gzip.h

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// gzip.h - written and placed in the public domain by Wei Dai


#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 : 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), m_totalLen(0) {}
        Gzip(const NameValuePairs &parameters, 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 : 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") {}};

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

protected:
        enum {
                MAGIC1=0x1f,
                MAGIC2=0x8b,
                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