OpenSystemsDevelopment / qpdf

This reverts commit 8ee83ca722baad9434119bb72d620dfd8e6103c4.

This is being removed because qpdf now has its own page rotation. The
example was an excellent contribution to qpdf, but now it illustrates
rotating pages "by hand", which is no longer needed because of
QPDFObjectHandle::rotatePage.

This is in preparation for implementing page groups.

Add a newline unconditionally before endstream even if a newline was
already written as part of the stream data.

Also accept more errors than before.

Eliminate PCRE and find endobj not preceded by endstream. Be more lax
about placement of endstream and endobj.

Also fix a bug resulting from incorrect use of PointerHolder because
of this unused parameter.

This is added to contrib rather than examples because it requires
c++-11 and lacks a test suite, but it is still useful enough to
include with the distribution.

When parsing content streams, allow content to be split arbitrarily
across stream boundaries.

When requested, QPDFWriter will do more aggress prechecking of streams
to make sure it can actually succeed in decoding them before
attempting to do so. This will allow preservation of raw data even
when the raw data is corrupted relative to the specified filters.

QPDFObjectHandle::parseInternal now issues warnings instead of
throwing exceptions for all error conditions that it finds (except
internal logic errors) and has stronger recovery for things like
invalid tokens and malformed dictionaries. This should improve qpdf's
ability to recover from a wide range of broken files that currently
cause it to fail.

fixes #117
fixes #118
fixes #119
fixes #120

Several other infinite loop bugs were fixed by previous changes.
Include their test files in the test suite.

During parsing of an object, sometimes parts of the object have to be
resolved. An example is stream lengths. If such an object directly or
indirectly points to the object being parsed, it can cause an infinite
loop. Guard against all cases of re-entrant resolution of objects.

This is CVE-2017-9208.

The QPDF library uses object ID 0 internally as a sentinel to
represent a direct object, but prior to this fix, was not blocking
handling of 0 0 obj or 0 0 R as a special case. Creating an object in
the file with 0 0 obj could cause various infinite loops. The PDF spec
doesn't allow for object 0. Having qpdf handle object 0 might be a
better fix, but changing all the places in the code that assumes objid
== 0 means direct would be risky.

This is CVE-2017-9209.

This is CVE-2017-9210.

The description string for an error message included unparsing an
object, which is too complex of a thing to try to do while throwing an
exception. There was only one example of this in the entire codebase,
so it is not a pervasive problem. Fixing this eliminated one class of
infinite loop errors.

If xref table entries lack the spec-required trailing whitespace or
contain a small amount of extra space, handle them anyway.

For non-encrypted files, determinstic ID generation uses file contents
instead of timestamp and file name. At a small runtime cost, this
enables generation of the same /ID if the same inputs are converted in
the same way multiple times.

fix-qdf was previously hard-coding the number of bytes for the f2
field of the xref stream entry. This addresses issue #37. Thanks
aluebcke for reporting.

As reported in issue #40, a call to CryptAcquireContext in
SecureRandomDataProvider fails in a fresh windows install prior to any
user keys being created in AppData\Roaming\Microsoft\Crypto\RSA.

Thanks michalrames.

QUtil.hh needs time.h to get time_t on some platforms. Thanks Peter
Korsgaard <peter@korsgaard.com>