qpdf/ChangeLog

2018-06-22  Jay Berkenbilt  <ejb@ql.org>

	* Add new option --preserved-unreferenced-resources, which
	suppresses removal of unreferenced objects from page resource
	dictionaries during page splitting operations.

2018-06-21  Jay Berkenbilt  <ejb@ql.org>

	* Add method QPDFPageObjectHelper::removeUnreferencedResources and
	also QPDFPageDocumentHelper::removeUnreferencedResources that
	calls the former on every page. This method removes any XObject or
	Font references from the page's resource dictionary if they are
	not referenced anywhere in any of the content streams. This
	significantly reduces the size of split files whose pages
	internally share resource dictionaries. Fixes #203.

	* The --rotate option to qpdf no longer requires an explicit page
	range. You can now rotate all pages of a document with
	qpdf --rotate=angle in.pdf out.pdf. Fixes #211.

	* Create examples/pdf-set-form-values.cc to illustrate use of
	interactive form helpers.

	* Added methods QPDFAcroFormDocumentHelper::setNeedAppearances and
	added methods to QPDFFormFieldObjectHelper to set a field's value,
	optionally updating the document to indicate that appearance
	streams need to be regenerated.

	* Added QPDFObject::newUnicodeString and QPDFObject::unparseBinary
	to allow for more convenient creation of strings that are
	explicitly encoded in UTF-16 BE. This is useful for creating
	Unicode strings that appear outside of content streams, such as in
	page labels, outlines, form field values, etc.

2018-06-20  Jay Berkenbilt  <ejb@ql.org>

	* Added new classes QPDFAcroFormDocumentHelper,
	QPDFFormFieldObjectHelper, and QPDFAnnotationObjectHelper to
	assist with working with interactive forms in PDF files. At
	present, API methods for reading forms, form fields, and widget
	annotations have been added. It is likely that some additional
	methods for modifying forms will be added in the future. Note that
	qpdf remains a library whose function is primarily focused around
	document structure and metadata rather than content. As such, it
	is not expected that qpdf will have higher level APIs for
	generating form contents, but qpdf will hopefully gain the
	capability to deal with the bookkeeping aspects of wiring up all
	the objects, which could make it a useful library for other
	software that works with PDF interactive forms. PDF forms are
	complex, and the terminology around them is confusing. Please see
	comments at the top of QPDFAcroFormDocumentHelper.hh for
	additional discussion.

	* Added new classes QPDFPageDocumentHelper and QPDFPageObjectHelper
	for page-level API functions. These classes introduce a new API
	pattern of document helpers and object helpers in qpdf. The helper
	classes provide a higher level API for working with certain types
	of structural features of PDF while still staying true to qpdf's
	philosophy of not isolating the user from the underlying
	structure. Please see the chapter in the documentation entitled
	"Design and Library Notes" for additional discussion. The examples
	have also been updated to use QPDFPageDocumentHelper and
	QPDFPageObjectHelper when performing page-level operations.

2018-06-19  Jay Berkenbilt  <ejb@ql.org>

	* New QPDFObject::Rectangle class will convert to and from arrays
	of four numerical values. Rectangles are used in various places
	within the PDF file format and are called out as a specific data
	type in the PDF specification.

2018-05-12  Jay Berkenbilt  <ejb@ql.org>

	* In newline before endstream mode, an extra newline was not
	inserted prior to the endstream that ends object streams.
	Fixes #205.

2018-04-15  Jay Berkenbilt  <ejb@ql.org>

	* Arbitrarily limit the depth of data structures represented by
	direct object. This is CVE-2018-9918. Fixes #202.

2018-03-06  Jay Berkenbilt  <ejb@ql.org>

	* 8.0.2: release

	* Properly handle pages with no contents. Fixes #194.

2018-03-05  Jay Berkenbilt  <ejb@ql.org>

	* Improve handling of loops while following cross reference
	tables. Fixes #192.

2018-03-04  Jay Berkenbilt  <ejb@ql.org>

	* 8.0.1: release

	* On the command line when specifying page ranges, support
	preceding a page number by "r" to indicate that it should be
	counted from the end. For example, the range r3-r1 would indicate
	the last three pages of a document.

2018-03-03  Jay Berkenbilt  <ejb@ql.org>

	* Ignore zlib data check errors while uncompressing streams. This
	is consistent with behaviors of other readers and enables handling
	of some incorrectly written zlib strems. Fixes #191.

2018-02-25  Jay Berkenbilt  <ejb@ql.org>

	* 8.0.0: release

2018-02-17  Jay Berkenbilt  <ejb@ql.org>

	* Fix QPDFObjectHandle::getUTF8Val() to properly handle strings
	that are encoded with PDF Doc Encoding. Fixes #179.

	* Add qpdf_check_pdf to the "C" API. This method just attempts to
	read the entire file and produce no output, making possible to
	assess whether the file has any errors that qpdf can detect.

	* Major enhancements to handling of type errors within the qpdf
	library. This fix is intended to eliminate those annoying cases
	where qpdf would exit with a message like "operation for
	dictionary object attemped on object of wrong type" without
	providing any context. Now qpdf keeps enough context to be able to
	issue a proper warning and to handle such conditions in a sensible
	way. This should greatly increase the number of bad files that
	qpdf can recover, and it should make it much easier to figure out
	what's broken when a file contains errors.

	* Error message fix: replace "file position" with "offset" in
	error messages that report lexical or parsing errors. Sometimes
	it's an offset in an object stream or a content stream rather than
	a file position, so this makes the error message less confusing in
	those cases. It still requires some knowledge to find the exact
	position of the error, since when it's not a file offset, it's
	probably an offset into a stream after uncompressing it.

	* Error message fix: correct some cases in which the object that
	contained a lexical error was omitted from the error message.

	* Error message fix: improve file name in the error message when
	there is a parser error inside an object stream.

2018-02-11  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::filterPageContents method to provide a
	different interface for applying token filters to page contents
	without modifying the ultimate output.

2018-02-04  Jay Berkenbilt  <ejb@ql.org>

        * Changes listed on today's date are numerous and reflect
	significant enhancements to qpdf's lexical layer. While many
	nuances are discussed and a handful of small bugs were fixed, it
	should be emphasized that none of these issues have any impact on
	any output or behavior of qpdf under "normal" operation. There are
	some changes that have an effect on content stream normalization
	as with qdf mode or on code that interacts with PDF files
	lexically using QPDFTokenizer. There are no incompatible changes
	for normal operation. There are a few changes that will affect the
	exact error messages issued on certain bad files, and there is a
	small non-compatible enhancement regarding the behavior of
	manually constructed QPDFTokenizer::Token objects. Users of the
	qpdf command line tool will see no changes other than the addition
	of a new command-line flag and possibly some improved error
	messages.

	* Significant lexer (tokenizer) enhancements. These are changes to
	the QPDFTokenizer class. These changes are of concern only to
	people who are operating with PDF files at the lexical layer using
	qpdf. They have little or no impact on most high-level interfaces
	or the command-line tool.

	New token types tt_space and tt_comment to recognize whitespace
	and comments. this makes it possible to tokenize a PDF file or
	stream and preserve everything about it.

	For backward compatibility, space and comment tokens are not
	returned by the tokenizer unless QPDFTokenizer.includeIgnorable()
	is called.

	Better handling of null bytes. These are now included in space
	tokens rather than being their own "tt_word" tokens. This should
	have no impact on any correct PDF file and has no impact on
	output, but it may change offsets in some error messages when
	trying to parse contents of bad files. Under default operation,
	qpdf does not attempt to parse content streams, so this change is
	mostly invisible.

	Bug fix to handling of bad tokens at ends of streams. Now, when
	allowEOF() has been called, these are treated as bad tokens
	(tt_bad or an exception, depending on invocation), and a
	separate tt_eof token is returned. Before the bad token
	contents were returned as the value of a tt_eof token. tt_eof
	tokens are always empty now.

	Fix a bug that would, on rare occasions, report the offset in an
	error message in the wrong space because of spaces or comments
	adjacent to a bad token.

	Clarify in comments exactly where the input source is positioned
	surrounding calls to readToken and getToken.

	* Add a new token type for inline images. This token type is only
	returned by QPDFTokenizer immediately following a call to
	expectInlineImage(). This change includes internal refactoring of
	a handful of places that all separately handled inline images, The
	logic of detecting inline images in content streams is now handled
	in one place in the code. Also we are more flexible about what
	characters may surround the EI operator that marks the end of an
	inline image.

	* New method QPDFObjectHandle::parsePageContents() to improve upon
	QPDFObjectHandle::parseContentStream(). The parseContentStream
	method used to operate on a single content stream, but was fixed
	to properly handle pages with contents split across multiple
	streams in an earlier release. The new method parsePageContents()
	can be called on the page object rather than the value of the
	page dictionary's /Contents key. This removes a few lines of
	boiler-plate code from any code that uses parseContentStream, and
	it also enables creation of more helpful error messages if
	problems are encountered as the error messages can include
	information about which page the streams come from.

	* Update content stream parsing example
	(examples/pdf-parse-content.cc) to use new
	QPDFObjectHandle::parsePageContents() method in favor of the older
	QPDFObjectHandle::parseContentStream() method.

	* Bug fix: change where the trailing newline is added to a stream
	in QDF mode when content normalization is enabled (the default for
	QDF mode). Before, the content normalizer ensured that the output
	ended with a trailing newline, but this had the undesired side
	effect of including the newline in the stream data for purposes of
	length computation. QPDFWriter already appends a newline without
	counting in length for better readability. Ordinarily this makes
	no difference, but in the rare case of a page's contents being
	split in the middle of a token, the old behavior could cause the
	extra newline to be interprted as part of the token. This bug
	could only be triggered in qdf mode, which is a mode intended for
	manual inspection of PDF files' contents, so it is very unlikely
	to have caused any actual problems for people using qpdf for
	production use. Even if it did, it would be very unusual for a PDF
	file to actually be adversely affected by this issue.

	* Add support for coalescing a page's contents into a single
	stream if they are represented as an array of streams. This can be
	performed from the command line using the --coalesce-contents
	option. Coalescing content streams can simplify things for
	software that wants to operate on a page's content streams without
	having to handle weird edge cases like content streams split in
	the middle of tokens. Note that
	QPDFObjectHandle::parsePageContents and
	QPDFObjectHandle::parseContentStream already handled split content
	streams. This is mainly to set the stage for new methods of
	operating on page contents. The new method
	QPDFObjectHandle::pipeContentStreams will pipe all of a page's
	content streams though a single pipeline. The new method
	QPDFObjectHandle.coalesceContentStreams, when called on a page
	object, will do nothing if the page's contents are a single
	stream, but if they are an array of streams, it will replace the
	page's contents with a single stream whose contents are the
	concatenation of the original streams.

	* A few library routines throw exceptions if called on non-page
	objects. These constraints have been relaxed somewhat to make qpdf
	more tolerant of files whose page dictionaries are not properly
	marked as such. Mostly exceptions about page operations being
	called on non page objects will only be thrown in cases where the
	operation had no chance of succeeding anyway. This change has no
	impact on any default mode operations, but it could allow
	applications that use page-level APIs in QPDFObjectHandle to be
	more tolerant of certain types of damaged files.

	* Add QPDFObjectHandle::TokenFilter class and methods to use it to
	perform lexical filtering on content streams. You can call
	QPDFObjectHandle::addTokenFilter on stream object, or you can call
	the higher level QPDFObjectHandle::addContentTokenFilter on a page
	object to cause the stream's contents to passed through a token
	filter while being retrieved by QPDFWriter or any other consumer.
	For details on using TokenFilter, please see comments in
	QPDFObjectHandle.hh.

	* Enhance the string, type QPDFTokenizer::Token constructor to
	initialize a raw value in addition to a value. Tokens have a
	value, which is a canonical representation, and a raw value. For
	all tokens except strings and names, the raw value and the value
	are the same. For strings, the value excludes the outer delimiters
	and has non-printing characters normalized. For names, the value
	resolves non-printing characters. In order to better facilitate
	token filters that mostly preserve contents and to enable
	developers to be mostly unconcerned about the nuances of token
	values and raw values, creating string and name tokens now
	properly handles this subtlety of values and raw values. When
	constructing string tokens, take care to avoid passing in the
	outer delimiters. This has always been the case, but it is now
	clarified in comments in QPDFObjectHandle.hh::TokenFilter. This
	has no impact on any existing code unless there's some code
	somewhere that was relying on Token::getRawValue() returning an
	empty string for a manually constructed token. The token class's
	operator== method still only looks at type and value, not raw
	value. For example, string tokens for <41> and (A) would still be
	equal because both are representations of the string "A".

	* Add QPDFObjectHandle::isDataModified method. This method just
	returns true if addTokenFilter has been called on the stream. It
	enables a caller to determine whether it is safe to optimize away
	piping of stream data in cases where the input and output are
	expected to be the same. QPDFWriter uses this internally to skip
	the optimization of not re-compressing already compressed streams
	if addTokenFilter has been called. Most developers will not have
	to worry about this as it is used internally in the library in the
	places that need it. If you are manually retrieving stream data
	with QPDFObjectHandle::getStreamData or
	QPDFObjectHandle::pipeStreamData, you don't need to worry about
	this at all.

	* Provide heavily annoated examples/pdf-filter-tokens.cc example
	that illustrates use of some simple token filters.

	* When normalizing content streams, as in qdf mode, issue warning
	about bad tokens. Content streams are only normalized when this is
	explicitly requested, so this has no impact on normal operation.
	However, in qdf mode, if qpdf detects a bad token, it means that
	either there's a bug in qpdf's lexer, that the file is damaged, or
	that the page's contents are split in a weird way. In any of those
	cases, qpdf could potentially damage the stream's contents by
	replacing carrige returns with newlines or otherwise messing with
	spaces. The mostly likely case of this would be an inline image's
	compressed data being divided across two streams and having the
	compressed data in the second stream contain a carriage return as
	part of its binary data. If you are using qdf mode just to look at
	PDF files in text editors, this usually doesn't matter. In cases
	of contents split across multiple streams, coalescing streams
	would eliminate the problem, so the warning mentions this. Prior
	to this enhancement, the chances of qdf mode writing incorrect
	data were already very low. This change should make it nearly
	impossible for qdf mode to unknowingly write invalid data.

2018-02-04  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFWriter::setLinearizationPass1Filename method and
	--linearize-pass1 command line option to allow specification of a
	file into which QPDFWriter will write its intermediate
	linearization pass 1 file. This is useful only for debugging qpdf.
	qpdf creates linearized files by computing the output in two
	passes. Ordinarily the first pass is discarded and not written
	anywhere. This option allows it to be inspected.

2018-02-04  Jay Berkenbilt  <ejb@ql.org>

	* 7.1.1: release

	* Bug fix: properly linearize files whose /ID has a length of
	other than 16 bytes.

	* Rename some test files to avoid files with three dots in their
	names. Fixes #173.

	* Fix various build and compilation issues on some platforms and
	compilers. Fixes #176, #172, #177

	* Fix a few typos and clarify a few comments in header files.

2018-01-14  Jay Berkenbilt  <ejb@ql.org>

	* 7.1.0: release

	* Allow raw encryption key to be specified in libary and command
	line with the QPDF::setPasswordIsHexKey method and
	--password-is-hex-key option. Allow encryption key to be displayed
	with --show-encryption-key option. Thanks to Didier Stevens
	<didier.stevens@gmail.com> for the idea and contribution of one
	implementation of this idea. See his blog post at
	https://blog.didierstevens.com/2017/12/28/cracking-encrypted-pdfs-part-3/
	for a discussion of using this for cracking encrypted PDFs. I hope
	that a future release of qpdf will include some additional
	recovery options that may also make use of this capability.

2018-01-13  Jay Berkenbilt  <ejb@ql.org>

	* Fix lexical error: the PDF specification allows floating point
	numbers to end with ".". Fixes #165.

	* Fix link order in the build to avoid conflicts when building
	from source while an older version of qpdf is installed. Fixes #158.

	* Add support for TIFF predictor for LZW and Flate streams. Now
	all predictor functions are supported. Fixes #171.

2017-12-25  Jay Berkenbilt  <ejb@ql.org>

	* Clarify documentation around options that control parsing but
	not output creation. Two options: --suppress-recovery and
	--ignore-xref-streams, were documented in the "Advanced
	Transformation Options" section of the manual and --help output
	even though they are not related to output. These are now
	described in a separate section called "Advanced Parsing Options."

	* Implement remaining PNG filters for decode. Prior versions could
	decode only the "up" filter. Now all PNG filters (sub, up,
	average, Paeth, optimal) are supported for decoding. Thanks to
	Tobias Hoffmann for providing a test PDF file that has images with
	all PNG filters along with different numbers of bits per sample
	and samples per pixel, and thanks to Casey Rojas for providing
	implementations of the remaining PNG filters.

	The implementation of the remaining PNG filters changed the
	interface to the private Pl_PNGFilter class, but this class's
	header file is not in the installation, and there is no public
	interface to the class. Within the library, the class is never
	allocated on the stack; it is only ever dynamically allocated. As
	such, this does not actually break binary compatibility of the
	library.

2017-09-15  Jay Berkenbilt  <ejb@ql.org>

	* 7.0.0: release

2017-09-12  Jay Berkenbilt  <ejb@ql.org>

	* Relicense qpdf under version 2.0 of the Apache License rather
	than version 2.0 of the Artistic License. Both are fine, but the
	Apache License is in more widespread use, and I like it a little
	better than Artistic-2.0. It is my intention that there be no
	change in what you can or can't do with qpdf. Versions of qpdf
	prior to version 7 were released under the terms of version 2.0 of
	the Artistic License. At your option, you may continue to consider
	qpdf to be licensed under those terms. Please see the manual for
	additional information.

	* Improve the error message that is issued when QPDFWriter
	encounters a stream that can't be decoded. In particular, mention
	that the stream will be copied without filtering to avoid data
	loss.

	* Add new methods to the C API to correspond to new additions to
	QPDFWriter:
	- qpdf_set_compress_streams
	- qpdf_set_decode_level
	- qpdf_set_preserve_unreferenced_objects
	- qpdf_set_newline_before_endstream

2017-08-25  Jay Berkenbilt  <ejb@ql.org>

	* Re-implement parser iteratively to avoid stack overflow on very
	deeply nested arrays and dictionaries. Fixes #146.

	* Detect infinite loop while finding additional xref tables. Fixes
	#149.

2017-08-22  Jay Berkenbilt  <ejb@ql.org>

	* 7.0.b1: release

	* Convert all README files to markdown. Names changed as follows:
	  - README --> README.md
	  - README.hardening --> README-hardening.md
	  - README.maintainer --> README-maintainer.md
	  - README-what-to-download.txt --> README-what-to-download.md
	  - README-windows.txt --> README-windows.md
	  The file README-windows-install.txt remains a text file.

2017-08-21  Jay Berkenbilt  <ejb@ql.org>

	* Add support for writing PCLm files. Most of the work was done by
	Sahil Arora <sahilarora.535@gmail.com> as part of a Google Summer
	of Code project in 2017. PCLm support is useful only for clients
	that specifically know how to create PCLm files. Support in qpdf
	is just for ensuring that objects are written in the correct order
	and for including some additional material in the output that is
	required by the PCLm standard.

2017-08-19  Jay Berkenbilt  <ejb@ql.org>

	* Remove --precheck-streams. This is enabled by default now
	without any efficiency cost. This feature was never released.

	* Update pdf-create example to illustrate use of additional image
	compression filters.

	* Add support for /RunLengthDecode and /DCTDecode:
	  - New pipeline types Pl_RunLength and Pl_DCT
	  - New command-line flags --compress-streams and --decode-level
	    to replace/enhance --stream-data
	  - New QPDFWriter::setCompressStreams and
 	    QPDFWriter::setDecodeLevel methods
	  Please see documentation, header files, and help messages for
	  details on these new features.

2017-08-12  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::rotatePage to apply rotation to a page
	object. Add --rotate option to qpdf to specify page rotation from
	the command line.

	* Provide --verbose option that causes qpdf to print an indication
	of what files it is writing.

	* Change --single-pages to --split-pages and make it take an
	optional argument specifying the number of pages per file.

2017-08-11  Jay Berkenbilt  <ejb@ql.org>

	* Fix --newline-before-endstream to always add a newline before
	endstream even if the last character was already a newline. This
	is actually what's required by PDF/A. Fixes #133.

	* Handle encrypted files whose encryption parameters are too
	short. Fixes #96.

2017-08-10  Jay Berkenbilt  <ejb@ql.org>

	* Remove dependency on libpcre.

	* Be more forgiving of certain types of errors in the xref table
	that don't interfere with interpreting the table.

	* Remove unused "tracing" parameter from PointerHolder's
	(T*, bool) constructor. This change breaks source code
	compatibility, but since this argument to PointerHolder has not
	used for a long time and the presence of a boolean parameter in
	the primary constructor makes it too easy to use that by mistake
	when trying to use PointerHolder for arrays, it seems like it's
	finally time to take it out. If you have a compile error because
	of this change, please check to see whether you intended to use
	the (bool, T*) version of the constructor instead. If not, just
	remove the second parameter.

2017-08-09  Jay Berkenbilt  <ejb@ql.org>

	* When recovering stream length, find endobj without endstream as
	well as just looking for endstream. Be a little more lax about
	where we allow it to be found.

2017-08-05  Jay Berkenbilt  <ejb@ql.org>

	* Add --single-pages option to cause output to be written to a
	separate file for each page rather than one big file.

	* Process --pages options earlier so that certain inspection
	options, like --show-pages, can show the state after the merging
	operations.

2017-08-02  Jay Berkenbilt  <ejb@ql.org>

	* Fix off-by-one error in parsing pages options. Fixes #129.

2017-07-29  Jay Berkenbilt  <ejb@ql.org>

	* Support @filename and @- in the qpdf command-line tool to read
	command-line arguments, one per line, from the named file. @-
	reads from standard input. Fixes #16.

	* Detect when input file and output file are the same and exit to
	avoid overwriting and losing input file. Fixes #29.

	* When passing multiple inspection arguments, run --check first,
	and defer exit until after all the checks have been run. This
	makes it possible to force operations such as --show-xref to be
	delayed until after recovery attempts have been made. For example,
	if you have a file with a syntactically valid xref table that has
	some offsets that are incorrect, running qpdf --check --show-xref
	on that file will first recover the xref and the dump the
	recovered xref, while just running qpdf --show-xref will show the
	xref table as present in the file. Fixes #42.

	* When recovering stream length, indicate the recovered length.
	Fixes #44.

	* Add --newline-before-endstream command-line option and
	setNewlineBeforeEndstream method to QPDFWriter. This forces qpdf
	to always add a newline before the endstream keyword. It is a
	necessary but not sufficient condition for PDF/A compliance. Fixes
	#103.

	* Handle zlib data errors when decoding streams. Fixes #106.

	* Improve handling of files where the "stream" keyword is not
	followed by proper line terminators. Fixes #104.

	* Fix content stream parsing to handle cases of structures within
	the stream split across stream boundaries. Fixes #73.

2017-07-28  Jay Berkenbilt  <ejb@ql.org>

	* Add --preserve-unreferenced command-line option and
	setPreserveUnreferencedObjects method to QPDFWriter. This option
	causes QPDFWriter to write all objects from the input file to the
	output file regardless of whether the objects are referenced.
	Objects are written to the output file in numerical order from the
	input file. This option has no effect for linearized files.

2017-07-27  Jay Berkenbilt  <ejb@ql.org>

	* Add --precheck-streams command-line option and setStreamPrecheck
	method to QPDFWriter to tell QPDFWriter to attempt decoding a
	stream fully before deciding whether to filter it or not.

	* Recover gracefully from streams that aren't filterable because
	the filter parameters are invalid in the stream dictionary or the
	dictionary itself is invalid.

	* Significantly improve recoverability from invalid qpdf objects.
	Most conditions in basic object parsing that used to cause qpdf to
	exit are now warnings. There are still many more opportunities for
	improvements of this sort beyond just object parsing.

2017-07-26  Jay Berkenbilt  <ejb@ql.org>

	* Fixes to infinite loops below also fix problems reported in
	other issues and cover CVE-2017-11624, CVE-2017-11625,
	CVE-2017-11626, and CVE-2017-11627.

	* Don't attempt to interpret syntactic keywords (like R and
	endobj) found while parsing content streams.

	* Detect infinite loops while resolving objects. This could happen
	if something inside an object that had to be resolved during
	parsing, such as a stream length, recursively referenced the
	object being resolved.

	* CVE-2017-9208: Handle references to and appearance of object 0
	as a special case. Object 0 is not allowed, and qpdf was using it
	internally to represent direct objects.

	* CVE-2017-9209: Fix infinite loop caused by attempting to
	reconstruct the xref table while already in the process of
	reconstructing the xref table.

	* CVE-2017-9210: Fix infinite loop caused by attempting to unparse
	an object for inclusion in the text of an exception.

2015-11-10  Jay Berkenbilt  <ejb@ql.org>

	* 6.0.0: release

	* No changes from 5.2.0. The 5.2.0 release broke binary
	compatibility and was withdrawn.

2015-10-31  Jay Berkenbilt  <ejb@ql.org>

	* 5.2.0: release

	* libqpdf/QPDF.cc (read_xrefTable): Be tolerant of some malformed
	xref tables that don't have the required trailing space after each
	line.

2015-10-29  Jay Berkenbilt  <ejb@ql.org>

	* Implement QPDFWriter::setDeterministicID and --deterministic-id
	commandline-flag to qpdf to request generation of a deterministic
	/ID for non-encrypted files.

2015-05-24  Jay Berkenbilt  <ejb@ql.org>

	* 5.1.3: release

	* Bug fix: fix-qdf was not handling object streams with more than
	255 objects in them.

	* Handle Microsoft crypt provider initialization properly for case
	where no keys have been previously created, such as in a fresh
	Windows installation.

	* Include time.h in QUtil.hh for time_t

2015-02-21  Jay Berkenbilt  <ejb@ql.org>

	* Detect loops in Pages structure. Thanks to Gynvael Coldwind and
	Mateusz Jurczyk of the Google Security Team for providing a sample
	file with this problem.

	* Prevent buffer overrun when converting a password to an
	encryption key. Thanks to Gynvael Coldwind and Mateusz Jurczyk of
	the Google Security Team for providing a sample file with this
	problem.

	* Ensure that arguments to "R" when parsing the file are direct
	objects before trying to resolve them. This prevents specially
	crafted files from causing qpdf to crash with a stack overflow.
	Thanks to Gynvael Coldwind and Mateusz Jurczyk of the Google
	Security Team for providing a sample file with this problem.

2014-12-01  Jay Berkenbilt  <ejb@ql.org>

	* Some broken PDF files lack the required /Type key for /Page and
	/Pages nodes in the page dictionary. QPDF now uses other methods
	to figure out what kind of node it is looking at so that it can
	handle those files. Original reported at
	https://bugs.launchpad.net/ubuntu/+source/qpdf/+bug/1397413

2014-11-14  Jay Berkenbilt  <ejb@ql.org>

	* Bug fix: QPDFObjectHandle::getPageContents() no longer throws an
	exception when called on a page that has no /Contents key in its
	dictionary. This is allowed by the spec, and some software
	packages generate files like this for pages that are blank in the
	original.

2014-06-07  Jay Berkenbilt  <ejb@ql.org>

	* 5.1.2: release

	* MS Visual C++ build: explicitly target Windows 5.0.1 (XP)

	* New example program: pdf-split-pages: efficiently split PDF
	files into individual pages.

	* Bug fix: don't fail on files that contain streams where /Filter
	or /DecodeParms references a stream. Before, qpdf would try to
	convert these to direct objects, which would fail because of the
	stream.

2014-02-22  Jay Berkenbilt  <ejb@ql.org>

	* Bug fix: if the last object in the first part of a linearized
	file had an offset that was below 65536 by less than the size of
	the hint stream, the xref stream was invalid and the resulting file
	is not usable.  This is now fixed.

2014-01-14  Jay Berkenbilt  <ejb@ql.org>

	* 5.1.1: release

2013-12-26  Jay Berkenbilt  <ejb@ql.org>

	* Bug fix: when copying foreign objects (which occurs during page
	splitting among other cases), avoid traversing the same object
	more than once if it appears more than once in the same direct
	object.  This bug is performance-only and does not affect the
	actual output.

2013-12-17  Jay Berkenbilt  <ejb@ql.org>

	* 5.1.0: release

2013-12-16  Jay Berkenbilt  <ejb@ql.org>

	* Document and make explicit that passing null to
	QUtil::setRandomDataProvider() resets the random data provider.

	* Provide QUtil::getRandomDataProvider().

2013-12-14  Jay Berkenbilt  <ejb@ql.org>

	* Allow anyspace rather than just newline to follow xref header.
	This allows qpdf to read a wider range of damaged files.

2013-11-30  Jay Berkenbilt  <ejb@ql.org>

	* Allow user-supplied random data provider to be used in place of
	OS-provided or insecure random number generation.  See
	documentation for 5.1.0 for details.

	* Add configure option --enable-os-secure-random (enabled by
	default).  Pass --disable-os-secure-random or define
	SKIP_OS_SECURE_RANDOM to avoid attempts to use the operating
	system-provided secure random number generation.  This can be
	especially useful on Windows if you wish to avoid any dependency
	on Microsoft's cryptography system.

2013-11-29  Jay Berkenbilt  <ejb@ql.org>

	* If NO_GET_ENVIRONMENT is #defined, for Windows only,
	QUtil::get_env will always return false.  This was added to
	support a user who needs to avoid calling GetEnvironmentVariable
	from the Windows API.  QUtil::get_env is not used for any
	functionality in qpdf and exists only to support the test suite
	including test coverage support with QTC (part of qtest).

	* Add /FS to msvc builds to allow parallel builds to work with
	Visual C++ 2013.

	* Add missing #include <algorithm> in some files that use std::min
	and std::max.

2013-11-21  Jay Berkenbilt  <ejb@ql.org>

	* Change image comparison tests, which are disabled by default, to
	use tiff files with 8 bits per sample rather than 4.  This works
	around a bug in tiffcmp but also increases time and disk space for
	image comparison tests.

2013-10-28  Jay Berkenbilt  <ejb@ql.org>

	* Fix MacOS compilation errors by adding a missing #include
	<string> in a header file.

2013-10-18  Jay Berkenbilt  <ejb@ql.org>

	* 5.0.1: release

	* Warn when -accessibility=n is specified with a modern encryption
	format (R > 3).  Also, accept this flag (and ignore with warning)
	with 256-bit encryption.  qpdf has always ignored the
	accessibility setting with R > 3, but it previously did so
	silently.

2013-10-05  Jay Berkenbilt  <ejb@ql.org>

	* Replace operator[] in std::string and std::vector with "at" in
	order to get bounds checking.  This reduces the chances that
	incorrect code will result in data exposure or buffer overruns.
	See README.hardening for additional notes.

	* Use cryptographically secure random number generation when
	available.  See additional notes in README.

	* Replace some assert() calls with std::logic_error exceptions.
	Ideally there shouldn't be assert() calls outside of testing.
	This change may make a few more potential code errors in handling
	invalid data recoverable.

	* Security fix: In places where std::vector<T>(size_t) was used,
	either validate that the size parameter is sane or refactor code
	to avoid the need to pre-allocate the vector.  This reduces the
	likelihood of allocating a lot of memory in response to invalid
	data in linearization hint streams.

	* Security fix: sanitize /W array in cross reference stream to
	avoid a potential integer overflow in a multiplication.  It is
	unlikely that any exploits were possible from this bug as
	additional checks were also performed.

	* Security fix: avoid buffer overrun that could be caused by bogus
	data in linearization hint streams.  The incorrect code could only
	be triggered when checking linearization data, which must be
	invoked explicitly.  qpdf does not check linearization data when
	reading or writing linearized files, but the qpdf --check command
	does check linearization data.

	* Security fix: properly handle empty strings in
	QPDF_Name::normalizeName.  The empty string is not a valid name
	and would never be parsed as a name, so there were no known
	conditions where this method could be called with an empty string.

	* Security fix: perform additional argument sanity checks when
	reading bit streams.

	* Security fix: in QUtil::toUTF8, change bounds checking to avoid
	having a pointer point temporarily outside the bounds of an
	array.  Some compiler optimizations could have made the original
	code unsafe.

2013-07-10  Jay Berkenbilt  <ejb@ql.org>

	* 5.0.0: release

	* 4.2.0 turned out to be binary incompatible on some platforms
	even though there were no changes to the public API.  Therefore
	the 4.2.0 release has been withdrawn, and is being replaced with a
	5.0.0 release that acknowledges the ABI change and also removes
	some problematic methods from the public API.

	* Remove methods from public API that were only intended to be
	used by QPDFWriter and really didn't make sense to call from
	anywhere else as they required internal knowledge that only
	QPDFWriter had:
	   - QPDF::getLinearizedParts
	   - QPDF::generateHintStream
	   - QPDF::getObjectStreamData
	   - QPDF::getCompressibleObjGens
	   - QPDF::getCompressibleObjects

2013-07-07  Jay Berkenbilt  <ejb@ql.org>

	* 4.2.0: release [withdrawn]

	* Ignore error case of a stream's decode parameters having invalid
	length when there are no stream filters.

	* qpdf: add --show-npages command-line option, which causes the
	number of pages in the input file to be printed on a line by
	itself.

	* qpdf: allow omission of range in --pages.  If range is omitted
	such that an argument that is supposed to be a range is an invalid
	range and a valid file name, the range of 1-z is assumed.  This
	makes it possible to merge a bunch of files with something like
	qpdf --empty out.pdf --pages *.pdf --

2013-06-15  Jay Berkenbilt  <ejb@ql.org>

	* Handle some additional broken files with missing /ID in trailer
	for encrypted files and with space rather than newline after xref.

2013-06-14  Jay Berkenbilt  <ejb@ql.org>

	* Detect and correct /Outlines dictionary being a direct object
	when linearizing files.  This is not allowed by the spec but has
	been seen in the wild.  Prior to this change, such a file would
	cause an internal error in the linearization code, which assumed
	/Outlines was indirect.

	* Add /Length key to crypt filter dictionary for encrypted files.
	This key is optional, but some version of MacOS reportedly fail to
	open encrypted PDF files without this key.

	* Bug fix: properly handle object stream generation when the
	original file has some compressible objects with generation != 0.

	* Add QPDF::getCompressibleObjGens() and deprecate
	QPDF::getCompressibleObjects(), which had a flaw in its logic.

	* Add new QPDFObjectHandle::getObjGen() method and indiciate in
	comments that its use is favored over getObjectID() and
	getGeneration() for most cases.

	* Add new QPDFObjGen object to represent an object ID/generation
	pair.

2013-04-14  Jay Berkenbilt  <ejb@ql.org>

	* 4.1.0: release

2013-03-25  Jay Berkenbilt  <ejb@ql.org>

	* manual/qpdf-manual.xml: Document the casting policy that is
	followed in qpdf's implementation.

2013-03-11  Jay Berkenbilt  <ejb@ql.org>

	* When creating Windows binary distributions, make sure to only
	copy DLLs of the correct type.  The ensures that the 32-bit
	distributions contain 32-bit DLLs and the 64-bit distributions
	contain 64-bit DLLs.

2013-03-07  Jay Berkenbilt  <ejb@ql.org>

	* Use ./install-sh (already present) instead of "install -c" to
	install executables to fix portability problems against different
	UNIX variants.

2013-03-03  Jay Berkenbilt  <ejb@ql.org>

	* Add protected terminateParsing method to
	QPDFObjectHandle::ParserCallbacks that implementor can call to
	terminate parsing of a content stream.

2013-02-28  Jay Berkenbilt  <ejb@ql.org>

	* Favor fopen_s and strerror_s on MSVC to avoid CRT security
	warnings.  This is useful for people who may want to use qpdf in
	an application that is Windows 8 certified.

	* New method QUtil::safe_fopen to wrap calls to fopen.  This is
	less cumbersome than calling QUtil::fopen_wrapper.

	* Remove all calls to sprintf

	* New method QUtil::int_to_string_base to convert to octal or
	hexademical (or decimal) strings without using sprintf

2013-02-26  Jay Berkenbilt  <ejb@ql.org>

	* Rewrite QUtil::int_to_string and QUtil::double_to_string to
	remove internal length limits but to remain backward compatible
	with the old versions for valid inputs.

2013-02-23  Jay Berkenbilt  <ejb@ql.org>

	* Bug fix: properly handle overridden compressed objects.  When
	caching objects from an object stream, only cache objects that,
	based on the xref table, would actually be resolved into this
	stream.  Prior to this fix, if an object stream A contained an
	object B that was overridden by an appended section of the file,
	qpdf would cache the old value of B if any non-overridden member
	of A was accessed before B.  This commit fixes that bug.

2013-01-31  Jay Berkenbilt  <ejb@ql.org>

	* Do not remove libtool's .la file during the make install step.
	Note to packagers: if your distribution wants to you remove the
	.la file, you will have to do that yourself now.

2013-01-25  Jay Berkenbilt  <ejb@ql.org>

	* New method QUtil::hex_encode to encode binary data as a
	hexadecimal string

	* qpdf --check was exiting with status 0 in some rare cases even
	when errors were found.  It now always exits with one of the
	document error codes (0 for success, 2 for errors, 3 or warnings).

2013-01-24  Jay Berkenbilt  <ejb@ql.org>

	* Make --enable-werror work for MSVC, and generally handle warning
	options better for that compiler.  Warning flags for that compiler
	were previous hard-coded into the build with /WX enabled
	unconditionally.

	* Split warning flags into WFLAGS in autoconf.mk to make them
	easier to override.  Before they were repeated in CFLAGS and
	CXXFLAGS and were commingled with other compiler flags.

	* qpdf --check now does syntactic checks all pages' content
	streams as well as checking overall document structure.  Semantic
	errors are still not checked, and there are no plans to add
	semantic checks.

2013-01-22  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::getTypeCode().  This method returns a
	unique integer (enumerated type) value corresponding to the object
	type of the QPDFObjectHandle.  It can be used as an alternative to
	the QPDFObjectHandle::is* methods for type testing, particularly
	where there is a desire to use a switch statement or optimize for
	performance when testing object types.

	* Add QPDFObjectHandle::getTypeName().  This method returns a
	string literal describing the object type.  It is useful for
	testing and debugging.

2013-01-20  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::parseContentStream, which parses the
	objects in a content stream and calls handlers in a callback
	class.  The example pdf-parse-content illustrates it use.

	* Add QPDF_Operator and QPDF_InlineImage types along with
	appropriate wrapper methods in QPDFObjectHandle.  These new object
	types are to facilitate content stream parsing.

2013-01-17  Jay Berkenbilt  <ejb@ql.org>

	* 4.0.1: release

	* Add clarifying comment in QPDF.hh for methods that return the
	user password to state that it is no longer possible with newer
	encryption formats to recover the user password knowing the owner
	password.

	* Fix detection of binary attachments in the test suite.  This
	resolves false test failures on some platforms.  No changes to the
	actual QPDF code were made.

2012-12-31  Jay Berkenbilt  <ejb@ql.org>

	* 4.0.0: release

	* Add new methods qpdf_get_pdf_extension_level,
	qpdf_set_r5_encryption_parameters,
	qpdf_set_r6_encryption_parameters,
	qpdf_set_minimum_pdf_version_and_extension, and
	qpdf_force_pdf_version_and_extension to support new functionality
	from the C API.

2012-12-30  Jay Berkenbilt  <ejb@ql.org>

	* Fix long-standing bug that could theoretically have resulted in
	possible misinterpretation of decode parameters in streams.  As
	far as I can tell, it is extremely unlikely that files with the
	characteristics that would have triggered the bug actually exist
	in cases that qpdf versions prior to 4.0.0 could have read.
	Unencrypted files with encrypted attachments would have triggered
	this bug, but qpdf versions prior to 4.0.0 already refused to open
	such files.

	* Fix long-standing bug in which a stream that used a crypt
	filter and was otherwise not filterable by qpdf would be decrypted
	properly but would retain the crypt filter indication in the
	file.  There are no known ways to create files like this, so it is
	unlikely that anyone ever hit this bug.

2012-12-29  Jay Berkenbilt  <ejb@ql.org>

	* Add read/write support for both the deprecated Acrobat IX
	encryption format and the Acrobat X/PDF 2.0 encryption format
	using 256-bit AES keys.  Using the Acrobat IX format (R=5) forces
	the version of the file to 1.7 with extension level 3.  Using the
	PDF 2.0 format (R=6) forces it to 1.7 extension level 8.

	* Add new method QPDF::getEncryptionKey to return the actual
	encryption key used for encryption of data in the file.  The key
	is returned as a std::string.

	* Non-compatible API change: change signature of
	QPDF::compute_data_key to take the R and V values from the
	encryption dictionary.  There is no reason for any application
	code to call this method since handling of encryption is done
	automatically by the qpdf libary.  It is used internally by
	QPDFWriter.

	* Support reading and decryption of files whose main text is not
	encrypted but whose attachments are.  More generally, support the
	case of files and streams encrypted differently with some
	limitations, described in the documentation.  This was not
	previously supported due to lack of test files, but I created test
	files using a trial version of Acrobat XI to fully implement this
	case.

	* Incorporate sha2 code from sphlib 3.0.  See README for
	licensing.  Create private pipeline class for computing hashes
	with sha256, sha384, and sha512.

	* Allow specification of initialization vector when using AES
	filtering.  This is required to compute the hash used in /R=6 (PDF
	2.0) encryption.

2012-12-28  Jay Berkenbilt  <ejb@ql.org>

	* Add random number generation functions to QUtil.

	* Fix old bug that could cause an infinite loop if user password
	recovery methods were called and a password contained the "("
	character (which happens to be the first byte of padding used by
	older PDF encryption formats).  This bug was noticed while reading
	code and would not happen under ordinary usage patterns even if
	the password contained that character.

2012-12-27  Jay Berkenbilt  <ejb@ql.org>

	* Add awareness of extension level to PDF Version methods for both
	reading and writing.  This includes adding method
	QPDF::getExtensionLevel and new versions of
	QPDFWriter::setMinimumPDFVersion and QPDFWriter::forcePDFVersion
	that support extension levels.  The qpdf command-line tool
	interprets version numbers of the form x.y.z as version x.y at
	extension level z.

	* Update AES classes to support use of 256-bit keys.

	* Non-compatible API change: Removed public method
	QPDF::flattenScalarReferences.  Instead, just flatten the scalar
	references we actually need to flatten.  Flattening scalar
	references was a wrong decision years ago and has occasionally
	caused other problems, among which were that it caused qpdf to
	visit otherwise unreferenced and possibly erroneous objects in the
	file when it didn't have to.  There's no reason that any
	non-internal code would have had to call this.

	* Non-compatible API change: Removed public method
	QPDF::decodeStreams which was previously used by qpdf --check but
	is no longer used.  The decodeStreams method could generate false
	positives since it would attempt to access all objects in the file
	including those that were not referenced.  There's no reason that
	any non-internal code would have had to call this.

	* Non-compatible API change: Removed public method
	QPDF::trimTrailerForWrite, which was only intended for use by
	QPDFWriter and which is no longer used.

2012-12-26  Jay Berkenbilt  <ejb@ql.org>

	* Add new fields to QPDF::EncryptionData to support newer
	encryption formats (V=5, R=5 and R=6)

	* Non-compatible API change: Change public nested class
	QPDF::EncryptionData to make all member fields private and to add
	method calls.  This is a non-compatible API change, but changing
	EncryptionData is necessary to support newer encryption formats,
	and making this change will prevent the need from making a
	non-compatible change in the future if new fields are added.  A
	public nested class should never have had public members to begin
	with.

2012-12-25  Jay Berkenbilt  <ejb@ql.org>

	* Allow PDF header to appear anywhere in the first 1024 bytes of
	the file as recommended in the implementation notes of the Adobe
	version of the PDF spec.

2012-11-20  Jay Berkenbilt  <ejb@ql.org>

	* Add zlib and libpcre to Requires.private in the pkg-config file
	to support static linking.  Thanks Tobias Hoffmann for pointing
	out the omission.

	* Ignore (with warning) non-freed objects in the xref table whose
	offset is 0.  Some PDF producers (incorrectly) do this.  See
	https://bugs.linuxfoundation.org/show_bug.cgi?id=1081.

2012-09-23  Jay Berkenbilt  <ejb@ql.org>

	* Add public methods QPDF::processInputSource and
	QPDFWriter::setOutputPipeline to allow users to read from custom
	input sources and to write to custom pipelines.  This allows the
	maximum flexibility in sources for reading and writing PDF files.

2012-09-06  Jay Berkenbilt  <ejb@ql.org>

	* 3.0.2: release

	* Add new method QPDFWriter::setExtraHeaderText to add extra text,
	such as application-specific comments, to near the beginning of a
	PDF file.  For linearized files, this appears after the
	linearization parameter dictionary.  For non-linearized files, it
	appears right after the PDF header and non-ASCII comment.

	* Make it possible to write the same QPDF object with two
	different QPDFWriter objects that have both called
	setLinearization(true) by making private method
	QPDF::calculateLinearizationData() properly initialize its state.

	* Bug fix: Writing after calling QPDFWriter::setOutputMemory()
	would cause a segmentation fault because of an internal field not
	being initialized, rendering that method useless.  This has been
	corrected.

2012-08-11  Jay Berkenbilt  <ejb@ql.org>

	* 3.0.1: release

	* Bug fix: let EOF terminate a literal token as well as
	whitespace or comments.

2012-07-31  Jay Berkenbilt  <ejb@ql.org>

	* 3.0.0: release

2012-07-29  Jay Berkenbilt  <ejb@ql.org>

	* 3.0.rc1: release

2012-07-25  Jay Berkenbilt  <ejb@ql.org>

	* From Tobias: add QPDFObjectHandle::replaceStreamData that takes
	a std::string analogous to the QPDFObjectHandle::newStream that
	takes a string that was added earlier.

2012-07-21  Jay Berkenbilt  <ejb@ql.org>

	* Change configure to have image comparison tests disabled by
	default.  Update README and README.maintainer with information
	about running them.

	* Add --pages command-line option to qpdf to enable page-based
	merging and splitting.

	* Add new method QPDFObjectHandle::replaceDict to replace a
	stream's dictionary.  Use with caution; see comments in
	QPDFObjectHandle.hh.

	* Add new method QPDFObjectHandle::parse for creation of
	QPDFObjectHandle objects from string representations of the
	objects.  Thanks to Tobias Hoffmann for the idea.

2012-07-15  Jay Berkenbilt  <ejb@ql.org>

	* add new QPDF::isEncrypted method that returns some additional
	information beyond other versions.

	* libqpdf/QPDFWriter.cc: fix copyEncryptionParameters to fix the
	minimum PDF version based on other file's encryption needs.  This
	is a fix to code added on 2012-07-14 and did not impact previously
	released code.

	* libqpdf/QPDFWriter.cc (copyEncryptionParameters): Bug fix: qpdf
	was not preserving whether or not AES encryption was being used
	when copying encryption parameters.  The file would still have
	been properly encrypted, but a file that started off encrypted
	with AES could have become encrypted with RC4.

2012-07-14  Jay Berkenbilt  <ejb@ql.org>

	* QPDFWriter: add public copyEncryptionParameters to allow copying
	encryption parameters from another file.

	* QPDFWriter: detect if the user has inserted an indirect object
	from another QPDF object and throw an exception directing the user
	to copyForeignObject.

2012-07-11  Jay Berkenbilt  <ejb@ql.org>

	* Added new APIs to copy objects from one QPDF to another.  This
	includes letting QPDF::addPage() (and QPDF::addPageAt()) accept a
	page object from another QPDF and adding
	QPDF::copyForeignObject().  See QPDF.hh for details.

	* Add method QPDFObjectHandle::getOwningQPDF() to return the QPDF
	object associated with an indirect QPDFObjectHandle.

	* Add convenience methods to QPDFObjectHandle: assertIndirect(),
	isPageObject(), isPagesObject()

	* Cache when QPDF::pushInheritedAttributesToPage() has been called
	to avoid traversing the pages trees multiple times.  This state is
	cleared by QPDF::updateAllPagesCache() and ignored by
	QPDF::flattenPagesTree().

2012-07-08  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::newReserved to create a reserved object
	and QPDF::replaceReserved to replace it with a real object.
	QPDFObjectHandle::newReserved reserves an object ID in a QPDF
	object and ensures that any references to it remain unresolved.
	When QPDF::replaceReserved is later called, previous references to
	the reserved object will properly resolve to the replaced object.

2012-07-07  Jay Berkenbilt  <ejb@ql.org>

	* NOTE: BREAKING API CHANGE.  Remove previously required length
	parameter from the version QPDFObjectHandle::replaceStreamData
	that uses a stream data provider.  Prior to qpdf 3.0.0, you had to
	compute the stream length in advance so that qpdf could internally
	verify that the stream data had the same length every time the
	provider was invoked.  Now this requirement is enforced a
	different way, and the length parameter is no longer required.
	Note that I take API-breaking changes very seriously and only did
	it in this case since the lack of need to know length in advance
	could significantly simplify people's code.  If you were
	previously going to a lot of trouble to compute the length of the
	new stream data in advance, you now no longer have to do that.
	You can just drop the length parameter and remove any code that
	was previously computing the length.  Thanks to Tobias Hoffmann
	for pointing out how annoying the original interface was.

2012-07-05  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFWriter methods to write to an already open stdio FILE*.
	Implementation and idea area based on contributions from Tobias
	Hoffmann.

2012-07-04  Jay Berkenbilt  <ejb@ql.org>

	* Accept changes from Tobias Hoffmann: add public method
	QPDF::pushInheritedAttributesToPage including warnings for
	non-inherited keys that may be discarded from /Pages by
	non-conformant PDF files when the /Pages tree is flattened.

2012-06-27  Jay Berkenbilt  <ejb@ql.org>

	* Add Pl_Concatenate pipeline for stream concatenation also
	implemented by Tobias Hoffmann.  Also added test code
	(libtests/concatenate.cc).

	* Add new methods implemented by Tobias Hoffmann:
	QPDFObjectHandle::newReal(double) and
	QPDFObjectHandle::newStream(QPDF*, std::string const&).

2012-06-26  Jay Berkenbilt  <ejb@ql.org>

	* Minor changes so that support for PDF files larger than 4GB
	works well with 32-bit and 64-bit Linux and also with 32-bit and
	64-bit Windows with both MSVC and mingw.

	* Rework internal methods for doing recovery of the cross
	reference tables for much greater efficiency both in terms of time
	and memory usage.

2012-06-24  Jay Berkenbilt  <ejb@ql.org>

	* Support PDF files larger than 4 GB.  This involved many changes
	to the ABI to increase the size of integer types used in various
	places as well as increasing the amount of padding used when
	creating linearized files.  Automated tests for large files are
	disabled by default.  Run ./configure --help for information on
	enabling them.  Running the tests requires 11 GB of free disk
	space and takes several minutes.

2012-06-22  Jay Berkenbilt  <ejb@ql.org>

	* examples/pdf-create.cc: Provide an example of creating a PDF
	from scratch.  This simple PDF has a single page with some text
	and an image.

	* Add empty QPDFObjectHandle factories for array and dictionary.
	With PDF-from-scratch capability, it is useful to be able to
	create empty arrays and dictionaries and add keys to them.
	Updated pdf_from_scratch.cc to use these interfaces.

2012-06-21  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDF::emptyPDF() to create an empty QPDF object suitable for
	adding pages and other objects to.  pdf_from_scratch.cc is test
	code that exercises it.

	* make/libtool.mk: Place user-specified CPPFLAGS and LDFLAGS later
	in the compilation so that if a user installs things in a
	non-standard place that they have to tell the build about, earlier
	versions of qpdf installed there won't break the build.  Thanks to
	Macports for reporting this.  (Fixes bug 3468860.)

	* Instead of using off_t in the public APIs, use qpdf_offset_t
	instead.  This is defined as long long in qpdf/Types.h.  If your
	system doesn't support long long, you can redefine it.

	* Add pkg-config files

	* QPDFObjectHandle: add shallowCopy() method

	* QPDF: add new APIs for adding and removing pages.  This includes
	addPage(), addPageAt(), and removePage().  Also a method
	updateAllPagesCache() is now available to force update of the
	internal pages cache if you should modify the pages structure
	manually.

	* QPDF: new processFile method that takes an open FILE*
	instead of a filename.

2012-06-20  Jay Berkenbilt  <ejb@ql.org>

	* Add new array mutation routines to QPDFObjectHandle.
	Implemented by Tobias Hoffmann.

	* Rework APIs that use size_t, off_t, and primative integer types
	so that size_t is used for sizes of memory and off_t is used for
	file offsets.  Also set _FILE_OFFSET_BITS so that large files can
	be supported on 32-bit UNIX/Linux platforms.  The code assumes in
	places that sizeof(off_t) >= sizeof(size_t).  This resulted in
	non-compatible ABI changes and hopefully clears the way for QPDF
	to work with files that are larger than 4 GiB in size.

	* Add support for versioned symbols on ELF platforms.

	* Various fixes for gcc 4.7

2011-04-06  Jay Berkenbilt  <ejb@ql.org>

        * Fix PCRE to stop using deprecated (and now dropped) interfaces.

2011-12-28  Jay Berkenbilt  <ejb@ql.org>

	* 2.3.1: release

	* include <stdint.h> if available to support MSVC 2010

	* Since PCRE is not necessarily thread safe, don't declare any
	PCRE objects to be static.

	* Disregard stderr output from ghostscript when using it to
	compare images in the test suite; see comments in qpdf.test for
	details.

	* Fixed a few documentation errors.

2011-08-11  Jay Berkenbilt  <ejb@ql.org>

	* 2.3.0: release

	* include/qpdf/qpdf-c.h ("C"): add new methods
	qpdf_init_write_memory, qpdf_get_buffer_length, and
	qpdf_get_buffer to support writing to memory from the C API.

	* include/qpdf/qpdf-c.h ("C"): add new methods qpdf_get_info_key
	and qpdf_set_info_key for manipulating text fields of the /Info
	dictionary.

2011-08-10  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/QPDFWriter.cc (copyEncryptionParameters): preserve
	whether metadata is encryption.  This fixes part of bug 3173659:
	the password becomes invalid if qpdf copies an encrypted file with
	cleartext-metadata.

	* include/qpdf/QPDFWriter.hh: add a new constructor that takes
	only a QPDF reference and leaves specification of output for
	later.  Add methods setOutputFilename() to set the output to a
	filename or stdout, and setOutputMemory() to indicate that output
	should go to a memory buffer.  Add method getBuffer() to retrieve
	the buffer used if output was saved to a memory buffer.

	* include/qpdf/QPDF.hh: add methods replaceObject() and
	swapObjects() to allow replacement of an object and swapping of
	two objects by object ID.

	* include/qpdf/QPDFObjectHandle.hh: add new methods getDictAsMap()
	and getArrayAsVector() for returning the elements of a dictionary
	or an array as a map or vector.

2011-06-25  Jay Berkenbilt  <ejb@ql.org>

	* 2.2.4: release

2011-06-23  Jay Berkenbilt  <ejb@ql.org>

	* make/libtool.mk (install): Do not strip executables and shared
	libraries during installation.  Leave that up to the packager.

	* configure.ac: disable -Werror by default.

2011-05-07  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/QPDF_linearization.cc (isLinearized): remove unused
	offset variable, found by a gcc 4.6 warning.

2011-04-30  Jay Berkenbilt  <ejb@ql.org>

	* 2.2.3: release

	* libqpdf/QPDF.cc (readObjectInternal): Accept the case of the
	stream keyword being followed by carriage return by itself.  While
	this is not permitted by the specification, there are PDF files
	that do this, and other readers can read them.

	* libqpdf/Pl_QPDFTokenizer.cc (processChar): When an inline image
	is detected, suspend normalization only up to the end of the
	inline image rather than for the remainder of the content stream.
	(Fixes qpdf-Bugs 3152169.)

2011-01-31  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/QPDF.cc (readObjectAtOffset): use -1 rather than 0 when
	reading an object at a given to indicate that no object number is
	expected.  This allows xref recovery to proceed even if a file
	uses the invalid object number 0 as a regular object.

	* libqpdf/QPDF_linearization.cc (isLinearized): use -1 rather than
	0 as a sentintel for not having found the first object in the
	file.  Since -1 can never match the regular expression, this
	prevents an infinite loop when checking a file that starts with
	(erroneous) 0 0 obj.  (Fixes qpdf-Bugs-3159950.)

2010-10-04  Jay Berkenbilt  <ejb@ql.org>

	* 2.2.2: release

	* include/qpdf/qpdf-c.h: Add qpdf_read_memory to C API to call
	QPDF::processMemoryFile.

2010-10-01  Jay Berkenbilt  <ejb@ql.org>

	* 2.2.1: release

	* include/qpdf/QPDF.hh: Add setOutputStreams method to allow
	redirection of library-generated output/error to alternative
	streams.

	* include/qpdf/QPDF.hh: Add processMemoryFile method for
	processing a PDF file from a memory buffer instead of a file.

2010-09-24  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/QPDF.cc: change private "file" method to be a
	PointerHolder<InputSource> to prepare qpdf for being able to work
	with PDF files loaded into memory in addition to working with
	files on disk.

	* include/qpdf/PointerHolder.hh: add operator* and operator->
	methods so that PointerHolder objects can be used like pointers.
	This is consistent with the smart pointer objects in the next
	revision of C++.

2010-09-05  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/QPDF.cc (readObjectInternal): Recognize empty objects
	and treat them as null.

	* libqpdf/QPDF_Stream.cc (filterable): Handle inline image filter
	abbreviations as stream filter abbreviations.  Although this is
	not technically allowed by the PDF specification, table H.1 in the
	pre-ISO spec indicates that Adobe's readers accept them.  Thanks
	to Jian Ma <stronghorse@tom.com> for bringing this to my
	attention.

2010-08-14  Jay Berkenbilt  <ejb@ql.org>

	* 2.2.0: release

	* Rename README.windows to README-windows.txt and convert its line
	endings to Windows-style line endings.  Also mention Jian Ma's VC6
	port in the manual and README-windows.txt.

2010-08-09  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::getRawStreamData to return raw
	(unfiltered) stream data.

2010-08-08  Jay Berkenbilt  <ejb@ql.org>

	* 2.2.rc1: release

2010-08-05  Jay Berkenbilt  <ejb@ql.org>

	* Add QPDFObjectHandle::addPageContents, a convenience routine for
	appending or prepending new streams to a page's content streams.
	The "pdf-double-page-size" example illustrates its use.

	* Add new methods to QPDFObjectHandle: replaceStreamData and
	newStream.  These methods allow users of the qpdf library to add
	new streams and to replace data of existing streams.  The
	"pdf-double-page-size" and "pdf-invert-images" examples illustrate
	their use.

2010-06-06  Jay Berkenbilt  <ejb@ql.org>

	* Fix memory leak for QPDF objects whose underlying PDF objects
	contain circular references.  Thanks to Jian Ma
	<stronghorse@tom.com> for calling my attention to the memory leak.

2010-04-25  Jay Berkenbilt  <ejb@ql.org>

	* 2.1.5: release

	* libqpdf/QPDF_encryption.cc (compute_encryption_key): remove
	restrictions on length of file identifier string.  (Fixes
	qpdf-Bugs-2991412.)

2010-04-18  Jay Berkenbilt  <ejb@ql.org>

	* 2.1.4: release

	* libqpdf/QPDFWriter.cc (writeLinearized): the padding calculation
	fix in 2.1.2 was applied in only one place but it was needed in
	two places since there are actually two cross reference streams in
	a linearized file.  The new padding calculation is now used for
	both streams.  Hopefully this should put an end to linearization
	padding problems.  (Fixes qpdf-Bugs-2979219.)

2010-04-10  Jay Berkenbilt  <ejb@ql.org>

	* qpdf/qpdf.cc (main): Since qpdf --check only checks syntax and
	stream encoding without doing any semantic checks, make the output
	clearer when no errors around found.  This is inspired by
	qpdf-Bugs-2983225.

2010-03-27  Jay Berkenbilt  <ejb@ql.org>

	* 2.1.3: release

	* libqpdf/QPDF_optimization.cc (flattenScalarReferences): Flatten
	scalar references for unreferenced objects as well as those seen
	during traversal of the file.  This matters when preserving object
	streams that contain unreferenced objects with indirect scalars.
	(Fixes qpdf-Bugs-2974522.)  Updated TODO with a description of a
	possibly better fix involving removal of flattenScalarReferences.

	* libqpdf/Pl_AES_PDF.cc (finish): Don't complain if an AES input
	buffer is not a multiple of 16 bytes.  Instead, just pad with
	nulls and hope for the best.  PDF files have been encountered "in
	the wild" that contain AES buffers that aren't a multiple of 16
	bytes.

2010-01-24  Jay Berkenbilt  <ejb@ql.org>

	* 2.1.2: release

	* libqpdf/QPDFWriter.cc: fix logic error in padding calculation.
	When writing linearized files with cross reference streams, the
	padding calculation failed to take differences in sizes of
	compressed data between pass 1 and pass 2 into consideration.

2009-12-14  Jay Berkenbilt  <ejb@ql.org>

	* 2.1.1: release

	* qpdf/qtest/qpdf.test: improve test for acroread to make sure it
	actually works and is not just present in the path.

2009-12-13  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/qpdf/Pl_AES_PDF.hh: include <stdint.h>, if available, so
	we have valid definitions of uint32_t.

2009-10-30  Jay Berkenbilt  <ejb@ql.org>

	* 2.1: release

	* libqpdf/QPDF.cc: be more forgiving of extraneous whitespace in
	the xref table and while recovering from error conditions.

2009-10-26  Jay Berkenbilt  <ejb@ql.org>

	* Work around failure of PCRE test case; this test case exercises
	an aspect of PCRE that qpdf does not use, and the test fails with
	the version of PCRE on Red Hat Enterprise Linux 5, so we ignore
	failure on this particular test case.

	* Fix RPM .spec file to include "C" examples

2009-10-24  Jay Berkenbilt  <ejb@ql.org>

	* 2.1.rc1: release

	* Provide interfaces for getting qpdf's own version number

2009-10-19  Jay Berkenbilt  <ejb@ql.org>

	* include/qpdf/QPDF.hh (QPDF): getWarnings now returns a list of
	QPDFExc rather than a list of strings.  This way, warnings may be
	inspected in more detail.

	* Include information about the last object read in most error
	messages.  Most of the time, this will provide a good hint as to
	which object contains the error, but it's possible that the last
	object read may not necessarily be the one that has the error if
	the erroneous object was previously read and cached.

2009-10-18  Jay Berkenbilt  <ejb@ql.org>

	* If forcing version, disable object stream creation and/or
	encryption if previous specifications are incompatible with new
	version.  It is still possible that PDF content, compression
	schemes, etc., may be incompatible with the new version, but at
	least this way, older viewers will at least have a chance.

	* libqpdf/QPDFWriter.cc (unparseObject): avoid compressing
	Metadata streams if possible.

2009-10-13  Jay Berkenbilt  <ejb@ql.org>

	* Upgrade embedded qtest to version 1.4, which allows the test
	suite to be run in Windows with MSYS and ActiveState Perl rather
	than requiring Cygwin perl.

2009-10-04  Jay Berkenbilt  <ejb@ql.org>

	* Implement support AES encrypt and crypt filters.  Implementation
	is not fully tested due to lack of test data but has been tested
	for several cases.

2009-10-04  Jay Berkenbilt  <ejb@ql.org>

	* Add methods to QPDFWriter and corresponding command line
	arguments to qpdf to set the minimum output PDF version and also
	to force the version to a particular value.

	* libqpdf/QPDF.cc (processXRefStream): warn and ignore extra xref
	stream entries when stream is larger than reported size.  This
	used to be a fatal error.  (Fixes qpdf-Bugs-2872265.)

2009-09-27  Jay Berkenbilt  <ejb@ql.org>

	* Add several methods to query permissions controlled by the
	encryption dictionary.  Note that qpdf does not enforce these
	permissions even though it allows the user to query them.

	* The function QPDF::getUserPassword returned the user password
	with the required padding as specified by the PDF specification.
	This is seldom useful to users.  This function has been replaced
	by QPDF::getPaddedUserPassword.  Call the new
	QPDF::getTrimmedUserPassword to retreive the user password in a
	human-readable format.

	* qpdf/qpdf.cc (main): qpdf --check now prints the PDF version
	number in addition to its other output.

2009-09-26  Jay Berkenbilt  <ejb@ql.org>

	* Removed all references to QEXC; now using std::runtime_error and
	std::logic_error and their subclasses for all exceptions.

2009-05-03  Jay Berkenbilt  <ejb@ql.org>

	* 2.0.6: release

	* libqpdf/QPDF_Stream.cc (filterable): ignore /DecodeParms if it's
	not a type we recognize.  (Fixes qpdf-Bugs-2779746.)

2009-03-10  Jay Berkenbilt  <ejb@ql.org>

	* 2.0.5: release

2009-03-09  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/Pl_LZWDecoder.cc: adjust LZWDecoder full table
	detection, now having been able to adequately test boundary
	conditions both and with and without early code change.  Also
	compared implementation with other LZW decoders.

2009-03-08  Jay Berkenbilt  <ejb@ql.org>

	* qpdf/fix-qdf (write_ostream): Adjust offsets while writing
	object streams to account for changes in the length of the
	dictionary and offset tables.

	* qpdf/qpdf.cc (main): In check mode, in addition to checking
	structure of file, attempt to decode all stream data.

	* libqpdf/QPDFWriter.cc (QPDFWriter::writeObject): In QDF mode,
	write a comment to the QDF file before each object that indicates
	the object ID of the corresponding object from the original file.
	Add --no-original-object-ids flag to qpdf and
	setSuppressOriginalObjectIDs() method to QPDFWriter to turn this
	behavior off.

	* libqpdf/QPDF.cc (QPDF::pipeStreamData): Issue a warning instead
	of failing if there is a problem found while decoding stream.

	* qpdf/qpdf.cc: Exit with a status of 3 if warnings were found
	regardless of what mode we're in.

2009-02-21  Jay Berkenbilt  <ejb@ql.org>

	* 2.0.4: release

2009-02-20  Jay Berkenbilt  <ejb@ql.org>

	* Fix many typos in comments and strings.

	* qpdf/qpdf.cc: in --check mode, if there are warnings but no
	errors, exit with a status of 3.

	* libqpdf/QPDF.cc (QPDF::insertXrefEntry): when recovering the
	cross-reference table, have objects we encounter later in the file
	supersede those we found earlier.  This improves the chances of
	being able to recover appended files with damaged cross-reference
	tables.

2009-02-19  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/Pl_LZWDecoder.cc: correct logic error for previously
	untested case of running the LZW decoder without the "early code
	change" flag.  Thanks to a bug report from "Atom Smasher", I
	finally was able to obtain an input stream compressed in this way.

2009-02-15  Jay Berkenbilt  <ejb@ql.org>

	* 2.0.3: release

2008-12-11  Jay Berkenbilt  <ejb@ql.org>

	* qpdf/qpdf.cc (main): Accept -help and -version as well as --help
	and --version

2008-11-23  Jay Berkenbilt  <ejb@ql.org>

	* Include stdio.h in a few files for proper compilation with (yet
	to be released) gcc 4.4

	* updated embedded qtest to version 1.3

	* libqpdf/QPDF_String.cc (QPDF_String::getUTF8Val): handle
	UTF-16BE properly rather than just treating the string as a string
	of 16-bit characters.

2008-06-30  Jay Berkenbilt  <ejb@ql.org>

	* 2.0.2: release

	* updated embedded qtest to version 1.2 (includes previous
	changes)

2008-06-07  Jay Berkenbilt  <ejb@ql.org>

	* qpdf/qtest/qpdf/diff-encrypted: change == to = so that the test
	suite passes when /bin/sh is not bash

2008-05-07  Jay Berkenbilt  <ejb@ql.org>

	* qtest/bin/qtest-driver (run_test): increase timeout for qtest to
	be more tolerant of slow machines

2008-05-06  Jay Berkenbilt  <ejb@ql.org>

	* 2.0.1: release

	* make/rules.mk: fix logic with .dep generation for .lo files so
	that dependencies work properly with libtool

2008-05-05  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/qpdf/MD5.hh: fix header to be 64-bit clean

	* configure.ac: add tests for sized integer types

2008-05-04  Jay Berkenbilt  <ejb@ql.org>

	* libqpdf/QPDF_encryption.cc: do not assume size_t is unsigned int

	* qpdf/qtest/qpdf.test: removed locale-specific tests.  These were
	really to check bugs in perl 5.8.0 and are obsolete now.  They
	also make the test suite fail in some environments that don't have
	all the locales fully configured.

	* various: updated several files for gcc 4.3 by adding missing
	includes (string.h, stdlib.h)

2008-04-26  Jay Berkenbilt  <ejb@ql.org>

	* 2.0: initial public release