#ifndef QUACHECKSUM32_H

#define QUACHECKSUM32_H

#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