OpenSystemsDevelopment / qpdf

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

Ideally, the library should never call assert outside of test code,
but it does in several places.  For some cases where the assertion
might conceivably fail because of a problem with the input data,
replace assertions with exceptions so that they can be trapped by the
calling application.  This commit surely misses some cases and
replaced some cases unnecessarily, but it should still be an
improvement.

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@796 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@697 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@668 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@662 71b93d88-0707-0410-a8cf-f5a4172ac649

consistent with other implementations and is required for one PDF file
in the test suite


git-svn-id: svn+q:///qpdf/trunk@656 71b93d88-0707-0410-a8cf-f5a4172ac649

…ually have test input

git-svn-id: svn+q:///qpdf/trunk@646 71b93d88-0707-0410-a8cf-f5a4172ac649

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