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.
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.
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.
Pushing inherited objects to pages and getting all pages were both
prone to stack overflow infinite loops if there were loops in the
Pages dictionary. There is a general weakness in the code in that any
part of the code that traverses the Pages structure would be prone to
this and would have to implement its own loop detection. A more robust
fix may provide some general method for handling the Pages structure,
but it's probably not worth doing.
Note: addition of *Internal2 private functions was done rather than
changing signatures of existing methods to avoid breaking
compatibility.
Add new RandomDataProvider object and implement existing random number
generation in terms of that. This enables end users to supply their
own random data providers.
4.2.0 was binary incompatible in spite of there being no deletions or
changes to any public methods. As such, we have to bump the ABI and
are fixing some API breakage while we're at it.
Previous 4.3.0 target is now 5.1.0.
Rework QPDFWriter to always track old object IDs and QPDFObjGen
instead of int, thus not discarding the generation number. Switch to
QPDF::getCompressibleObjGen() to properly handle the case of an old
object eligible for compression that has a generation of other than
zero.
Explicitly state how QPDF handles empty passwords when writing files.
Apparently some libraries treat the empty string as the owner password
as an instruction to generate a random password.
Remove const qualifier from getTypeCode and get getTypeName methods of
QPDFObjectHandle, make them work properly for indirect objects, and
exercise them much better in the test suite.
Change object type Keyword to Operator, and place the order of the
object types in object_type_e in the same order as they are mentioned
in the PDF specification.
Note that this change only breaks backward compatibility with code
that has not yet been released.
Original code was written before we could shallow copy objects, so all
the filtering was done by suppressing the output of certain keys and
replacing them with other keys. Now we can simplify the code greatly
by modifying shallow copies of dictionaries in place.
Read and write support is implemented for /V=5 with /R=5 as well as
/R=6. /R=5 is the deprecated encryption method used by Acrobat IX.
/R=6 is the encryption method used by PDF 2.0 from ISO 32000-2.
