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// gzip.h - written and placed in the public domain by Wei Dai
//! \file gzip.h
//! \brief GZIP compression and decompression (RFC 1952)
#ifndef CRYPTOPP_GZIP_H
#define CRYPTOPP_GZIP_H
#include "cryptlib.h"
#include "zdeflate.h"
#include "zinflate.h"
#include "crc.h"
NAMESPACE_BEGIN(CryptoPP)
//! \class Gzip
//! \brief GZIP Compression (RFC 1952)
class Gzip : public Deflator
{
public:
//! \brief Construct a Gzip compressor
//! \param attachment an attached transformation
//! \param deflateLevel the deflate level
//! \param log2WindowSize the window size
//! \param detectUncompressible flag to detect if data is compressible
//! \details detectUncompressible makes it faster to process uncompressible files, but
//! if a file has both compressible and uncompressible parts, it may fail to compress
//! some of the compressible parts.
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), m_totalLen(0) {}
//! \brief Construct a Gzip compressor
//! \param parameters a set of NameValuePairs to initialize this object
//! \param attachment an attached transformation
//! \details Possible parameter names: Log2WindowSize, DeflateLevel, DetectUncompressible
Gzip(const NameValuePairs ¶meters, BufferedTransformation *attachment=NULL)
: Deflator(parameters, attachment), m_totalLen(0) {}
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;
};
//! \class Gunzip
//! \brief GZIP Decompression (RFC 1952)
class Gunzip : public Inflator
{
public:
typedef Inflator::Err Err;
//! \class HeaderErr
//! \brief Exception thrown when a header decoding error occurs
class HeaderErr : public Err {public: HeaderErr() : Err(INVALID_DATA_FORMAT, "Gunzip: header decoding error") {}};
//! \class TailErr
//! \brief Exception thrown when the tail is too short
class TailErr : public Err {public: TailErr() : Err(INVALID_DATA_FORMAT, "Gunzip: tail too short") {}};
//! \class CrcErr
//! \brief Exception thrown when a CRC error occurs
class CrcErr : public Err {public: CrcErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: CRC check error") {}};
//! \class LengthErr
//! \brief Exception thrown when a length error occurs
class LengthErr : public Err {public: LengthErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: length check error") {}};
//! \brief Construct a Gunzip decompressor
//! \param attachment an attached transformation
//! \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 {
//! \brief First header magic value
MAGIC1=0x1f,
//! \brief Second header magic value
MAGIC2=0x8b,
//! \brief Deflated flag
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
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