OpenSystemsDevelopment / qpdf

Also fix a bug in checking consistency of length for stream data
providers. Length should not be checked or recorded if the provider
says it failed to generate the data.

Use C++14 [[deprecated]] tag

Keep a std::pair internal to the iterators so that operator* can
return a reference and operator-> can work, and each can work without
copying pairs of objects around.

Add constructors that take a QPDF object so we can issue warnings and
create new indirect objects.

Make some more methods in QPDFPageObjectHelper work with form
XObjects, provide forEach methods to walk through nested form
XObjects, possibly recursively. This should make it easier to work
with form XObjects from user code.

Specifically, if a stream had its stream data replaced and had
indirect /Filter or /DecodeParms, it would result in non-silent loss
of data and/or internal error.

StreamDataProvider::provideStreamData now has a rich enough API for it
to effectively proxy to pipeStreamData.

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.

This code was essentially duplicated between test_driver and
standalone_fuzz_target_runner.

This makes all integer type conversions that have potential data loss
explicit with calls that do range checks and raise an exception. After
this commit, qpdf builds with no warnings when -Wsign-conversion
-Wconversion is used with gcc or clang or when -W3 -Wd4800 is used
with MSVC. This significantly reduces the likelihood of potential
crashes from bogus integer values.

There are some parts of the code that take int when they should take
size_t or an offset. Such places would make qpdf not support files
with more than 2^31 of something that usually wouldn't be so large. In
the event that such a file shows up and is valid, at least qpdf would
raise an error in the right spot so the issue could be legitimately
addressed rather than failing in some weird way because of a silent
overflow condition.

Full parser context
    test_driver.cc(208): parsing: void runtest(int,const char *,const char *)

There have been issues reported where exceptions are not thrown
properly across shared library/DLL boundaries, so add a test
specifically to ensure that exceptions are caught as thrown.

When linearizing a file or getting the list of all pages in a file,
detect if the pages tree contains a duplicated page object and, if so,
shallow copy it. This makes it possible to have a one to one mapping
of page positions to page objects.

Support conversion of pages to form XObjects and placement of form
XObjects on pages.