postgis/lwgeom_geos_clean.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * PostGIS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright 2009-2010 Sandro Santilli <strk@kbt.io>
 *
 **********************************************************************/


#include "postgres.h"
#include "fmgr.h"
#include "funcapi.h"

#include "../postgis_config.h"
#include "lwgeom_geos.h"
#include "liblwgeom.h"
#include "lwgeom_pg.h"

#include <string.h>
#include <assert.h>

/* #define POSTGIS_DEBUG_LEVEL 4 */

Datum ST_MakeValid(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(ST_MakeValid);
Datum ST_MakeValid(PG_FUNCTION_ARGS)
{
        GSERIALIZED *in, *out;
        LWGEOM *lwgeom_in, *lwgeom_out;

        in = PG_GETARG_GSERIALIZED_P(0);
        lwgeom_in = lwgeom_from_gserialized(in);

        switch ( lwgeom_in->type )
        {
        case POINTTYPE:
        case MULTIPOINTTYPE:
        case LINETYPE:
        case POLYGONTYPE:
        case MULTILINETYPE:
        case MULTIPOLYGONTYPE:
        case COLLECTIONTYPE:
                break;

        default:
                lwpgerror("ST_MakeValid: unsupported geometry type %s",
                        lwtype_name(lwgeom_in->type));
                PG_RETURN_NULL();
                break;
        }

        lwgeom_out = lwgeom_make_valid(lwgeom_in);
        if ( ! lwgeom_out )
        {
                PG_FREE_IF_COPY(in, 0);
                PG_RETURN_NULL();
        }

        out = geometry_serialize(lwgeom_out);

        PG_RETURN_POINTER(out);
}

/* Uses GEOS internally */
static LWGEOM* lwgeom_clean(LWGEOM* lwgeom_in);
static LWGEOM*
lwgeom_clean(LWGEOM* lwgeom_in)
{
        LWGEOM* lwgeom_out;

        lwgeom_out = lwgeom_make_valid(lwgeom_in);
        if ( ! lwgeom_out )
        {
                return NULL;
        }

        /* Check dimensionality is the same as input */
        if ( lwgeom_dimensionality(lwgeom_in) != lwgeom_dimensionality(lwgeom_out) )
        {
                lwpgnotice("lwgeom_clean: dimensional collapse (%d to %d)",
                         lwgeom_dimensionality(lwgeom_in), lwgeom_dimensionality(lwgeom_out));

                return NULL;
        }

        /* Check that the output is not a collection if the input wasn't */
        if ( lwgeom_out->type == COLLECTIONTYPE &&
                lwgeom_in->type != COLLECTIONTYPE )
        {
                lwpgnotice("lwgeom_clean: mixed-type output (%s) "
                         "from single-type input (%s)",
                         lwtype_name(lwgeom_out->type),
                         lwtype_name(lwgeom_in->type));
                return NULL;
        }

        /* Force right-hand-rule (will only affect polygons) */
        /* gout := ST_ForceRHR(gout); */

        /* Remove repeated duplicated points ? */
        /* gout = ST_RemoveRepeatedPoints(gout); */

        return lwgeom_out;
}


Datum ST_CleanGeometry(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(ST_CleanGeometry);
Datum ST_CleanGeometry(PG_FUNCTION_ARGS)
{
        GSERIALIZED *in, *out;
        LWGEOM *lwgeom_in, *lwgeom_out;

        in = PG_GETARG_GSERIALIZED_P(0);
        lwgeom_in = lwgeom_from_gserialized(in);

        /* Short-circuit: empty geometry are the cleanest ! */
#if 0
        if ( lwgeom_is_empty(lwgeom_in) )
        {
                out = geometry_serialize(lwgeom_in);
                PG_FREE_IF_COPY(in, 0);
                PG_RETURN_POINTER(out);
        }
#endif

        lwgeom_out = lwgeom_clean(lwgeom_in);
        if ( ! lwgeom_out )
        {
                PG_FREE_IF_COPY(in, 0);
                PG_RETURN_NULL();
        }

        out = geometry_serialize(lwgeom_out);
        PG_RETURN_POINTER(out);
}