------------------

#define XSECCANNON_BUFFER_START_SIZE		8192		/* Default size for the outBuffer */


// --------------------------------------------------------------------------------
//           XSECCanon Virtual Class definition
// --------------------------------------------------------------------------------

// Most of the interface work is done within this class.  However the actual
// processing is done via the processNextNode virtual function that must be
// implemented by all children classes.

class CANON_EXPORT XSECCanon {

protected:

	// Data structures

	DOMDocument			*mp_doc;			// Xerces DOM Node that defines the document
	DOMNode				*mp_startNode,		// Node to start processing from
						*mp_nextNode;		// Next Node to be processeed
	safeBuffer			m_buffer;			// Buffer holding parsed output
	int					m_bufferLength,		// Length of input currently in buffer
						m_bufferPoint;		// Next "character" to copy out
	bool				m_allNodesDone;		// Have we completed?


public:

	// Constructors

	XSECCanon();
	XSECCanon(DOMDocument *newDoc);
	XSECCanon(DOMDocument *newDoc, DOMNode *newStartNode);

	// Destructors

	virtual ~XSECCanon();

	// Public Methods

	// outputBuffer is used by all canonicalisers to output the next numBytes bytes of
	// canonicalised XML to the nominated buffer

	int outputBuffer(unsigned char *outBuffer, int numBytes);
	
	// setStartNode sets the starting point for the output if it is a sub-document 
	// that needs canonicalisation and we want to re-start
	
	bool setStartNode(DOMNode *newStartNode);

protected:

	// processNextNode is the pure virtual function that must be implemented by all canons

	virtual int processNextNode() = 0;

};