Return-Path: <tiff-admin@remotesensing.org>
Received: from inmx006.isp.belgacom.be (inmx006.isp.belgacom.be [195.238.2.106])
        by mailst006.isp.belgacom.be (8.12.9/8.12.9/Skynet-MAILSTORE-2.14) with ESMTP id i3NDF4jv000884
        for <joris.at.lebbeke@skynet.be>; Fri, 23 Apr 2004 15:15:04 +0200
        (envelope-from <tiff-admin@remotesensing.org>)
Received: from yoda.imagelinks.com ([208.24.120.44])
        by inmx006.isp.belgacom.be (8.12.9/8.12.9/Skynet-IN-2.32) with ESMTP id i3NDEuMi000343
        for <joris.at.lebbeke@skynet.be>; Fri, 23 Apr 2004 15:14:57 +0200
        (envelope-from <tiff-admin@remotesensing.org>)
Received: from yoda.imagelinks.com (localhost.localdomain [127.0.0.1])
	by yoda.imagelinks.com (8.11.6/8.11.6) with ESMTP id i3NDD5n26865;
	Fri, 23 Apr 2004 09:13:05 -0400
Received: from outmx002.isp.belgacom.be (outmx002.isp.belgacom.be [195.238.3.52])
	by yoda.imagelinks.com (8.11.6/8.11.6) with ESMTP id i3NDCfn26797
	for <tiff@remotesensing.org>; Fri, 23 Apr 2004 09:12:41 -0400
Received: from dfgrrxsknr4e (42-87.240.81.adsl.skynet.be [81.240.87.42])
        by outmx002.isp.belgacom.be (8.12.9/8.12.9/Skynet-OUT-2.21) with SMTP id i3NDCP6Q026405;
	Fri, 23 Apr 2004 15:12:26 +0200
        (envelope-from <joris.at.lebbeke@skynet.be>)
Message-ID: <000f01c42934$afb6d690$2a57f051@dfgrrxsknr4e>
From: "Joris" <joris.at.lebbeke@skynet.be>
To: "John Aldridge" <john.aldridge@informatix.co.uk>,
   "Tiff mailing list" <tiff@remotesensing.org>
References: <Pine.GSO.4.44.0404221641250.11901-100000@scooby.simplesystems.org> <p0521061cbcadf0a4cb7d@[153.32.48.223]> <001e01c428b9$962b7df0$837988d9@dfgrrxsknr4e> <p0521061dbcadf8729fcf@[153.32.48.223]> <40890FE4.7080302@informatix.co.uk>
Subject: Re: [Tiff] Large TIFF files
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2800.1409
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409
X-RAVMilter-Version: 8.4.3(snapshot 20030212) (outmx002.isp.belgacom.be)
Sender: tiff-admin@remotesensing.org
Errors-To: tiff-admin@remotesensing.org
X-BeenThere: tiff@remotesensing.org
X-Mailman-Version: 2.0.13
Precedence: bulk
List-Help: <mailto:tiff-request@remotesensing.org?subject=help>
List-Post: <mailto:tiff@remotesensing.org>
List-Subscribe: <http://remotesensing.org/mailman/listinfo/tiff>,
	<mailto:tiff-request@remotesensing.org?subject=subscribe>
List-Id: TIFF and libtiff discussion <tiff.remotesensing.org>
List-Unsubscribe: <http://remotesensing.org/mailman/listinfo/tiff>,
	<mailto:tiff-request@remotesensing.org?subject=unsubscribe>
List-Archive: <http://remotesensing.org/pipermail/tiff/>
Date: Fri, 23 Apr 2004 15:12:52 +0200
X-UIDL: 6b1998cb0005c6d8061a4b18f8d6430b

John Aldridge wrote:
> Most important is that any file which does not in
> fact exceed 2GB must be readable by old code.

I think there may be consensus about that, the point has been raised before, but
little has been said about how exactly to achieve this.

The library cannot know in advance how large the TIFF to write is going to be,
right? In fact, it's quite possible that the library user / application code
does not know in advance, even disregarding unpredictable compression factors.

Bob raised the hope that a simple redefinition of some types may allready do the
job. I'm not a C man myself, wouldn't know for sure, but does this not exclude
32bit and 64bit TIFF living in the same library? If I'm not mistaking, this is
the way LibJpeg supports both 8 and 12 bit jpeg, but one needs two seperate
compiled LibJpeg libraries to support 'em both in the same app as a consequence.
But I'm not a C man, please point out the errors in my thinking.

Is it then an option to include a boolean 32bit/64bit selector in the main
LibTiff TIFF structure instead? Thus allowing applications to select either
bitdepth *in advance*, for example by means of a flag of some sorts in the
TIFFOpen/TIFFClientOpen call? And rewriting some of the IFD handling code to
deal with either case?


Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html

_______________________________________________
Tiff mailing list
Tiff@remotesensing.org
http://remotesensing.org/mailman/listinfo/tiff
