Hey,
i encountered a PDF where the offset to the xref table points not to the
'xref' token, but right into the entry of
the first object in that xref table (specificly to the second digit of
the generation number of the first object).
Podofo finds the offset and the xref token and assumes the xref table is
valid and must be parsed.
Podofo then tries to read the objectnumber and generationnumber from
there and crashes when it encounters the "f" (or "n") token, because its
trying to read a number (and f/n are not numbers).
Furthermore the xref table has wrong lineendings. In a hexeditor you can
see that only "A0" is used as lineendings (no second line ending
character D0 nor a whitespace).
I know that this pdf is faulty and not according to spec but it opens in
adobe and we could scan the file for objects and make a xreftable
ourselfs...
Why are we not handling this error better? We could ignore the xref
table if we encounter an error while parsing it, and then just treat it
as if this pdf doesnt have a xref table.
Edit: While writing this mail i found:
https://sourceforge.net/p/podofo/mailman/message/18520832/ which is the
same problem but from 2008.
Greetings,
Dennis
Error Stack (from podofo browser trying to open that file):
#0 error source: PDfParser.cpp:214
#1 error source: PdfParser.cpp320
#2 error source: PdfParserObject.cpp:97
#3 error source: PdfTokenizer.cpp:353
--
dots <http://www.dots.de/en/>
Dennis Voss
dots Software GmbH
Schlesische Str. 27, 10997 Berlin, Germany
Tel: +49 (0)30 695 799-47
Fax: +49 (0)30 695 799-55
dennis.v...@dots.de <mailto:dennis.v...@dots.de>
http://www.dots.de <http://www.dots.de/>
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