diff options
author | Jay Berkenbilt <ejb@ql.org> | 2020-12-23 12:12:49 +0100 |
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committer | Jay Berkenbilt <ejb@ql.org> | 2020-12-28 18:58:19 +0100 |
commit | 39bfa0130713defc9abb478a70717ca07377cdab (patch) | |
tree | 18b6370d5f2f7d10a3f1ef09a8f0dd3b9281bd3c /libqpdf/SF_FlateLzwDecode.cc | |
parent | 1fb26f08ad91d08f67ac30e2557ddcadd8b9ccac (diff) | |
download | qpdf-39bfa0130713defc9abb478a70717ca07377cdab.tar.zst |
Implement user-provided stream filters
Refactor QPDF_Stream to use stream filter classes to handle supported
stream filters as well.
Diffstat (limited to 'libqpdf/SF_FlateLzwDecode.cc')
-rw-r--r-- | libqpdf/SF_FlateLzwDecode.cc | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/libqpdf/SF_FlateLzwDecode.cc b/libqpdf/SF_FlateLzwDecode.cc new file mode 100644 index 00000000..29064cc0 --- /dev/null +++ b/libqpdf/SF_FlateLzwDecode.cc @@ -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); +} |