BUG: Fix Parsing of Inline Images

[speedplane]

The inline image parser does not look for whitespace before the EI keyword as it should. Thus if you have a content stream as follows, the parser would crash:

BI [inline image dictionary]
ID
asfASF213ad>]asf
213lkasdf9as12EI
QsdkfjasdfkjfdiI
EI
Q

Notice the EI on one line and the Q on the following line occurs in two places. To properly check, we need to make sure the EI is preceded by white-space.

Also, added a protection against infinite loops in case the PDF is corrupt and the inline image never ends.

[vstoykov]

#331 is also implements protection against incorrect images. Also make parsing of inline images a lot faster.

[MartinThoma]

The current solution is not compatible with the recent BytesIO implementation. Do you mind to adjust your PR?

[speedplane]

I fixed the merge conflict, I'm not sure what you're referring to re BytesIO.

[MartinThoma]

I fixed the merge conflict, I'm not sure what you're referring to re BytesIO.

CI is failing:

[MartinThoma]

@speedplane We made some pretty heavy changes to PyPDF2 recently. If you search for if tok2 == b"I": in generic.py, you can see the section that you adjusted. Do you want to adjust the PR / open a new PR?

Do you have an example PDF where this adjustment is necessary? Does it close one of the open issues?

[MartinThoma]

It would help me a lot if we had an image that shows the described issue.

[speedplane]

Sorry, this is all I have. I can't remember what this fixed or how it fixes it.

[MartinThoma]

@speedplane The issue you addressed was fixed via #1327 .

May I add you to https://pypdf2.readthedocs.io/en/latest/meta/CONTRIBUTORS.html ? Your PR was not merged, but you did make a valuable contribution with this PR. It was just me not being able to understand it at the time.