postgis/liblwgeom/gbox.c

/**********************************************************************
 *
 * 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 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 **********************************************************************/

#include "liblwgeom_internal.h"
#include "lwgeodetic.h"
#include "lwgeom_log.h"
#include <stdlib.h>
#include <math.h>


GBOX* gbox_new(lwflags_t flags)
{
	GBOX *g = (GBOX*)lwalloc(sizeof(GBOX));
	gbox_init(g);
	g->flags = flags;
	return g;
}

void gbox_init(GBOX *gbox)
{
	memset(gbox, 0, sizeof(GBOX));
}

GBOX* gbox_clone(const GBOX *gbox)
{
	GBOX *g = lwalloc(sizeof(GBOX));
	memcpy(g, gbox, sizeof(GBOX));
	return g;
}

/* TODO to be removed */
BOX3D* box3d_from_gbox(const GBOX *gbox)
{
	BOX3D *b;
	assert(gbox);

	b = lwalloc(sizeof(BOX3D));

	b->xmin = gbox->xmin;
	b->xmax = gbox->xmax;
	b->ymin = gbox->ymin;
	b->ymax = gbox->ymax;

	if ( FLAGS_GET_Z(gbox->flags) )
	{
		b->zmin = gbox->zmin;
		b->zmax = gbox->zmax;
	}
	else
	{
		b->zmin = b->zmax = 0.0;
	}

	b->srid = SRID_UNKNOWN;
 	return b;
}

/* TODO to be removed */
GBOX* box3d_to_gbox(const BOX3D *b3d)
{
	GBOX *b;
	assert(b3d);

	b = lwalloc(sizeof(GBOX));

	b->xmin = b3d->xmin;
	b->xmax = b3d->xmax;
	b->ymin = b3d->ymin;
	b->ymax = b3d->ymax;
	b->zmin = b3d->zmin;
	b->zmax = b3d->zmax;

 	return b;
}

void gbox_expand(GBOX *g, double d)
{
	g->xmin -= d;
	g->xmax += d;
	g->ymin -= d;
	g->ymax += d;
	if (FLAGS_GET_Z(g->flags) || FLAGS_GET_GEODETIC(g->flags))
	{
		g->zmin -= d;
		g->zmax += d;
	}
	if (FLAGS_GET_M(g->flags))
	{
		g->mmin -= d;
		g->mmax += d;
	}
}

void gbox_expand_xyzm(GBOX *g, double dx, double dy, double dz, double dm)
{
	g->xmin -= dx;
	g->xmax += dx;
	g->ymin -= dy;
	g->ymax += dy;

	if (FLAGS_GET_Z(g->flags))
	{
		g->zmin -= dz;
		g->zmax += dz;
	}

	if (FLAGS_GET_M(g->flags))
	{
		g->mmin -= dm;
		g->mmax += dm;
	}
}

int gbox_union(const GBOX *g1, const GBOX *g2, GBOX *gout)
{
	if ( ( ! g1 ) && ( ! g2 ) )
		return LW_FALSE;
	else if (!g1)
	{
		memcpy(gout, g2, sizeof(GBOX));
		return LW_TRUE;
	}
	else if (!g2)
	{
		memcpy(gout, g1, sizeof(GBOX));
		return LW_TRUE;
	}

	gout->flags = g1->flags;

	gout->xmin = FP_MIN(g1->xmin, g2->xmin);
	gout->xmax = FP_MAX(g1->xmax, g2->xmax);

	gout->ymin = FP_MIN(g1->ymin, g2->ymin);
	gout->ymax = FP_MAX(g1->ymax, g2->ymax);

	gout->zmin = FP_MIN(g1->zmin, g2->zmin);
	gout->zmax = FP_MAX(g1->zmax, g2->zmax);

	return LW_TRUE;
}

int gbox_same(const GBOX *g1, const GBOX *g2)
{
	if (FLAGS_GET_ZM(g1->flags) != FLAGS_GET_ZM(g2->flags))
		return LW_FALSE;

	if (!gbox_same_2d(g1, g2)) return LW_FALSE;

	if (FLAGS_GET_Z(g1->flags) && (g1->zmin != g2->zmin || g1->zmax != g2->zmax))
		return LW_FALSE;
	if (FLAGS_GET_M(g1->flags) && (g1->mmin != g2->mmin || g1->mmax != g2->mmax))
		return LW_FALSE;

	return LW_TRUE;
}

int gbox_same_2d(const GBOX *g1, const GBOX *g2)
{
    if (g1->xmin == g2->xmin && g1->ymin == g2->ymin &&
        g1->xmax == g2->xmax && g1->ymax == g2->ymax)
		return LW_TRUE;
	return LW_FALSE;
}

int gbox_same_2d_float(const GBOX *g1, const GBOX *g2)
{
  if  ((g1->xmax == g2->xmax || next_float_up(g1->xmax)   == next_float_up(g2->xmax))   &&
       (g1->ymax == g2->ymax || next_float_up(g1->ymax)   == next_float_up(g2->ymax))   &&
       (g1->xmin == g2->xmin || next_float_down(g1->xmin) == next_float_down(g1->xmin)) &&
       (g1->ymin == g2->ymin || next_float_down(g2->ymin) == next_float_down(g2->ymin)))
      return LW_TRUE;
  return LW_FALSE;
}

int gbox_is_valid(const GBOX *gbox)
{
	/* X */
	if ( ! isfinite(gbox->xmin) || isnan(gbox->xmin) ||
	     ! isfinite(gbox->xmax) || isnan(gbox->xmax) )
		return LW_FALSE;

	/* Y */
	if ( ! isfinite(gbox->ymin) || isnan(gbox->ymin) ||
	     ! isfinite(gbox->ymax) || isnan(gbox->ymax) )
		return LW_FALSE;

	/* Z */
	if ( FLAGS_GET_GEODETIC(gbox->flags) || FLAGS_GET_Z(gbox->flags) )
	{
		if ( ! isfinite(gbox->zmin) || isnan(gbox->zmin) ||
		     ! isfinite(gbox->zmax) || isnan(gbox->zmax) )
			return LW_FALSE;
	}

	/* M */
	if ( FLAGS_GET_M(gbox->flags) )
	{
		if ( ! isfinite(gbox->mmin) || isnan(gbox->mmin) ||
		     ! isfinite(gbox->mmax) || isnan(gbox->mmax) )
			return LW_FALSE;
	}

	return LW_TRUE;
}

int gbox_merge_point3d(const POINT3D *p, GBOX *gbox)
{
	if ( gbox->xmin > p->x ) gbox->xmin = p->x;
	if ( gbox->ymin > p->y ) gbox->ymin = p->y;
	if ( gbox->zmin > p->z ) gbox->zmin = p->z;
	if ( gbox->xmax < p->x ) gbox->xmax = p->x;
	if ( gbox->ymax < p->y ) gbox->ymax = p->y;
	if ( gbox->zmax < p->z ) gbox->zmax = p->z;
	return LW_SUCCESS;
}

int gbox_init_point3d(const POINT3D *p, GBOX *gbox)
{
	gbox->xmin = gbox->xmax = p->x;
	gbox->ymin = gbox->ymax = p->y;
	gbox->zmin = gbox->zmax = p->z;
	return LW_SUCCESS;
}

int gbox_contains_point3d(const GBOX *gbox, const POINT3D *pt)
{
	if ( gbox->xmin > pt->x || gbox->ymin > pt->y || gbox->zmin > pt->z ||
	     gbox->xmax < pt->x || gbox->ymax < pt->y || gbox->zmax < pt->z )
	{
		return LW_FALSE;
	}
	return LW_TRUE;
}

int gbox_merge(const GBOX *new_box, GBOX *merge_box)
{
	assert(merge_box);

	if ( FLAGS_GET_ZM(merge_box->flags) != FLAGS_GET_ZM(new_box->flags) )
		return LW_FAILURE;

	if ( new_box->xmin < merge_box->xmin) merge_box->xmin = new_box->xmin;
	if ( new_box->ymin < merge_box->ymin) merge_box->ymin = new_box->ymin;
	if ( new_box->xmax > merge_box->xmax) merge_box->xmax = new_box->xmax;
	if ( new_box->ymax > merge_box->ymax) merge_box->ymax = new_box->ymax;

	if ( FLAGS_GET_Z(merge_box->flags) || FLAGS_GET_GEODETIC(merge_box->flags) )
	{
		if ( new_box->zmin < merge_box->zmin) merge_box->zmin = new_box->zmin;
		if ( new_box->zmax > merge_box->zmax) merge_box->zmax = new_box->zmax;
	}
	if ( FLAGS_GET_M(merge_box->flags) )
	{
		if ( new_box->mmin < merge_box->mmin) merge_box->mmin = new_box->mmin;
		if ( new_box->mmax > merge_box->mmax) merge_box->mmax = new_box->mmax;
	}

	return LW_SUCCESS;
}

int gbox_overlaps(const GBOX *g1, const GBOX *g2)
{

	/* Make sure our boxes are consistent */
	if ( FLAGS_GET_GEODETIC(g1->flags) != FLAGS_GET_GEODETIC(g2->flags) )
		lwerror("gbox_overlaps: cannot compare geodetic and non-geodetic boxes");

	/* Check X/Y first */
	if ( g1->xmax < g2->xmin || g1->ymax < g2->ymin ||
	     g1->xmin > g2->xmax || g1->ymin > g2->ymax )
		return LW_FALSE;

	/* Deal with the geodetic case special: we only compare the geodetic boxes (x/y/z) */
	/* Never the M dimension */
	if ( FLAGS_GET_GEODETIC(g1->flags) && FLAGS_GET_GEODETIC(g2->flags) )
	{
		if ( g1->zmax < g2->zmin || g1->zmin > g2->zmax )
			return LW_FALSE;
		else
			return LW_TRUE;
	}

	/* If both geodetic or both have Z, check Z */
	if ( FLAGS_GET_Z(g1->flags) && FLAGS_GET_Z(g2->flags) )
	{
		if ( g1->zmax < g2->zmin || g1->zmin > g2->zmax )
			return LW_FALSE;
	}

	/* If both have M, check M */
	if ( FLAGS_GET_M(g1->flags) && FLAGS_GET_M(g2->flags) )
	{
		if ( g1->mmax < g2->mmin || g1->mmin > g2->mmax )
			return LW_FALSE;
	}

	return LW_TRUE;
}

int
gbox_overlaps_2d(const GBOX *g1, const GBOX *g2)
{

	/* Make sure our boxes are consistent */
	if ( FLAGS_GET_GEODETIC(g1->flags) != FLAGS_GET_GEODETIC(g2->flags) )
		lwerror("gbox_overlaps: cannot compare geodetic and non-geodetic boxes");

	/* Check X/Y first */
	if ( g1->xmax < g2->xmin || g1->ymax < g2->ymin ||
	     g1->xmin > g2->xmax || g1->ymin > g2->ymax )
		return LW_FALSE;

	return LW_TRUE;
}

int
gbox_contains_2d(const GBOX *g1, const GBOX *g2)
{
	if ( ( g2->xmin < g1->xmin ) || ( g2->xmax > g1->xmax ) ||
	     ( g2->ymin < g1->ymin ) || ( g2->ymax > g1->ymax ) )
	{
		return LW_FALSE;
	}
	return LW_TRUE;
}

int
gbox_contains_point2d(const GBOX *g, const POINT2D *p)
{
	if ( ( g->xmin <= p->x ) && ( g->xmax >= p->x ) &&
	     ( g->ymin <= p->y ) && ( g->ymax >= p->y ) )
	{
		return LW_TRUE;
	}
	return LW_FALSE;
}

/**
* Warning, this function is only good for x/y/z boxes, used
* in unit testing of geodetic box generation.
*/
GBOX* gbox_from_string(const char *str)
{
	const char *ptr = str;
	char *nextptr;
	char *gbox_start = strstr(str, "GBOX((");
	GBOX *gbox = gbox_new(lwflags(0,0,1));
	if ( ! gbox_start ) return NULL; /* No header found */
	ptr += 6;
	gbox->xmin = strtod(ptr, &nextptr);
	if ( ptr == nextptr ) return NULL; /* No double found */
	ptr = nextptr + 1;
	gbox->ymin = strtod(ptr, &nextptr);
	if ( ptr == nextptr ) return NULL; /* No double found */
	ptr = nextptr + 1;
	gbox->zmin = strtod(ptr, &nextptr);
	if ( ptr == nextptr ) return NULL; /* No double found */
	ptr = nextptr + 3;
	gbox->xmax = strtod(ptr, &nextptr);
	if ( ptr == nextptr ) return NULL; /* No double found */
	ptr = nextptr + 1;
	gbox->ymax = strtod(ptr, &nextptr);
	if ( ptr == nextptr ) return NULL; /* No double found */
	ptr = nextptr + 1;
	gbox->zmax = strtod(ptr, &nextptr);
	if ( ptr == nextptr ) return NULL; /* No double found */
	return gbox;
}

char* gbox_to_string(const GBOX *gbox)
{
	const size_t sz = 138;
	char *str = NULL;

	if ( ! gbox )
		return lwstrdup("NULL POINTER");

	str = (char*)lwalloc(sz);

	if ( FLAGS_GET_GEODETIC(gbox->flags) )
	{
		snprintf(str, sz, "GBOX((%.8g,%.8g,%.8g),(%.8g,%.8g,%.8g))", gbox->xmin, gbox->ymin, gbox->zmin, gbox->xmax, gbox->ymax, gbox->zmax);
		return str;
	}
	if ( FLAGS_GET_Z(gbox->flags) && FLAGS_GET_M(gbox->flags) )
	{
		snprintf(str, sz, "GBOX((%.8g,%.8g,%.8g,%.8g),(%.8g,%.8g,%.8g,%.8g))", gbox->xmin, gbox->ymin, gbox->zmin, gbox->mmin, gbox->xmax, gbox->ymax, gbox->zmax, gbox->mmax);
		return str;
	}
	if ( FLAGS_GET_Z(gbox->flags) )
	{
		snprintf(str, sz, "GBOX((%.8g,%.8g,%.8g),(%.8g,%.8g,%.8g))", gbox->xmin, gbox->ymin, gbox->zmin, gbox->xmax, gbox->ymax, gbox->zmax);
		return str;
	}
	if ( FLAGS_GET_M(gbox->flags) )
	{
		snprintf(str, sz, "GBOX((%.8g,%.8g,%.8g),(%.8g,%.8g,%.8g))", gbox->xmin, gbox->ymin, gbox->mmin, gbox->xmax, gbox->ymax, gbox->mmax);
		return str;
	}
	snprintf(str, sz, "GBOX((%.8g,%.8g),(%.8g,%.8g))", gbox->xmin, gbox->ymin, gbox->xmax, gbox->ymax);
	return str;
}

GBOX* gbox_copy(const GBOX *box)
{
	GBOX *copy = (GBOX*)lwalloc(sizeof(GBOX));
	memcpy(copy, box, sizeof(GBOX));
	return copy;
}

void gbox_duplicate(const GBOX *original, GBOX *duplicate)
{
	assert(duplicate);
	assert(original);
	memcpy(duplicate, original, sizeof(GBOX));
}

size_t gbox_serialized_size(lwflags_t flags)
{
	if (FLAGS_GET_GEODETIC(flags))
		return 6 * sizeof(float);
	else
		return 2 * FLAGS_NDIMS(flags) * sizeof(float);
}


/* ********************************************************************************
** Compute cartesian bounding GBOX boxes from LWGEOM.
*/

int lw_arc_calculate_gbox_cartesian_2d(const POINT2D *A1, const POINT2D *A2, const POINT2D *A3, GBOX *gbox)
{
	POINT2D xmin, ymin, xmax, ymax;
	POINT2D C;
	int A2_side;
	double radius_A;

	LWDEBUG(2, "lw_arc_calculate_gbox_cartesian_2d called.");

	radius_A = lw_arc_center(A1, A2, A3, &C);

	/* Negative radius signals straight line, p1/p2/p3 are collinear */
	if (radius_A < 0.0)
	{
        gbox->xmin = FP_MIN(A1->x, A3->x);
        gbox->ymin = FP_MIN(A1->y, A3->y);
        gbox->xmax = FP_MAX(A1->x, A3->x);
        gbox->ymax = FP_MAX(A1->y, A3->y);
	    return LW_SUCCESS;
	}

	/* Matched start/end points imply circle */
	if ( A1->x == A3->x && A1->y == A3->y )
	{
		gbox->xmin = C.x - radius_A;
		gbox->ymin = C.y - radius_A;
		gbox->xmax = C.x + radius_A;
		gbox->ymax = C.y + radius_A;
		return LW_SUCCESS;
	}

	/* First approximation, bounds of start/end points */
    gbox->xmin = FP_MIN(A1->x, A3->x);
    gbox->ymin = FP_MIN(A1->y, A3->y);
    gbox->xmax = FP_MAX(A1->x, A3->x);
    gbox->ymax = FP_MAX(A1->y, A3->y);

	/* Create points for the possible extrema */
	xmin.x = C.x - radius_A;
	xmin.y = C.y;
	ymin.x = C.x;
	ymin.y = C.y - radius_A;
	xmax.x = C.x + radius_A;
	xmax.y = C.y;
	ymax.x = C.x;
	ymax.y = C.y + radius_A;

	/* Divide the circle into two parts, one on each side of a line
	   joining p1 and p3. The circle extrema on the same side of that line
	   as p2 is on, are also the extrema of the bbox. */

	A2_side = lw_segment_side(A1, A3, A2);

	if ( A2_side == lw_segment_side(A1, A3, &xmin) )
		gbox->xmin = xmin.x;

	if ( A2_side == lw_segment_side(A1, A3, &ymin) )
		gbox->ymin = ymin.y;

	if ( A2_side == lw_segment_side(A1, A3, &xmax) )
		gbox->xmax = xmax.x;

	if ( A2_side == lw_segment_side(A1, A3, &ymax) )
		gbox->ymax = ymax.y;

	return LW_SUCCESS;
}


static int lw_arc_calculate_gbox_cartesian(const POINT4D *p1, const POINT4D *p2, const POINT4D *p3, GBOX *gbox)
{
	int rv;

	LWDEBUG(2, "lw_arc_calculate_gbox_cartesian called.");

	rv = lw_arc_calculate_gbox_cartesian_2d((POINT2D*)p1, (POINT2D*)p2, (POINT2D*)p3, gbox);
    gbox->zmin = FP_MIN(p1->z, p3->z);
    gbox->mmin = FP_MIN(p1->m, p3->m);
    gbox->zmax = FP_MAX(p1->z, p3->z);
    gbox->mmax = FP_MAX(p1->m, p3->m);
	return rv;
}

static void
ptarray_calculate_gbox_cartesian_2d(const POINTARRAY *pa, GBOX *gbox)
{
	const POINT2D *p = getPoint2d_cp(pa, 0);

	gbox->xmax = gbox->xmin = p->x;
	gbox->ymax = gbox->ymin = p->y;

	for (uint32_t i = 1; i < pa->npoints; i++)
	{
		p = getPoint2d_cp(pa, i);
		gbox->xmin = FP_MIN(gbox->xmin, p->x);
		gbox->xmax = FP_MAX(gbox->xmax, p->x);
		gbox->ymin = FP_MIN(gbox->ymin, p->y);
		gbox->ymax = FP_MAX(gbox->ymax, p->y);
	}
}

/* Works with X/Y/Z. Needs to be adjusted after if X/Y/M was required */
static void
ptarray_calculate_gbox_cartesian_3d(const POINTARRAY *pa, GBOX *gbox)
{
	const POINT3D *p = getPoint3d_cp(pa, 0);

	gbox->xmax = gbox->xmin = p->x;
	gbox->ymax = gbox->ymin = p->y;
	gbox->zmax = gbox->zmin = p->z;

	for (uint32_t i = 1; i < pa->npoints; i++)
	{
		p = getPoint3d_cp(pa, i);
		gbox->xmin = FP_MIN(gbox->xmin, p->x);
		gbox->xmax = FP_MAX(gbox->xmax, p->x);
		gbox->ymin = FP_MIN(gbox->ymin, p->y);
		gbox->ymax = FP_MAX(gbox->ymax, p->y);
		gbox->zmin = FP_MIN(gbox->zmin, p->z);
		gbox->zmax = FP_MAX(gbox->zmax, p->z);
	}
}

static void
ptarray_calculate_gbox_cartesian_4d(const POINTARRAY *pa, GBOX *gbox)
{
	const POINT4D *p = getPoint4d_cp(pa, 0);

	gbox->xmax = gbox->xmin = p->x;
	gbox->ymax = gbox->ymin = p->y;
	gbox->zmax = gbox->zmin = p->z;
	gbox->mmax = gbox->mmin = p->m;

	for (uint32_t i = 1; i < pa->npoints; i++)
	{
		p = getPoint4d_cp(pa, i);
		gbox->xmin = FP_MIN(gbox->xmin, p->x);
		gbox->xmax = FP_MAX(gbox->xmax, p->x);
		gbox->ymin = FP_MIN(gbox->ymin, p->y);
		gbox->ymax = FP_MAX(gbox->ymax, p->y);
		gbox->zmin = FP_MIN(gbox->zmin, p->z);
		gbox->zmax = FP_MAX(gbox->zmax, p->z);
		gbox->mmin = FP_MIN(gbox->mmin, p->m);
		gbox->mmax = FP_MAX(gbox->mmax, p->m);
	}
}

int
ptarray_calculate_gbox_cartesian(const POINTARRAY *pa, GBOX *gbox)
{
	if (!pa || pa->npoints == 0)
		return LW_FAILURE;
	if (!gbox)
		return LW_FAILURE;

	int has_z = FLAGS_GET_Z(pa->flags);
	int has_m = FLAGS_GET_M(pa->flags);
	gbox->flags = lwflags(has_z, has_m, 0);
	LWDEBUGF(4, "ptarray_calculate_gbox Z: %d M: %d", has_z, has_m);
	int coordinates = 2 + has_z + has_m;

	switch (coordinates)
	{
	case 2:
	{
		ptarray_calculate_gbox_cartesian_2d(pa, gbox);
		break;
	}
	case 3:
	{
		if (has_z)
		{
			ptarray_calculate_gbox_cartesian_3d(pa, gbox);
		}
		else
		{
			double zmin = gbox->zmin;
			double zmax = gbox->zmax;
			ptarray_calculate_gbox_cartesian_3d(pa, gbox);
			gbox->mmin = gbox->zmin;
			gbox->mmax = gbox->zmax;
			gbox->zmin = zmin;
			gbox->zmax = zmax;
		}
		break;
	}
	default:
	{
		ptarray_calculate_gbox_cartesian_4d(pa, gbox);
		break;
	}
	}
	return LW_SUCCESS;
}

static int lwcircstring_calculate_gbox_cartesian(LWCIRCSTRING *curve, GBOX *gbox)
{
	GBOX tmp = {0};
	POINT4D p1, p2, p3;
	uint32_t i;

	if (!curve) return LW_FAILURE;
	if (curve->points->npoints < 3) return LW_FAILURE;

	tmp.flags =
	    lwflags(FLAGS_GET_Z(curve->flags), FLAGS_GET_M(curve->flags), 0);

	/* Initialize */
	gbox->xmin = gbox->ymin = gbox->zmin = gbox->mmin = FLT_MAX;
	gbox->xmax = gbox->ymax = gbox->zmax = gbox->mmax = -1*FLT_MAX;

	for ( i = 2; i < curve->points->npoints; i += 2 )
	{
		getPoint4d_p(curve->points, i-2, &p1);
		getPoint4d_p(curve->points, i-1, &p2);
		getPoint4d_p(curve->points, i, &p3);

		if (lw_arc_calculate_gbox_cartesian(&p1, &p2, &p3, &tmp) == LW_FAILURE)
			continue;

		gbox_merge(&tmp, gbox);
	}

	return LW_SUCCESS;
}

static int lwpoint_calculate_gbox_cartesian(LWPOINT *point, GBOX *gbox)
{
	if ( ! point ) return LW_FAILURE;
	return ptarray_calculate_gbox_cartesian( point->point, gbox );
}

static int lwline_calculate_gbox_cartesian(LWLINE *line, GBOX *gbox)
{
	if ( ! line ) return LW_FAILURE;
	return ptarray_calculate_gbox_cartesian( line->points, gbox );
}

static int lwtriangle_calculate_gbox_cartesian(LWTRIANGLE *triangle, GBOX *gbox)
{
	if ( ! triangle ) return LW_FAILURE;
	return ptarray_calculate_gbox_cartesian( triangle->points, gbox );
}

static int lwpoly_calculate_gbox_cartesian(LWPOLY *poly, GBOX *gbox)
{
	if ( ! poly ) return LW_FAILURE;
	if ( poly->nrings == 0 ) return LW_FAILURE;
	/* Just need to check outer ring */
	return ptarray_calculate_gbox_cartesian( poly->rings[0], gbox );
}

static int lwcollection_calculate_gbox_cartesian(LWCOLLECTION *coll, GBOX *gbox)
{
	GBOX subbox = {0};
	uint32_t i;
	int result = LW_FAILURE;
	int first = LW_TRUE;
	assert(coll);
	if ( (coll->ngeoms == 0) || !gbox)
		return LW_FAILURE;

	subbox.flags = coll->flags;

	for ( i = 0; i < coll->ngeoms; i++ )
	{
		if ( lwgeom_calculate_gbox_cartesian((LWGEOM*)(coll->geoms[i]), &subbox) == LW_SUCCESS )
		{
			/* Keep a copy of the sub-bounding box for later
			if ( coll->geoms[i]->bbox )
				lwfree(coll->geoms[i]->bbox);
			coll->geoms[i]->bbox = gbox_copy(&subbox); */
			if ( first )
			{
				gbox_duplicate(&subbox, gbox);
				first = LW_FALSE;
			}
			else
			{
				gbox_merge(&subbox, gbox);
			}
			result = LW_SUCCESS;
		}
	}
	return result;
}

int lwgeom_calculate_gbox_cartesian(const LWGEOM *lwgeom, GBOX *gbox)
{
	if ( ! lwgeom ) return LW_FAILURE;
	LWDEBUGF(4, "lwgeom_calculate_gbox got type (%d) - %s", lwgeom->type, lwtype_name(lwgeom->type));

	switch (lwgeom->type)
	{
	case POINTTYPE:
		return lwpoint_calculate_gbox_cartesian((LWPOINT *)lwgeom, gbox);
	case LINETYPE:
		return lwline_calculate_gbox_cartesian((LWLINE *)lwgeom, gbox);
	case CIRCSTRINGTYPE:
		return lwcircstring_calculate_gbox_cartesian((LWCIRCSTRING *)lwgeom, gbox);
	case POLYGONTYPE:
		return lwpoly_calculate_gbox_cartesian((LWPOLY *)lwgeom, gbox);
	case TRIANGLETYPE:
		return lwtriangle_calculate_gbox_cartesian((LWTRIANGLE *)lwgeom, gbox);
	case COMPOUNDTYPE:
	case CURVEPOLYTYPE:
	case MULTIPOINTTYPE:
	case MULTILINETYPE:
	case MULTICURVETYPE:
	case MULTIPOLYGONTYPE:
	case MULTISURFACETYPE:
	case POLYHEDRALSURFACETYPE:
	case TINTYPE:
	case COLLECTIONTYPE:
		return lwcollection_calculate_gbox_cartesian((LWCOLLECTION *)lwgeom, gbox);
	}
	/* Never get here, please. */
	lwerror("unsupported type (%d) - %s", lwgeom->type, lwtype_name(lwgeom->type));
	return LW_FAILURE;
}

void gbox_float_round(GBOX *gbox)
{
	gbox->xmin = next_float_down(gbox->xmin);
	gbox->xmax = next_float_up(gbox->xmax);

	gbox->ymin = next_float_down(gbox->ymin);
	gbox->ymax = next_float_up(gbox->ymax);

	if ( FLAGS_GET_M(gbox->flags) )
	{
		gbox->mmin = next_float_down(gbox->mmin);
		gbox->mmax = next_float_up(gbox->mmax);
	}

	if ( FLAGS_GET_Z(gbox->flags) )
	{
		gbox->zmin = next_float_down(gbox->zmin);
		gbox->zmax = next_float_up(gbox->zmax);
	}
}

uint64_t
gbox_get_sortable_hash(const GBOX *g, const int32_t srid)
{
	union floatuint {
		uint32_t u;
		float f;
	};

	union floatuint x, y;

	/*
	* Since in theory the bitwise representation of an IEEE
	* float is sortable (exponents come before mantissa, etc)
	* we just copy the bits directly into an int and then
	* interleave those ints.
	*/
	if (FLAGS_GET_GEODETIC(g->flags))
	{
		GEOGRAPHIC_POINT gpt;
		POINT3D p;
		p.x = (g->xmax + g->xmin) / 2.0;
		p.y = (g->ymax + g->ymin) / 2.0;
		p.z = (g->zmax + g->zmin) / 2.0;
		normalize(&p);
		cart2geog(&p, &gpt);
		/* We know range for geography, so build the curve taking it into account */
		x.f = 1.5 + gpt.lon / 512.0;
		y.f = 1.5 + gpt.lat / 256.0;
	}
	else
	{
		x.f = (g->xmax + g->xmin) / 2;
		y.f = (g->ymax + g->ymin) / 2;
		/*
		 * Tweak for popular SRID values: push floating point values into 1..2 range,
		 * a region where exponent is constant and thus Hilbert curve
		 * doesn't have compression artifact when X or Y value is close to 0.
		 * If someone has out of bounds value it will still expose the arifact but not crash.
		 * TODO: reconsider when we will have machinery to properly get bounds by SRID.
		 */
		if (srid == 3857 || srid == 3395)
		{
			x.f = 1.5 + x.f / 67108864.0;
			y.f = 1.5 + y.f / 67108864.0;
		}
		else if (srid == 4326)
		{
			x.f = 1.5 + x.f / 512.0;
			y.f = 1.5 + y.f / 256.0;
		}
	}

	return uint32_hilbert(y.u, x.u);
}