dgnread.cpp

在Linux环境下读写DGN文件

        unsigned char *pabyRawView = psDGN->abyElem + 46 + iView*118;
        DGNViewInfo *psView = psTCB->views + iView;
        int i;

        psView->flags = pabyRawView[0] + pabyRawView[1] * 256;
        memcpy( psView->levels, pabyRawView + 2, 8 );
        
        psView->origin.x = DGN_INT32( pabyRawView + 10 );
        psView->origin.y = DGN_INT32( pabyRawView + 14 );
        psView->origin.z = DGN_INT32( pabyRawView + 18 );

        DGNTransformPoint( psDGN, &(psView->origin) );

        psView->delta.x = DGN_INT32( pabyRawView + 22 );
        psView->delta.y = DGN_INT32( pabyRawView + 26 );
        psView->delta.z = DGN_INT32( pabyRawView + 30 );

        psView->delta.x *= psDGN->scale;
        psView->delta.y *= psDGN->scale;
        psView->delta.z *= psDGN->scale;

        memcpy( psView->transmatrx, pabyRawView + 34, sizeof(double) * 9 );
        for( i = 0; i < 9; i++ )
            DGN2IEEEDouble( psView->transmatrx + i );

        memcpy( &(psView->conversion), pabyRawView + 106, sizeof(double) );
        DGN2IEEEDouble( &(psView->conversion) );

        psView->activez = DGN_INT32( pabyRawView + 114 );
    }

    return psElement;
}

/************************************************************************/
/*                           DGNFreeElement()                           */
/************************************************************************/

/**
 * Free an element structure.
 *
 * This function will deallocate all resources associated with any element
 * structure returned by DGNReadElement(). 
 *
 * @param hDGN handle to file from which the element was read.
 * @param psElement the element structure returned by DGNReadElement().
 */

void DGNFreeElement( DGNHandle hDGN, DGNElemCore *psElement )

{
    if( psElement->attr_data != NULL )
        VSIFree( psElement->attr_data );

    if( psElement->raw_data != NULL )
        VSIFree( psElement->raw_data );

    if( psElement->stype == DGNST_TAG_SET )
    {
        int		iTag;

        DGNElemTagSet *psTagSet = (DGNElemTagSet *) psElement;
        CPLFree( psTagSet->tagSetName );

        for( iTag = 0; iTag < psTagSet->tagCount; iTag++ )
        {
            CPLFree( psTagSet->tagList[iTag].name );
            CPLFree( psTagSet->tagList[iTag].prompt );

            if( psTagSet->tagList[iTag].type == 1 )
                CPLFree( psTagSet->tagList[iTag].defaultValue.string );
        }
        CPLFree( psTagSet->tagList );
    }
    else if( psElement->stype == DGNST_TAG_VALUE )
    {
        if( ((DGNElemTagValue *) psElement)->tagType == 1 )
            CPLFree( ((DGNElemTagValue *) psElement)->tagValue.string );
    }

    CPLFree( psElement );
}

/************************************************************************/
/*                             DGNRewind()                              */
/************************************************************************/

/**
 * Rewind element reading.
 *
 * Rewind the indicated DGN file, so the next element read with 
 * DGNReadElement() will be the first.  Does not require indexing like
 * the more general DGNReadElement() function.
 *
 * @param hDGN handle to file.
 */

void DGNRewind( DGNHandle hDGN )

{
    DGNInfo	*psDGN = (DGNInfo *) hDGN;

    VSIRewind( psDGN->fp );

    psDGN->next_element_id = 0;
    psDGN->in_complex_group = FALSE;
}

/************************************************************************/
/*                         DGNTransformPoint()                          */
/************************************************************************/

void DGNTransformPoint( DGNInfo *psDGN, DGNPoint *psPoint )

{
    psPoint->x = psPoint->x * psDGN->scale - psDGN->origin_x;
    psPoint->y = psPoint->y * psDGN->scale - psDGN->origin_y;
    psPoint->z = psPoint->z * psDGN->scale - psDGN->origin_z;
}

/************************************************************************/
/*                      DGNInverseTransformPoint()                      */
/************************************************************************/

void DGNInverseTransformPoint( DGNInfo *psDGN, DGNPoint *psPoint )

{
    psPoint->x = (psPoint->x + psDGN->origin_x) / psDGN->scale;
    psPoint->y = (psPoint->y + psDGN->origin_y) / psDGN->scale;
    psPoint->z = (psPoint->z + psDGN->origin_z) / psDGN->scale;

    psPoint->x = MAX(-2147483647,MIN(2147483647,psPoint->x));
    psPoint->y = MAX(-2147483647,MIN(2147483647,psPoint->y));
    psPoint->z = MAX(-2147483647,MIN(2147483647,psPoint->z));
}

/************************************************************************/
/*                   DGNInverseTransformPointToInt()                    */
/************************************************************************/

void DGNInverseTransformPointToInt( DGNInfo *psDGN, DGNPoint *psPoint,
                                    unsigned char *pabyTarget )

{
    double     adfCT[3];
    int        i;

    adfCT[0] = (psPoint->x + psDGN->origin_x) / psDGN->scale;
    adfCT[1] = (psPoint->y + psDGN->origin_y) / psDGN->scale;
    adfCT[2] = (psPoint->z + psDGN->origin_z) / psDGN->scale;

    for( i = 0; i < psDGN->dimension; i++ )
    {
        GInt32 nCTI;
        unsigned char *pabyCTI = (unsigned char *) &nCTI;

        nCTI = (GInt32) MAX(-2147483647,MIN(2147483647,adfCT[i]));
        
#ifdef WORDS_BIGENDIAN 
        pabyTarget[i*4+0] = pabyCTI[1];
        pabyTarget[i*4+1] = pabyCTI[0];
        pabyTarget[i*4+2] = pabyCTI[3];
        pabyTarget[i*4+3] = pabyCTI[2];
#else
        pabyTarget[i*4+3] = pabyCTI[1];
        pabyTarget[i*4+2] = pabyCTI[0];
        pabyTarget[i*4+1] = pabyCTI[3];
        pabyTarget[i*4+0] = pabyCTI[2];
#endif        
    }
}

/************************************************************************/
/*                         DGNGetElementIndex()                         */
/************************************************************************/

/**
 * Fetch element index.
 *
 * This function will return an array with brief information about every
 * element in a DGN file.  It requires one pass through the entire file to
 * generate (this is not repeated on subsequent calls). 
 *
 * The returned array of DGNElementInfo structures contain the level, type, 
 * stype, and other flags for each element in the file.  This can facilitate
 * application level code representing the number of elements of various types
 * effeciently. 
 *
 * Note that while building the index requires one pass through the whole file,
 * it does not generally request much processing for each element. 
 *
 * @param hDGN the file to get an index for.
 * @param pnElementCount the integer to put the total element count into. 
 *
 * @return a pointer to an internal array of DGNElementInfo structures (there 
 * will be *pnElementCount entries in the array), or NULL on failure.  The
 * returned array should not be modified or freed, and will last only as long
 * as the DGN file remains open. 
 */

const DGNElementInfo *DGNGetElementIndex( DGNHandle hDGN, int *pnElementCount )

{
    DGNInfo	*psDGN = (DGNInfo *) hDGN;

    DGNBuildIndex( psDGN );

    if( pnElementCount != NULL )
        *pnElementCount = psDGN->element_count;
    
    return psDGN->element_index;
}

/************************************************************************/
/*                           DGNGetExtents()                            */
/************************************************************************/

/**
 * Fetch overall file extents.
 *
 * The extents are collected for each element while building an index, so
 * if an index has not already been built, it will be built when 
 * DGNGetExtents() is called.  
 * 
 * The Z min/max values are generally meaningless (0 and 0xffffffff in uor
 * space). 
 * 
 * @param hDGN the file to get extents for.
 * @param padfExtents pointer to an array of six doubles into which are loaded
 * the values xmin, ymin, zmin, xmax, ymax, and zmax.
 *
 * @return TRUE on success or FALSE on failure.
 */

int DGNGetExtents( DGNHandle hDGN, double * padfExtents )

{
    DGNInfo	*psDGN = (DGNInfo *) hDGN;
    DGNPoint	sMin, sMax;

    DGNBuildIndex( psDGN );

    if( !psDGN->got_bounds )
        return FALSE;

    sMin.x = psDGN->min_x - 2147483648.0;
    sMin.y = psDGN->min_y - 2147483648.0;
    sMin.z = psDGN->min_z - 2147483648.0;
    
    DGNTransformPoint( psDGN, &sMin );

    padfExtents[0] = sMin.x;
    padfExtents[1] = sMin.y;
    padfExtents[2] = sMin.z;
    
    sMax.x = psDGN->max_x - 2147483648.0;
    sMax.y = psDGN->max_y - 2147483648.0;
    sMax.z = psDGN->max_z - 2147483648.0;

    DGNTransformPoint( psDGN, &sMax );

    padfExtents[3] = sMax.x;
    padfExtents[4] = sMax.y;
    padfExtents[5] = sMax.z;

    return TRUE;
}

/************************************************************************/
/*                           DGNBuildIndex()                            */
/************************************************************************/

void DGNBuildIndex( DGNInfo *psDGN )

{
    int	nMaxElements, nType, nLevel;
    long nLastOffset;
    GUInt32 anRegion[6];

    if( psDGN->index_built ) 
        return;

    psDGN->index_built = TRUE;
    
    DGNRewind( psDGN );

    nMaxElements = 0;

    nLastOffset = VSIFTell( psDGN->fp );
    while( DGNLoadRawElement( psDGN, &nType, &nLevel ) )
    {
        DGNElementInfo	*psEI;

        if( psDGN->element_count == nMaxElements )
        {
            nMaxElements = (int) (nMaxElements * 1.5) + 500;
            
            psDGN->element_index = (DGNElementInfo *) 
                CPLRealloc( psDGN->element_index, 
                            nMaxElements * sizeof(DGNElementInfo) );
        }

        psEI = psDGN->element_index + psDGN->element_count;
        psEI->level = nLevel;
        psEI->type = nType;
        psEI->flags = 0;
        psEI->offset = nLastOffset;

        if( psDGN->abyElem[0] & 0x80 )
            psEI->flags |= DGNEIF_COMPLEX;

        if( psDGN->abyElem[1] & 0x80 )
            psEI->flags |= DGNEIF_DELETED;

        if( nType == DGNT_LINE || nType == DGNT_LINE_STRING
            || nType == DGNT_SHAPE || nType == DGNT_CURVE
            || nType == DGNT_BSPLINE )
            psEI->stype = DGNST_MULTIPOINT;

        else if( nType == DGNT_GROUP_DATA && nLevel == DGN_GDL_COLOR_TABLE )
        {
            DGNElemCore	*psCT = DGNParseColorTable( psDGN );
            DGNFreeElement( (DGNHandle) psDGN, psCT );
            psEI->stype = DGNST_COLORTABLE;
        }
        else if( nType == DGNT_ELLIPSE || nType == DGNT_ARC )
            psEI->stype = DGNST_ARC;
        
        else if( nType == DGNT_COMPLEX_SHAPE_HEADER 
                 || nType == DGNT_COMPLEX_CHAIN_HEADER )
            psEI->stype = DGNST_COMPLEX_HEADER;
        
        else if( nType == DGNT_TEXT )
            psEI->stype = DGNST_TEXT;

        else if( nType == DGNT_TAG_VALUE )
            psEI->stype = DGNST_TAG_VALUE;

        else if( nType == DGNT_APPLICATION_ELEM )
        {
            if( nLevel == 24 )
                psEI->stype = DGNST_TAG_SET;
            else
                psEI->stype = DGNST_CORE;
        }
        else if( nType == DGNT_TCB )
        {
            DGNElemCore	*psTCB = DGNParseTCB( psDGN );
            DGNFreeElement( (DGNHandle) psDGN, psTCB );
            psEI->stype = DGNST_TCB;
        }
        else
            psEI->stype = DGNST_CORE;

        if( !(psEI->flags & DGNEIF_DELETED)
            && !(psEI->flags & DGNEIF_COMPLEX) 
            && DGNGetRawExtents( psDGN, nType, NULL,
                                 anRegion+0, anRegion+1, anRegion+2,
                                 anRegion+3, anRegion+4, anRegion+5 ) )
        {
#ifdef notdef
            printf( "panRegion[%d]=%.1f,%.1f,%.1f,%.1f,%.1f,%.1f\n", 
                    psDGN->element_count,
                    anRegion[0] - 2147483648.0,
                    anRegion[1] - 2147483648.0,
                    anRegion[2] - 2147483648.0,
                    anRegion[3] - 2147483648.0,
                    anRegion[4] - 2147483648.0,
                    anRegion[5] - 2147483648.0 );
#endif            
            if( psDGN->got_bounds )
            {
                psDGN->min_x = MIN(psDGN->min_x, anRegion[0]);
                psDGN->min_y = MIN(psDGN->min_y, anRegion[1]);
                psDGN->min_z = MIN(psDGN->min_z, anRegion[2]);
                psDGN->max_x = MAX(psDGN->max_x, anRegion[3]);
                psDGN->max_y = MAX(psDGN->max_y, anRegion[4]);
                psDGN->max_z = MAX(psDGN->max_z, anRegion[5]);
            }
            else
            {
                memcpy( &(psDGN->min_x), anRegion, sizeof(GInt32) * 6 );
                psDGN->got_bounds = TRUE;
            }
        }

        psDGN->element_count++;

        nLastOffset = VSIFTell( psDGN->fp );
    }

    DGNRewind( psDGN );

    psDGN->max_element_count = nMaxElements;
}