dgnread.cpp

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

/******************************************************************************
 * $Id: dgnread.cpp,v 1.46 2004/06/02 15:53:00 warmerda Exp $
 *
 * Project:  Microstation DGN Access Library
 * Purpose:  DGN Access Library element reading code.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 2000, Avenza Systems Inc, http://www.avenza.com/
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ******************************************************************************
 *
 * $Log: dgnread.cpp,v $
 * Revision 1.46  2004/06/02 15:53:00  warmerda
 * improve divide by zero error checking
 *
 * Revision 1.45  2004/04/06 04:24:51  warmerda
 * Always make any new color table encountered the default color
 * table when it is read.
 *
 * Revision 1.44  2004/01/23 16:15:22  warmerda
 * DGN_LEVEL_SYMBOLOGY has no disphdr, DGNParseCore() wont read negative attr
 *
 * Revision 1.43  2003/11/24 14:17:40  warmerda
 * Added a bunch more no-disphdr elements as per email from Marius.
 *
 * Revision 1.42  2003/11/18 21:11:40  warmerda
 * Added DGNElemTypeHasDispHdr() function.
 *
 * Revision 1.41  2003/11/07 13:59:45  warmerda
 * added DGNLoadTCB()
 *
 * Revision 1.40  2003/09/22 05:59:24  warmerda
 * Fixed setting of offset for element index.
 * Don't try to extract attribute data on TCB elements.
 *
 * Revision 1.39  2003/08/19 20:16:56  warmerda
 * Added support for reading Cone (23), 3D surface (18) and 3D solid (19)
 * elements.  Added code to read transformation matrices for Cell headers
 * Marius Kintel
 *
 * Revision 1.38  2003/06/27 14:38:26  warmerda
 * avoid warnings
 *
 * Revision 1.37  2003/05/21 03:42:01  warmerda
 * Expanded tabs
 *
 * Revision 1.36  2003/05/12 18:48:57  warmerda
 * added preliminary 3D write support
 *
 * Revision 1.35  2002/11/13 21:26:32  warmerda
 * added more documentation
 *
 * Revision 1.34  2002/11/12 23:11:52  warmerda
 * fixed error with tags in DGNFreeElement()
 *
 * Revision 1.33  2002/11/12 19:45:27  warmerda
 * added support to parse view infos in TCB
 *
 * Revision 1.32  2002/11/11 20:38:13  warmerda
 * provide external extents call, add inverse to int function
 *
 * Revision 1.31  2002/10/29 19:44:08  warmerda
 * fixed complex group handling with spatial queries
 *
 * Revision 1.30  2002/10/29 19:25:18  warmerda
 * fixed serious bug in applying color table to DGNInfo structure
 *
 * Revision 1.29  2002/09/24 14:34:19  warmerda
 * fix collection of background color
 *
 * Revision 1.28  2002/05/30 19:24:38  warmerda
 * add partial support for tag type 5
 *
 * Revision 1.27  2002/04/22 20:42:40  warmerda
 * fixed problem with tag set ids > 255
 *
 * Revision 1.26  2002/04/08 21:25:59  warmerda
 * removed tagDef->id = iTag+1 assumption
 *
 * Revision 1.25  2002/03/14 21:40:03  warmerda
 * expose DGNLoadRawElement, add max_element_count in psDGN
 *
 * Revision 1.24  2002/03/12 17:11:31  warmerda
 * ensure tag elements are indexed
 *
 * Revision 1.23  2002/03/12 17:07:26  warmerda
 * added tagset and tag value element support
 *
 * Revision 1.22  2002/02/22 22:17:42  warmerda
 * Ensure that components of complex chain/shapes are spatially selected
 * based on the decision made for their owner (header).
 *
 * Revision 1.21  2002/02/06 22:39:08  warmerda
 * dont filter out non-spatial features with spatial filter
 *
 * Revision 1.20  2002/02/06 20:32:33  warmerda
 * handle improbably large elements
 *
 * Revision 1.19  2002/01/21 20:53:33  warmerda
 * a bunch of reorganization to support spatial filtering
 *
 * Revision 1.18  2002/01/15 06:38:51  warmerda
 * moved some functions to dgnhelp.cpp
 *
 * Revision 1.17  2001/12/19 15:29:56  warmerda
 * added preliminary cell header support
 *
 * Revision 1.16  2001/11/09 14:55:29  warmerda
 * fixed 3D support for arcs
 *
 * Revision 1.15  2001/09/27 14:28:44  warmerda
 * first hack at 3D support
 *
 * Revision 1.14  2001/08/28 21:27:07  warmerda
 * added prototype multi-byte character support
 *
 * Revision 1.13  2001/08/21 03:01:39  warmerda
 * added raw_data support
 *
 * Revision 1.12  2001/07/18 04:55:16  warmerda
 * added CPL_CSVID
 *
 * Revision 1.11  2001/06/25 15:07:51  warmerda
 * Added support for DGNElemComplexHeader
 * Don't include elements with the complex bit (such as shared cell definition
 * elements) in extents computation for fear they are in a different coord sys.
 *
 * Revision 1.10  2001/03/07 13:56:44  warmerda
 * updated copyright to be held by Avenza Systems
 *
 * Revision 1.9  2001/03/07 13:52:15  warmerda
 * Don't include deleted elements in the total extents.
 * Capture attribute data.
 *
 * Revision 1.7  2001/02/02 22:20:29  warmerda
 * compute text height/width properly
 *
 * Revision 1.6  2001/01/17 16:07:33  warmerda
 * ensure that TCB and ColorTable side effects occur on indexing pass too
 *
 * Revision 1.5  2001/01/16 18:12:52  warmerda
 * Added arc support, DGNLookupColor
 *
 * Revision 1.4  2001/01/10 16:13:45  warmerda
 * added docs and extents api
 *
 * Revision 1.3  2000/12/28 21:28:59  warmerda
 * added element index support
 *
 * Revision 1.2  2000/12/14 17:10:57  warmerda
 * implemented TCB, Ellipse, TEXT
 *
 * Revision 1.1  2000/11/28 19:03:47  warmerda
 * New
 *
 */

#include "dgnlibp.h"

CPL_CVSID("$Id: dgnread.cpp,v 1.46 2004/06/02 15:53:00 warmerda Exp $");

static DGNElemCore *DGNParseTCB( DGNInfo * );
static DGNElemCore *DGNParseColorTable( DGNInfo * );
static DGNElemCore *DGNParseTagSet( DGNInfo * );

/************************************************************************/
/*                           DGNGotoElement()                           */
/************************************************************************/

/**
 * Seek to indicated element.
 *
 * Changes what element will be read on the next call to DGNReadElement(). 
 * Note that this function requires and index, and one will be built if
 * not already available.
 *
 * @param hDGN the file to affect.
 * @param element_id the element to seek to.  These values are sequentially
 * ordered starting at zero for the first element.
 * 
 * @return returns TRUE on success or FALSE on failure. 
 */

int DGNGotoElement( DGNHandle hDGN, int element_id )

{
    DGNInfo     *psDGN = (DGNInfo *) hDGN;

    DGNBuildIndex( psDGN );

    if( element_id < 0 || element_id >= psDGN->element_count )
        return FALSE;

    if( VSIFSeek( psDGN->fp, psDGN->element_index[element_id].offset, 
                  SEEK_SET ) != 0 )
        return FALSE;

    psDGN->next_element_id = element_id;
    psDGN->in_complex_group = FALSE;

    return TRUE;
}

/************************************************************************/
/*                         DGNLoadRawElement()                          */
/************************************************************************/

int DGNLoadRawElement( DGNInfo *psDGN, int *pnType, int *pnLevel )

{
/* -------------------------------------------------------------------- */
/*      Read the first four bytes to get the level, type, and word      */
/*      count.                                                          */
/* -------------------------------------------------------------------- */
    int         nType, nWords, nLevel;

    if( VSIFRead( psDGN->abyElem, 1, 4, psDGN->fp ) != 4 )
        return FALSE;

    /* Is this an 0xFFFF endof file marker? */
    if( psDGN->abyElem[0] == 0xff && psDGN->abyElem[1] == 0xff )
        return FALSE;

    nWords = psDGN->abyElem[2] + psDGN->abyElem[3]*256;
    nType = psDGN->abyElem[1] & 0x7f;
    nLevel = psDGN->abyElem[0] & 0x3f;

/* -------------------------------------------------------------------- */
/*      Read the rest of the element data into the working buffer.      */
/* -------------------------------------------------------------------- */
    CPLAssert( nWords * 2 + 4 <= (int) sizeof(psDGN->abyElem) );

    if( (int) VSIFRead( psDGN->abyElem + 4, 2, nWords, psDGN->fp ) != nWords )
        return FALSE;

    psDGN->nElemBytes = nWords * 2 + 4;

    psDGN->next_element_id++;

/* -------------------------------------------------------------------- */
/*      Return requested info.                                          */
/* -------------------------------------------------------------------- */
    if( pnType != NULL )
        *pnType = nType;
    
    if( pnLevel != NULL )
        *pnLevel = nLevel;
    
    return TRUE;
}

/************************************************************************/
/*                          DGNGetRawExtents()                          */
/*                                                                      */
/*      Returns FALSE if the element type does not have reconisable     */
/*      element extents, other TRUE and the extents will be updated.    */
/*                                                                      */
/*      It is assumed the raw element data has been loaded into the     */
/*      working area by DGNLoadRawElement().                            */
/************************************************************************/

static int 
DGNGetRawExtents( DGNInfo *psDGN, int nType, unsigned char *pabyRawData,
                  GUInt32 *pnXMin, GUInt32 *pnYMin, GUInt32 *pnZMin, 
                  GUInt32 *pnXMax, GUInt32 *pnYMax, GUInt32 *pnZMax )

{
    if( pabyRawData == NULL )
        pabyRawData = psDGN->abyElem + 0;

    switch( nType )
    {
      case DGNT_LINE:
      case DGNT_LINE_STRING:
      case DGNT_SHAPE:
      case DGNT_CURVE:
      case DGNT_BSPLINE:
      case DGNT_ELLIPSE:
      case DGNT_ARC:
      case DGNT_TEXT:
      case DGNT_COMPLEX_CHAIN_HEADER:
      case DGNT_COMPLEX_SHAPE_HEADER:
      case DGNT_CONE:
      case DGNT_3DSURFACE_HEADER:
      case DGNT_3DSOLID_HEADER:
        *pnXMin = DGN_INT32( pabyRawData + 4 );
        *pnYMin = DGN_INT32( pabyRawData + 8 );
        if( pnZMin != NULL )
            *pnZMin = DGN_INT32( pabyRawData + 12 );

        *pnXMax = DGN_INT32( pabyRawData + 16 );
        *pnYMax = DGN_INT32( pabyRawData + 20 );
        if( pnZMax != NULL )
            *pnZMax = DGN_INT32( pabyRawData + 24 );
        return TRUE;

      default:
        return FALSE;
    }
}

/************************************************************************/
/*                        DGNGetElementExtents()                        */
/************************************************************************/

/**
 * Fetch extents of an element.
 *
 * This function will return the extents of the passed element if possible.
 * The extents are extracted from the element header if it contains them,
 * and transformed into master georeferenced format.  Some element types 
 * do not have extents at all and will fail.  
 *
 * This call will also fail if the extents raw data for the element is not
 * available.  This will occur if it was not the most recently read element,
 * and if the raw_data field is not loaded. 
 *
 * @param hDGN the handle of the file to read from.
 *
 * @param psElement the element to extract extents from.
 *
 * @param psMin structure loaded with X, Y and Z minimum values for the 
 * extent. 
 *
 * @param psMax structure loaded with X, Y and Z maximum values for the 
 * extent. 
 *
 * @return TRUE on success of FALSE if extracting extents fails. 
 */

int DGNGetElementExtents( DGNHandle hDGN, DGNElemCore *psElement, 
                          DGNPoint *psMin, DGNPoint *psMax )

{
    DGNInfo     *psDGN = (DGNInfo *) hDGN;
    GUInt32 anMin[3], anMax[3];
    int bResult;

/* -------------------------------------------------------------------- */
/*      Get the extents if we have raw data in the element, or          */
/*      loaded in the file buffer.                                      */
/* -------------------------------------------------------------------- */
    if( psElement->raw_data != NULL )
        bResult = DGNGetRawExtents( psDGN, psElement->type, 
                                    psElement->raw_data, 
                                    anMin + 0, anMin + 1, anMin + 2,
                                    anMax + 0, anMax + 1, anMax + 2 );
    else if( psElement->element_id == psDGN->next_element_id - 1 )
        bResult = DGNGetRawExtents( psDGN, psElement->type,