OpenSystemsDevelopment / qpdf

…y, modify bounds checks, and adjust affected tests.

… to use subscript operators, and simplify object access logic.

Refactor array handling in `QPDFObjectHandle`: replace `int` with `size_t` for size and index operations, introduce utility functions for type conversions, and simplify sparse array logic.

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.

Move all array-specific methods to new class qpdf::Array.

Change the return type to a std::pair<bool, QPDFObjectHandle> in order to
allow a default constructed object handle (which is currently returned to
indicate failure) to become a valid object.

Create unresolved objects only for objects in the xref table (except during
parsing of the xref table). Do not add indirect nulls into the the object
cache as the result of a cache miss during a call to getObject except
during parsing or creation/updating from JSON. To support this behaviour,
add new private methods getObjectForParser and getObjectForJSON.

As a result of this change, dangling references are treated as direct nulls
rather than indirect nulls.

Prevent my future self or other contributors from using assert in
tests and then having that assert not do anything because of the
NDEBUG macro.

Run this:

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