mirror of https://github.com/JakubMelka/PDF4QT.git
93 lines
2.8 KiB
C++
93 lines
2.8 KiB
C++
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// Copyright (C) 2020 Jakub Melka
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//
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// This file is part of PdfForQt.
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//
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// PdfForQt 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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// (at your option) any later version.
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//
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// PdfForQt 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 PDFForQt. If not, see <https://www.gnu.org/licenses/>.
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#include "pdfexecutionpolicy.h"
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#include <QThread>
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namespace pdf
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{
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struct PDFExecutionPolicyHolder
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{
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PDFExecutionPolicy policy;
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} s_execution_policy;
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void PDFExecutionPolicy::setStrategy(Strategy strategy)
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{
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s_execution_policy.policy.m_strategy.store(strategy, std::memory_order_relaxed);
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}
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bool PDFExecutionPolicy::isParallelizing(Scope scope)
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{
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const Strategy strategy = s_execution_policy.policy.m_strategy.load(std::memory_order_relaxed);
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switch (strategy)
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{
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case Strategy::SingleThreaded:
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return false;
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case Strategy::PageMultithreaded:
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{
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switch (scope)
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{
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case Scope::Page:
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case Scope::Unknown:
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return true; // We are parallelizing pages...
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case Scope::Content:
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{
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// Jakub Melka: this is a bit complicated. We must count number of content streams
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// being processed and if it is large enough, then do not parallelize.
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const size_t threadLimit = s_execution_policy.policy.m_threadLimit.load(std::memory_order_relaxed);
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const size_t contentStreamsCount = s_execution_policy.policy.m_contentStreamsCount.load(std::memory_order_seq_cst);
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return contentStreamsCount < threadLimit;
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}
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}
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break;
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}
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case Strategy::AlwaysMultithreaded:
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return true;
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}
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// It should never go here...
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Q_ASSERT(false);
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return false;
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}
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void PDFExecutionPolicy::startProcessingContentStream()
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{
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++s_execution_policy.policy.m_contentStreamsCount;
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}
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void PDFExecutionPolicy::endProcessingContentStream()
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{
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--s_execution_policy.policy.m_contentStreamsCount;
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}
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PDFExecutionPolicy::PDFExecutionPolicy() :
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m_contentStreamsCount(0),
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m_threadLimit(QThread::idealThreadCount()),
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m_strategy(Strategy::PageMultithreaded)
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{
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}
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} // namespace pdf
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