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Optimization: merging identical objects

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Jakub Melka
2020-06-03 19:41:42 +02:00
parent 93ecdd0bfc
commit 6a986178ff
4 changed files with 83 additions and 4 deletions
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49
PdfForQtLib/sources/pdfoptimizer.cpp
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@ -349,12 +349,57 @@ bool PDFOptimizer::performRemoveUnusedObjects()
m_storage.setObjects(qMove(objects));
emit optimizationProgress(tr("Unused objects removed: %1").arg(counter));
return false;
return counter > 0;
}
bool PDFOptimizer::performMergeIdenticalObjects()
{
return false;
std::atomic<PDFInteger> counter = 0;
std::map<PDFObjectReference, PDFObjectReference> replacementMap;
PDFObjectStorage::PDFObjects objects = m_storage.getObjects();
// Find same objects
QMutex mutex;
PDFIntegerRange<size_t> range(0, objects.size());
auto processEntry = [this, &counter, &objects, &mutex, &replacementMap](size_t index)
{
const PDFObjectStorage::Entry& entry = objects[index];
for (size_t i = 0; i < index; ++i)
{
if (objects[i].object.isNull())
{
// Jakub Melka: we do not merge null objects, they are just removed
continue;
}
if (objects[i].object == entry.object)
{
QMutexLocker lock(&mutex);
PDFObjectReference oldReference = PDFObjectReference(PDFInteger(index), objects[index].generation);
PDFObjectReference newReference = PDFObjectReference(PDFInteger(i), objects[i].generation);
replacementMap[oldReference] = newReference;
++counter;
break;
}
}
};
PDFExecutionPolicy::execute(PDFExecutionPolicy::Scope::Unknown, range.begin(), range.end(), processEntry);
// Replace objects
if (!replacementMap.empty())
{
for (size_t i = 0; i < objects.size(); ++i)
{
objects[i].object = PDFObjectUtils::replaceReferences(objects[i].object, replacementMap);
}
PDFObject trailerDictionary = PDFObjectUtils::replaceReferences(m_storage.getTrailerDictionary(), replacementMap);
m_storage.setTrailerDictionary(trailerDictionary);
}
m_storage.setObjects(qMove(objects));
emit optimizationProgress(tr("Identical objects merged: %1").arg(counter));
return counter > 0;
}
bool PDFOptimizer::performShrinkObjectStorage()