dgnwrite.cpp

在Linux环境下读写DGN文件

/******************************************************************************
 * $Id: dgnwrite.cpp,v 1.5 2002/11/13 21:26:32 warmerda Exp $
 *
 * Project:  Microstation DGN Access Library
 * Purpose:  DGN Access functions related to writing DGN elements.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 2002, Frank Warmerdam <[e-mail]>
 *
 * 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: dgnwrite.cpp,v $
 * Revision 1.5  2002/11/13 21:26:32  warmerda
 * added more documentation
 *
 * Revision 1.4  2002/11/12 19:45:54  warmerda
 * added support to update TCB in DGNCreate
 *
 * Revision 1.3  2002/11/11 20:38:43  warmerda
 * implemented write api
 *
 * Revision 1.2  2002/10/20 01:50:20  warmerda
 * added new write prototypes
 *
 * Revision 1.1  2002/03/14 21:40:43  warmerda
 * New
 *
 */

#include "dgnlibp.h"

CPL_CVSID("$Id: dgnwrite.cpp,v 1.5 2002/11/13 21:26:32 warmerda Exp $");

/************************************************************************/
/*                          DGNResizeElement()                          */
/************************************************************************/

/**
 * Resize an existing element.
 *
 * If the new size is the same as the old nothing happens. 
 *
 * Otherwise, the old element in the file is marked as deleted, and the
 * DGNElemCore.offset and element_id are set to -1 indicating that the
 * element should be written to the end of file when next written by
 * DGNWriteElement().  The internal raw data buffer is updated to the new
 * size.
 * 
 * Only elements with "raw_data" loaded may be moved.
 *
 * In normal use the DGNResizeElement() call would be called on a previously
 * loaded element, and afterwards the raw_data would be updated before calling
 * DGNWriteElement().  If DGNWriteElement() isn't called after 
 * DGNResizeElement() then the element will be lost having been marked as
 * deleted in it's old position but never written at the new location. 
 *
 * @param hDGN the DGN file on which the element lives.
 * @param psElement the element to alter.  
 * @param nNewSize the desired new size of the element in bytes.  Must be
 * a multiple of 2. 
 *
 * @return TRUE on success, or FALSE on error.
 */

int DGNResizeElement( DGNHandle hDGN, DGNElemCore *psElement, int nNewSize )

{
    DGNInfo	*psDGN = (DGNInfo *) hDGN;

/* -------------------------------------------------------------------- */
/*      Check various conditions.                                       */
/* -------------------------------------------------------------------- */
    if( psElement->raw_bytes == 0 
        || psElement->raw_bytes != psElement->size )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Raw bytes not loaded, or not matching element size." );
        return FALSE;
    }

    if( nNewSize % 2 == 1 )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "DGNResizeElement(%d): "
                  "can't change to odd (not divisible by two) size.", 
                  nNewSize );
        return FALSE;
    }

    if( nNewSize == psElement->raw_bytes )
        return TRUE;

/* -------------------------------------------------------------------- */
/*      Mark the existing element as deleted if the element has to      */
/*      move to the end of the file.                                    */
/* -------------------------------------------------------------------- */

    if( psElement->offset != -1 )
    {
        int nOldFLoc = VSIFTell( psDGN->fp );
        unsigned char abyLeader[2];
        
        if( VSIFSeek( psDGN->fp, psElement->offset, SEEK_SET ) != 0
            || VSIFRead( abyLeader, sizeof(abyLeader), 1, psDGN->fp ) != 1 )
        {
            CPLError( CE_Failure, CPLE_AppDefined, 
                      "Failed seek or read when trying to mark existing\n"
                      "element as deleted in DGNResizeElement()\n" );
            return FALSE;
        }

        abyLeader[1] |= 0x80;
        
        if( VSIFSeek( psDGN->fp, psElement->offset, SEEK_SET ) != 0
            || VSIFWrite( abyLeader, sizeof(abyLeader), 1, psDGN->fp ) != 1 )
        {
            CPLError( CE_Failure, CPLE_AppDefined, 
                      "Failed seek or write when trying to mark existing\n"
                      "element as deleted in DGNResizeElement()\n" );
            return FALSE;
        }

        VSIFSeek( psDGN->fp, SEEK_SET, nOldFLoc );

        if( psElement->element_id != -1 && psDGN->index_built )
            psDGN->element_index[psElement->element_id].flags 
                |= DGNEIF_DELETED;
    }

    psElement->offset = -1; /* move to end of file. */
    psElement->element_id = -1;

/* -------------------------------------------------------------------- */
/*      Set the new size information, and realloc the raw data buffer.  */
/* -------------------------------------------------------------------- */
    psElement->size = nNewSize;
    psElement->raw_data = (unsigned char *) 
        CPLRealloc( psElement->raw_data, nNewSize );
    psElement->raw_bytes = nNewSize;

/* -------------------------------------------------------------------- */
/*      Update the size information within the raw buffer.              */
/* -------------------------------------------------------------------- */
    int nWords = (nNewSize / 2) - 2;

    psElement->raw_data[2] = nWords % 256;
    psElement->raw_data[3] = nWords / 256;

    return TRUE;
}

/************************************************************************/
/*                          DGNWriteElement()                           */
/************************************************************************/

/** 
 * Write element to file. 
 *
 * Only elements with "raw_data" loaded may be written.
 *
 * The passed element is written to the indicated file.  If the 
 * DGNElemCore.offset field is -1 then the element is written at the end of
 * the file (and offset/element are reset properly) otherwise the element 
 * is written back to the location indicated by DGNElemCore.offset.  
 *
 * If the element is added at the end of the file, and if an element index
 * has already been built, it will be updated to reference the new element.
 *
 * This function takes care of ensuring that the end-of-file marker is 
 * maintained after the last element.
 *
 * @param hDGN the file to write the element to.
 * @param psElement the element to write. 
 *
 * @return TRUE on success or FALSE in case of failure.
 */

int DGNWriteElement( DGNHandle hDGN, DGNElemCore *psElement )

{
    DGNInfo	*psDGN = (DGNInfo *) hDGN;

/* ==================================================================== */
/*      If this element hasn't been positioned yet, place it at the     */
/*      end of the file.                                                */
/* ==================================================================== */
    if( psElement->offset == -1 )
    {
        int nJunk;

        // We must have an index, in order to properly assign the 
        // element id of the newly written element.  Ensure it is built.
        if( !psDGN->index_built )
            DGNBuildIndex( psDGN );

        // Read the current "last" element.
        if( !DGNGotoElement( hDGN, psDGN->element_count-1 ) )
            return FALSE;

        if( !DGNLoadRawElement( psDGN, &nJunk, &nJunk ) )
            return FALSE;

        // Establish the position of the new element.
        psElement->offset = VSIFTell( psDGN->fp );
        psElement->element_id = psDGN->element_count;

        // Grow element buffer if needed.
        if( psDGN->element_count == psDGN->max_element_count )
        {
            psDGN->max_element_count += 500;
            
            psDGN->element_index = (DGNElementInfo *) 
                CPLRealloc( psDGN->element_index, 
                            psDGN->max_element_count * sizeof(DGNElementInfo));
        }

        // Set up the element info
        DGNElementInfo *psInfo;
        
        psInfo = psDGN->element_index + psDGN->element_count;
        psInfo->level = psElement->level;
        psInfo->type = psElement->type;
        psInfo->stype = psElement->stype;
        psInfo->offset = psElement->offset;
        if( psElement->complex )
            psInfo->flags = DGNEIF_COMPLEX;
        else
            psInfo->flags = 0;
    
        psDGN->element_count++;
    }

/* -------------------------------------------------------------------- */
/*      Write out the element.                                          */
/* -------------------------------------------------------------------- */
    if( VSIFSeek( psDGN->fp, psElement->offset, SEEK_SET ) != 0 
        || VSIFWrite( psElement->raw_data, psElement->raw_bytes, 
                      1, psDGN->fp) != 1 )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Error seeking or writing new element of %d bytes at %d.",
                  psElement->offset, 
                  psElement->raw_bytes );
        return FALSE;
    }

    psDGN->next_element_id = psElement->element_id + 1;

/* -------------------------------------------------------------------- */
/*      Write out the end of file 0xffff marker (if we were             */
/*      extending the file), but push the file pointer back before      */
/*      this EOF when done.                                             */
/* -------------------------------------------------------------------- */
    if( psDGN->next_element_id == psDGN->element_count )
    {
        unsigned char abyEOF[2];

        abyEOF[0] = 0xff;
        abyEOF[1] = 0xff;

        VSIFWrite( abyEOF, 2, 1, psDGN->fp );
        VSIFSeek( psDGN->fp, -2, SEEK_CUR );
    }
        
    return TRUE;
}
    
/************************************************************************/
/*                             DGNCreate()                              */
/************************************************************************/

/**
 * Create new DGN file.
 *
 * This function will create a new DGN file based on the provided seed
 * file, and return a handle on which elements may be read and written.
 *
 * The following creation flags may be passed:
 * <ul>
 * <li> DGNCF_USE_SEED_UNITS: The master and subunit resolutions and names
 * from the seed file will be used in the new file.  The nMasterUnitPerSubUnit,
 * nUORPerSubUnit, pszMasterUnits, and pszSubUnits arguments will be ignored.
 * <li> DGNCF_USE_SEED_ORIGIN: The origin from the seed file will be used
 * and the X, Y and Z origin passed into the call will be ignored. 
 * <li> DGNCF_COPY_SEED_FILE_COLOR_TABLE: Should the first color table occuring
 * in the seed file also be copied? 
 * <li> DGNCF_COPY_WHOLE_SEED_FILE: By default only the first three elements
 * (TCB, Digitizer Setup and Level Symbology) are copied from the seed file. 
 * If this flag is provided the entire seed file is copied verbatim (with the
 * TCB origin and units possibly updated).
 * </ul>
 * 
 * @param pszNewFilename the filename to create.  If it already exists
 * it will be overwritten.
 * @param pszSeedFile the seed file to copy header from.
 * @param nCreationFlags An ORing of DGNCF_* flags that are to take effect.
 * @param dfOriginX the X origin for the file.  
 * @param dfOriginY the Y origin for the file. 
 * @param dfOriginZ the Z origin for the file. 
 * @param nSubUnitPerMasterUnit the number of subunits in one master unit.
 * @param nUORPerSubUnit the number of UOR (units of resolution) per subunit.
 * @param pszMasterUnits the name of the master units (2 characters). 
 * @param pszSubUnits the name of the subunits (2 characters). 
 */

DGNHandle
      DGNCreate( const char *pszNewFilename, const char *pszSeedFile, 
                 int nCreationFlags, 
                 double dfOriginX, double dfOriginY, double dfOriginZ,
                 int nSubUnitsPerMasterUnit, int nUORPerSubUnit, 
                 const char *pszMasterUnits, const char *pszSubUnits )

{
    DGNInfo *psSeed, *psDGN;
    FILE    *fpNew;
    DGNElemCore *psSrcTCB;

/* -------------------------------------------------------------------- */
/*      Open seed file, and read TCB element.                           */
/* -------------------------------------------------------------------- */
    psSeed = (DGNInfo *) DGNOpen( pszSeedFile, FALSE );
    if( psSeed == NULL )
        return NULL;

    DGNSetOptions( psSeed, DGNO_CAPTURE_RAW_DATA );
    
    psSrcTCB = DGNReadElement( psSeed );

    CPLAssert( psSrcTCB->raw_bytes >= 1536 );
    
/* -------------------------------------------------------------------- */
/*      Open output file.                                               */
/* -------------------------------------------------------------------- */
    fpNew = VSIFOpen( pszNewFilename, "wb" );
    if( fpNew == NULL )
    {
        CPLError( CE_Failure, CPLE_OpenFailed, 
                  "Failed to open output file: %s", pszNewFilename );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Modify TCB appropriately for the output file.                   */
/* -------------------------------------------------------------------- */
    GByte *pabyRawTCB = (GByte *) CPLMalloc(psSrcTCB->raw_bytes);
    
    memcpy( pabyRawTCB, psSrcTCB->raw_data, psSrcTCB->raw_bytes );

    if( !(nCreationFlags & DGNCF_USE_SEED_UNITS) )
    {
        memcpy( pabyRawTCB+1120, pszMasterUnits, 2 );
        memcpy( pabyRawTCB+1122, pszSubUnits, 2 );

        DGN_WRITE_INT32( nUORPerSubUnit, pabyRawTCB+1116 );
        DGN_WRITE_INT32( nSubUnitsPerMasterUnit, pabyRawTCB+1112 );
    }
    else
    {
        nUORPerSubUnit = DGN_INT32( pabyRawTCB+1120 );
        nSubUnitsPerMasterUnit = DGN_INT32( pabyRawTCB+1112 );
    }

    if( !(nCreationFlags & DGNCF_USE_SEED_ORIGIN) )
    {
        dfOriginX *= (nUORPerSubUnit * nSubUnitsPerMasterUnit);
        dfOriginY *= (nUORPerSubUnit * nSubUnitsPerMasterUnit);
        dfOriginZ *= (nUORPerSubUnit * nSubUnitsPerMasterUnit);

        memcpy( pabyRawTCB+1240, &dfOriginX, 8 );
        memcpy( pabyRawTCB+1248, &dfOriginY, 8 );
        memcpy( pabyRawTCB+1256, &dfOriginZ, 8 );

        IEEE2DGNDouble( pabyRawTCB+1240 );
        IEEE2DGNDouble( pabyRawTCB+1248 );
        IEEE2DGNDouble( pabyRawTCB+1246 );
    }

/* -------------------------------------------------------------------- */
/*      Write TCB and EOF to new file.                                  */
/* -------------------------------------------------------------------- */
    unsigned char abyEOF[2];
    
    VSIFWrite( pabyRawTCB, psSrcTCB->raw_bytes, 1, fpNew );

    abyEOF[0] = 0xff;