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September 2004

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2004.09.16 19:12 "BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.16 19:23 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.16 19:36 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.16 19:38 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.16 20:08 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 01:14 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.16 22:39 "Re: BigTIFF Tag Value Count issue", by Ian Ameline
2004.09.17 00:09 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 00:32 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 01:54 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 02:29 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 02:58 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 03:08 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 04:20 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 04:39 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 11:25 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 14:31 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 14:40 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 15:02 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:41 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 14:53 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 15:06 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:36 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 05:46 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 11:40 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 13:11 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 13:34 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 15:10 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 15:10 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 15:55 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 16:00 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 16:33 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 16:13 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 16:34 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 16:43 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:48 "Re: BigTIFF Tag Value Count issue", by Ross A Finlayson
2004.09.17 22:15 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:41 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 11:38 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 06:35 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
2004.09.17 11:43 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 12:46 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
2004.09.17 12:55 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 13:20 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
2004.09.17 13:47 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 13:08 "Re: BigTIFF Tag Value Count issue", by Ross A Finlayson
2004.09.19 12:31 "Re: BigTIFF Tag Value Count issue", by Andrey Kiselev
2004.09.19 16:43 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.20 16:18 "Re: BigTIFF Tag Value Count issue", by Ed Grissom
2004.09.20 22:05 "Re: BigTIFF Tag Value Count issue", by Steve Carlsen
2004.09.20 23:09 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn

2004.09.17 14:53 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme

> > If I'm not mistaking, on most processors there is a gain from aligning of
> > data, whilst things still work if data is not aligned. Thus, it pays to 
> > build...
>
> With some processors (particularly RISC type processors), attempting
> to read unaligned data results in a program crash.  Probably Intel x86
> is not one of those processors.

IIRC, there's a processor flag that can be set on Intel Pentium familly that
mimicks that behaviour, but I may be misremembering.

But I wish you would draw conclusions, as, to me, you seem to be stepping on
your own point. If misaligned data can cause such disasters, and you're memory
mapping the file, you'll have to design your code to check correct alignment
anyway, and be prepared to copy the structures if needed to properly aligned
locations, since we can't trust everyone to align the IFD structure as we lay it
out in the BigTIFF spec. If all this code logic has to be built anyway, does
this not make designing aligment in the spec less important, and is this not
another argument pro regular IO instead of memory mapping for this kind of codec
application?

So I remain with my original point of view
- memory mapping is not really good design, but let's be friendly to memory
mappers if there's no cost to us
- alignment inside a file is not really an important issue, but let's do it
anyway if there's no substantial cost to us


Joris Van Damme
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