ogrgmldatasource.cpp

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/******************************************************************************
 * $Id: ogrgmldatasource.cpp 11193 2007-04-03 22:29:41Z mloskot $
 *
 * Project:  OGR
 * Purpose:  Implements OGRGMLDataSource class.
 * 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.
 ****************************************************************************/

#include "ogr_gml.h"
#include "cpl_conv.h"
#include "cpl_string.h"

CPL_CVSID("$Id: ogrgmldatasource.cpp 11193 2007-04-03 22:29:41Z mloskot $");

/************************************************************************/
/*                         OGRGMLDataSource()                         */
/************************************************************************/

OGRGMLDataSource::OGRGMLDataSource()

{
    pszName = NULL;
    papoLayers = NULL;
    nLayers = 0;

    poReader = NULL;
    fpOutput = NULL;

    papszCreateOptions = NULL;
}

/************************************************************************/
/*                        ~OGRGMLDataSource()                         */
/************************************************************************/

OGRGMLDataSource::~OGRGMLDataSource()

{

    if( fpOutput != NULL )
    {
        VSIFPrintf( fpOutput, "%s", 
                    "</ogr:FeatureCollection>\n" );

        InsertHeader();

        if( nBoundedByLocation != -1 
            && sBoundingRect.IsInit() 
            && VSIFSeek( fpOutput, nBoundedByLocation, SEEK_SET ) == 0 )
        {
            VSIFPrintf( fpOutput, "  <gml:boundedBy>\n" );
            VSIFPrintf( fpOutput, "    <gml:Box>\n" );
            VSIFPrintf( fpOutput, 
                        "      <gml:coord><gml:X>%.16g</gml:X>"
                        "<gml:Y>%.16g</gml:Y></gml:coord>\n",
                        sBoundingRect.MinX, sBoundingRect.MinY );
            VSIFPrintf( fpOutput, 
                        "      <gml:coord><gml:X>%.16g</gml:X>"
                        "<gml:Y>%.16g</gml:Y></gml:coord>\n",
                        sBoundingRect.MaxX, sBoundingRect.MaxY );
            VSIFPrintf( fpOutput, "    </gml:Box>\n" );
            VSIFPrintf( fpOutput, "  </gml:boundedBy>" );
        }

        if( fpOutput != stdout )
            VSIFClose( fpOutput );
    }

    CSLDestroy( papszCreateOptions );
    CPLFree( pszName );

    for( int i = 0; i < nLayers; i++ )
        delete papoLayers[i];
    
    CPLFree( papoLayers );

    if( poReader )
        delete poReader;
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

int OGRGMLDataSource::Open( const char * pszNewName, int bTestOpen )

{
    FILE        *fp;
    char        szHeader[1000];

/* -------------------------------------------------------------------- */
/*      Open the source file.                                           */
/* -------------------------------------------------------------------- */
    fp = VSIFOpen( pszNewName, "r" );
    if( fp == NULL )
    {
        if( !bTestOpen )
            CPLError( CE_Failure, CPLE_OpenFailed, 
                      "Failed to open GML file `%s'.", 
                      pszNewName );

        return FALSE;
    }

/* -------------------------------------------------------------------- */
/*      If we aren't sure it is GML, load a header chunk and check      */
/*      for signs it is GML                                             */
/* -------------------------------------------------------------------- */
    if( bTestOpen )
    {
        VSIFRead( szHeader, 1, sizeof(szHeader), fp );
        szHeader[sizeof(szHeader)-1] = '\0';

/* -------------------------------------------------------------------- */
/*      Check for a UTF-8 BOM and skip if found                         */
/*                                                                      */
/*      TODO: BOM is variable-lenght parameter and depends on encoding. */
/*            Add BOM detection for other encodings.                    */
/* -------------------------------------------------------------------- */

        // Used to skip to actual beginning of XML data
        char* szPtr = szHeader;

        if( ( (unsigned char)szHeader[0] == 0xEF )
            && ( (unsigned char)szHeader[1] == 0xBB )
            && ( (unsigned char)szHeader[2] == 0xBF) )
        {
            szPtr += 3;
        }

/* -------------------------------------------------------------------- */
/*      Here, we expect the opening chevrons of GML tree root element   */
/* -------------------------------------------------------------------- */
        if( szPtr[0] != '<' 
            || strstr(szPtr,"opengis.net/gml") == NULL )
        {
            VSIFClose( fp );
            return FALSE;
        }
    }
    
/* -------------------------------------------------------------------- */
/*      We assume now that it is GML.  Close and instantiate a          */
/*      GMLReader on it.                                                */
/* -------------------------------------------------------------------- */
    VSIFClose( fp );
    
    poReader = CreateGMLReader();
    if( poReader == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "File %s appears to be GML but the GML reader can't\n"
                  "be instantiated, likely because Xerces support wasn't\n"
                  "configured in.", 
                  pszNewName );
        return FALSE;
    }

    poReader->SetSourceFile( pszNewName );
    
    pszName = CPLStrdup( pszNewName );

/* -------------------------------------------------------------------- */
/*      Can we find a GML Feature Schema (.gfs) for the input file?     */
/* -------------------------------------------------------------------- */
    const char *pszGFSFilename;
    VSIStatBuf sGFSStatBuf, sGMLStatBuf;
    int        bHaveSchema = FALSE;

    pszGFSFilename = CPLResetExtension( pszNewName, "gfs" );
    if( CPLStat( pszGFSFilename, &sGFSStatBuf ) == 0 )
    {
        CPLStat( pszNewName, &sGMLStatBuf );

        if( sGMLStatBuf.st_mtime > sGFSStatBuf.st_mtime )
        {
            CPLDebug( "GML", 
                      "Found %s but ignoring because it appears\n"
                      "be older than the associated GML file.", 
                      pszGFSFilename );
        }
        else
        {
            bHaveSchema = poReader->LoadClasses( pszGFSFilename );
        }
    }

/* -------------------------------------------------------------------- */
/*      Can we find an xsd which might conform to tbe GML3 Level 0      */
/*      profile?  We really ought to look for it based on the rules     */
/*      schemaLocation in the GML feature collection but for now we     */
/*      just hopes it is in the same director with the same name.       */
/* -------------------------------------------------------------------- */
    const char *pszXSDFilename;

    if( !bHaveSchema )
    {
        pszXSDFilename = CPLResetExtension( pszNewName, "xsd" );
        if( CPLStat( pszXSDFilename, &sGMLStatBuf ) == 0 )
        {
            bHaveSchema = poReader->ParseXSD( pszXSDFilename );
        }
    }
    
/* -------------------------------------------------------------------- */
/*      Force a first pass to establish the schema.  Eventually we      */
/*      will have mechanisms for remembering the schema and related     */
/*      information.                                                    */
/* -------------------------------------------------------------------- */
    if( !bHaveSchema && !poReader->PrescanForSchema( TRUE ) )
    {
        // we assume an errors have been reported.
        return FALSE;
    }

/* -------------------------------------------------------------------- */
/*      Save the schema file if possible.  Don't make a fuss if we      */
/*      can't ... could be read-only directory or something.            */
/* -------------------------------------------------------------------- */
    if( !bHaveSchema )
    {
        FILE    *fp = NULL;

        pszGFSFilename = CPLResetExtension( pszNewName, "gfs" );
        if( CPLStat( pszGFSFilename, &sGFSStatBuf ) != 0 
            && (fp = VSIFOpen( pszGFSFilename, "wt" )) != NULL )
        {
            VSIFClose( fp );
            poReader->SaveClasses( pszGFSFilename );
        }
        else
        {
            CPLDebug("GML", 
                     "Not saving %s files already exists or can't be created.",
                     pszGFSFilename );
        }
    }