OpenSystemsDevelopment / qpdf

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 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.

* [bcc32 Error] QPDF.cc(375): E2268 Call to undefined function 'atof'
  Full parser context
    QPDF.cc(358): parsing: void QPDF::parse(const char *)

* [bcc32 Error] QPDFTokenizer.cc(183): E2268 Call to undefined function 'strtol'
  Full parser context
    QPDFTokenizer.cc(163): parsing: void QPDFTokenizer::resolveLiteral()

* [bcc32 Error] pdf-split-pages.cc(52): E2268 Call to undefined function 'exit'
  Full parser context
    pdf-split-pages.cc(50): parsing: void usage()

* PR #295: Including "cstdlib" should be replaced with "stdlib.h" to be more consistent. At the same time I changed the order of the surrounding includes to reflect alphabetical order, because at some files this already have been the case.

Now uses QPDFOutlineDocumentHelper and QPDFOutlineObjectHelper.

This fix allows qpdf to compile/test cleanly with gcc 8.

The QPDF_String::getUTF8Val() method was not treating strings that
weren't explicitly Unicode as PDF Doc Encoded. This only affects
characters in the range 0x80 through 0xa0.

Expose Pl_QPDFTokenizer, and have it do more of the work of managing
the token filter's pipeline.

Adding a trailing newline in content normalization damages files whose
contents are split across streams in the middle of tokens. Let
QPDFWriter add the newline with the indicator to ignore the newline,
which it already does. This changes the way some qdf files look.

Some file names had `...` in their name, which causes problems on some
systems.

Make sure to link from the source tree before linking from the system.
In many environments, this is necessary to allow a newly built qpdf to
link properly instead of trying to link or resolve libraries from an
older installed version.

The latter catches underflow/overflow.

pdf-create now creates images with different color spaces and encoding
schemes and verifies them for data correctness.

This commit adds several API methods that enable control over which
types of filters QPDF will attempt to decode. It also adds support for
/RunLengthDecode and /DCTDecode filters for both encoding and
decoding.

For cross compiling.

Make sure people know that static ID should be used only for testing.

This is faster than using qpdf --pages to do it.

If NO_GET_ENVIRONMENT is #defined at compile time on Windows, do not
call GetEnvironmentVariable.  QUtil::get_env will always return
false.  This option is not available through configure.  This was
added to support a specific user's requirements to avoid calling
GetEnvironmentVariable from the Windows API.  Nothing in qpdf outside
the test coverage system in qtest relies on QUtil::get_env.

For std::string and std::vector, replace operator[] with at.  This was
done using an automated process.  See README.hardening for details.

In internal code and examples, replace calls to getObjectID() and
getGeneration() with calls to getObjGen() where possible.

Remove needless calls to open, close, and fileno; call remove instead
of unlink.

Add QUtil::hex_encode to encode binary data has a hexadecimal string,
and use it in place of sprintf where possible.