00001 #ifndef CRYPTOPP_ZDEFLATE_H
00002 #define CRYPTOPP_ZDEFLATE_H
00003
00004 #include "filters.h"
00005 #include "misc.h"
00006
00007 NAMESPACE_BEGIN(CryptoPP)
00008
00009
00010 class LowFirstBitWriter : public Filter
00011 {
00012 public:
00013 LowFirstBitWriter(BufferedTransformation *attachment);
00014 void PutBits(unsigned long value, unsigned int length);
00015 void FlushBitBuffer();
00016 void ClearBitBuffer();
00017
00018 void StartCounting();
00019 unsigned long FinishCounting();
00020
00021 protected:
00022 bool m_counting;
00023 unsigned long m_bitCount;
00024 unsigned long m_buffer;
00025 unsigned int m_bitsBuffered, m_bytesBuffered;
00026 FixedSizeSecBlock<byte, 256> m_outputBuffer;
00027 };
00028
00029
00030 class HuffmanEncoder
00031 {
00032 public:
00033 typedef unsigned int code_t;
00034 typedef unsigned int value_t;
00035
00036 HuffmanEncoder() {}
00037 HuffmanEncoder(const unsigned int *codeBits, unsigned int nCodes);
00038 void Initialize(const unsigned int *codeBits, unsigned int nCodes);
00039
00040 static void GenerateCodeLengths(unsigned int *codeBits, unsigned int maxCodeBits, const unsigned int *codeCounts, unsigned int nCodes);
00041
00042 void Encode(LowFirstBitWriter &writer, value_t value) const;
00043
00044 struct Code
00045 {
00046 unsigned int code;
00047 unsigned int len;
00048 };
00049
00050 SecBlock<Code> m_valueToCode;
00051 };
00052
00053
00054
00055 class Deflator : public LowFirstBitWriter
00056 {
00057 public:
00058 enum {MIN_DEFLATE_LEVEL = 0, DEFAULT_DEFLATE_LEVEL = 6, MAX_DEFLATE_LEVEL = 9};
00059 enum {MIN_LOG2_WINDOW_SIZE = 9, DEFAULT_LOG2_WINDOW_SIZE = 15, MAX_LOG2_WINDOW_SIZE = 15};
00060 Deflator(BufferedTransformation *attachment=NULL, int deflateLevel=DEFAULT_DEFLATE_LEVEL, int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE);
00061
00062 Deflator(const NameValuePairs ¶meters, BufferedTransformation *attachment=NULL);
00063
00064
00065 void SetDeflateLevel(int deflateLevel);
00066 int GetDeflateLevel() const {return m_deflateLevel;}
00067 int GetLog2WindowSize() const {return m_log2WindowSize;}
00068
00069 void IsolatedInitialize(const NameValuePairs ¶meters);
00070 unsigned int Put2(const byte *inString, unsigned int length, int messageEnd, bool blocking);
00071 bool IsolatedFlush(bool hardFlush, bool blocking);
00072
00073 private:
00074 virtual void WritePrestreamHeader() {}
00075 virtual void ProcessUncompressedData(const byte *string, unsigned int length) {}
00076 virtual void WritePoststreamTail() {}
00077
00078 enum {STORED = 0, STATIC = 1, DYNAMIC = 2};
00079 enum {MIN_MATCH = 3, MAX_MATCH = 258};
00080
00081 void InitializeStaticEncoders();
00082 void Reset(bool forceReset = false);
00083 unsigned int FillWindow(const byte *str, unsigned int length);
00084 unsigned int ComputeHash(const byte *str) const;
00085 unsigned int LongestMatch(unsigned int &bestMatch) const;
00086 void InsertString(unsigned int start);
00087 void ProcessBuffer();
00088
00089 void LiteralByte(byte b);
00090 void MatchFound(unsigned int distance, unsigned int length);
00091 void EncodeBlock(bool eof, unsigned int blockType);
00092 void EndBlock(bool eof);
00093
00094 struct EncodedMatch
00095 {
00096 unsigned literalCode : 9;
00097 unsigned literalExtra : 5;
00098 unsigned distanceCode : 5;
00099 unsigned distanceExtra : 13;
00100 };
00101
00102 int m_deflateLevel, m_log2WindowSize;
00103 unsigned int DSIZE, DMASK, HSIZE, HMASK, GOOD_MATCH, MAX_LAZYLENGTH, MAX_CHAIN_LENGTH;
00104 bool m_headerWritten, m_matchAvailable;
00105 unsigned int m_dictionaryEnd, m_stringStart, m_lookahead, m_minLookahead, m_previousMatch, m_previousLength;
00106 HuffmanEncoder m_staticLiteralEncoder, m_staticDistanceEncoder, m_dynamicLiteralEncoder, m_dynamicDistanceEncoder;
00107 SecByteBlock m_byteBuffer;
00108 SecBlock<word16> m_head, m_prev;
00109 FixedSizeSecBlock<unsigned int, 286> m_literalCounts;
00110 FixedSizeSecBlock<unsigned int, 30> m_distanceCounts;
00111 SecBlock<EncodedMatch> m_matchBuffer;
00112 unsigned int m_matchBufferEnd, m_blockStart, m_blockLength;
00113 };
00114
00115 NAMESPACE_END
00116
00117 #endif