OpenSystemsDevelopment / qpdf

This comment expands all tabs using an 8-character tab-width. You
should ignore this commit when using git blame or use git blame -w.

In the early days, I used to use tabs where possible for indentation,
since emacs did this automatically. In recent years, I have switched
to only using spaces, which means qpdf source code has been a mixture
of spaces and tabs. I have avoided cleaning this up because of not
wanting gratuitous whitespaces change to cloud the output of git
blame, but I changed my mind after discussing with users who view qpdf
source code in editors/IDEs that have other tab widths by default and
in light of the fact that I am planning to start applying automatic
code formatting soon.

Use the first of ASCII, PDFDocEncoding, or UTF-16 that is capable of
encoding the string.

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.

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.

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

Put a specific comment marker next to every piece of code that MSVC
gives warning 4996 for.  This warning is generated for calls to
functions that Microsoft considers insecure or deprecated.  This
change is in preparation for fixing all these cases even though none
of them are actually incorrect or insecure as used in qpdf.  The
comment marker makes them easier to find so they can be fixed in
subsequent commits.

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

Add virtual methods to QPDFObject, wrappers to QPDFObjectHandle, and
implementations to all the QPDF_Object types.

Significantly improve the code's use of off_t for file offsets, size_t
for memory sizes, and integer types in cases where there has to be
compatibility with external interfaces.  Rework sections of the code
that would have prevented qpdf from working on files larger than 2 (or
maybe 4) GB in size.

git-svn-id: svn+q:///qpdf/trunk@810 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@709 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@639 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@599 71b93d88-0707-0410-a8cf-f5a4172ac649