static int OGRDGNDriverIdentify( GDALOpenInfo* poOpenInfo )
{
return poOpenInfo->fpL != NULL &&
poOpenInfo->nHeaderBytes >= 512 &&
DGNTestOpen(poOpenInfo->pabyHeader, poOpenInfo->nHeaderBytes);
}
int OGRDGNDataSource::Open( const char * pszNewName,
int bTestOpen,
int bUpdate )
{
CPLAssert( nLayers == 0 );
/* -------------------------------------------------------------------- */
/* For now we require files to have the .dgn or .DGN */
/* extension. Eventually we will implement a more */
/* sophisticated test to see if it is a dgn file. */
/* -------------------------------------------------------------------- */
if( bTestOpen )
{
FILE *fp;
GByte abyHeader[512];
int nHeaderBytes = 0;
fp = VSIFOpen( pszNewName, "rb" );
if( fp == NULL )
return FALSE;
nHeaderBytes = (int) VSIFRead( abyHeader, 1, sizeof(abyHeader), fp );
VSIFClose( fp );
if( nHeaderBytes < 512 )
return FALSE;
if( !DGNTestOpen( abyHeader, nHeaderBytes ) )
return FALSE;
}
/* -------------------------------------------------------------------- */
/* Try to open the file as a DGN file. */
/* -------------------------------------------------------------------- */
hDGN = DGNOpen( pszNewName, bUpdate );
if( hDGN == NULL )
{
if( !bTestOpen )
CPLError( CE_Failure, CPLE_AppDefined,
"Unable to open %s as a Microstation .dgn file.\n",
pszNewName );
return FALSE;
}
/* -------------------------------------------------------------------- */
/* Create the layer object. */
/* -------------------------------------------------------------------- */
OGRDGNLayer *poLayer;
poLayer = new OGRDGNLayer( "elements", hDGN, bUpdate );
pszName = CPLStrdup( pszNewName );
/* -------------------------------------------------------------------- */
/* Add layer to data source layer list. */
/* -------------------------------------------------------------------- */
papoLayers = (OGRDGNLayer **)
CPLRealloc( papoLayers, sizeof(OGRDGNLayer *) * (nLayers+1) );
papoLayers[nLayers++] = poLayer;
return TRUE;
}
DGNHandle DGNOpen( const char * pszFilename, int bUpdate )
{
DGNInfo *psDGN;
FILE *fp;
/* -------------------------------------------------------------------- */
/* Open the file. */
/* -------------------------------------------------------------------- */
if( bUpdate )
fp = VSIFOpen( pszFilename, "rb+" );
else
fp = VSIFOpen( pszFilename, "rb" );
if( fp == NULL )
{
CPLError( CE_Failure, CPLE_OpenFailed,
"Unable to open `%s' for read access.\n",
pszFilename );
return NULL;
}
/* -------------------------------------------------------------------- */
/* Verify the format ... add later. */
/* -------------------------------------------------------------------- */
GByte abyHeader[512];
VSIFRead( abyHeader, 1, sizeof(abyHeader), fp );
if( !DGNTestOpen( abyHeader, sizeof(abyHeader) ) )
{
CPLError( CE_Failure, CPLE_AppDefined,
"File `%s' does not have expected DGN header.\n",
pszFilename );
VSIFClose( fp );
return NULL;
}
VSIRewind( fp );
/* -------------------------------------------------------------------- */
/* Create the info structure. */
/* -------------------------------------------------------------------- */
psDGN = (DGNInfo *) CPLCalloc(sizeof(DGNInfo),1);
psDGN->fp = fp;
psDGN->next_element_id = 0;
psDGN->got_tcb = FALSE;
psDGN->scale = 1.0;
psDGN->origin_x = 0.0;
psDGN->origin_y = 0.0;
psDGN->origin_z = 0.0;
psDGN->index_built = FALSE;
psDGN->element_count = 0;
psDGN->element_index = NULL;
psDGN->got_bounds = FALSE;
if( abyHeader[0] == 0xC8 )
psDGN->dimension = 3;
else
psDGN->dimension = 2;
psDGN->has_spatial_filter = FALSE;
psDGN->sf_converted_to_uor = FALSE;
psDGN->select_complex_group = FALSE;
psDGN->in_complex_group = FALSE;
return (DGNHandle) psDGN;
}
