PDF4QT/Pdf4QtLib/sources/pdfprogress.cpp

67 lines
2.0 KiB
C++

// Copyright (C) 2019-2021 Jakub Melka
//
// This file is part of PDF4QT.
//
// PDF4QT is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// with the written consent of the copyright owner, any later version.
//
// PDF4QT is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
#include "pdfprogress.h"
namespace pdf
{
PDFProgress::PDFProgress(QObject* parent) :
QObject(parent)
{
qRegisterMetaType<pdf::ProgressStartupInfo>();
}
void PDFProgress::start(size_t stepCount, ProgressStartupInfo startupInfo)
{
Q_ASSERT(stepCount > 0);
m_currentStep = 0;
m_stepCount = stepCount;
m_percentage = 0;
emit progressStarted(qMove(startupInfo));
}
void PDFProgress::step()
{
// Atomically increment by one. We must add + 1 to the current step,
// because fetch_add will return old value. Then we must test, if percentage
// has been changed.
size_t currentStep = m_currentStep.fetch_add(1) + 1;
int newPercentage = int((size_t(100) * currentStep) / m_stepCount);
int oldPercentage = m_percentage.load(std::memory_order_acquire);
bool emitSignal = oldPercentage < newPercentage;
do
{
emitSignal = oldPercentage < newPercentage;
} while (oldPercentage < newPercentage && !m_percentage.compare_exchange_weak(oldPercentage, newPercentage, std::memory_order_release, std::memory_order_relaxed));
if (emitSignal)
{
emit progressStep(newPercentage);
}
}
void PDFProgress::finish()
{
emit progressFinished();
}
} // namespace pdf