Geografic-Information-System/lib/vector/Vlib/open_ogr.c

/*!
   \file open_ogr.c

   \brief Vector library - open vector map (OGR format)

   Higher level functions for reading/writing/manipulating vectors.

   (C) 2001-2008 by the GRASS Development Team

   This program is free software under the 
   GNU General Public License (>=v2). 
   Read the file COPYING that comes with GRASS
   for details.

   \author Original author CERL, probably Dave Gerdes or Mike Higgins.
   Update to GRASS 5.7 Radim Blazek and David D. Gray.

   \date 2001
 */

#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <grass/Vect.h>
#include <grass/gis.h>
#include <grass/glocale.h>

#ifdef HAVE_OGR
#include <ogr_api.h>

/**
   \brief Open existing vector map

   Map->name and Map->mapset must be set before.

   \param Map pointer to vector map
   \param update non-zero for write mode, otherwise read-only
   (write mode is currently not supported)

   \return 0 success
   \return -1 error
*/
int V1_open_old_ogr(struct Map_info *Map, int update)
{
    int i, layer, nLayers;
    OGRDataSourceH Ogr_ds;
    OGRLayerH Ogr_layer = NULL;
    OGRFeatureDefnH Ogr_featuredefn;

    if (update) {
	G_warning(_("OGR format cannot be updated"));
	return -1;
    }

    G_debug(2, "V1_open_old_ogr(): dsn = %s layer = %s", Map->fInfo.ogr.dsn,
	    Map->fInfo.ogr.layer_name);

    OGRRegisterAll();

    /*Data source handle */
    Ogr_ds = OGROpen(Map->fInfo.ogr.dsn, FALSE, NULL);
    if (Ogr_ds == NULL)
	G_fatal_error(_("Unable to open OGR data source '%s'"),
		      Map->fInfo.ogr.dsn);
    Map->fInfo.ogr.ds = Ogr_ds;

    /* Layer number */
    layer = -1;
    nLayers = OGR_DS_GetLayerCount(Ogr_ds);
    G_debug(2, "%d layers found in data source", nLayers);

    for (i = 0; i < nLayers; i++) {
	Ogr_layer = OGR_DS_GetLayer(Ogr_ds, i);
	Ogr_featuredefn = OGR_L_GetLayerDefn(Ogr_layer);
	if (strcmp(OGR_FD_GetName(Ogr_featuredefn), Map->fInfo.ogr.layer_name)
	    == 0) {
	    layer = i;
	    break;
	}
    }
    if (layer == -1) {
	OGR_DS_Destroy(Ogr_ds);
	G_fatal_error(_("Unable to open layer <%s>"),
		      Map->fInfo.ogr.layer_name);
    }
    G_debug(2, "OGR layer %d opened", layer);

    Map->fInfo.ogr.layer = Ogr_layer;

    Map->fInfo.ogr.lines = NULL;
    Map->fInfo.ogr.lines_types = NULL;
    Map->fInfo.ogr.lines_alloc = 0;
    Map->fInfo.ogr.lines_num = 0;
    Map->fInfo.ogr.lines_next = 0;

    Map->head.with_z = WITHOUT_Z;	/* TODO: 3D */

    Map->fInfo.ogr.feature_cache = NULL;
    Map->fInfo.ogr.feature_cache_id = -1;	/* FID >= 0 */

    return (0);
}

/**
   \brief Open OGR specific level 2 files (feature index)

   \param Map pointer to vector map

   \return 0 success
   \return -1 error
*/
int V2_open_old_ogr(struct Map_info *Map)
{
    char elem[GPATH_MAX];
    char buf[5];		/* used for format version */
    long length;
    GVFILE fp;
    struct Port_info port;
    int Version_Major, Version_Minor, Back_Major, Back_Minor, byte_order;

    G_debug(3, "V2_open_old_ogr()");

    sprintf(elem, "%s/%s", GRASS_VECT_DIRECTORY, Map->name);
    dig_file_init(&fp);
    fp.file = G_fopen_old(elem, "fidx", Map->mapset);
    if (fp.file == NULL) {
	G_warning(_("Unable to open fidx file for vector map <%s@%s>"),
		  Map->name, Map->mapset);
	return -1;
    }

    /* Header */
    if (0 >= dig__fread_port_C(buf, 5, &fp))
	return (-1);
    Version_Major = buf[0];
    Version_Minor = buf[1];
    Back_Major = buf[2];
    Back_Minor = buf[3];
    byte_order = buf[4];


    /* check version numbers */
    if (Version_Major > 5 || Version_Minor > 0) {
	if (Back_Major > 5 || Back_Minor > 0) {
	    G_fatal_error(_("Feature index format version %d.%d is not supported by this release."
			   " Try to rebuild topology or upgrade GRASS."),
			  Version_Major, Version_Minor);
	    return (-1);
	}
	G_warning(_("Your GRASS version does not fully support feature index format %d.%d of the vector."
		   " Consider to rebuild topology or upgrade GRASS."),
		  Version_Major, Version_Minor);
    }

    dig_init_portable(&port, byte_order);
    dig_set_cur_port(&port);

    /* Body */
    /* bytes 6 - 9 : header size */
    if (0 >= dig__fread_port_L(&length, 1, &fp))
	return (-1);
    G_debug(3, "  header size %ld", length);

    fseek(fp.file, length, SEEK_SET);

    /* number of records  */
    if (0 >= dig__fread_port_I(&(Map->fInfo.ogr.offset_num), 1, &fp))
	return (-1);

    /* alloc space */
    Map->fInfo.ogr.offset =
	(int *)G_malloc(Map->fInfo.ogr.offset_num * sizeof(int));
    Map->fInfo.ogr.offset_alloc = Map->fInfo.ogr.offset_num;

    /* offsets */
    if (0 >= dig__fread_port_I(Map->fInfo.ogr.offset,
			       Map->fInfo.ogr.offset_num, &fp))
	return (-1);

    fclose(fp.file);

    G_debug(3, "%d records read from fidx", Map->fInfo.ogr.offset_num);


    Map->fInfo.ogr.next_line = 1;

    return 0;
}

#endif