~zooko/cryptopp/trunk

#ifndef CRYPTOPP_GZIP_H

#define CRYPTOPP_GZIP_H

#include "zdeflate.h"

#include "zinflate.h"

#include "crc.h"

NAMESPACE_BEGIN(CryptoPP)

/// GZIP Compression (RFC 1952)

class Gzip : public Deflator

{

public:

	Gzip(BufferedTransformation *attachment=NULL, unsigned int deflateLevel=DEFAULT_DEFLATE_LEVEL, unsigned int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE, bool detectUncompressible=true)

		: Deflator(attachment, deflateLevel, log2WindowSize, detectUncompressible) {}

	Gzip(const NameValuePairs &parameters, BufferedTransformation *attachment=NULL)

		: Deflator(parameters, attachment) {}

protected:

	enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header

		  DEFLATED=8, FAST=4, SLOW=2};

	void WritePrestreamHeader();

	void ProcessUncompressedData(const byte *string, size_t length);

	void WritePoststreamTail();

	word32 m_totalLen;

	CRC32 m_crc;

};

/// GZIP Decompression (RFC 1952)

class Gunzip : public Inflator

{

public:

	typedef Inflator::Err Err;

	class HeaderErr : public Err {public: HeaderErr() : Err(INVALID_DATA_FORMAT, "Gunzip: header decoding error") {}};

	class TailErr : public Err {public: TailErr() : Err(INVALID_DATA_FORMAT, "Gunzip: tail too short") {}};

	class CrcErr : public Err {public: CrcErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: CRC check error") {}};

	class LengthErr : public Err {public: LengthErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: length check error") {}};

	/*! \param repeat decompress multiple compressed streams in series

		\param autoSignalPropagation 0 to turn off MessageEnd signal

	*/

	Gunzip(BufferedTransformation *attachment = NULL, bool repeat = false, int autoSignalPropagation = -1);

protected:

	enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header

		DEFLATED=8};

	enum FLAG_MASKS {

		CONTINUED=2, EXTRA_FIELDS=4, FILENAME=8, COMMENTS=16, ENCRYPTED=32};

	unsigned int MaxPrestreamHeaderSize() const {return 1024;}

	void ProcessPrestreamHeader();

	void ProcessDecompressedData(const byte *string, size_t length);

	unsigned int MaxPoststreamTailSize() const {return 8;}

	void ProcessPoststreamTail();

	word32 m_length;

	CRC32 m_crc;

};

NAMESPACE_END

#endif