As far as I can see the problem was introduced by commit ed0c9640abcbea459e3a276ee0b27631b01c32c4 (from 8th of April). Instead of

  bitmaps = (JBIG2Bitmap **)gmallocn_checkoverflow(numInputSyms + numNewSyms,
				     sizeof(JBIG2Bitmap *));
  if (!bitmaps) {

it should be 

  bitmaps = (JBIG2Bitmap **)gmallocn_checkoverflow(numInputSyms + numNewSyms,
				     sizeof(JBIG2Bitmap *));
  if (!bitmaps && numInputSyms + numNewSyms > 0) {

(In tricky pdf numInputSyms and numNewSyms are both 0).

Can You repair that, Albert? I'm quite close finishing the Coldwind stuff (probably closing it this weekend), but I can handle this afterwards...

sure, i'll get this

Unfortunately this only removes the warning output, the file is still not totally renderer correctly

This is not critical

(In reply to comment #3)
> Unfortunately this only removes the warning output, the file is still not
> totally renderer correctly

yes, I tried 0.20.4, no error, but the output does not correct.

Created attachment 122419 [details] [review]
SDNUMEXSYMS is allowed to be 0!

This patch fixes it

The patch now doesn't break reading of the JBIG2 bitmap, and the PDF is rendered correct, but we get error messages again:

./utils/pdftoppm -png -cropbox 54579.open/tricky.pdf output/tricky
Syntax Error (1498): 1 extraneous byte after segment
Syntax Error (1536): 1 extraneous byte after segment

This happens when a segment with SDNUMEXSYMS = 0 was read (happens two times!). I digged into the spec, but I can't find out why there is exact one extraneous byte here or if there is something missing to read by the method. I looked into other JBIG2 decoders like jbic2dec, but these decoders don't complain about extraneous byte(s), they just skip to the next sgement.

So we probably can just skip silently, too, but that I let up to You Albert ;-)

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