mirror of https://github.com/JakubMelka/PDF4QT.git
485 lines
15 KiB
C++
485 lines
15 KiB
C++
// Copyright (C) 2020-2021 Jakub Melka
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//
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// This file is part of PDF4QT.
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//
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// PDF4QT is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// with the written consent of the copyright owner, any later version.
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//
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// PDF4QT is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
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#include "pdfobjectutils.h"
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#include "pdfvisitor.h"
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#include "pdfexecutionpolicy.h"
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#include "pdfdocumentwriter.h"
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namespace pdf
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{
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class PDFCollectReferencesVisitor : public PDFAbstractVisitor
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{
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public:
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explicit PDFCollectReferencesVisitor(std::set<PDFObjectReference>& references) :
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m_references(references)
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{
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}
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virtual void visitArray(const PDFArray* array) override;
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virtual void visitDictionary(const PDFDictionary* dictionary) override;
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virtual void visitStream(const PDFStream* stream) override;
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virtual void visitReference(const PDFObjectReference reference) override;
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private:
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std::set<PDFObjectReference>& m_references;
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};
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void PDFCollectReferencesVisitor::visitArray(const PDFArray* array)
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{
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acceptArray(array);
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}
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void PDFCollectReferencesVisitor::visitDictionary(const PDFDictionary* dictionary)
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{
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acceptDictionary(dictionary);
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}
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void PDFCollectReferencesVisitor::visitStream(const PDFStream* stream)
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{
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acceptStream(stream);
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}
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void PDFCollectReferencesVisitor::visitReference(const PDFObjectReference reference)
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{
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m_references.insert(reference);
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}
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class PDFReplaceReferencesVisitor : public PDFAbstractVisitor
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{
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public:
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explicit PDFReplaceReferencesVisitor(const std::map<PDFObjectReference, PDFObjectReference>& replacements) :
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m_replacements(replacements)
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{
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m_objectStack.reserve(32);
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}
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virtual void visitNull() override;
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virtual void visitBool(bool value) override;
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virtual void visitInt(PDFInteger value) override;
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virtual void visitReal(PDFReal value) override;
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virtual void visitString(PDFStringRef string) override;
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virtual void visitName(PDFStringRef name) override;
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virtual void visitArray(const PDFArray* array) override;
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virtual void visitDictionary(const PDFDictionary* dictionary) override;
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virtual void visitStream(const PDFStream* stream) override;
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virtual void visitReference(const PDFObjectReference reference) override;
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PDFObject getObject();
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private:
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const std::map<PDFObjectReference, PDFObjectReference>& m_replacements;
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std::vector<PDFObject> m_objectStack;
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};
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void PDFReplaceReferencesVisitor::visitNull()
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{
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m_objectStack.push_back(PDFObject::createNull());
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}
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void PDFReplaceReferencesVisitor::visitBool(bool value)
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{
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m_objectStack.push_back(PDFObject::createBool(value));
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}
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void PDFReplaceReferencesVisitor::visitInt(PDFInteger value)
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{
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m_objectStack.push_back(PDFObject::createInteger(value));
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}
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void PDFReplaceReferencesVisitor::visitReal(PDFReal value)
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{
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m_objectStack.push_back(PDFObject::createReal(value));
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}
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void PDFReplaceReferencesVisitor::visitString(PDFStringRef string)
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{
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m_objectStack.push_back(PDFObject::createString(string));
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}
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void PDFReplaceReferencesVisitor::visitName(PDFStringRef name)
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{
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m_objectStack.push_back(PDFObject::createName(name));
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}
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void PDFReplaceReferencesVisitor::visitArray(const PDFArray* array)
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{
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acceptArray(array);
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// We have all objects on the stack
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Q_ASSERT(array->getCount() <= m_objectStack.size());
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auto it = std::next(m_objectStack.cbegin(), m_objectStack.size() - array->getCount());
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std::vector<PDFObject> objects(it, m_objectStack.cend());
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PDFObject object = PDFObject::createArray(std::make_shared<PDFArray>(qMove(objects)));
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m_objectStack.erase(it, m_objectStack.cend());
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m_objectStack.push_back(object);
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}
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void PDFReplaceReferencesVisitor::visitDictionary(const PDFDictionary* dictionary)
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{
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Q_ASSERT(dictionary);
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std::vector<PDFDictionary::DictionaryEntry> entries;
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entries.reserve(dictionary->getCount());
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for (size_t i = 0, count = dictionary->getCount(); i < count; ++i)
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{
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dictionary->getValue(i).accept(this);
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entries.emplace_back(dictionary->getKey(i), m_objectStack.back());
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m_objectStack.pop_back();
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}
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m_objectStack.push_back(PDFObject::createDictionary(std::make_shared<PDFDictionary>(qMove(entries))));
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}
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void PDFReplaceReferencesVisitor::visitStream(const PDFStream* stream)
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{
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// Replace references in the dictionary
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visitDictionary(stream->getDictionary());
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PDFObject dictionaryObject = m_objectStack.back();
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m_objectStack.pop_back();
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m_objectStack.push_back(PDFObject::createStream(std::make_shared<PDFStream>(PDFDictionary(*dictionaryObject.getDictionary()), QByteArray(*stream->getContent()))));
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}
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void PDFReplaceReferencesVisitor::visitReference(const PDFObjectReference reference)
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{
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auto it = m_replacements.find(reference);
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if (it != m_replacements.cend())
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{
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// Replace the reference
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m_objectStack.push_back(PDFObject::createReference(it->second));
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}
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else
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{
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// Preserve old reference
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m_objectStack.push_back(PDFObject::createReference(reference));
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}
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}
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PDFObject PDFReplaceReferencesVisitor::getObject()
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{
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Q_ASSERT(m_objectStack.size() == 1);
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return qMove(m_objectStack.back());
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}
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std::set<PDFObjectReference> PDFObjectUtils::getReferences(const std::vector<PDFObject>& objects, const PDFObjectStorage& storage)
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{
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std::set<PDFObjectReference> references;
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{
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PDFCollectReferencesVisitor collectReferencesVisitor(references);
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for (const PDFObject& object : objects)
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{
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object.accept(&collectReferencesVisitor);
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}
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}
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// Iterative algorihm, which adds additional references from referenced objects.
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// If new reference is added, then we must also check, that all referenced objects
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// from this object are added.
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std::set<PDFObjectReference> workSet = references;
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while (!workSet.empty())
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{
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std::set<PDFObjectReference> addedReferences;
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PDFCollectReferencesVisitor collectReferencesVisitor(addedReferences);
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for (const PDFObjectReference& objectReference : workSet)
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{
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storage.getObject(objectReference).accept(&collectReferencesVisitor);
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}
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workSet.clear();
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std::set_difference(addedReferences.cbegin(), addedReferences.cend(), references.cbegin(), references.cend(), std::inserter(workSet, workSet.cend()));
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references.merge(addedReferences);
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}
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return references;
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}
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std::set<PDFObjectReference> PDFObjectUtils::getDirectReferences(const PDFObject& object)
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{
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std::set<PDFObjectReference> references;
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PDFCollectReferencesVisitor collectReferencesVisitor(references);
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object.accept(&collectReferencesVisitor);
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return references;
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}
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PDFObject PDFObjectUtils::replaceReferences(const PDFObject& object, const std::map<PDFObjectReference, PDFObjectReference>& referenceMapping)
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{
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PDFReplaceReferencesVisitor replaceReferencesVisitor(referenceMapping);
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object.accept(&replaceReferencesVisitor);
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return replaceReferencesVisitor.getObject();
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}
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QString PDFObjectUtils::getObjectTypeName(PDFObject::Type type)
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{
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switch (type)
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{
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case pdf::PDFObject::Type::Null:
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return PDFTranslationContext::tr("Null");
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case pdf::PDFObject::Type::Bool:
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return PDFTranslationContext::tr("Boolean");
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case pdf::PDFObject::Type::Int:
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return PDFTranslationContext::tr("Integer");
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case pdf::PDFObject::Type::Real:
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return PDFTranslationContext::tr("Real");
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case pdf::PDFObject::Type::String:
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return PDFTranslationContext::tr("String");
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case pdf::PDFObject::Type::Name:
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return PDFTranslationContext::tr("Name");
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case pdf::PDFObject::Type::Array:
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return PDFTranslationContext::tr("Array");
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case pdf::PDFObject::Type::Dictionary:
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return PDFTranslationContext::tr("Dictionary");
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case pdf::PDFObject::Type::Stream:
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return PDFTranslationContext::tr("Stream");
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case pdf::PDFObject::Type::Reference:
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return PDFTranslationContext::tr("Reference");
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default:
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Q_ASSERT(false);
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break;
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}
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return QString();
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}
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void PDFObjectClassifier::classify(const PDFDocument* document)
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{
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// Clear old classification, if it exist
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m_classification.clear();
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m_allTypesUsed = None;
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if (!document)
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{
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return;
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}
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PDFDocumentDataLoaderDecorator loader(document);
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const PDFObjectStorage& storage = document->getStorage();
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const PDFObjectStorage::PDFObjects& objects = storage.getObjects();
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m_classification.resize(objects.size(), Classification());
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for (size_t i = 0; i < objects.size(); ++i)
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{
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PDFObjectReference reference(i, objects[i].generation);
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m_classification[i].reference = reference;
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}
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// First, iterate trough pages of the document
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const PDFCatalog* catalog = document->getCatalog();
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const size_t pageCount = catalog->getPageCount();
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for (size_t i = 0; i < pageCount; ++i)
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{
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const PDFPage* page = catalog->getPage(i);
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if (!page)
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{
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continue;
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}
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// Handle page itself
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if (hasObject(page->getPageReference()))
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{
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mark(page->getPageReference(), Page);
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}
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// Handle annotations
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for (const PDFObjectReference& reference : page->getAnnotations())
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{
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if (hasObject(reference))
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{
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mark(reference, Annotation);
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}
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}
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// Handle contents
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PDFObject pageObject = document->getObjectByReference(page->getPageReference());
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Q_ASSERT(pageObject.isDictionary());
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const PDFDictionary* dictionary = pageObject.getDictionary();
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const PDFObject& contentsObject = dictionary->get("Contents");
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if (contentsObject.isReference())
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{
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mark(contentsObject.getReference(), ContentStream);
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}
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// Handle resources
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if (const PDFDictionary* resourcesDictionary = document->getDictionaryFromObject(dictionary->get("Resources")))
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{
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markDictionary(document, resourcesDictionary->get("ExtGState"), GraphicState);
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markDictionary(document, resourcesDictionary->get("ColorSpace"), ColorSpace);
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markDictionary(document, resourcesDictionary->get("Pattern"), Pattern);
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markDictionary(document, resourcesDictionary->get("Shading"), Shading);
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markDictionary(document, resourcesDictionary->get("Font"), Font);
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if (const PDFDictionary* xobjectDictionary = document->getDictionaryFromObject(resourcesDictionary->get("XObject")))
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{
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const size_t count = xobjectDictionary->getCount();
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for (size_t i = 0; i < count; ++i)
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{
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const PDFObject& item = xobjectDictionary->getValue(i);
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if (item.isReference() && hasObject(item.getReference()))
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{
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if (const PDFDictionary* xobjectItemDictionary = document->getDictionaryFromObject(item))
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{
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QByteArray subtype = loader.readNameFromDictionary(xobjectItemDictionary, "Subtype");
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if (subtype == "Image")
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{
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mark(item.getReference(), Image);
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}
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else if (subtype == "Form")
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{
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mark(item.getReference(), Form);
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}
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}
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}
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}
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}
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}
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}
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for (Classification& classification : m_classification)
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{
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if (const PDFDictionary* dictionary = document->getDictionaryFromObject(document->getObjectByReference(classification.reference)))
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{
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QByteArray typeName = loader.readNameFromDictionary(dictionary, "Type");
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if (typeName == "Action")
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{
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classification.types.setFlag(Action);
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}
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}
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}
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for (const Classification& classification : m_classification)
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{
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m_allTypesUsed |= classification.types;
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}
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}
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bool PDFObjectClassifier::hasObject(PDFObjectReference reference) const
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{
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return reference.isValid() &&
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reference.objectNumber < PDFInteger(m_classification.size()) &&
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m_classification[reference.objectNumber].reference == reference;
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}
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std::vector<PDFObjectReference> PDFObjectClassifier::getObjectsByType(Type type) const
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{
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std::vector<PDFObjectReference> result;
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for (const Classification& classification : m_classification)
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{
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if (classification.types.testFlag(type))
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{
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result.push_back(classification.reference);
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}
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}
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return result;
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}
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PDFObjectClassifier::Statistics PDFObjectClassifier::calculateStatistics(const PDFDocument* document) const
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{
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Statistics result;
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// Jakub Melka: prepare statistics map
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result.statistics[None];
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for (uint i = 0; i < 32; ++i)
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{
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uint32_t mask = 1 << i;
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if (m_allTypesUsed & mask)
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{
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result.statistics[Type(mask)];
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}
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}
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auto processEntry = [document, &result](const Classification& entry)
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{
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const PDFObject& object = document->getObjectByReference(entry.reference);
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if (object.isNull())
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{
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return;
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}
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Type type = Type(uint32_t(entry.types));
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if (!result.statistics.count(type))
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{
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type = None;
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}
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Q_ASSERT(result.statistics.count(type));
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const qint64 objectSize = PDFDocumentWriter::getObjectSize(document, entry.reference);
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StatisticsItem& statisticsItem = result.statistics.at(type);
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statisticsItem.count.fetch_add(1);
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statisticsItem.bytes.fetch_add(objectSize);
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};
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PDFExecutionPolicy::execute(PDFExecutionPolicy::Scope::Unknown, m_classification.cbegin(), m_classification.cend(), processEntry);
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PDFStatisticsCollector collector;
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PDFApplyVisitor(*document, &collector);
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for (PDFObject::Type objectType : PDFObject::getTypes())
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{
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result.objectCountByType[size_t(objectType)] = collector.getObjectCount(objectType);
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}
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return result;
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}
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void PDFObjectClassifier::mark(PDFObjectReference reference, Type type)
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{
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Q_ASSERT(hasObject(reference));
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m_classification[reference.objectNumber].types.setFlag(type, true);
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}
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void PDFObjectClassifier::markDictionary(const PDFDocument* document, PDFObject object, Type type)
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{
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if (const PDFDictionary* dictionary = document->getDictionaryFromObject(object))
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{
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const size_t count = dictionary->getCount();
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for (size_t i = 0; i < count; ++i)
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{
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const PDFObject& item = dictionary->getValue(i);
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if (item.isReference() && hasObject(item.getReference()))
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{
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mark(item.getReference(), type);
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}
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}
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}
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}
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} // namespace pdf
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