예제 #1
0
Datum
interpt_pp(PG_FUNCTION_ARGS)
{
	PATH	   *p1 = PG_GETARG_PATH_P(0);
	PATH	   *p2 = PG_GETARG_PATH_P(1);
	int			i,
				j;
	LSEG		seg1,
				seg2;
	bool		found;			/* We've found the intersection */

	found = false;				/* Haven't found it yet */

	for (i = 0; i < p1->npts - 1 && !found; i++)
	{
		regress_lseg_construct(&seg1, &p1->p[i], &p1->p[i + 1]);
		for (j = 0; j < p2->npts - 1 && !found; j++)
		{
			regress_lseg_construct(&seg2, &p2->p[j], &p2->p[j + 1]);
			if (DatumGetBool(DirectFunctionCall2(lseg_intersect,
												 LsegPGetDatum(&seg1),
												 LsegPGetDatum(&seg2))))
				found = true;
		}
	}

	if (!found)
		PG_RETURN_NULL();

	/*
	 * Note: DirectFunctionCall2 will kick out an error if lseg_interpt()
	 * returns NULL, but that should be impossible since we know the two
	 * segments intersect.
	 */
	PG_RETURN_DATUM(DirectFunctionCall2(lseg_interpt,
										LsegPGetDatum(&seg1),
										LsegPGetDatum(&seg2)));
}
예제 #2
0
Datum
regress_path_dist(PG_FUNCTION_ARGS)
{
	PATH	   *p1 = PG_GETARG_PATH_P(0);
	PATH	   *p2 = PG_GETARG_PATH_P(1);
	bool		have_min = false;
	float8		min = 0.0;		/* initialize to keep compiler quiet */
	float8		tmp;
	int			i,
				j;
	LSEG		seg1,
				seg2;

	for (i = 0; i < p1->npts - 1; i++)
	{
		for (j = 0; j < p2->npts - 1; j++)
		{
			regress_lseg_construct(&seg1, &p1->p[i], &p1->p[i + 1]);
			regress_lseg_construct(&seg2, &p2->p[j], &p2->p[j + 1]);

			tmp = DatumGetFloat8(DirectFunctionCall2(lseg_distance,
													 LsegPGetDatum(&seg1),
													 LsegPGetDatum(&seg2)));
			if (!have_min || tmp < min)
			{
				min = tmp;
				have_min = true;
			}
		}
	}

	if (!have_min)
		PG_RETURN_NULL();

	PG_RETURN_FLOAT8(min);
}
예제 #3
0
Datum
regress_dist_ptpath(PG_FUNCTION_ARGS)
{
	Point	   *pt = PG_GETARG_POINT_P(0);
	PATH	   *path = PG_GETARG_PATH_P(1);
	float8		result = 0.0;	/* keep compiler quiet */
	float8		tmp;
	int			i;
	LSEG		lseg;

	switch (path->npts)
	{
		case 0:
			PG_RETURN_NULL();
		case 1:
			result = point_dt(pt, &path->p[0]);
			break;
		default:

			/*
			 * the distance from a point to a path is the smallest distance
			 * from the point to any of its constituent segments.
			 */
			Assert(path->npts > 1);
			for (i = 0; i < path->npts - 1; ++i)
			{
				regress_lseg_construct(&lseg, &path->p[i], &path->p[i + 1]);
				tmp = DatumGetFloat8(DirectFunctionCall2(dist_ps,
														 PointPGetDatum(pt),
													  LsegPGetDatum(&lseg)));
				if (i == 0 || tmp < result)
					result = tmp;
			}
			break;
	}
	PG_RETURN_FLOAT8(result);
}