OpenSystemsDevelopment / qpdf

This change updates all occurrences of `std::endl` to `\n` across various files for improved efficiency and consistency. It reduces unnecessary flushing of output buffers associated with `std::endl` while maintaining the same output format.

Fixes oss-fuzz case 394129398.

Issue arose from chaining multiple runlength filters and inflating a
compressed stream of ~100 bytes to several gigabytes.

There is no obvious fix without imposing an arbitrary implementation limit
and therefore potentially excluding valid PDF files.

Fixes fuzz issue 71689.

Also, add additional qpdf_fuzzer test case.

Throw damagedFile if max_warnings is exceeded. Change qpdf_fuzzer warnings limit to
limit to 500.

As a rule, we should avoid conditional compilation is it always causes
code paths that are sometimes not even seen lexically by the compiler.
Also, we want the actual code being fuzzed to be as close as possible
to the real code. Conditional compilation is suitable to handle
underlying system differences.

Instead, favor configuration using callbacks or other methods that can
be triggered in the places where they need to be exercised.

Add extra fuzz test case and amend memory limit for Pl_DCT.

Also, add diagnostic messages in qpdf_fuzzer and additional fuzz test case.

Remove variables obsoleted by commit 4f24617.

Update getJSON() methods and calls to them

Where not possible, use "auto" to get the iterator type.

Editorial note: I have avoid this change for a long time because of
not wanting to make gratuitous changes to version history, which can
obscure when certain changes were made, but with having recently
touched every single file to apply automatic code formatting and with
making several broad changes to the API, I decided it was time to take
the plunge and get rid of the older (pre-C++11) verbose iterator
syntax. The new code is just easier to read and understand, and in
many cases, it will be more effecient as fewer temporary copies are
being made.

m-holger, if you're reading, you can see that I've finally come
around. :-)

Increase to POINTERHOLDER_TRANSITION=3

patrepl s/PointerHolder/std::shared_ptr/g **/*.cc **/*.hh
patrepl s/make_pointer_holder/std::make_shared/g **/*.cc
patrepl s/make_array_pointer_holder/QUtil::make_shared_array/g **/*.cc
patrepl s,qpdf/std::shared_ptr,qpdf/PointerHolder, **/*.cc **/*.hh
git restore include/qpdf/PointerHolder.hh
git restore libtests/pointer_holder.cc
cleanpatch
./format-code

Run this:

for i in  **/*.cc **/*.c **/*.h **/*.hh; do
  clang-format < $i >| $i.new && mv $i.new $i
done

This comment expands all tabs using an 8-character tab-width. You
should ignore this commit when using git blame or use git blame -w.

In the early days, I used to use tabs where possible for indentation,
since emacs did this automatically. In recent years, I have switched
to only using spaces, which means qpdf source code has been a mixture
of spaces and tabs. I have avoided cleaning this up because of not
wanting gratuitous whitespaces change to cloud the output of git
blame, but I changed my mind after discussing with users who view qpdf
source code in editors/IDEs that have other tab widths by default and
in light of the fact that I am planning to start applying automatic
code formatting soon.

The jpeg library has some assembly code that is missed by the compiler
instrumentation used by memory sanitization. There is a runtime
environment variable that is used to work around this issue.

This change works around STL problems with Embarcadero C++ Builder
version 10.2, but std::vector is more common than std::list in qpdf,
and this is a relatively new API, so an API change is tolerable.

Thanks to Thorsten Schöning <6223655+ams-tschoening@users.noreply.github.com>
for the fix.