Datum LWGEOM_line_substring(PG_FUNCTION_ARGS)
{
GSERIALIZED *geom = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
double from = PG_GETARG_FLOAT8(1);
double to = PG_GETARG_FLOAT8(2);
LWGEOM *olwgeom;
POINTARRAY *ipa, *opa;
GSERIALIZED *ret;
int type = gserialized_get_type(geom);
if ( from < 0 || from > 1 )
{
elog(ERROR,"line_interpolate_point: 2nd arg isnt within [0,1]");
PG_RETURN_NULL();
}
if ( to < 0 || to > 1 )
{
elog(ERROR,"line_interpolate_point: 3rd arg isnt within [0,1]");
PG_RETURN_NULL();
}
if ( from > to )
{
elog(ERROR, "2nd arg must be smaller then 3rd arg");
PG_RETURN_NULL();
}
if ( type == LINETYPE )
{
LWLINE *iline = lwgeom_as_lwline(lwgeom_from_gserialized(geom));
if ( lwgeom_is_empty((LWGEOM*)iline) )
{
/* TODO return empty line */
lwline_release(iline);
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_NULL();
}
ipa = iline->points;
opa = ptarray_substring(ipa, from, to, 0);
if ( opa->npoints == 1 ) /* Point returned */
olwgeom = (LWGEOM *)lwpoint_construct(iline->srid, NULL, opa);
else
olwgeom = (LWGEOM *)lwline_construct(iline->srid, NULL, opa);
}
else if ( type == MULTILINETYPE )
{
LWMLINE *iline;
int i = 0, g = 0;
int homogeneous = LW_TRUE;
LWGEOM **geoms = NULL;
double length = 0.0, sublength = 0.0, minprop = 0.0, maxprop = 0.0;
iline = lwgeom_as_lwmline(lwgeom_from_gserialized(geom));
if ( lwgeom_is_empty((LWGEOM*)iline) )
{
/* TODO return empty collection */
lwmline_release(iline);
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_NULL();
}
/* Calculate the total length of the mline */
for ( i = 0; i < iline->ngeoms; i++ )
{
LWLINE *subline = (LWLINE*)iline->geoms[i];
if ( subline->points && subline->points->npoints > 1 )
length += ptarray_length_2d(subline->points);
}
geoms = lwalloc(sizeof(LWGEOM*) * iline->ngeoms);
/* Slice each sub-geometry of the multiline */
for ( i = 0; i < iline->ngeoms; i++ )
{
LWLINE *subline = (LWLINE*)iline->geoms[i];
double subfrom = 0.0, subto = 0.0;
if ( subline->points && subline->points->npoints > 1 )
sublength += ptarray_length_2d(subline->points);
/* Calculate proportions for this subline */
minprop = maxprop;
maxprop = sublength / length;
/* This subline doesn't reach the lowest proportion requested
or is beyond the highest proporton */
if ( from > maxprop || to < minprop )
continue;
if ( from <= minprop )
subfrom = 0.0;
if ( to >= maxprop )
subto = 1.0;
if ( from > minprop && from <= maxprop )
subfrom = (from - minprop) / (maxprop - minprop);
if ( to < maxprop && to >= minprop )
subto = (to - minprop) / (maxprop - minprop);
opa = ptarray_substring(subline->points, subfrom, subto, 0);
if ( opa && opa->npoints > 0 )
{
if ( opa->npoints == 1 ) /* Point returned */
{
geoms[g] = (LWGEOM *)lwpoint_construct(iline->srid, NULL, opa);
homogeneous = LW_FALSE;
}
else
{
geoms[g] = (LWGEOM *)lwline_construct(iline->srid, NULL, opa);
}
g++;
}
}
/* If we got any points, we need to return a GEOMETRYCOLLECTION */
if ( ! homogeneous )
type = COLLECTIONTYPE;
olwgeom = (LWGEOM*)lwcollection_construct(type, iline->srid, NULL, g, geoms);
}
else
{
elog(ERROR,"line_interpolate_point: 1st arg isnt a line");
PG_RETURN_NULL();
}
ret = geometry_serialize(olwgeom);
lwgeom_free(olwgeom);
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_POINTER(ret);
}
Datum LWGEOM_interiorringn_polygon(PG_FUNCTION_ARGS)
{
GSERIALIZED *geom;
int32 wanted_index;
LWCURVEPOLY *curvepoly = NULL;
LWPOLY *poly = NULL;
POINTARRAY *ring;
LWLINE *line;
LWGEOM *lwgeom;
GSERIALIZED *result;
GBOX *bbox = NULL;
int type;
POSTGIS_DEBUG(2, "LWGEOM_interierringn_polygon called.");
wanted_index = PG_GETARG_INT32(1);
if ( wanted_index < 1 )
{
/* elog(ERROR, "InteriorRingN: ring number is 1-based"); */
PG_RETURN_NULL(); /* index out of range */
}
geom = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
type = gserialized_get_type(geom);
if ( (type != POLYGONTYPE) && (type != CURVEPOLYTYPE) )
{
elog(ERROR, "InteriorRingN: geom is not a polygon");
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_NULL();
}
lwgeom = lwgeom_from_gserialized(geom);
if( lwgeom_is_empty(lwgeom) )
{
lwpoly_free(poly);
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_NULL();
}
if ( type == POLYGONTYPE)
{
poly = lwgeom_as_lwpoly(lwgeom_from_gserialized(geom));
/* Ok, now we have a polygon. Let's see if it has enough holes */
if ( wanted_index >= poly->nrings )
{
lwpoly_free(poly);
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_NULL();
}
ring = poly->rings[wanted_index];
/* COMPUTE_BBOX==TAINTING */
if ( poly->bbox )
{
bbox = lwalloc(sizeof(GBOX));
ptarray_calculate_gbox_cartesian(ring, bbox);
}
/* This is a LWLINE constructed by interior ring POINTARRAY */
line = lwline_construct(poly->srid, bbox, ring);
result = geometry_serialize((LWGEOM *)line);
lwline_release(line);
lwpoly_free(poly);
}
else
{
curvepoly = lwgeom_as_lwcurvepoly(lwgeom_from_gserialized(geom));
if (wanted_index >= curvepoly->nrings)
{
PG_FREE_IF_COPY(geom, 0);
lwgeom_release((LWGEOM *)curvepoly);
PG_RETURN_NULL();
}
result = geometry_serialize(curvepoly->rings[wanted_index]);
lwgeom_free((LWGEOM*)curvepoly);
}
PG_FREE_IF_COPY(geom, 0);
PG_RETURN_POINTER(result);
}
