lwcurvepoly.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
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 * PostGIS is distributed in the hope that it will be useful,
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 * 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/>.
 *
 **********************************************************************
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 * Copyright (C) 2001-2006 Refractions Research Inc.
 *
 **********************************************************************/


/* basic LWCURVEPOLY manipulation */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "liblwgeom_internal.h"
#include "lwgeom_log.h"


LWCURVEPOLY *
lwcurvepoly_construct_empty(int srid, char hasz, char hasm)
{
        LWCURVEPOLY *ret;

        ret = lwalloc(sizeof(LWCURVEPOLY));
        ret->type = CURVEPOLYTYPE;
        ret->flags = gflags(hasz, hasm, 0);
        ret->srid = srid;
        ret->nrings = 0;
        ret->maxrings = 1; /* Allocate room for sub-members, just in case. */
        ret->rings = lwalloc(ret->maxrings * sizeof(LWGEOM*));
        ret->bbox = NULL;

        return ret;
}

LWCURVEPOLY *
lwcurvepoly_construct_from_lwpoly(LWPOLY *lwpoly)
{
        LWCURVEPOLY *ret;
        int i;
        ret = lwalloc(sizeof(LWCURVEPOLY));
        ret->type = CURVEPOLYTYPE;
        ret->flags = lwpoly->flags;
        ret->srid = lwpoly->srid;
        ret->nrings = lwpoly->nrings;
        ret->maxrings = lwpoly->nrings; /* Allocate room for sub-members, just in case. */
        ret->rings = lwalloc(ret->maxrings * sizeof(LWGEOM*));
        ret->bbox = lwpoly->bbox ? gbox_clone(lwpoly->bbox) : NULL;
        for ( i = 0; i < ret->nrings; i++ )
        {
                ret->rings[i] = lwline_as_lwgeom(lwline_construct(ret->srid, NULL, ptarray_clone_deep(lwpoly->rings[i])));
        }
        return ret;
}

int lwcurvepoly_add_ring(LWCURVEPOLY *poly, LWGEOM *ring)
{
        int i;

        /* Can't do anything with NULLs */
        if( ! poly || ! ring )
        {
                LWDEBUG(4,"NULL inputs!!! quitting");
                return LW_FAILURE;
        }

        /* Check that we're not working with garbage */
        if ( poly->rings == NULL && (poly->nrings || poly->maxrings) )
        {
                LWDEBUG(4,"mismatched nrings/maxrings");
                lwerror("Curvepolygon is in inconsistent state. Null memory but non-zero collection counts.");
                return LW_FAILURE;
        }

        /* Check that we're adding an allowed ring type */
        if ( ! ( ring->type == LINETYPE || ring->type == CIRCSTRINGTYPE || ring->type == COMPOUNDTYPE ) )
        {
                LWDEBUGF(4,"got incorrect ring type: %s",lwtype_name(ring->type));
                return LW_FAILURE;
        }


        /* In case this is a truly empty, make some initial space  */
        if ( poly->rings == NULL )
        {
                poly->maxrings = 2;
                poly->nrings = 0;
                poly->rings = lwalloc(poly->maxrings * sizeof(LWGEOM*));
        }

        /* Allocate more space if we need it */
        if ( poly->nrings == poly->maxrings )
        {
                poly->maxrings *= 2;
                poly->rings = lwrealloc(poly->rings, sizeof(LWGEOM*) * poly->maxrings);
        }

        /* Make sure we don't already have a reference to this geom */
        for ( i = 0; i < poly->nrings; i++ )
        {
                if ( poly->rings[i] == ring )
                {
                        LWDEBUGF(4, "Found duplicate geometry in collection %p == %p", poly->rings[i], ring);
                        return LW_SUCCESS;
                }
        }

        /* Add the ring and increment the ring count */
        poly->rings[poly->nrings] = (LWGEOM*)ring;
        poly->nrings++;
        return LW_SUCCESS;
}

double
lwcurvepoly_area(const LWCURVEPOLY *curvepoly)
{
        double area = 0.0;
        LWPOLY *poly;
        if( lwgeom_is_empty((LWGEOM*)curvepoly) )
                return 0.0;
        poly = lwcurvepoly_stroke(curvepoly, 32);
        area = lwpoly_area(poly);
        lwpoly_free(poly);
        return area;
}


double
lwcurvepoly_perimeter(const LWCURVEPOLY *poly)
{
        double result=0.0;
        int i;

        for (i=0; i<poly->nrings; i++)
                result += lwgeom_length(poly->rings[i]);

        return result;
}

double
lwcurvepoly_perimeter_2d(const LWCURVEPOLY *poly)
{
        double result=0.0;
        int i;

        for (i=0; i<poly->nrings; i++)
                result += lwgeom_length_2d(poly->rings[i]);

        return result;
}