Path: csiph.com!x330-a1.tempe.blueboxinc.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!border3.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!postnews.google.com!15g2000vbw.googlegroups.com!not-for-mail
From: Tom McGlynn <taqmcglynn@googlemail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: Arithmetic overflow checking
Date: Thu, 21 Jul 2011 07:15:59 -0700 (PDT)
Organization: http://groups.google.com
Lines: 34
Message-ID: <208c3e0b-4e3e-4180-97ae-53db9b8ec2e9@15g2000vbw.googlegroups.com>
References: <015aeb15-57db-48ab-9cd4-77f8448b632f@w24g2000yqw.googlegroups.com> <knha175c4hu8491pmmek09thqmo7niq3s2@4ax.com> <1f9c17dltrhlmhifuigoa914477r4rg1e1@4ax.com> <l_qdnfmZ-4tpt4vTnZ2dnUVZ_sqdnZ2d@earthlink.com> <koic171t5gas91890r8l9914v26snm7k1v@4ax.com> <b3d4a08b-3428-442a-8cce-30edc2868a47@5g2000yqb.googlegroups.com> <09fe171s46ilvq9qmn254dctunm6noh0ps@4ax.com> <f6ed8d08-bc7a-43e4-aecf-878511705353@j15g2000yqf.googlegroups.com> <4e262731$0$314$14726298@news.sunsite.dk> <j059o8$684$1@dont-email.me> <4e26300b$0$309$14726298@news.sunsite.dk> <cdyVp.5929$Vn5.2217@newsfe18.iad> <4e26b4ed$0$2501$db0fefd9@news.zen.co.uk> <f126e0ad-e1e5-47c8-949e-e38b3598d5ff@m5g2000prh.googlegroups.com> <4e28097f$0$2533$da0feed9@news.zen.co.uk> <j096t3$7rj$2@localhost.localdomain>
NNTP-Posting-Host: 128.154.208.243
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-Trace: posting.google.com 1311257855 25469 127.0.0.1 (21 Jul 2011 14:17:35 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Thu, 21 Jul 2011 14:17:35 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: 15g2000vbw.googlegroups.com; posting-host=128.154.208.243; posting-account=uCwGCAkAAADsLxg6F1MzUXy8bLSglYNp
User-Agent: G2/1.0
X-Google-Web-Client: true
X-Google-Header-Order: HUALESNKRC
X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.19) Gecko/20110420 SeaMonkey/2.0.14,gzip(gfe)
Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:6340

On Jul 21, 8:43=A0am, Martin Gregorie <mar...@address-in-sig.invalid>
wrote:
...
> Agreed, but there's another way to handle this in Java that would
> probably cater for most overflow and out of range requirements without
> affecting existing programs or the language at all:
>
> Just add range checking constructors to Integer and friends, e.g:
>
> =A0 =A0 =A0 =A0 Integer boundedValue =3D new Integer(0,1,10);
>
> to declare an Integer, initialised to zero and with the range 1:10. The
> overheads would be minimal if the checks were only enabled if limits were
> added. It could either throw an unchecked exception or provide a range
> checking method:
>

How would this help given that Integers can't change anyway? It can
only check that the initialization value is in range.  You'd have to
somehow make these Integers 'sticky' in some way so that any
expression using one of them is also subject to bounds checking.

E.g.,
   Integer firstValue =3D new Integer(Integer.MAX_VALUE, 0,
                             Integer.MAX_VALUE);
   Integer nextValue =3D new Integer(firstValue+Integer.MAX_VALUE+3,
       0, 10);

clearly overflows, but it would work fine unless something significant
were added to the language.

    Regards,
    Tom McGlynn