OpenSystemsDevelopment / qpdf

…pport for configurable global limits via `qpdf_global_get_uint32` and `qpdf_global_set_uint32`.

…dom_string`, improve readability of salts and keys handling, and streamline `compute_Perms_value_V5_clear` logic by returning strings directly.

Converted multiple occurrences of `count()` to `contains()` throughout the codebase where the goal was to check key existence in containers. This improves code readability and aligns with modern C++ practices, particularly with C++20, making the intent more explicit and potentially aiding performance.

Add new private Util.hh header to define inline functions and expose as
ordinary functions in QUtil.

This improves indentation of long strings. This commit also fixes some
trailing whitespace in ChangeLog.

Avoid representing as PDF Doc encoding any string whose PDF Doc
encoding representation starts with a UTF-16 or UTF-8 marker.

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. :-)

Character transcoding from Unicode to single-byte characters used
hard-coded switch statements because the code predated our adoption of
C++11. Now we have thread-safe, static initialization of map literals,
so use that instead.

* Merge overloaded functions by adding default values
* Remove non-const methods that are identical to const methods

Increase to POINTERHOLDER_TRANSITION=4

(patrepl and cleanpatch are my own utilities)

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

Run this:

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