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145 lines
6.2 KiB
145 lines
6.2 KiB
![]()
4 years ago
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// gzip.h - originally written and placed in the public domain by Wei Dai
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/// \file gzip.h
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/// \brief GZIP compression and decompression (RFC 1952)
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#ifndef CRYPTOPP_GZIP_H
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#define CRYPTOPP_GZIP_H
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#include "cryptlib.h"
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#include "zdeflate.h"
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#include "zinflate.h"
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#include "crc.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief GZIP Compression (RFC 1952)
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class Gzip : public Deflator
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{
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public:
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/// \brief Construct a Gzip compressor
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/// \param attachment an attached transformation
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/// \param deflateLevel the deflate level
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/// \param log2WindowSize the window size
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/// \param detectUncompressible flag to detect if data is compressible
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/// \details detectUncompressible makes it faster to process uncompressible files, but
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/// if a file has both compressible and uncompressible parts, it may fail to compress
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/// some of the compressible parts.
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Gzip(BufferedTransformation *attachment=NULLPTR, unsigned int deflateLevel=DEFAULT_DEFLATE_LEVEL, unsigned int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE, bool detectUncompressible=true)
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: Deflator(attachment, deflateLevel, log2WindowSize, detectUncompressible), m_totalLen(0), m_filetime(0) { }
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/// \brief Construct a Gzip compressor
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/// \param parameters a set of NameValuePairs to initialize this object
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/// \param attachment an attached transformation
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/// \details Possible parameter names: Log2WindowSize, DeflateLevel, DetectUncompressible
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Gzip(const NameValuePairs ¶meters, BufferedTransformation *attachment=NULLPTR)
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: Deflator(parameters, attachment), m_totalLen(0), m_filetime(0)
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{
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IsolatedInitialize(parameters);
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}
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/// \param filetime the filetime to set in the header. The application is responsible for setting it.
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void SetFiletime(word32 filetime) { m_filetime = filetime; }
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/// \param filename the original filename to set in the header. The application is responsible for setting it.
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/// RFC 1952 requires a ISO/IEC 8859-1 encoding.
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/// \param throwOnEncodingError if throwOnEncodingError is true, then the filename is checked to ensure it is
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/// ISO/IEC 8859-1 encoded. If the filename does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat
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/// is thrown. If throwOnEncodingError is false then the filename is not checked.
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void SetFilename(const std::string& filename, bool throwOnEncodingError = false);
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/// \param comment the comment to set in the header. The application is responsible for setting it.
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/// RFC 1952 requires a ISO/IEC 8859-1 encoding.
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/// \param throwOnEncodingError if throwOnEncodingError is true, then the comment is checked to ensure it is
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/// ISO/IEC 8859-1 encoded. If the comment does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat
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/// is thrown. If throwOnEncodingError is false then the comment is not checked.
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void SetComment(const std::string& comment, bool throwOnEncodingError = false);
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void IsolatedInitialize(const NameValuePairs ¶meters);
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protected:
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enum {MAGIC1=0x1f, MAGIC2=0x8b, // flags for the header
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DEFLATED=8, FAST=4, SLOW=2};
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enum FLAG_MASKS {
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FILENAME=8, COMMENTS=16};
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void WritePrestreamHeader();
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void ProcessUncompressedData(const byte *string, size_t length);
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void WritePoststreamTail();
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word32 m_totalLen;
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CRC32 m_crc;
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word32 m_filetime;
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std::string m_filename;
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std::string m_comment;
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};
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/// \brief GZIP Decompression (RFC 1952)
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class Gunzip : public Inflator
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{
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public:
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typedef Inflator::Err Err;
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/// \brief Exception thrown when a header decoding error occurs
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class HeaderErr : public Err {public: HeaderErr() : Err(INVALID_DATA_FORMAT, "Gunzip: header decoding error") {}};
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/// \brief Exception thrown when the tail is too short
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class TailErr : public Err {public: TailErr() : Err(INVALID_DATA_FORMAT, "Gunzip: tail too short") {}};
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/// \brief Exception thrown when a CRC error occurs
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class CrcErr : public Err {public: CrcErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: CRC check error") {}};
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/// \brief Exception thrown when a length error occurs
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class LengthErr : public Err {public: LengthErr() : Err(DATA_INTEGRITY_CHECK_FAILED, "Gunzip: length check error") {}};
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/// \brief Construct a Gunzip decompressor
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/// \param attachment an attached transformation
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/// \param repeat decompress multiple compressed streams in series
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/// \param autoSignalPropagation 0 to turn off MessageEnd signal
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Gunzip(BufferedTransformation *attachment = NULLPTR, bool repeat = false, int autoSignalPropagation = -1);
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/// \return the filetime of the stream as set in the header. The application is responsible for setting it on the decompressed file.
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word32 GetFiletime() const { return m_filetime; }
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/// \return the filename of the stream as set in the header. The application is responsible for setting it on the decompressed file.
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/// \param throwOnEncodingError if throwOnEncodingError is true, then the filename is checked to ensure it is
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/// ISO/IEC 8859-1 encoded. If the filename does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat is thrown.
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/// If throwOnEncodingError is false then the filename is not checked.
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const std::string& GetFilename(bool throwOnEncodingError = false) const;
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/// \return the comment of the stream as set in the header.
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/// \param throwOnEncodingError if throwOnEncodingError is true, then the comment is checked to ensure it is
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/// ISO/IEC 8859-1 encoded. If the comment does not adhere to ISO/IEC 8859-1, then a InvalidDataFormat is thrown.
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/// If throwOnEncodingError is false then the comment is not checked.
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const std::string& GetComment(bool throwOnEncodingError = false) const;
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protected:
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enum {
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/// \brief First header magic value
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MAGIC1=0x1f,
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/// \brief Second header magic value
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MAGIC2=0x8b,
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/// \brief Deflated flag
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DEFLATED=8
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};
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enum FLAG_MASKS {
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CONTINUED=2, EXTRA_FIELDS=4, FILENAME=8, COMMENTS=16, ENCRYPTED=32};
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unsigned int MaxPrestreamHeaderSize() const {return 1024;}
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void ProcessPrestreamHeader();
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void ProcessDecompressedData(const byte *string, size_t length);
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unsigned int MaxPoststreamTailSize() const {return 8;}
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void ProcessPoststreamTail();
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word32 m_length;
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CRC32 m_crc;
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word32 m_filetime;
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std::string m_filename;
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std::string m_comment;
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};
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NAMESPACE_END
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#endif
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