Re: Why is it that png files are not dependable over the long haul

On 08/05/2018 11:36 PM, Cosmin Truta wrote:
> On Thu, 2 Aug 2018 at 02:37, J Decker wrote:
>> Experimenting with the chromium modified zlib, I found a flag  INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
> 
> That's in the original zlib, also. But you don't need it.
> 
> What you need is the following libpng function call:
> 
>     png_set_option(png_ptr,
>         PNG_MAXIMUM_INFLATE_WINDOW,
>         PNG_OPTION_ON);
> 
> See the libpng manual for details.
> 
> To conclude the story from my previous email:
> 
> If PNG_MAXIMUM_INFLATE_WINDOW is set to PNG_OPTION_OFF (i.e. the
> default), libpng can diagnose the error, but not recover from it.
> Conversely, if PNG_MAXIMUM_INFLATE_WINDOW is set to PNG_OPTION_ON,
> libpng can decode the image, but not know that the image had an error.
> It's an either/or proposition, unfortunately.
> 
> Sincerely,
> Cosmin
> 

Am I going to be able to recover these image files?

Ruben


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot