Article View: comp.sources.bugs
Article #901robots2
From: oleg
Date: Sat, 22 Aug 1987 17:02
Date: Sat, 22 Aug 1987 17:02
43 lines
1916 bytes
1916 bytes
While playing the new robots game (posted recently to comp.sources.games),
I discovered that the game would coredump when checking "safety" of a teleport
destination.
Not having much time to analyze the game, I put in a check for the validity of
the examined location before a call to "move()" and it seemed to have fixed
the problem. I am not sure if this is REALLY a correct fix, however, and there
may be more places where bounds checking needs to be done. Just goes to show:
always compile with "-g" and never strip your executables until you are REALLY
sure... :-)
*** good.c.orig Thu Aug 13 15:02:21 1987
--- good.c Thu Aug 13 15:03:43 1987
***************
*** 90,95
/* we are 2 steps out */
if( blocked(ty, tx, y, x))
continue;
move(ty+y,tx+x);
if ( abs(x) == 2 && abs(y) == 2
&& inch() == FROBOT){
--- 90,99 -----
/* we are 2 steps out */
if( blocked(ty, tx, y, x))
continue;
+ if ((ty+y) < 0 || (tx+x) < 0 || (ty+y) > VERT
+ || (tx+x) > HORIZ)
+ continue;
+
move(ty+y,tx+x);
if ( abs(x) == 2 && abs(y) == 2
&& inch() == FROBOT){
--
Oleg Kiselev -- oleg@quad1.quad.com -- {...!psivax|seismo!gould}!quad1!oleg
DISCLAIMER: All grammatical and spelling errors are inserted deliberately to
test the software I am developing. In fact, that is the only reason I am
posting. Yeah, that's the ticket! All my postings are just test data! Yeah!!
Technical Details
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!cbosgd!cwruecmp!hal!ncoast!oleg From: oleg@ncoast.UUCP Newsgroups: comp.sources.bugs Subject: robots2 Message-ID: <4230@ncoast.UUCP> Date: Sat, 22-Aug-87 13:02:18 EDT Article-I.D.: ncoast.4230 Posted: Sat Aug 22 13:02:18 1987 Date-Received: Sun, 23-Aug-87 19:38:35 EDT Sender: allbery@ncoast.UUCP Lines: 43