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gzip.h

00001 #ifndef CRYPTOPP_GZIP_H
00002 #define CRYPTOPP_GZIP_H
00003 
00004 #include "zdeflate.h"
00005 #include "zinflate.h"
00006 #include "crc.h"
00007 
00008 NAMESPACE_BEGIN(CryptoPP)
00009 
00010 /// GZIP Compression (RFC 1952)
00011 class Gzip : public Deflator
00012 {
00013 public:
00014     Gzip(BufferedTransformation *attachment=NULL, unsigned int deflateLevel=DEFAULT_DEFLATE_LEVEL, unsigned int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE, bool detectUncompressible=true)
00015         : Deflator(attachment, deflateLevel, log2WindowSize, detectUncompressible) {}
00016     Gzip(const NameValuePairs &parameters, BufferedTransformation *attachment=NULL)
00017         : Deflator(parameters, attachment) {}
00018 
00019 protected:
00020     enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header
00021           DEFLATED=8, FAST=4, SLOW=2};
00022 
00023     void WritePrestreamHeader();
00024     void ProcessUncompressedData(const byte *string, size_t length);
00025     void WritePoststreamTail();
00026 
00027     word32 m_totalLen;
00028     CRC32 m_crc;
00029 };
00030 
00031 /// GZIP Decompression (RFC 1952)
00032 class Gunzip : public Inflator
00033 {
00034 public:
00035     typedef Inflator::Err Err;
00036     class HeaderErr : public Err {public: HeaderErr() : Err(INVALID_DATA_FORMAT, "Gunzip: header decoding error") {}};
00037     class TailErr : public Err {public: TailErr() : Err(INVALID_DATA_FORMAT, "Gunzip: tail too short") {}};
00038     class CrcErr : public Err {public: CrcErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: CRC check error") {}};
00039     class LengthErr : public Err {public: LengthErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: length check error") {}};
00040 
00041     /*! \param repeat decompress multiple compressed streams in series
00042         \param autoSignalPropagation 0 to turn off MessageEnd signal
00043     */
00044     Gunzip(BufferedTransformation *attachment = NULL, bool repeat = false, int autoSignalPropagation = -1);
00045 
00046 protected:
00047     enum {MAGIC1=0x1f, MAGIC2=0x8b,   // flags for the header
00048         DEFLATED=8};
00049 
00050     enum FLAG_MASKS {
00051         CONTINUED=2, EXTRA_FIELDS=4, FILENAME=8, COMMENTS=16, ENCRYPTED=32};
00052 
00053     unsigned int MaxPrestreamHeaderSize() const {return 1024;}
00054     void ProcessPrestreamHeader();
00055     void ProcessDecompressedData(const byte *string, size_t length);
00056     unsigned int MaxPoststreamTailSize() const {return 8;}
00057     void ProcessPoststreamTail();
00058 
00059     word32 m_length;
00060     CRC32 m_crc;
00061 };
00062 
00063 NAMESPACE_END
00064 
00065 #endif

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