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Diffstat (limited to 'cryptopp562/zdeflate.h')
| -rw-r--r-- | cryptopp562/zdeflate.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/cryptopp562/zdeflate.h b/cryptopp562/zdeflate.h new file mode 100644 index 0000000..8bbd14e --- /dev/null +++ b/cryptopp562/zdeflate.h @@ -0,0 +1,121 @@ +#ifndef CRYPTOPP_ZDEFLATE_H +#define CRYPTOPP_ZDEFLATE_H + +#include "filters.h" +#include "misc.h" + +NAMESPACE_BEGIN(CryptoPP) + +//! _ +class LowFirstBitWriter : public Filter +{ +public: + LowFirstBitWriter(BufferedTransformation *attachment); + void PutBits(unsigned long value, unsigned int length); + void FlushBitBuffer(); + void ClearBitBuffer(); + + void StartCounting(); + unsigned long FinishCounting(); + +protected: + bool m_counting; + unsigned long m_bitCount; + unsigned long m_buffer; + unsigned int m_bitsBuffered, m_bytesBuffered; + FixedSizeSecBlock<byte, 256> m_outputBuffer; +}; + +//! Huffman Encoder +class HuffmanEncoder +{ +public: + typedef unsigned int code_t; + typedef unsigned int value_t; + + HuffmanEncoder() {} + HuffmanEncoder(const unsigned int *codeBits, unsigned int nCodes); + void Initialize(const unsigned int *codeBits, unsigned int nCodes); + + static void GenerateCodeLengths(unsigned int *codeBits, unsigned int maxCodeBits, const unsigned int *codeCounts, size_t nCodes); + + void Encode(LowFirstBitWriter &writer, value_t value) const; + + struct Code + { + unsigned int code; + unsigned int len; + }; + + SecBlock<Code> m_valueToCode; +}; + +//! DEFLATE (RFC 1951) compressor + +class Deflator : public LowFirstBitWriter +{ +public: + enum {MIN_DEFLATE_LEVEL = 0, DEFAULT_DEFLATE_LEVEL = 6, MAX_DEFLATE_LEVEL = 9}; + enum {MIN_LOG2_WINDOW_SIZE = 9, DEFAULT_LOG2_WINDOW_SIZE = 15, MAX_LOG2_WINDOW_SIZE = 15}; + /*! \note 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. */ + Deflator(BufferedTransformation *attachment=NULL, int deflateLevel=DEFAULT_DEFLATE_LEVEL, int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE, bool detectUncompressible=true); + //! possible parameter names: Log2WindowSize, DeflateLevel, DetectUncompressible + Deflator(const NameValuePairs ¶meters, BufferedTransformation *attachment=NULL); + + //! this function can be used to set the deflate level in the middle of compression + void SetDeflateLevel(int deflateLevel); + int GetDeflateLevel() const {return m_deflateLevel;} + int GetLog2WindowSize() const {return m_log2WindowSize;} + + void IsolatedInitialize(const NameValuePairs ¶meters); + size_t Put2(const byte *inString, size_t length, int messageEnd, bool blocking); + bool IsolatedFlush(bool hardFlush, bool blocking); + +protected: + virtual void WritePrestreamHeader() {} + virtual void ProcessUncompressedData(const byte *string, size_t length) {} + virtual void WritePoststreamTail() {} + + enum {STORED = 0, STATIC = 1, DYNAMIC = 2}; + enum {MIN_MATCH = 3, MAX_MATCH = 258}; + + void InitializeStaticEncoders(); + void Reset(bool forceReset = false); + unsigned int FillWindow(const byte *str, size_t length); + unsigned int ComputeHash(const byte *str) const; + unsigned int LongestMatch(unsigned int &bestMatch) const; + void InsertString(unsigned int start); + void ProcessBuffer(); + + void LiteralByte(byte b); + void MatchFound(unsigned int distance, unsigned int length); + void EncodeBlock(bool eof, unsigned int blockType); + void EndBlock(bool eof); + + struct EncodedMatch + { + unsigned literalCode : 9; + unsigned literalExtra : 5; + unsigned distanceCode : 5; + unsigned distanceExtra : 13; + }; + + int m_deflateLevel, m_log2WindowSize, m_compressibleDeflateLevel; + unsigned int m_detectSkip, m_detectCount; + unsigned int DSIZE, DMASK, HSIZE, HMASK, GOOD_MATCH, MAX_LAZYLENGTH, MAX_CHAIN_LENGTH; + bool m_headerWritten, m_matchAvailable; + unsigned int m_dictionaryEnd, m_stringStart, m_lookahead, m_minLookahead, m_previousMatch, m_previousLength; + HuffmanEncoder m_staticLiteralEncoder, m_staticDistanceEncoder, m_dynamicLiteralEncoder, m_dynamicDistanceEncoder; + SecByteBlock m_byteBuffer; + SecBlock<word16> m_head, m_prev; + FixedSizeSecBlock<unsigned int, 286> m_literalCounts; + FixedSizeSecBlock<unsigned int, 30> m_distanceCounts; + SecBlock<EncodedMatch> m_matchBuffer; + unsigned int m_matchBufferEnd, m_blockStart, m_blockLength; +}; + +NAMESPACE_END + +#endif |