<s>
Rigi	B-Protocol
is	O
an	O
interactive	O
graph	O
editor	O
tool	O
for	O
software	O
reverse	O
engineering	O
using	O
the	O
white	B-General_Concept
box	I-General_Concept
method	I-General_Concept
,	O
i.e.	O
</s>
<s>
necessitating	O
source	O
code	O
,	O
thus	O
it	O
is	O
mainly	O
aimed	O
at	O
program	B-General_Concept
comprehension	I-General_Concept
.	O
</s>
<s>
Rigi	B-Protocol
is	O
distributed	O
by	O
its	O
main	O
author	O
,	O
Hausi	O
A	O
.	O
Müller	O
and	O
the	O
Rigi	B-Protocol
research	O
group	O
at	O
the	O
University	O
of	O
Victoria	O
.	O
</s>
<s>
Rigi	B-Protocol
provides	O
interactive	O
links	O
from	O
the	O
graphs	O
it	O
produces	O
to	O
the	O
source	O
code	O
,	O
but	O
not	O
vice	O
versa	O
.	O
</s>
<s>
Rigi	B-Protocol
renders	O
trees	O
and	O
grid-layout	O
graphs	O
using	O
its	O
own	O
internal	O
engine	O
,	O
but	O
relies	O
on	O
University	O
of	O
Passau	O
's	O
GraphEd	O
for	O
more	O
advanced	O
layouts	O
.	O
</s>
<s>
The	O
public	O
version	O
of	O
Rigi	B-Protocol
has	O
built-in	O
parsers	B-Language
(	O
"	O
fact	O
extractors	O
"	O
)	O
for	O
C	O
and	O
Cobol	O
,	O
and	O
can	O
leverage	O
the	O
C++	O
parser	B-Language
of	O
IBM	O
Visual	B-Language
Age	I-Language
.	O
</s>
<s>
It	O
can	O
also	O
accept	O
external	O
data	O
in	O
an	O
RSF	O
format	O
(	O
it	O
introduced	O
)	O
,	O
so	O
external	O
parses	O
can	O
also	O
feed	O
it	O
data	O
,	O
for	O
example	O
SHriMP	O
tool	O
's	O
Java	O
parser	B-Language
.	O
</s>
<s>
Some	O
efforts	O
were	O
made	O
to	O
integrate	O
Rigi	B-Protocol
in	O
Microsoft	B-Application
Visual	I-Application
Studio	I-Application
.NET	I-Application
.	O
</s>
<s>
Early	O
versions	O
of	O
Bauhaus	O
were	O
also	O
built	O
on	O
top	O
of	O
Rigi	B-Protocol
;	O
the	O
author	O
of	O
this	O
latter	O
tool	O
notes	O
that	O
the	O
combination	O
was	O
rather	O
slow	O
for	O
graphs	O
having	O
more	O
than	O
500	O
nodes	O
.	O
</s>
<s>
Rigi	B-Protocol
was	O
reportedly	O
used	O
to	O
analyze	O
some	O
(	O
undisclosed	O
)	O
embedded	O
software	O
at	O
Nokia	O
,	O
in	O
the	O
range	O
of	O
hundreds	O
of	O
thousands	O
of	O
lines	O
of	O
code	O
,	O
and	O
was	O
met	O
with	O
positive	O
feedback	O
from	O
the	O
Nokia	O
engineers	O
.	O
</s>
<s>
Active	O
development	O
of	O
Rigi	B-Protocol
has	O
ceased	O
in	O
1999	O
,	O
with	O
the	O
last	O
official	O
version	O
released	O
in	O
2003	O
.	O
</s>
