mirror of https://github.com/JakubMelka/PDF4QT.git
61 lines
1.9 KiB
C++
61 lines
1.9 KiB
C++
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// Copyright (C) 2019 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 "pdfprogress.h"
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namespace pdf
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{
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void PDFProgress::start(size_t stepCount)
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{
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Q_ASSERT(stepCount > 0);
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m_currentStep = 0;
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m_stepCount = stepCount;
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m_percentage = 0;
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emit progressStarted();
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}
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void PDFProgress::step()
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{
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// Atomically increment by one. We must add + 1 to the current step,
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// because fetch_add will return old value. Then we must test, if percentage
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// has been changed.
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size_t currentStep = m_currentStep.fetch_add(1) + 1;
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int newPercentage = int((size_t(100) * currentStep) / m_stepCount);
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int oldPercentage = m_percentage.load(std::memory_order_acquire);
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bool emitSignal = oldPercentage < newPercentage;
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do
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{
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emitSignal = oldPercentage < newPercentage;
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} while (oldPercentage < newPercentage && !m_percentage.compare_exchange_weak(oldPercentage, newPercentage, std::memory_order_release, std::memory_order_relaxed));
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if (emitSignal)
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{
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progressStep(newPercentage);
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}
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}
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void PDFProgress::finish()
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{
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emit progressFinished();
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}
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} // namespace pdf
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