[postgis-users] Bug? Strange code in lwline_crossing_direction()

Kohei KaiGai kaigai at heterodb.com
Sat Apr 18 08:32:20 PDT 2020


Hello,

I noticed a strange code at liblwgeom/lwalgorithm.c
https://github.com/postgis/postgis/blob/master/liblwgeom/lwalgorithm.c#L509

lwline_crossing_direction() is the main logic of ST_LineCrossingDirection.
It walks on all the edges of the supplied geometry (line), and calls
lw_segment_intersects to check intersections.

It looks to me the local variable 'first_cross' is used to remember the first
result from the lw_segment_intersects, however, it saves different value
on the second if-block at L526.

Is it expected? Or, just mistake by copy & paste?

Best regards,
-- 
HeteroDB, Inc / The PG-Strom Project
KaiGai Kohei <kaigai at heterodb.com>


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