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Re: Nautilus + TIF file = memory insanity



On Tue, May 11, 2004 at 09:26:20AM -0700, Billy Charlton wrote:
> > The images size (not file size) is huge:
> >
> > mustang:~/downloads> identify sfstreets.tif
> > sfstreets.tif TIFF 11248x14484+0+0 PseudoClass 2c 8-bit 209.4kb 1.570u 0:02
> >
> > That's like 164 times the area (in square pixels) of my monitor!
> >
> > I have no idea how to make those programs more efficient.  Can you
> > make do with a scaled down image?  I scaled it down to 20% in the
> > gimp and it is very readable at 2250x2897.  I guess it depends on your
> > application as to whether this is acceptable.

There was a discussion about 'risks' associated with exploding files
exactly like this.  "Decompression bombs" they called them.

  See ftp.aerasec.de/pub/advisories/decompressionbombs/

In "pictures" you will see giff and png versions of the same 
problem.

Some compression tools are very good on silly data and 
the resulting  decompression bomb effect is astounding.

    $ bzip2 -v zarro
      zarro:   685000.000:1,  0.000 bits/byte, 100.00% saved, 100010000 in, 146 out.
    $ ls -l
    -rw-rw-r--  1 mitch mitch 100010000 May 14 17:46 zarro
    $ ls -l
    -rw-rw-r--  1 mitch mitch 146 May 14 17:46 zarro.bz2

Astounding....

   146 bytes --grows to-->  100010000


-- 
	T o m  M i t c h e l l 
	/dev/null the ultimate in secure storage.



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