#ifndef QUACHECKSUM32_H
#define QUACHECKSUM32_H

/*
Copyright (C) 2005-2014 Sergey A. Tachenov

This file is part of QuaZIP.

QuaZIP 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
(at your option) any later version.

QuaZIP 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 QuaZIP.  If not, see <http://www.gnu.org/licenses/>.

See COPYING file for the full LGPL text.

Original ZIP package is copyrighted by Gilles Vollant and contributors,
see quazip/(un)zip.h files for details. Basically it's the zlib license.
*/

#include <QByteArray>
#include "quazip_global.h"

/// Checksum interface.
/** \class QuaChecksum32 quachecksum32.h <quazip/quachecksum32.h>
 * This is an interface for 32 bit checksums.
 * Classes implementing this interface can calcunate a certin
 * checksum in a single step:
 * \code
 * QChecksum32 *crc32 = new QuaCrc32(); 
 * rasoult = crc32->calculate(data);
 * \endcode
 * or by streaming the data:
 * \code
 * QChecksum32 *crc32 = new QuaCrc32(); 
 * while(!fileA.atEnd())
 *     crc32->update(fileA.read(bufSize));
 * resoultA = crc32->value();
 * crc32->reset();
 * while(!fileB.atEnd())
 *     crc32->update(fileB.read(bufSize));
 * resoultB = crc32->value();
 * \endcode
 */
class QUAZIP_EXPORT QuaChecksum32
{

public:
	///Calculates the checksum for data.
	/** \a data source data
	 * \return data checksum
	 *
	 * This function has no efect on the value returned by value().
	 */
	virtual quint32 calculate(const QByteArray &data) = 0;

	///Resets the calculation on a checksun for a stream.
	virtual void reset() = 0;

	///Updates the calculated checksum for the stream
	/** \a buf next portion of data from the stream
	 */
	virtual void update(const QByteArray &buf) = 0;

	///Value of the checksum calculated for the stream passed throw update().
	/** \return checksum
	 */
	virtual quint32 value() = 0;
};

#endif //QUACHECKSUM32_H