lzw.h

几种常用的压缩算法 本程序包含以下功能： 1、 Arithmetic coding 2、 Huffman coding 3、 LZ77 coding 4、 LZ78 coding 5、 L

#ifndef __LZW_H
#define __LZW_H

#include "Gendef.h"

#define	compLT(a, b)	(a->key_word < b->key_word)
#define	compEQ(a, b)	(a->key_word == b->key_word)
#include "redblack.t"

class CLZW
{
private:
	struct tagNode;
	struct tagKey;
	struct tagKey
	{
		BYTE	key;
		tagNode *node;
		tagNode *pnode;
		tagKey	*prev;
		tagKey	*next;
	};
	struct tagNode
	{
		DWORD	key_word;
		long	level;
		tagKey	nill_key;
		tagKey *parent;
	} nill;
	DWORD LastKey;
	DWORD border;
	DWORD bits_len;
	typedef TRedBlack<tagNode*>	RedBlackNode;
	RedBlackNode tree;
	private:
		// source can`t be more then 2^28 bytes (2^28 = 268435456)
		// key-word 0 is predefined for single character
		void bitscpy(BYTE *target, long &toffset, BYTE *source, long &soffset, long bitslen);
		
		tagNode *FindKeyWord(DWORD key_word);
		tagNode *FindKey(tagNode *node, BYTE key);
		tagNode *AddKey(tagNode *node, DWORD key_word, BYTE key);
		DWORD GenerateKey();
		
		void DeleteNode(tagNode *node);
		void DeleteKey(tagKey *key);
		void CleanAll();
		void InitTable();
		
		long EncodeOnce(BYTE *target, long &toffset, BYTE *source, long slength, tagNode **last_node);
		long DecodeOnce(BYTE *target, BYTE *source, long &soffset, tagNode **last_node);
	public:
		CLZW();
		virtual ~CLZW();
		
		void Encode(BYTE *target, long &tlen, BYTE *source, long slen);
		long Decode(BYTE *target, long &tlen, BYTE *source, long slen);
		long GetMaxEncoded(long len);
		long GetMaxDecoded(BYTE *source);
		
		virtual void OnStep() = 0;
};

#endif