mitab_mapfile.cpp

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

 * Convert from coordinates system units as defined in the file's 
 * coordsys clause to long integer (internal) coordinates.
 *
 * Note that the false easting/northing and the conversion factor from
 * datum to coordsys units are not included in the calculation.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABMAPFile::Coordsys2Int(double dX, double dY, GInt32 &nX, GInt32 &nY, 
                             GBool bIgnoreOverflow/*=FALSE*/)
{
    if (m_poHeader == NULL)
        return -1;

    return m_poHeader->Coordsys2Int(dX, dY, nX, nY, bIgnoreOverflow);
}

/**********************************************************************
 *                   TABMAPFile::Int2CoordsysDist()
 *
 * Convert a pair of X,Y size (or distance) values from long integer
 * (internal) to coordinates system units as defined in the file's coordsys
 * clause.
 *
 * The difference with Int2Coordsys() is that this function only applies
 * the scaling factor: it does not apply the displacement.
 *
 * Since the calculations on the X and Y values are independent, either
 * one can be omitted (i.e. passed as 0)
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABMAPFile::Int2CoordsysDist(GInt32 nX, GInt32 nY, double &dX, double &dY)
{
    if (m_poHeader == NULL)
        return -1;

    return m_poHeader->Int2CoordsysDist(nX, nY, dX, dY);
}

/**********************************************************************
 *                   TABMAPFile::Coordsys2IntDist()
 *
 * Convert a pair of X,Y size (or distance) values from coordinates 
 * system units as defined in the file's coordsys clause to long 
 * integer (internal) coordinate units.
 *
 * The difference with Int2Coordsys() is that this function only applies
 * the scaling factor: it does not apply the displacement.
 *
 * Since the calculations on the X and Y values are independent, either
 * one can be omitted (i.e. passed as 0)
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABMAPFile::Coordsys2IntDist(double dX, double dY, GInt32 &nX, GInt32 &nY)
{
    if (m_poHeader == NULL)
        return -1;

    return m_poHeader->Coordsys2IntDist(dX, dY, nX, nY);
}

/**********************************************************************
 *                   TABMAPFile::SetCoordsysBounds()
 *
 * Set projection coordinates bounds of the newly created dataset.
 *
 * This function must be called after creating a new dataset and before any
 * feature can be written to it.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int TABMAPFile::SetCoordsysBounds(double dXMin, double dYMin, 
                                  double dXMax, double dYMax)
{
    int nStatus = 0;

    if (m_poHeader == NULL)
        return -1;

    nStatus = m_poHeader->SetCoordsysBounds(dXMin, dYMin, dXMax, dYMax);

    if (nStatus == 0)
        ResetCoordFilter();

    return nStatus;
}

/**********************************************************************
 *                   TABMAPFile::GetMaxObjId()
 *
 * Return the value of the biggest valid object id.
 *
 * Note that object ids are positive and start at 1.
 *
 * Returns a value >= 0 on success, -1 on error.
 **********************************************************************/
GInt32 TABMAPFile::GetMaxObjId()
{
    if (m_poIdIndex)
        return m_poIdIndex->GetMaxObjId();

    return -1;
}

/**********************************************************************
 *                   TABMAPFile::MoveToObjId()
 *
 * Get ready to work with the object with the specified id.  The object
 * data pointer (inside m_poCurObjBlock) will be moved to the first byte
 * of data for this map object.  
 *
 * The object type and id (i.e. table row number) will be accessible 
 * using GetCurObjType() and GetCurObjId().
 * 
 * Note that object ids are positive and start at 1.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int   TABMAPFile::MoveToObjId(int nObjId)
{
    int nFileOffset;

    /*-----------------------------------------------------------------
     * In read access mode, since the .MAP/.ID are optional, if the 
     * file is not opened then we can still act as if one existed and
     * make any object id look like a TAB_GEOM_NONE
     *----------------------------------------------------------------*/
    if (m_fp == NULL && m_eAccessMode == TABRead)
    {
        CPLAssert(m_poIdIndex == NULL && m_poCurObjBlock == NULL);
        m_nCurObjPtr = 0;
        m_nCurObjId = nObjId;
        m_nCurObjType = TAB_GEOM_NONE;

        return 0;
    }

    if (m_poIdIndex == NULL || m_poCurObjBlock == NULL)
    {
        CPLError(CE_Failure, CPLE_AssertionFailed,
                 "MoveToObjId(): file not opened!");
        m_nCurObjPtr = m_nCurObjId = m_nCurObjType = -1;
        return -1;
    }

    /*-----------------------------------------------------------------
     * Move map object pointer to the right location.  Fetch location
     * from the index file, unless we are already pointing at it.
     *----------------------------------------------------------------*/
    if( m_nCurObjId == nObjId )
        nFileOffset = m_nCurObjPtr;
    else
        nFileOffset = m_poIdIndex->GetObjPtr(nObjId);

    if (nFileOffset == 0)
    {
        /*---------------------------------------------------------
         * Object with no geometry... this is a valid case.
         *--------------------------------------------------------*/
        m_nCurObjPtr = 0;
        m_nCurObjId = nObjId;
        m_nCurObjType = TAB_GEOM_NONE;
    }
    else if ( m_poCurObjBlock->GotoByteInFile(nFileOffset) == 0)
    {
        /*-------------------------------------------------------------
         * OK, it worked, read the object type and row id.
         *------------------------------------------------------------*/
        m_nCurObjPtr = nFileOffset;
        m_nCurObjType = m_poCurObjBlock->ReadByte();
        m_nCurObjId   = m_poCurObjBlock->ReadInt32();

        // Do a consistency check...
        if (m_nCurObjId != nObjId)
        {
            CPLError(CE_Failure, CPLE_FileIO,
                 "Object ID from the .ID file (%d) differs from the value "
                 "in the .MAP file (%d).  File may be corrupt.",
                 nObjId, m_nCurObjId);
            m_nCurObjPtr = m_nCurObjId = m_nCurObjType = -1;
            return -1;
        }
    }
    else
    {
        /*---------------------------------------------------------
         * Failed positioning input file... CPLError has been called.
         *--------------------------------------------------------*/
        m_nCurObjPtr = m_nCurObjId = m_nCurObjType = -1;
        return -1;
    }

    return 0;
}

/**********************************************************************
 *                   TABMAPFile::PrepareNewObj()
 *
 * Get ready to write a new object of the specified type and with the 
 * specified id.  
 *
 * m_poCurObjBlock will be set to be ready to receive the new object, and
 * a new block will be created if necessary (in which case the current 
 * block contents will be committed to disk, etc.)  The object type and 
 * row ID will be written to the m_poCurObjBlock, so it will be ready to
 * receive the first byte of data for this map object.  
 *
 * If this object type uses coordinate blocks, then the coordinate block
 * will be prepared to receive coordinates.
 *
 * This function will also take care of updating the .ID index entry for
 * the new object.
 *
 * Note that object ids are positive and start at 1.
 *
 * Returns 0 on success, -1 on error.
 **********************************************************************/
int   TABMAPFile::PrepareNewObj(int nObjId, GByte nObjType)
{
    int nObjSize;

    m_nCurObjPtr = m_nCurObjId = m_nCurObjType = -1;

    if (m_eAccessMode != TABWrite || 
        m_poIdIndex == NULL || m_poHeader == NULL)
    {
        CPLError(CE_Failure, CPLE_AssertionFailed,
                 "PrepareNewObj() failed: file not opened for write access.");
        return -1;
    }

    /*-----------------------------------------------------------------
     * For objects with no geometry, we just update the .ID file and return
     *----------------------------------------------------------------*/
    if (nObjType == TAB_GEOM_NONE)
    {
        m_nCurObjType = nObjType;
        m_nCurObjId   = nObjId;
        m_nCurObjPtr  = 0;
        m_poIdIndex->SetObjPtr(m_nCurObjId, 0);

        return 0;
    }

    /*-----------------------------------------------------------------
     * Update count of objects by type in the header block
     *----------------------------------------------------------------*/
    if (nObjType == TAB_GEOM_SYMBOL ||
        nObjType == TAB_GEOM_FONTSYMBOL ||
        nObjType == TAB_GEOM_CUSTOMSYMBOL ||
        nObjType == TAB_GEOM_SYMBOL_C ||
        nObjType == TAB_GEOM_FONTSYMBOL_C ||
        nObjType == TAB_GEOM_CUSTOMSYMBOL_C)
    {
        m_poHeader->m_numPointObjects++;
    }
    else if (nObjType == TAB_GEOM_LINE ||
             nObjType == TAB_GEOM_PLINE ||
             nObjType == TAB_GEOM_MULTIPLINE ||
             nObjType == TAB_GEOM_V450_MULTIPLINE ||
             nObjType == TAB_GEOM_ARC ||
             nObjType == TAB_GEOM_LINE_C ||
             nObjType == TAB_GEOM_PLINE_C ||
             nObjType == TAB_GEOM_MULTIPLINE_C ||
             nObjType == TAB_GEOM_V450_MULTIPLINE_C ||
             nObjType == TAB_GEOM_ARC_C)
    {
        m_poHeader->m_numLineObjects++;
    }
    else if (nObjType == TAB_GEOM_REGION ||
             nObjType == TAB_GEOM_V450_REGION ||
             nObjType == TAB_GEOM_RECT ||
             nObjType == TAB_GEOM_ROUNDRECT ||
             nObjType == TAB_GEOM_ELLIPSE ||
             nObjType == TAB_GEOM_REGION_C ||
             nObjType == TAB_GEOM_V450_REGION_C ||
             nObjType == TAB_GEOM_RECT_C ||
             nObjType == TAB_GEOM_ROUNDRECT_C ||
             nObjType == TAB_GEOM_ELLIPSE_C)
    {
        m_poHeader->m_numRegionObjects++;
    }
    else if (nObjType == TAB_GEOM_TEXT ||
             nObjType == TAB_GEOM_TEXT_C)
    {
        m_poHeader->m_numTextObjects++;
    }

    /*-----------------------------------------------------------------
     * Check for V450-specific object types and minimum TAB file version number
     *----------------------------------------------------------------*/
    if (m_nMinTABVersion < 450 &&
        (nObjType == TAB_GEOM_V450_REGION ||
         nObjType == TAB_GEOM_V450_MULTIPLINE ||
         nObjType == TAB_GEOM_V450_REGION_C ||
         nObjType == TAB_GEOM_V450_MULTIPLINE_C) )
    {
        m_nMinTABVersion = 450;
    }
    /*-----------------------------------------------------------------
     * Check for V460-specific object types (multipoint and collection)
     *----------------------------------------------------------------*/
    if (m_nMinTABVersion < 650 &&
        (nObjType == TAB_GEOM_MULTIPOINT   ||
         nObjType == TAB_GEOM_MULTIPOINT_C ||
         nObjType == TAB_GEOM_COLLECTION   ||
         nObjType == TAB_GEOM_COLLECTION_C    ) )
    {
        m_nMinTABVersion = 650;
    }

    /*-----------------------------------------------------------------
     * OK, looks like we will need object block... check if it exists and
     * create it if it has not been created yet (first time for this file).
     * We do not create the object block in the open() call because
     * files that contained only "NONE" geometries ended up with empty
     * object and spatial index blocks.
     * Note: A coord block will be created only if needed later.
     *----------------------------------------------------------------*/
    if (m_poCurObjBlock == NULL)
    {
        m_poCurObjBlock = new TABMAPObjectBlock(m_eAccessMode);

        int nBlockOffset = m_oBlockManager.AllocNewBlock();

        m_poCurObjBlock->InitNewBlock(m_fp, 512, nBlockOffset);

        // The reference to the first object block should 
        // actually go through the index blocks... this will be 
        // updated when file is closed.
        m_poHeader->m_nFirstIndexBlock = nBlockOffset;
    }

    /*-----------------------------------------------------------------
     * Fetch new object size, make sure there is enough room in obj. 
     * block for new object, and save/create a new one if necessary.
     *----------------------------------------------------------------*/
    nObjSize = m_poHeader->GetMapObjectSize(nObjType);
    if (m_poCurObjBlock->GetNumUnusedBytes() < nObjSize )
    {
        /*-------------------------------------------------------------
         * OK, the new object won't fit in the current block.  Commit
         * the current block to disk, and init a new one.
         *
         * __TODO__ To create an optimum file, we should split the object
         * block at this point and update the index blocks... however the
         * file should still be usable even if we don't do it.
         *------------------------------------------------------------*/
        CommitObjBlock(TRUE);
    }

    /*-----------------------------------------------------------------
     * Init member vars and write new object type/id
     *----------------------------------------------------------------*/
    m_nCurObjType = nObjType;
    m_nCurObjId   = nObjId;
    m_nCurObjPtr = m_poCurObjBlock->GetFirstUnusedByteOffset();

    m_poCurObjBlock->GotoByteInFile(m_nCurObjPtr);

    m_poCurObjBlock->WriteByte(m_nCurObjType);
    m_poCurObjBlock->WriteInt32(m_nCurObjId);

    // Move write pointer to start location of next object (padding with zeros)