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Implement user-provided stream filters

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Refactor QPDF_Stream to use stream filter classes to handle supported
stream filters as well.
This commit is contained in:
Jay Berkenbilt 2020-12-23 06:12:49 -05:00
parent 1fb26f08ad
commit 39bfa01307
16 changed files with 587 additions and 279 deletions
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10
ChangeLog
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@ -1,3 +1,13 @@
2020-12-23 Jay Berkenbilt <ejb@ql.org>
* Allow library users to provide their own decoders for stream
filters by deriving classes from QPDFStreamFilter and registering
them using QPDF::registerStreamFilter. Registered stream filters
provide code to validate and interpret /DecodeParms for a specific
/Filter and also to provide a pipeline that will decode. Note that
it is possible to encode to a filter type that is not supported
even without this feature.
2020-12-22 Jay Berkenbilt <ejb@ql.org>
* Add QPDFObjectHandle::makeDirect(bool allow_streams) -- if

7
TODO
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@ -317,13 +317,6 @@ I find it useful to make reference to them in this list
is exercised elsewhere in qpdf's test suite, so this is not that
pressing.
* Support user-pluggable stream filters. This would enable external
code to provide interpretation for filters that are missing from
qpdf. Make it possible for user-provided filters to override
built-in filters. Make sure that the pluggable filters can be
prioritized so that we can poll all registered filters to see
whether they are capable of filtering a particular stream.
* If possible, consider adding CCITT3, CCITT4, or any other easy
filters. For some reference code that we probably can't use but may
be handy anyway, see

17
include/qpdf/QPDF.hh
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@ -31,6 +31,8 @@
#include <list>
#include <iostream>
#include <vector>
#include <functional>
#include <memory>
#include <qpdf/QIntC.hh>
#include <qpdf/QPDFExc.hh>
@ -39,6 +41,7 @@
#include <qpdf/QPDFXRefEntry.hh>
#include <qpdf/QPDFObjectHandle.hh>
#include <qpdf/QPDFTokenizer.hh>
#include <qpdf/QPDFStreamFilter.hh>
#include <qpdf/Buffer.hh>
#include <qpdf/InputSource.hh>
@ -132,6 +135,20 @@ class QPDF
QPDF_DLL
void emptyPDF();
// From 10.1: register a new filter implementation for a specific
// stream filter. You can add your own implementations for new
// filter types or override existing ones provided by the library.
// Registered stream filters are used for decoding only as you can
// override encoding with stream data providers. For example, you
// could use this method to support for one of the other filter
// types by using additional third-party libraries that qpdf does
// not presently use. The standard filters are implemented using
// QPDFStreamFilter classes.
QPDF_DLL
static void registerStreamFilter(
std::string const& filter_name,
std::function<std::shared_ptr<QPDFStreamFilter> ()> factory);
// Parameter settings
// By default, warning messages are issued to std::cerr and output

78
include/qpdf/QPDFStreamFilter.hh Normal file
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@ -0,0 +1,78 @@
// Copyright (c) 2005-2020 Jay Berkenbilt
//
// This file is part of qpdf.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// 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.
#ifndef QPDFSTREAMFILTER_HH
#define QPDFSTREAMFILTER_HH
#include <qpdf/DLL.h>
#include <qpdf/QPDFObjectHandle.hh>
#include <qpdf/Pipeline.hh>
class QPDF_DLL_CLASS QPDFStreamFilter
{
public:
QPDF_DLL
QPDFStreamFilter() = default;
QPDF_DLL
virtual ~QPDFStreamFilter() = default;
// A QPDFStreamFilter class must implement, at a minimum,
// setDecodeParms() and getDecodePipeline(). QPDF will always call
// setDecodeParms() before calling getDecodePipeline(). It is
// expected that you will store any needed information from
// decode_parms (or the decode_parms object iself) in your
// instance so that it can be used to construct the decode
// pipeline.
// Return a boolean indicating whether your filter can proceed
// with the given /DecodeParms. The default implementation accepts
// a null object and rejects everything else.
QPDF_DLL
virtual bool setDecodeParms(QPDFObjectHandle decode_parms);
// Return a pipeline that will decode data encoded with your
// filter. Your implementation must ensure that the pipeline is
// deleted when the instance of your class is destroyed.
QPDF_DLL
virtual Pipeline* getDecodePipeline(Pipeline* next) = 0;
// If your filter implements "specialized" compression or lossy
// compression, override one or both of these methods. The default
// implementations return false. See comments in QPDFWriter for
// details. QPDF defines specialized compression as non-lossy
// compression not intended for general-purpose data. qpdf, by
// default, doesn't mess with streams that are compressed with
// specialized compression, the idea being that the decision to
// use that compression scheme would fall outside of what
// QPDFWriter would know anything about, so any attempt to decode
// and re-encode would probably be undesirable.
QPDF_DLL
virtual bool isSpecializedCompression();
QPDF_DLL
virtual bool isLossyCompression();
private:
QPDFStreamFilter(QPDFStreamFilter const&) = delete;
QPDFStreamFilter& operator=(QPDFStreamFilter const&) = delete;
};
#endif // QPDFSTREAMFILTER_HH

8
libqpdf/QPDF.cc
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@ -269,6 +269,14 @@ QPDF::emptyPDF()
processMemoryFile("empty PDF", EMPTY_PDF, strlen(EMPTY_PDF));
}
void
QPDF::registerStreamFilter(
std::string const& filter_name,
std::function<std::shared_ptr<QPDFStreamFilter> ()> factory)
{
QPDF_Stream::registerStreamFilter(filter_name, factory);
}
void
QPDF::setIgnoreXRefStreams(bool val)
{

19
libqpdf/QPDFStreamFilter.cc Normal file
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@ -0,0 +1,19 @@
#include <qpdf/QPDFStreamFilter.hh>
bool
QPDFStreamFilter::setDecodeParms(QPDFObjectHandle decode_parms)
{
return decode_parms.isNull();
}
bool
QPDFStreamFilter::isSpecializedCompression()
{
return false;
}
bool
QPDFStreamFilter::isLossyCompression()
{
return false;
}

375
libqpdf/QPDF_Stream.cc
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@ -3,15 +3,7 @@
#include <qpdf/QUtil.hh>
#include <qpdf/Pipeline.hh>
#include <qpdf/Pl_Flate.hh>
#include <qpdf/Pl_PNGFilter.hh>
#include <qpdf/Pl_TIFFPredictor.hh>
#include <qpdf/Pl_RC4.hh>
#include <qpdf/Pl_Buffer.hh>
#include <qpdf/Pl_ASCII85Decoder.hh>
#include <qpdf/Pl_ASCIIHexDecoder.hh>
#include <qpdf/Pl_LZWDecoder.hh>
#include <qpdf/Pl_RunLength.hh>
#include <qpdf/Pl_DCT.hh>
#include <qpdf/Pl_Count.hh>
#include <qpdf/ContentNormalizer.hh>
#include <qpdf/QTC.hh>
@ -19,10 +11,78 @@
#include <qpdf/QPDFExc.hh>
#include <qpdf/Pl_QPDFTokenizer.hh>
#include <qpdf/QIntC.hh>
#include <qpdf/SF_FlateLzwDecode.hh>
#include <qpdf/SF_DCTDecode.hh>
#include <qpdf/SF_RunLengthDecode.hh>
#include <qpdf/SF_ASCII85Decode.hh>
#include <qpdf/SF_ASCIIHexDecode.hh>
#include <stdexcept>
std::map<std::string, std::string> QPDF_Stream::filter_abbreviations;
class SF_Crypt: public QPDFStreamFilter
{
public:
SF_Crypt() = default;
virtual ~SF_Crypt() = default;
virtual bool setDecodeParms(QPDFObjectHandle decode_parms)
{
if (decode_parms.isNull())
{
return true;
}
bool filterable = true;
for (auto const& key: decode_parms.getKeys())
{
if (((key == "/Type") || (key == "/Name")) &&
(decode_parms.getKey("/Type").isNull() ||
(decode_parms.getKey("/Type").isName() &&
(decode_parms.getKey("/Type").getName() ==
"/CryptFilterDecodeParms"))))
{
// we handle this in decryptStream
}
else
{
filterable = false;
}
}
return filterable;
}
virtual Pipeline* getDecodePipeline(Pipeline*)
{
// Not used -- handled by pipeStreamData
return nullptr;
}
};
std::map<std::string, std::string> QPDF_Stream::filter_abbreviations = {
// The PDF specification provides these filter abbreviations for
// use in inline images, but according to table H.1 in the pre-ISO
// versions of the PDF specification, Adobe Reader also accepts
// them for stream filters.
{"/AHx", "/ASCIIHexDecode"},
{"/A85", "/ASCII85Decode"},
{"/LZW", "/LZWDecode"},
{"/Fl", "/FlateDecode"},
{"/RL", "/RunLengthDecode"},
{"/CCF", "/CCITTFaxDecode"},
{"/DCT", "/DCTDecode"},
};
std::map<
std::string,
std::function<std::shared_ptr<QPDFStreamFilter>()>>
QPDF_Stream::filter_factories = {
{"/Crypt", []() { return std::make_shared<SF_Crypt>(); }},
{"/FlateDecode", SF_FlateLzwDecode::flate_factory},
{"/LZWDecode", SF_FlateLzwDecode::lzw_factory},
{"/RunLengthDecode", SF_RunLengthDecode::factory},
{"/DCTDecode", SF_DCTDecode::factory},
{"/ASCII85Decode", SF_ASCII85Decode::factory},
{"/ASCIIHexDecode", SF_ASCIIHexDecode::factory},
};
QPDF_Stream::QPDF_Stream(QPDF* qpdf, int objid, int generation,
QPDFObjectHandle stream_dict,
@ -47,6 +107,14 @@ QPDF_Stream::~QPDF_Stream()
{
}
void
QPDF_Stream::registerStreamFilter(
std::string const& filter_name,
std::function<std::shared_ptr<QPDFStreamFilter>()> factory)
{
filter_factories[filter_name] = factory;
}
void
QPDF_Stream::releaseResolved()
{
@ -190,125 +258,18 @@ QPDF_Stream::getRawStreamData()
}
bool
QPDF_Stream::understandDecodeParams(
std::string const& filter, QPDFObjectHandle decode_obj,
int& predictor, int& columns,
int& colors, int& bits_per_component,
bool& early_code_change)
{
bool filterable = true;
std::set<std::string> keys = decode_obj.getKeys();
for (std::set<std::string>::iterator iter = keys.begin();
iter != keys.end(); ++iter)
{
std::string const& key = *iter;
if (((filter == "/FlateDecode") || (filter == "/LZWDecode")) &&
(key == "/Predictor"))
{
QPDFObjectHandle predictor_obj = decode_obj.getKey(key);
if (predictor_obj.isInteger())
{
predictor = predictor_obj.getIntValueAsInt();
if (! ((predictor == 1) || (predictor == 2) ||
((predictor >= 10) && (predictor <= 15))))
{
filterable = false;
}
}
else
{
filterable = false;
}
}
else if ((filter == "/LZWDecode") && (key == "/EarlyChange"))
{
QPDFObjectHandle earlychange_obj = decode_obj.getKey(key);
if (earlychange_obj.isInteger())
{
int earlychange = earlychange_obj.getIntValueAsInt();
early_code_change = (earlychange == 1);
if (! ((earlychange == 0) || (earlychange == 1)))
{
filterable = false;
}
}
else
{
filterable = false;
}
}
else if ((key == "/Columns") ||
(key == "/Colors") ||
(key == "/BitsPerComponent"))
{
QPDFObjectHandle param_obj = decode_obj.getKey(key);
if (param_obj.isInteger())
{
int val = param_obj.getIntValueAsInt();
if (key == "/Columns")
{
columns = val;
}
else if (key == "/Colors")
{
colors = val;
}
else if (key == "/BitsPerComponent")
{
bits_per_component = val;
}
}
else
{
filterable = false;
}
}
else if ((filter == "/Crypt") &&
(((key == "/Type") || (key == "/Name")) &&
(decode_obj.getKey("/Type").isNull() ||
(decode_obj.getKey("/Type").isName() &&
(decode_obj.getKey("/Type").getName() ==
"/CryptFilterDecodeParms")))))
{
// we handle this in decryptStream
}
else
{
filterable = false;
}
}
return filterable;
}
bool
QPDF_Stream::filterable(std::vector<std::string>& filters,
QPDF_Stream::filterable(
std::vector<std::shared_ptr<QPDFStreamFilter>>& filters,
bool& specialized_compression,
bool& lossy_compression,
int& predictor, int& columns,
int& colors, int& bits_per_component,
bool& early_code_change)
bool& lossy_compression)
{
if (filter_abbreviations.empty())
{
// The PDF specification provides these filter abbreviations
// for use in inline images, but according to table H.1 in the
// pre-ISO versions of the PDF specification, Adobe Reader
// also accepts them for stream filters.
filter_abbreviations["/AHx"] = "/ASCIIHexDecode";
filter_abbreviations["/A85"] = "/ASCII85Decode";
filter_abbreviations["/LZW"] = "/LZWDecode";
filter_abbreviations["/Fl"] = "/FlateDecode";
filter_abbreviations["/RL"] = "/RunLengthDecode";
filter_abbreviations["/CCF"] = "/CCITTFaxDecode";
filter_abbreviations["/DCT"] = "/DCTDecode";
}
// Check filters
QPDFObjectHandle filter_obj = this->stream_dict.getKey("/Filter");
bool filters_okay = true;
std::vector<std::string> filter_names;
if (filter_obj.isNull())
{
// No filters
@ -316,7 +277,7 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
else if (filter_obj.isName())
{
// One filter
filters.push_back(filter_obj.getName());
filter_names.push_back(filter_obj.getName());
}
else if (filter_obj.isArray())
{
@ -327,7 +288,7 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
QPDFObjectHandle item = filter_obj.getArrayItem(i);
if (item.isName())
{
filters.push_back(item.getName());
filter_names.push_back(item.getName());
}
else
{
@ -351,34 +312,23 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
bool filterable = true;
for (std::vector<std::string>::iterator iter = filters.begin();
iter != filters.end(); ++iter)
for (auto& filter_name: filter_names)
{
std::string& filter = *iter;
if (filter_abbreviations.count(filter))
if (filter_abbreviations.count(filter_name))
{
QTC::TC("qpdf", "QPDF_Stream expand filter abbreviation");
filter = filter_abbreviations[filter];
filter_name = filter_abbreviations[filter_name];
}
if (filter == "/RunLengthDecode")
{
specialized_compression = true;
}
else if (filter == "/DCTDecode")
{
specialized_compression = true;
lossy_compression = true;
}
else if (! ((filter == "/Crypt") ||
(filter == "/FlateDecode") ||
(filter == "/LZWDecode") ||
(filter == "/ASCII85Decode") ||
(filter == "/ASCIIHexDecode")))
auto ff = filter_factories.find(filter_name);
if (ff == filter_factories.end())
{
filterable = false;
}
else
{
filters.push_back((ff->second)());
}
}
if (! filterable)
@ -386,15 +336,8 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
return false;
}
// `filters' now contains a list of filters to be applied in
// order. See which ones we can support.
// Initialize values to their defaults as per the PDF spec
predictor = 1;
columns = 0;
colors = 1;
bits_per_component = 8;
early_code_change = true;
// filters now contains a list of filters to be applied in order.
// See which ones we can support.
// See if we can support any decode parameters that are specified.
@ -413,7 +356,7 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
}
else
{
for (unsigned int i = 0; i < filters.size(); ++i)
for (unsigned int i = 0; i < filter_names.size(); ++i)
{
decode_parms.push_back(decode_obj);
}
@ -436,21 +379,21 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
return false;
}
for (unsigned int i = 0; i < filters.size(); ++i)
for (size_t i = 0; i < filters.size(); ++i)
{
QPDFObjectHandle decode_item = decode_parms.at(i);
if (decode_item.isNull())
auto filter = filters.at(i);
auto decode_item = decode_parms.at(i);
if (filter->setDecodeParms(decode_item))
{
// okay
if (filter->isSpecializedCompression())
{
specialized_compression = true;
}
else if (decode_item.isDictionary())
if (filter->isLossyCompression())
{
if (! understandDecodeParams(
filters.at(i), decode_item,
predictor, columns, colors, bits_per_component,
early_code_change))
{
filterable = false;
specialized_compression = true;
lossy_compression = true;
}
}
else
@ -459,17 +402,6 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
}
}
if ((predictor > 1) && (columns == 0))
{
// invalid
filterable = false;
}
if (! filterable)
{
return false;
}
return filterable;
}
@ -479,12 +411,7 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool* filterp,
qpdf_stream_decode_level_e decode_level,
bool suppress_warnings, bool will_retry)
{
std::vector<std::string> filters;
int predictor = 1;
int columns = 0;
int colors = 1;
int bits_per_component = 8;
bool early_code_change = true;
std::vector<std::shared_ptr<QPDFStreamFilter>> filters;
bool specialized_compression = false;
bool lossy_compression = false;
bool ignored;
@ -497,10 +424,8 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool* filterp,
bool success = true;
if (filter)
{
filter = filterable(filters, specialized_compression, lossy_compression,
predictor, columns,
colors, bits_per_component,
early_code_change);
filter = filterable(
filters, specialized_compression, lossy_compression);
if ((decode_level < qpdf_dl_all) && lossy_compression)
{
filter = false;
@ -524,8 +449,10 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool* filterp,
}
// Construct the pipeline in reverse order. Force pipelines we
// create to be deleted when this function finishes.
std::vector<PointerHolder<Pipeline> > to_delete;
// create to be deleted when this function finishes. Pipelines
// created by QPDFStreamFilter objects will be deleted by those
// objects.
std::vector<PointerHolder<Pipeline>> to_delete;
PointerHolder<ContentNormalizer> normalizer;
if (filter)
@ -555,79 +482,13 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool* filterp,
to_delete.push_back(pipeline);
}
for (std::vector<std::string>::reverse_iterator f_iter =
filters.rbegin();
for (auto f_iter = filters.rbegin();
f_iter != filters.rend(); ++f_iter)
{
std::string const& filter_name = *f_iter;
if ((filter_name == "/FlateDecode") ||
(filter_name == "/LZWDecode"))
auto decode_pipeline = (*f_iter)->getDecodePipeline(pipeline);
if (decode_pipeline)
{
if ((predictor >= 10) && (predictor <= 15))
{
QTC::TC("qpdf", "QPDF_Stream PNG filter");
pipeline = new Pl_PNGFilter(
"png decode", pipeline, Pl_PNGFilter::a_decode,
QIntC::to_uint(columns),
QIntC::to_uint(colors),
QIntC::to_uint(bits_per_component));
to_delete.push_back(pipeline);
}
else if (predictor == 2)
{
QTC::TC("qpdf", "QPDF_Stream TIFF predictor");
pipeline = new Pl_TIFFPredictor(
"tiff decode", pipeline, Pl_TIFFPredictor::a_decode,
QIntC::to_uint(columns),
QIntC::to_uint(colors),
QIntC::to_uint(bits_per_component));
to_delete.push_back(pipeline);
}
}
if (filter_name == "/Crypt")
{
// Ignore -- handled by pipeStreamData
}
else if (filter_name == "/FlateDecode")
{
pipeline = new Pl_Flate("stream inflate",
pipeline, Pl_Flate::a_inflate);
to_delete.push_back(pipeline);
}
else if (filter_name == "/ASCII85Decode")
{
pipeline = new Pl_ASCII85Decoder("ascii85 decode", pipeline);
to_delete.push_back(pipeline);
}
else if (filter_name == "/ASCIIHexDecode")
{
pipeline = new Pl_ASCIIHexDecoder("asciiHex decode", pipeline);
to_delete.push_back(pipeline);
}
else if (filter_name == "/LZWDecode")
{
pipeline = new Pl_LZWDecoder("lzw decode", pipeline,
early_code_change);
to_delete.push_back(pipeline);
}
else if (filter_name == "/RunLengthDecode")
{
pipeline = new Pl_RunLength("runlength decode", pipeline,
Pl_RunLength::a_decode);
to_delete.push_back(pipeline);
}
else if (filter_name == "/DCTDecode")
{
pipeline = new Pl_DCT("DCT decode", pipeline);
to_delete.push_back(pipeline);
}
else
{
throw std::logic_error(
"INTERNAL ERROR: QPDFStream: unknown filter "
"encountered after check");
pipeline = decode_pipeline;
}
}
}

153
libqpdf/SF_FlateLzwDecode.cc Normal file
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@ -0,0 +1,153 @@
#include <qpdf/SF_FlateLzwDecode.hh>
#include <qpdf/Pl_PNGFilter.hh>
#include <qpdf/Pl_TIFFPredictor.hh>
#include <qpdf/Pl_Flate.hh>
#include <qpdf/Pl_LZWDecoder.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QIntC.hh>
SF_FlateLzwDecode::SF_FlateLzwDecode(bool lzw) :
lzw(lzw),
// Initialize values to their defaults as per the PDF spec
predictor(1),
columns(0),
colors(1),
bits_per_component(8),
early_code_change(true)
{
}
bool
SF_FlateLzwDecode::setDecodeParms(QPDFObjectHandle decode_parms)
{
if (decode_parms.isNull())
{
return true;
}
bool filterable = true;
std::set<std::string> keys = decode_parms.getKeys();
for (auto const& key: keys)
{
QPDFObjectHandle value = decode_parms.getKey(key);
if (key == "/Predictor")
{
if (value.isInteger())
{
this->predictor = value.getIntValueAsInt();
if (! ((this->predictor == 1) || (this->predictor == 2) ||
((this->predictor >= 10) && (this->predictor <= 15))))
{
filterable = false;
}
}
else
{
filterable = false;
}
}
else if ((key == "/Columns") ||
(key == "/Colors") ||
(key == "/BitsPerComponent"))
{
if (value.isInteger())
{
int val = value.getIntValueAsInt();
if (key == "/Columns")
{
this->columns = val;
}
else if (key == "/Colors")
{
this->colors = val;
}
else if (key == "/BitsPerComponent")
{
this->bits_per_component = val;
}
}
else
{
filterable = false;
}
}
else if (lzw && (key == "/EarlyChange"))
{
if (value.isInteger())
{
int earlychange = value.getIntValueAsInt();
this->early_code_change = (earlychange == 1);
if (! ((earlychange == 0) || (earlychange == 1)))
{
filterable = false;
}
}
else
{
filterable = false;
}
}
}
if ((this->predictor > 1) && (this->columns == 0))
{
filterable = false;
}
return filterable;
}
Pipeline*
SF_FlateLzwDecode::getDecodePipeline(Pipeline* next)
{
std::shared_ptr<Pipeline> pipeline;
if ((this->predictor >= 10) && (this->predictor <= 15))
{
QTC::TC("qpdf", "SF_FlateLzwDecode PNG filter");
pipeline = std::make_shared<Pl_PNGFilter>(
"png decode", next, Pl_PNGFilter::a_decode,
QIntC::to_uint(this->columns),
QIntC::to_uint(this->colors),
QIntC::to_uint(this->bits_per_component));
this->pipelines.push_back(pipeline);
next = pipeline.get();
}
else if (this->predictor == 2)
{
QTC::TC("qpdf", "SF_FlateLzwDecode TIFF predictor");
pipeline = std::make_shared<Pl_TIFFPredictor>(
"tiff decode", next, Pl_TIFFPredictor::a_decode,
QIntC::to_uint(this->columns),
QIntC::to_uint(this->colors),
QIntC::to_uint(this->bits_per_component));
this->pipelines.push_back(pipeline);
next = pipeline.get();
}
if (lzw)
{
pipeline = std::make_shared<Pl_LZWDecoder>(
"lzw decode", next, early_code_change);
}
else
{
pipeline = std::make_shared<Pl_Flate>(
"stream inflate", next, Pl_Flate::a_inflate);
}
this->pipelines.push_back(pipeline);
return pipeline.get();
}
std::shared_ptr<QPDFStreamFilter>
SF_FlateLzwDecode::flate_factory()
{
return std::make_shared<SF_FlateLzwDecode>(false);
}
std::shared_ptr<QPDFStreamFilter>
SF_FlateLzwDecode::lzw_factory()
{
return std::make_shared<SF_FlateLzwDecode>(true);
}

2
libqpdf/build.mk
View File

@ -70,6 +70,7 @@ SRCS_libqpdf = \
libqpdf/QPDFPageDocumentHelper.cc \
libqpdf/QPDFPageLabelDocumentHelper.cc \
libqpdf/QPDFPageObjectHelper.cc \
libqpdf/QPDFStreamFilter.cc \
libqpdf/QPDFSystemError.cc \
libqpdf/QPDFTokenizer.cc \
libqpdf/QPDFWriter.cc \
@ -94,6 +95,7 @@ SRCS_libqpdf = \
libqpdf/QUtil.cc \
libqpdf/RC4.cc \
libqpdf/SecureRandomDataProvider.cc \
libqpdf/SF_FlateLzwDecode.cc \
libqpdf/SparseOHArray.cc \
libqpdf/qpdf-c.cc

23
libqpdf/qpdf/QPDF_Stream.hh
View File

@ -5,6 +5,10 @@
#include <qpdf/QPDFObject.hh>
#include <qpdf/QPDFObjectHandle.hh>
#include <qpdf/QPDFStreamFilter.hh>
#include <functional>
#include <memory>
class Pipeline;
class QPDF;
@ -49,6 +53,10 @@ class QPDF_Stream: public QPDFObject
void replaceDict(QPDFObjectHandle new_dict);
static void registerStreamFilter(
std::string const& filter_name,
std::function<std::shared_ptr<QPDFStreamFilter>()> factory);
// Replace object ID and generation. This may only be called if
// object ID and generation are 0. It is used by QPDFObjectHandle
// when adding streams to files.
@ -59,20 +67,15 @@ class QPDF_Stream: public QPDFObject
private:
static std::map<std::string, std::string> filter_abbreviations;
static std::map<
std::string,
std::function<std::shared_ptr<QPDFStreamFilter>()>> filter_factories;
void replaceFilterData(QPDFObjectHandle const& filter,
QPDFObjectHandle const& decode_parms,
size_t length);
bool understandDecodeParams(
std::string const& filter, QPDFObjectHandle decode_params,
int& predictor, int& columns,
int& colors, int& bits_per_component,
bool& early_code_change);
bool filterable(std::vector<std::string>& filters,
bool& specialized_compression, bool& lossy_compression,
int& predictor, int& columns,
int& colors, int& bits_per_component,
bool& early_code_change);
bool filterable(std::vector<std::shared_ptr<QPDFStreamFilter>>& filters,
bool& specialized_compression, bool& lossy_compression);
void warn(QPDFExc const& e);
void setDictDescription();
void setStreamDescription();

30
libqpdf/qpdf/SF_ASCII85Decode.hh Normal file
View File

@ -0,0 +1,30 @@
#include <qpdf/QPDFStreamFilter.hh>
#include <qpdf/Pl_ASCII85Decoder.hh>
#include <memory>
#ifndef SF_ASCII85DECODE_HH
#define SF_ASCII85DECODE_HH
class SF_ASCII85Decode: public QPDFStreamFilter
{
public:
SF_ASCII85Decode() = default;
virtual ~SF_ASCII85Decode() = default;
virtual Pipeline* getDecodePipeline(Pipeline* next) override
{
this->pipeline = std::make_shared<Pl_ASCII85Decoder>(
"ascii85 decode", next);
return this->pipeline.get();
}
static std::shared_ptr<QPDFStreamFilter> factory()
{
return std::make_shared<SF_ASCII85Decode>();
}
private:
std::shared_ptr<Pipeline> pipeline;
};
#endif // SF_ASCII85DECODE_HH

30
libqpdf/qpdf/SF_ASCIIHexDecode.hh Normal file
View File

@ -0,0 +1,30 @@
#include <qpdf/QPDFStreamFilter.hh>
#include <qpdf/Pl_ASCIIHexDecoder.hh>
#include <memory>
#ifndef SF_ASCIIHEXDECODE_HH
#define SF_ASCIIHEXDECODE_HH
class SF_ASCIIHexDecode: public QPDFStreamFilter
{
public:
SF_ASCIIHexDecode() = default;
virtual ~SF_ASCIIHexDecode() = default;
virtual Pipeline* getDecodePipeline(Pipeline* next) override
{
this->pipeline = std::make_shared<Pl_ASCIIHexDecoder>(
"asciiHex decode", next);
return this->pipeline.get();
}
static std::shared_ptr<QPDFStreamFilter> factory()
{
return std::make_shared<SF_ASCIIHexDecode>();
}
private:
std::shared_ptr<Pipeline> pipeline;
};
#endif // SF_ASCIIHEXDECODE_HH

39
libqpdf/qpdf/SF_DCTDecode.hh Normal file
View File

@ -0,0 +1,39 @@
#include <qpdf/QPDFStreamFilter.hh>
#include <qpdf/Pl_DCT.hh>
#include <memory>
#ifndef SF_DCTDECODE_HH
#define SF_DCTDECODE_HH
class SF_DCTDecode: public QPDFStreamFilter
{
public:
SF_DCTDecode() = default;
virtual ~SF_DCTDecode() = default;
virtual Pipeline* getDecodePipeline(Pipeline* next) override
{
this->pipeline = std::make_shared<Pl_DCT>("DCT decode", next);
return this->pipeline.get();
}
static std::shared_ptr<QPDFStreamFilter> factory()
{
return std::make_shared<SF_DCTDecode>();
}
virtual bool isSpecializedCompression() override
{
return true;
}
virtual bool isLossyCompression() override
{
return true;
}
private:
std::shared_ptr<Pipeline> pipeline;
};
#endif // SF_DCTDECODE_HH

30
libqpdf/qpdf/SF_FlateLzwDecode.hh Normal file
View File

@ -0,0 +1,30 @@
#include <qpdf/QPDFStreamFilter.hh>
#include <memory>
#include <vector>
#ifndef SF_FLATELZWDECODE_HH
#define SF_FLATELZWDECODE_HH
class SF_FlateLzwDecode: public QPDFStreamFilter
{
public:
SF_FlateLzwDecode(bool lzw);
virtual ~SF_FlateLzwDecode() = default;
virtual bool setDecodeParms(QPDFObjectHandle decode_parms);
virtual Pipeline* getDecodePipeline(Pipeline* next);
static std::shared_ptr<QPDFStreamFilter> flate_factory();
static std::shared_ptr<QPDFStreamFilter> lzw_factory();
private:
bool lzw;
int predictor;
int columns;
int colors;
int bits_per_component;
bool early_code_change;
std::vector<std::shared_ptr<Pipeline>> pipelines;
};
#endif // SF_FLATELZWDECODE_HH

35
libqpdf/qpdf/SF_RunLengthDecode.hh Normal file
View File

@ -0,0 +1,35 @@
#include <qpdf/QPDFStreamFilter.hh>
#include <qpdf/Pl_RunLength.hh>
#include <memory>
#ifndef SF_RUNLENGTHDECODE_HH
#define SF_RUNLENGTHDECODE_HH
class SF_RunLengthDecode: public QPDFStreamFilter
{
public:
SF_RunLengthDecode() = default;
virtual ~SF_RunLengthDecode() = default;
virtual Pipeline* getDecodePipeline(Pipeline* next) override
{
this->pipeline = std::make_shared<Pl_RunLength>(
"runlength decode", next, Pl_RunLength::a_decode);
return this->pipeline.get();
}
static std::shared_ptr<QPDFStreamFilter> factory()
{
return std::make_shared<SF_RunLengthDecode>();
}
virtual bool isSpecializedCompression() override
{
return true;
}
private:
std::shared_ptr<Pipeline> pipeline;
};
#endif // SF_RUNLENGTHDECODE_HH

4
qpdf/qpdf.testcov
View File

@ -86,7 +86,7 @@ QPDF prev key in trailer dictionary 0
QPDF found xref stream 0
QPDF ignoring XRefStm in trailer 0
QPDF xref deleted object 0
QPDF_Stream PNG filter 0
SF_FlateLzwDecode PNG filter 0
QPDF xref /Index is null 0
QPDF xref /Index is array 1
QPDFWriter copy Extends 0
@ -294,7 +294,7 @@ qpdf-c called qpdf_set_decode_level 0
qpdf-c called qpdf_set_compress_streams 0
qpdf-c called qpdf_set_preserve_unreferenced_objects 0
qpdf-c called qpdf_set_newline_before_endstream 0
QPDF_Stream TIFF predictor 0
SF_FlateLzwDecode TIFF predictor 0
QPDFTokenizer inline image at EOF 0
Pl_QPDFTokenizer found ID 0
QPDFObjectHandle non-stream in stream array 0