lwgeom_box.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 2001-2009 Refractions Research Inc.
 * Copyright 2009 Mark Cave-Ayland <mark.cave-ayland@siriusit.co.uk>
 *
 **********************************************************************/


#include "postgres.h"
#include "access/gist.h"
#include "access/itup.h"
#include "fmgr.h"
#include "utils/elog.h"
#include "utils/geo_decls.h"

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

#include <math.h>
#include <float.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>


/* forward defs */
Datum BOX2D_in(PG_FUNCTION_ARGS);
Datum BOX2D_out(PG_FUNCTION_ARGS);
Datum LWGEOM_to_BOX2D(PG_FUNCTION_ARGS);
Datum LWGEOM_to_BOX2DF(PG_FUNCTION_ARGS);
Datum BOX2D_expand(PG_FUNCTION_ARGS);
Datum BOX2D_to_BOX3D(PG_FUNCTION_ARGS);
Datum BOX2D_combine(PG_FUNCTION_ARGS);
Datum BOX2D_to_LWGEOM(PG_FUNCTION_ARGS);
Datum BOX2D_construct(PG_FUNCTION_ARGS);

/* parser - "BOX(xmin ymin,xmax ymax)" */
PG_FUNCTION_INFO_V1(BOX2D_in);
Datum BOX2D_in(PG_FUNCTION_ARGS)
{
        char *str = PG_GETARG_CSTRING(0);
        int nitems;
        double tmp;
        GBOX box;
        int i;

        gbox_init(&box);

        for(i = 0; str[i]; i++) {
          str[i] = tolower(str[i]);
        }

        nitems = sscanf(str,"box(%lf %lf,%lf %lf)", &box.xmin, &box.ymin, &box.xmax, &box.ymax);
        if (nitems != 4)
        {
                elog(ERROR,"box2d parser - couldnt parse.  It should look like: BOX(xmin ymin,xmax ymax)");
                PG_RETURN_NULL();
        }

        if (box.xmin > box.xmax)
        {
                tmp = box.xmin;
                box.xmin = box.xmax;
                box.xmax = tmp;
        }
        if (box.ymin > box.ymax)
        {
                tmp = box.ymin;
                box.ymin = box.ymax;
                box.ymax = tmp;
        }
        PG_RETURN_POINTER(gbox_copy(&box));
}

/*writer  "BOX(xmin ymin,xmax ymax)" */
PG_FUNCTION_INFO_V1(BOX2D_out);
Datum BOX2D_out(PG_FUNCTION_ARGS)
{
        char tmp[500]; /* big enough */
        char *result;
        int size;

        GBOX *box = (GBOX *)PG_GETARG_POINTER(0);
        /* Avoid unaligned access to the gbox struct */
        GBOX box_aligned;
        memcpy(&box_aligned, box, sizeof(GBOX));

        size = sprintf(tmp,
                       "BOX(%.15g %.15g,%.15g %.15g)",
                       box_aligned.xmin,
                       box_aligned.ymin,
                       box_aligned.xmax,
                       box_aligned.ymax);

        result= palloc(size+1); /* +1= null term */
        memcpy(result,tmp,size+1);
        result[size] = '\0';

        PG_RETURN_CSTRING(result);
}


/*convert a GSERIALIZED to BOX2D */
PG_FUNCTION_INFO_V1(LWGEOM_to_BOX2D);
Datum LWGEOM_to_BOX2D(PG_FUNCTION_ARGS)
{
        GSERIALIZED *geom = PG_GETARG_GSERIALIZED_P(0);
        LWGEOM *lwgeom = lwgeom_from_gserialized(geom);
        GBOX gbox;

        /* Cannot box empty! */
        if ( lwgeom_is_empty(lwgeom) )
                PG_RETURN_NULL();

        /* Cannot calculate box? */
        if ( lwgeom_calculate_gbox(lwgeom, &gbox) == LW_FAILURE )
                PG_RETURN_NULL();

        /* Strip out higher dimensions */
        FLAGS_SET_Z(gbox.flags, 0);
        FLAGS_SET_M(gbox.flags, 0);

        PG_FREE_IF_COPY(geom, 0);
        PG_RETURN_POINTER(gbox_copy(&gbox));
}


/*convert a GSERIALIZED to BOX2D */
PG_FUNCTION_INFO_V1(LWGEOM_to_BOX2DF);
Datum LWGEOM_to_BOX2DF(PG_FUNCTION_ARGS)
{
        GSERIALIZED *geom = PG_GETARG_GSERIALIZED_P(0);
        GBOX gbox;

        if ( gserialized_get_gbox_p(geom, &gbox) == LW_FAILURE )
                PG_RETURN_NULL();

        /* Strip out higher dimensions */
        FLAGS_SET_Z(gbox.flags, 0);
        FLAGS_SET_M(gbox.flags, 0);

        PG_FREE_IF_COPY(geom, 0);
        PG_RETURN_POINTER(gbox_copy(&gbox));
}


/*----------------------------------------------------------
 *      Relational operators for BOXes.
 *              <, >, <=, >=, and == are based on box area.
 *---------------------------------------------------------*/

/*
 * box_same - are two boxes identical?
 */
PG_FUNCTION_INFO_V1(BOX2D_same);
Datum BOX2D_same(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPeq(box1->xmax, box2->xmax) &&
                       FPeq(box1->xmin, box2->xmin) &&
                       FPeq(box1->ymax, box2->ymax) &&
                       FPeq(box1->ymin, box2->ymin));
}

/*
 * box_overlap - does box1 overlap box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_overlap);
Datum BOX2D_overlap(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);
        bool       result;


        result = ((FPge(box1->xmax, box2->xmax) &&
                   FPle(box1->xmin, box2->xmax)) ||
                  (FPge(box2->xmax, box1->xmax) &&
                   FPle(box2->xmin, box1->xmax)))
                 &&
                 ((FPge(box1->ymax, box2->ymax) &&
                   FPle(box1->ymin, box2->ymax)) ||
                  (FPge(box2->ymax, box1->ymax) &&
                   FPle(box2->ymin, box1->ymax)));

        PG_RETURN_BOOL(result);
}


/*
 * box_overleft - is the right edge of box1 to the left of
 *                the right edge of box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_overleft);
Datum BOX2D_overleft(PG_FUNCTION_ARGS)
{
        GBOX *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPle(box1->xmax, box2->xmax));
}

/*
 * box_left - is box1 strictly left of box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_left);
Datum BOX2D_left(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPlt(box1->xmax, box2->xmin));
}

/*
 * box_right - is box1 strictly right of box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_right);
Datum BOX2D_right(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPgt(box1->xmin, box2->xmax));
}

/*
 * box_overright - is the left edge of box1 to the right of
 *                 the left edge of box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_overright);
Datum BOX2D_overright(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPge(box1->xmin, box2->xmin));
}

/*
 * box_overbelow - is the bottom edge of box1 below
 *                 the bottom edge of box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_overbelow);
Datum BOX2D_overbelow(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPle(box1->ymax, box2->ymax));
}

/*
 * box_below - is box1 strictly below box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_below);
Datum BOX2D_below(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPlt(box1->ymax, box2->ymin));
}

/*
 * box_above - is box1 strictly above box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_above);
Datum BOX2D_above(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPgt(box1->ymin, box2->ymax));
}

/*
 * box_overabove - the top edge of box1 above
 *                 the top edge of box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_overabove);
Datum BOX2D_overabove(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPge(box1->ymin, box2->ymin));
}

/*
 * box_contained - is box1 contained by box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_contained);
Datum BOX2D_contained(PG_FUNCTION_ARGS)
{
        GBOX               *box1 =(GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPle(box1->xmax, box2->xmax) &&
                       FPge(box1->xmin, box2->xmin) &&
                       FPle(box1->ymax, box2->ymax) &&
                       FPge(box1->ymin, box2->ymin));
}

/*
 * box_contain - does box1 contain box2?
 */
PG_FUNCTION_INFO_V1(BOX2D_contain);
Datum BOX2D_contain(PG_FUNCTION_ARGS)
{
        GBOX               *box1 = (GBOX *) PG_GETARG_POINTER(0);
        GBOX               *box2 = (GBOX *) PG_GETARG_POINTER(1);

        PG_RETURN_BOOL(FPge(box1->xmax, box2->xmax) &&
                       FPle(box1->xmin, box2->xmin) &&
                       FPge(box1->ymax, box2->ymax) &&
                       FPle(box1->ymin, box2->ymin));

}

PG_FUNCTION_INFO_V1(BOX2D_intersects);
Datum BOX2D_intersects(PG_FUNCTION_ARGS)
{
        GBOX *a = (GBOX *) PG_GETARG_POINTER(0);
        GBOX *b = (GBOX *) PG_GETARG_POINTER(1);
        GBOX *n;


        n = (GBOX *) palloc(sizeof(GBOX));

        n->xmax = Min(a->xmax, b->xmax);
        n->ymax = Min(a->ymax, b->ymax);
        n->xmin = Max(a->xmin, b->xmin);
        n->ymin = Max(a->ymin, b->ymin);


        if (n->xmax < n->xmin || n->ymax < n->ymin)
        {
                pfree(n);
                /* Indicate "no intersection" by returning NULL pointer */
                n = NULL;
        }

        PG_RETURN_POINTER(n);
}


/*
 * union of two BOX2Ds
 */
PG_FUNCTION_INFO_V1(BOX2D_union);
Datum BOX2D_union(PG_FUNCTION_ARGS)
{
        GBOX *a = (GBOX*) PG_GETARG_POINTER(0);
        GBOX *b = (GBOX*) PG_GETARG_POINTER(1);
        GBOX *n;

        n = (GBOX *) lwalloc(sizeof(GBOX));
        if ( ! gbox_union(a,b,n) ) PG_RETURN_NULL();
        PG_RETURN_POINTER(n);
}


PG_FUNCTION_INFO_V1(BOX2D_expand);
Datum BOX2D_expand(PG_FUNCTION_ARGS)
{
        GBOX *box = (GBOX *)PG_GETARG_POINTER(0);
        GBOX *result = (GBOX *)palloc(sizeof(GBOX));
        memcpy(result, box, sizeof(GBOX));

        if (PG_NARGS() == 2)
        {
                double d = PG_GETARG_FLOAT8(1);
                gbox_expand(result, d);
        }
        else
        {
                double dx = PG_GETARG_FLOAT8(1);
                double dy = PG_GETARG_FLOAT8(2);

                gbox_expand_xyzm(result, dx, dy, 0, 0);
        }

        PG_RETURN_POINTER(result);
}

PG_FUNCTION_INFO_V1(BOX2D_to_BOX3D);
Datum BOX2D_to_BOX3D(PG_FUNCTION_ARGS)
{
        GBOX *box = (GBOX *)PG_GETARG_POINTER(0);
        BOX3D *result = box3d_from_gbox(box);
        PG_RETURN_POINTER(result);
}

PG_FUNCTION_INFO_V1(BOX2D_combine);
Datum BOX2D_combine(PG_FUNCTION_ARGS)
{
        Pointer box2d_ptr = PG_GETARG_POINTER(0);
        Pointer geom_ptr = PG_GETARG_POINTER(1);
        GBOX *a,*b;
        GSERIALIZED *lwgeom;
        GBOX box, *result;

        if  ( (box2d_ptr == NULL) && (geom_ptr == NULL) )
        {
                PG_RETURN_NULL(); /* combine_box2d(null,null) => null */
        }

        result = (GBOX *)palloc(sizeof(GBOX));

        if (box2d_ptr == NULL)
        {
                lwgeom = PG_GETARG_GSERIALIZED_P(1);
                /* empty geom would make getbox2d_p return NULL */
                if ( ! gserialized_get_gbox_p(lwgeom, &box) ) PG_RETURN_NULL();
                memcpy(result, &box, sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }

        /* combine_bbox(BOX3D, null) => BOX3D */
        if (geom_ptr == NULL)
        {
                memcpy(result, (char *)PG_GETARG_DATUM(0), sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }

        /*combine_bbox(BOX3D, geometry) => union(BOX3D, geometry->bvol) */

        lwgeom = PG_GETARG_GSERIALIZED_P(1);
        if ( ! gserialized_get_gbox_p(lwgeom, &box) )
        {
                /* must be the empty geom */
                memcpy(result, (char *)PG_GETARG_DATUM(0), sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }

        a = (GBOX *)PG_GETARG_DATUM(0);
        b = &box;

        result->xmax = Max(a->xmax, b->xmax);
        result->ymax = Max(a->ymax, b->ymax);
        result->xmin = Min(a->xmin, b->xmin);
        result->ymin = Min(a->ymin, b->ymin);

        PG_RETURN_POINTER(result);
}

PG_FUNCTION_INFO_V1(BOX2D_to_LWGEOM);
Datum BOX2D_to_LWGEOM(PG_FUNCTION_ARGS)
{
        GBOX *box = (GBOX *)PG_GETARG_POINTER(0);
        POINTARRAY *pa = ptarray_construct_empty(0, 0, 5);
        POINT4D pt;
        GSERIALIZED *result;


        /*
         * Alter BOX2D cast so that a valid geometry is always
         * returned depending upon the size of the BOX2D. The
         * code makes the following assumptions:
         *     - If the BOX2D is a single point then return a
         *     POINT geometry
         *     - If the BOX2D represents either a horizontal or
         *     vertical line, return a LINESTRING geometry
         *     - Otherwise return a POLYGON
         */

        if ( (box->xmin == box->xmax) && (box->ymin == box->ymax) )
        {
                /* Construct and serialize point */
                LWPOINT *point = lwpoint_make2d(SRID_UNKNOWN, box->xmin, box->ymin);
                result = geometry_serialize(lwpoint_as_lwgeom(point));
                lwpoint_free(point);
        }
        else if ( (box->xmin == box->xmax) || (box->ymin == box->ymax) )
        {
                LWLINE *line;

                /* Assign coordinates to point array */
                pt.x = box->xmin;
                pt.y = box->ymin;
                ptarray_append_point(pa, &pt, LW_TRUE);
                pt.x = box->xmax;
                pt.y = box->ymax;
                ptarray_append_point(pa, &pt, LW_TRUE);

                /* Construct and serialize linestring */
                line = lwline_construct(SRID_UNKNOWN, NULL, pa);
                result = geometry_serialize(lwline_as_lwgeom(line));
                lwline_free(line);
        }
        else
        {
                POINT4D points[4];
                LWPOLY *poly;

                /* Initialize the 4 vertices of the polygon */
                points[0] = (POINT4D) { box->xmin, box->ymin };
                points[1] = (POINT4D) { box->xmin, box->ymax };
                points[2] = (POINT4D) { box->xmax, box->ymax };
                points[3] = (POINT4D) { box->xmax, box->ymin };

                /* Construct polygon */
                poly = lwpoly_construct_rectangle(LW_FALSE, LW_FALSE, &points[0], &points[1],
                                &points[2], &points[3]);
                result = geometry_serialize(lwpoly_as_lwgeom(poly));
                lwpoly_free(poly);
        }

        PG_RETURN_POINTER(result);
}

PG_FUNCTION_INFO_V1(BOX2D_construct);
Datum BOX2D_construct(PG_FUNCTION_ARGS)
{
        GSERIALIZED *pgmin = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *pgmax = PG_GETARG_GSERIALIZED_P(1);
        GBOX *result;
        LWPOINT *minpoint, *maxpoint;
        double min, max, tmp;

        minpoint = (LWPOINT*)lwgeom_from_gserialized(pgmin);
        maxpoint = (LWPOINT*)lwgeom_from_gserialized(pgmax);

        if ( (minpoint->type != POINTTYPE) || (maxpoint->type != POINTTYPE) )
        {
                elog(ERROR, "GBOX_construct: arguments must be points");
                PG_RETURN_NULL();
        }

        error_if_srid_mismatch(minpoint->srid, maxpoint->srid);

        result = gbox_new(gflags(0, 0, 0));

        /* Process X min/max */
        min = lwpoint_get_x(minpoint);
        max = lwpoint_get_x(maxpoint);
        if ( min > max )
        {
                tmp = min;
                min = max;
                max = tmp;
        }
        result->xmin = min;
        result->xmax = max;

        /* Process Y min/max */
        min = lwpoint_get_y(minpoint);
        max = lwpoint_get_y(maxpoint);
        if ( min > max )
        {
                tmp = min;
                min = max;
                max = tmp;
        }
        result->ymin = min;
        result->ymax = max;

        PG_RETURN_POINTER(result);
}