Xref: utzoo comp.sources.d:2747 comp.sys.att:4423 unix-pc.general:1483
Path: utzoo!utgpu!water!watmath!clyde!att!cbnews!res
From: res@cbnews.ATT.COM (Robert E. Stampfli)
Newsgroups: comp.sources.d,comp.sys.att,unix-pc.general
Subject: Re: help with arc
Message-ID: <1485@cbnews.ATT.COM>
Date: 7 Oct 88 19:38:06 GMT
References: <204@arnold.UUCP> <209@arnold.UUCP>
Reply-To: res@cbnews.ATT.COM (Robert E. Stampfli)
Organization: AT&T Bell Laboratories, Columbus
Lines: 33

In article <209@arnold.UUCP> dave@arnold.UUCP (Dave Arnold) writes:
>>I am trying to build arc for System V.  Everything compiles
>>and runs ok---except it always creates corrupted archives.
>>Anybody have similar problems?

I tried mailing this to Dave, but apparently he didn't get it -- maybe
others will find it useful, too.  From his later posting, I am certain
he was bit by the same bug I was.

I am running a Unix-PC 7300 with version 3.5 of the OS (all known fixes
applied).  This is what I did to make the ARC 5.21 distributed by Howard
Chu useable on my UNIX-pc:

1. In file arccode.c, look at the last function, code(), and change
   the declaration for the argument from "char c" to "unsigned char c".
   This circumvents a compiler bug which manifests itself in a sign
   extension problem on 8-bit quantities returned by code().  ARC will
   now decode crunched data correctly.

2. In file arcusq.c, look for the declaration of structure nd and change
   the instance of "int child[2]" to "short child[2]".  This circumvents
   a compiler bug which causes problems with the unsqueeze of a large
   squeezed file.  (Not to mention saving a little space.)

3. In file arcpack.c, look for the line that prints the percent compression
   and insert a check to prevent the divide by zero that occurs if you try
   to insert a zero length file into an archive.  This is a program bug.


Hope this helps,
Rob Stampfli
att!cbnews!res
osu-cis!n8emr!kd8wk!res