Application: gvSIG desktop

/********************************************************

** Copyright 2002 Earth Resource Mapping Ltd.

** This document contains proprietary source code of

** Earth Resource Mapping Ltd, and can only be used under

** one of the three licenses as described in the 

** license.txt file supplied with this distribution. 

** See separate license.txt file for license details 

** and conditions.

**

** This software is covered by US patent #6,442,298,

** #6,102,897 and #6,633,688.  Rights to use these patents 

** is included in the license agreements.

**

** FILE:     $Archive: /NCS/Source/include/NCSJPCPacketLengthType.h $

** CREATED:  18/12/2002 3:27:34 PM

** AUTHOR:   Simon Cope

** PURPOSE:  CNCSJPCPacketLengthType class header

** EDITS:    [xx] ddMmmyy NAME COMMENTS

 *******************************************************/

#ifndef NCSJPCPACKETLENGTHTYPE_H

#define NCSJPCPACKETLENGTHTYPE_H

#include "NCSJPCMarker.h"

        /**

         * CNCSJPCPacketLengthType class - the JPC Packet Length Type.

         * 

         * @author       Simon Cope

         * @version      $Revision: 1458 $ $Author: igbrotru $ $Date: 2005-02-15 08:52:16 +0100 (Tue, 15 Feb 2005) $ 

         */        

class NCSJPC_EXPORT_ALL CNCSJPCPacketLengthType {

public:

                /** Packet length - Header usually includes Data, except when using PPM or PPT markers */

        UINT32        m_nHeaderLength;

                /** Packet data length - Only when using PPM or PPT markers */

        UINT32        m_nDataLength;

                /** Default constructor, initialises members */

        CNCSJPCPacketLengthType();

                /** 

                 * Parse the fields from the JPC codestream.

                 * @param                Stream                IOStream to use to parse file.

                 * @return      bool                true on success.

                 */

        NCS_INLINE bool Parse(CNCSJPCIOStream &Stream) {

                        UINT32 nTmp = 0;

                        bool bRet = false;

                        UINT8 t8;

                        while(bRet = Stream.ReadUINT8(t8)) {

                                nTmp = (nTmp << 7) | (t8 & 0x7f);

                                if((t8 & 0x80) == 0) {

                                        break;

                                }

                        }

                        m_nHeaderLength = nTmp;

                        return(bRet);

                };

                /** 

                 * Parse the fields from a chunk of memory.

                 * @param                UINT8*                Memory buffer to parse length from.

                 * @param                &i                        Index into memory buffer, incremented before return

                 * @return      bool                true on success.

                 */

        NCS_INLINE bool Parse(UINT8 *pBuf, INT32 &i) {

                        UINT32 nTmp = 0;

                        while(true) {

                                UINT8 t8 = pBuf[i++];

                                nTmp = (nTmp << 7) | (t8 & 0x7f);

                                if((t8 & 0x80) == 0) {

                                        break;

                                }

                        }

                        m_nHeaderLength = nTmp;

                        return(true);

                };

                /** 

                 * UnParse the fields to the JPC codestream.

                 * @param                Stream                IOStream to use to parse file.

                 * @return      bool                true on success.

                 */

        NCS_INLINE bool UnParse(CNCSJPCIOStream &Stream) {

                        UINT32 nMask = 0xffffffff;

                        INT8 nShift = 0;

                        bool bRet = true;

                        while(nMask & m_nHeaderLength) {

                                nMask <<= 7;

                                nShift++;

                        }

                        if(nShift > 0) {

                                nShift--;

                                nMask >>= 7;

                                nMask = 0x7f << (nShift * 7);

                                while(nShift >= 0 && bRet) {

                                        bRet &= Stream.WriteUINT8((UINT8)(((m_nHeaderLength & nMask) >> (nShift * 7)) | ((nShift > 0) ? 0x80 : 0x00)));

                                        nShift--;

                                        nMask >>= 7;

                                }

                        } else {

                                // Zero length

                                bRet &= Stream.WriteUINT8((UINT8)0x00);

                        }

                        return(bRet);

                };

};

#endif // !NCSJPCPACKETLENGTHTYPE_H