OpenSystemsDevelopment / qpdf

Move object parsing code from QPDF to QPDFObjectHandle and
parameterize the parts of it that are specific to a QPDF object.
Provide a version that can't handle indirect objects and that can be
called on an arbitrary string.

A side effect of this change is that the offset used when reporting
invalid stream length has changed, but since the new value seems like
a better value than the old one, the test suite has been updated
rather than making the code backward compatible.  This only effects
the offset reported for invalid streams that lack /Length or have an
invalid /Length key.

Updated some test code and exmaples to use QPDFObjectHandle::parse.

Supporting changes include adding a BufferInputSource constructor that
takes a string.

InputSource, FileInputSource, and BufferInputSource are now top-level
classes instead of privately nested inside QPDF.

Add --copy-encryption and --encryption-file-password options to qpdf.
Also strengthen test suite for copying encryption.  The strengthened
test suite would have caught the failure to preserve AES and the
failure to update the file version, which was invalidating the
encrypted data.

This fixes were to code added yesterday; the problems would not have
impacted any previously released code.  These are all changes related
to the possibility that copyEncryptionParameters may be called on
behalf a different QPDF than the one being written.

from qpdf command-line tool

Method to copy encryption parameters from another file.  Adapted from
existing code to copy encryption parameters from the original file.

Throw an exception that directs the user to QPDF::copyForeignObject.

This includes QPDF::copyForeignObject and supporting foreign objects
as arguments to addPage*.

QPDFObjectHandle::{new,is,assert}Reserved, QPDF::replaceReserved
provide a mechanism to add objects to a PDF file when there are
circular references.  This is a prerequisite to copying objects from
one PDF to another.

Breaking API change: length parameter has disappeared from the
StreamDataProvider version of QPDFObjectHandle::replaceStreamData
since it is no longer necessary to compute it in advance.  This
breaking change is justified by the fact that removing the length
parameter provides the caller an opportunity to simplify the calling
code.

Previous versions of qpdf incorrectly passed arbitrary objects from
/Pages objects down to individual pages in direct contradition with
the PDF specification.  These are now left in /Pages.  When
intermediate /Pages nodes are being discarded as when the /Pages tree
is being flattened, a warning is issued when unknown keys are
encountered.

Refactored optimizePagesTree to pushInheritedAttributesToPage and made
public

Test coverage case for new newStream method
Expose decimal_places argument for double-based newReal

All enhancements suggested by Tobias.

This makes the code simpler than having to create a buffer of a fixed
size and copy the string to it.

This rework makes xref reconstruction run much faster and use much
less memory.

With QPDF allowing integers to contain 64-bit quantities, this change
is necessary to be able to linearize files whose sizes might be larger
than 10 digits.

This makes it possible to store offsets that are larger than 2 GB in
the trailer dictionary.

This just makes it safer to pull up this file in an editor.

Also updated pdf_from_scratch test driver to use the new factories,
and made some cosmetic improvements and documentation updates for the
emptyPDF() method.