Article View: net.bugs.usg
Article #279"regexp.h" does an incorrect comparison of a "char" against 255
From: Guy Harris
Date: Wed, 26 Mar 1986 05:04
Date: Wed, 26 Mar 1986 05:04
83 lines
2167 bytes
2167 bytes
"regexp.h" compares a "char" expression against 255. On a machine with
8-bit signed "char"s and a correct C compiler, this comparison will always
indicate that the value of the expression is not equal to 255. What it
intended to do was mask the character with 0377 and then do the comparison.
Here's a context diff of the fix, with two free "lint" fixes courtesy of Doug
Gwyn:
*** /archbeluga/s5r2/usr/include/regexp.h Sat Nov 5 09:42:54 1983
--- /tmp/regexp.h Tue Mar 25 20:59:36 1986
***************
*** 220,225
*ep++ = c;
}
}
}
step(p1, p2)
--- 220,226 -----
*ep++ = c;
}
}
+ /*NOTREACHED*/
}
step(p1, p2)
***************
*** 400,405
}
}
}
static
--- 401,407 -----
}
}
+ /*NOTREACHED*/
}
static
***************
*** 406,411
getrnge(str)
register char *str;
{
low = *str++ & 0377;
size = (*str == 255)? 20000: (*str &0377) - low;
}
--- 408,415 -----
getrnge(str)
register char *str;
{
+ register int sizecode;
+
low = *str++ & 0377;
sizecode = *str & 0377;
if (sizecode == 255)
***************
*** 407,411
register char *str;
{
low = *str++ & 0377;
! size = (*str == 255)? 20000: (*str &0377) - low;
}
--- 411,419 -----
register int sizecode;
low = *str++ & 0377;
! sizecode = *str & 0377;
! if (sizecode == 255)
! size = 20000;
! else
! size = sizecode - low;
}
--
Guy Harris
{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
guy@sun.arpa (yes, really)
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!petrus!bellcore!decvax!decwrl!sun!guy From: guy@sun.uucp (Guy Harris) Newsgroups: net.bugs.usg Subject: "regexp.h" does an incorrect comparison of a "char" against 255 Message-ID: <3404@sun.uucp> Date: Wed, 26-Mar-86 00:04:49 EST Article-I.D.: sun.3404 Posted: Wed Mar 26 00:04:49 1986 Date-Received: Thu, 27-Mar-86 07:24:15 EST Distribution: net Organization: Sun Microsystems, Inc. Lines: 83