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