ST_LocateBetween()

Datum ST_LocateBetween

(

PG_FUNCTION_ARGS

)

Definition at line 110 of file lwgeom_functions_lrs.c.

{
        GSERIALIZED *geom_in = PG_GETARG_GSERIALIZED_P(0);
        double from = PG_GETARG_FLOAT8(1);
        double to = PG_GETARG_FLOAT8(2);
        double offset = PG_GETARG_FLOAT8(3);
        LWCOLLECTION *geom_out = NULL;
        LWGEOM *line_in = NULL;
        static char ordinate = 'M'; /* M */
 
        if ( ! gserialized_has_m(geom_in) )
        {
                elog(ERROR,"This function only accepts geometries that have an M dimension.");
                PG_RETURN_NULL();
        }
 
        /* This should be a call to ST_LocateAlong! */
        if ( to == from )
        {
                PG_RETURN_DATUM(DirectFunctionCall3(ST_LocateAlong, PG_GETARG_DATUM(0), PG_GETARG_DATUM(1), PG_GETARG_DATUM(3)));
        }
 
        line_in = lwgeom_from_gserialized(geom_in);
        geom_out = lwgeom_clip_to_ordinate_range(line_in,  ordinate, from, to, offset);
        lwgeom_free(line_in);
        PG_FREE_IF_COPY(geom_in, 0);
 
        if ( ! geom_out )
        {
                elog(ERROR,"lwline_clip_to_ordinate_range returned null");
                PG_RETURN_NULL();
        }
 
        PG_RETURN_POINTER(geometry_serialize((LWGEOM*)geom_out));
}

References geometry_serialize(), gserialized_has_m(), lwgeom_clip_to_ordinate_range(), lwgeom_free(), lwgeom_from_gserialized(), and ST_LocateAlong().

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