trikV4l2VideoDevice.h

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/* Copyright 2018 Ivan Tyulyandin and CyberTech Labs Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License. */

#pragma once

#include <QObject>
#include <QSocketNotifier>
#include <QtCore/QString>
#include <QtCore/QVector>
#include <QtCore/QSocketNotifier>
#include <linux/videodev2.h>

using convertFunctionPtr = QVector<uint8_t> (*)(const QVector<uint8_t> &realCameraShot, int height, int width);

class TrikV4l2VideoDevice: QObject
{
    Q_OBJECT
public:

    explicit TrikV4l2VideoDevice(const QString &inputFile);

    ~TrikV4l2VideoDevice();

    const QVector<uint8_t> & makeShot();

    const QVector<uint8_t> & getFrame() const { return mFrame; }

signals:
    void dataReady();

public slots:
    void readFrameData(int fd);

private:
    void closeDevice();
    void setFormat();
    void openDevice();
    int xioctl(unsigned long request, void *arg, const QString &possibleError);
    void initMMAP();
    void startCapturing();
    int readFrame();
    void stopCapturing();
    void freeMMAP();

    int mFileDescriptor = -1;
    const QString fileDevicePath;

    struct buffer {
        uint8_t *start;
        size_t  length;
    };
    QVector<uint8_t> mFrame;
    QVector<buffer> buffers;
    v4l2_format mFormat {};
    QSocketNotifier *mNotifier {}; // Has ownership
    convertFunctionPtr mConvertFunc; // convert real camera shot to RGB888
};