gzip.h

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// gzip.h - originally 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=NULLPTR, unsigned int deflateLevel=DEFAULT_DEFLATE_LEVEL, unsigned int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE, bool detectUncompressible=true)
                : Deflator(attachment, deflateLevel, log2WindowSize, detectUncompressible), m_totalLen(0), m_filetime(0) { }
 
        Gzip(const NameValuePairs &parameters, BufferedTransformation *attachment=NULLPTR)
                : Deflator(parameters, attachment), m_totalLen(0), m_filetime(0)
        {
                IsolatedInitialize(parameters);
        }
 
        void SetFiletime(word32 filetime) { m_filetime = filetime; }
 
        void SetFilename(const std::string& filename, bool throwOnEncodingError = false);
 
        void SetComment(const std::string& comment, bool throwOnEncodingError = false);
 
        void IsolatedInitialize(const NameValuePairs &parameters);
 
protected:
        enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header
                  DEFLATED=8, FAST=4, SLOW=2};
 
        enum FLAG_MASKS {
                FILENAME=8, COMMENTS=16};
 
        void WritePrestreamHeader();
        void ProcessUncompressedData(const byte *string, size_t length);
        void WritePoststreamTail();
 
        word32 m_totalLen;
        CRC32 m_crc;
 
        word32 m_filetime;
        std::string m_filename;
        std::string m_comment;
};
 
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 = NULLPTR, bool repeat = false, int autoSignalPropagation = -1);
 
        word32 GetFiletime() const { return m_filetime; }
 
        const std::string& GetFilename(bool throwOnEncodingError = false) const;
 
        const std::string& GetComment(bool throwOnEncodingError = false) const;
 
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;
 
        word32 m_filetime;
        std::string m_filename;
        std::string m_comment;
};
 
NAMESPACE_END
 
#endif