PacFileSlicer.h

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/***************************************************************************
 *   Copyright (C) 2008-2010 by Matthias Nagl                              *
 *   mnagl@uni-goettingen.de                                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program 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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
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 ***************************************************************************/

#ifndef PACFILESLICER_H
#define PACFILESLICER_H

#include <QIODevice>
#include <QFile>

class PacFileSlicer : public QIODevice
{
Q_OBJECT
public:
  explicit PacFileSlicer(QFile *input, quint64 beginning, quint64 end, QObject *parent = 0) : QIODevice(parent), input(input), slicebeginning(beginning), sliceend(end) { input->seek(beginning); };
    virtual ~PacFileSlicer() {};

    virtual void selectSlice(quint64 beginning, quint64 end) {
      Q_ASSERT(beginning <= end);
      slicebeginning = beginning;
      sliceend = end;
      input->seek(slicebeginning);
    };
    virtual bool isSequential() const { return true; };
    virtual qint64 bytesAvailable() const { return sliceend-input->pos() + QIODevice::bytesAvailable(); };

signals:

public slots:

protected:
    virtual qint64 readData(char * data, qint64 maxSize) { return input->read(data, qMin(qint64(sliceend)-input->pos(), maxSize)); };
    virtual qint64 writeData(const char *, qint64) { return -1; };

private:
    QFile *input;
    quint64 slicebeginning, sliceend;
};

#endif // PACFILESLICER_H