#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