Initial revision

1 files changed, 117 insertions, 0 deletions

diff --git a/zdeflate.h b/zdeflate.h
new file mode 100644
index 00000000..60970d0a
--- /dev/null
+++ b/zdeflate.h
@@ -0,0 +1,117 @@
+#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, unsigned int 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};
+	Deflator(BufferedTransformation *attachment=NULL, int deflateLevel=DEFAULT_DEFLATE_LEVEL, int log2WindowSize=DEFAULT_LOG2_WINDOW_SIZE);
+	//! possible parameter names: Log2WindowSize, DeflateLevel
+	Deflator(const NameValuePairs &parameters, 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 &parameters);
+	unsigned int Put2(const byte *inString, unsigned int length, int messageEnd, bool blocking);
+	bool IsolatedFlush(bool hardFlush, bool blocking);
+
+private:
+	virtual void WritePrestreamHeader() {}
+	virtual void ProcessUncompressedData(const byte *string, unsigned int 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, unsigned int 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;
+	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