OpenSystemsDevelopment / qpdf

…for improved readability, and remove redundant variables.

…jectHelper`: replace `getArrayNItems` with `size`, simplify array traversal, and centralize `empty` checks for improved clarity and efficiency.

…`warn`, streamline condition handling.

Ensure an appearance stream is not shared  before generating text appearances, improving error handling and data integrity.

Streamlined method definitions, replaced explicit loop counters with range-based loops, and added `final` specifier to class and methods to ensure overriding restrictions. Simplified constructor and member variable initialization.

Simplified code by removing redundant `this` qualifiers where they are not essential, improving readability and alignment with coding standards. No changes were made to functionality.

Return the display value if the choices entry is an array of strings rather
than a single string.

Test file is need-appearances.pdf modified to contain one array entry.

API was defined, but .cc had no implementation. PDF 2.0 manual is surprisingly unclear as to on/off values, giving /Yes in an example and /Off in descriptive text as "not on".

Adjusting for under/overflow by repeated incrementing/decrementing can
cause excessive runtime with invalid BBox coordinates.

Fixes oss-fuzz issue 409905355.

Replace data member oh with accessors.

Remove redundant overloads from QPDFObjGen::set.

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

The code accepted values other than /Yes but still used /Yes as the
checked value instead of obeying the normal appearance dictionary.

Add new convenience class QPDFObjGen::Guard

Also, inline method and add optional parameter error_msg.

(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

Add comments to force line breaks, parenthesize function arguments
that are contatenated strings, etc. -- these kinds of changes improve
clang-format's results and also cause emacs cc-mode to match
clang-format. After this type of change, most of the time, when
clang-format and emacs disagree, clang-format is better.

Run this:

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

This is so it will fit on one line after a qtest upgrade allows us to
split lines.