aricoder.h

This is a little console mode utility program which is able to (de-)compress single files with a s

/*****************************************************************************

  AriCoder
  --------

  Revisions: 001

  This is a class for compressing a giving block of data with the Arithmetic
  compression algorithm which is patented !

  The core algorithm is ripped out of "The Data Compression Book" by Mark Nelson.

  The output buffers are freed by the class itself in its class destructor.

  by yoda

  WWW:      y0da.cjb.net
  E-mail:   [e-mail]

  You are allowed to use this source code in your own projects if you mention
  my name.

*****************************************************************************/

#pragma once

#include <windows.h>
#include "ByteReader.h"
#include "ByteWriter.h"

//
// constants
//
#define ALPHABET_SIZE          257

//
// structures
//
typedef struct _ARI_SYM
{
	WORD          low;
	WORD          high;
	WORD          scale;
} ARI_SYM, *PARI_SYM;

//
// AriCoder class
//
class AriCoder  
{
public:
	__declspec( property( get=GetSymTblCntSize ) )   DWORD  m_cbSymCntTbl;

	AriCoder();
	~AriCoder();

	BOOL   CompressData( PBYTE p, DWORD cb, PBYTE &pOut, DWORD &cbOut );
	BOOL   DecompressData( PBYTE p, DWORD cb, PBYTE &pOut, DWORD &cbOut );
	DWORD  GetSymTblCntSize() { return m_cbTable; };

private:
	BYTE   m_Occurrences[ALPHABET_SIZE];
	UINT   m_Totals[ALPHABET_SIZE + 1];
	DWORD  m_cbTable;
	PBYTE  m_pbyOutBuff;
	LONG   m_cbOutBuff;

	WORD   m_wLow;
	WORD   m_wHigh;
	LONG   m_cUnderflowBits;
	WORD   m_wCode;	

	void   Init();
	void   Dispose();
	void   FreeOutBuff();
	void   CountSymbols( PBYTE p, DWORD cb );
	void   BuildTotals();
	void   BuildModelFromData( PBYTE p, DWORD cb );
	DWORD  EmitCounts( PBYTE p, DWORD cb );
	DWORD  GrabCounts( PBYTE p );
	void   InitEncoder();
	void   InitDecoder( ByteReader &reader );
	void   GetSymbolInfo( WORD symbol, struct _ARI_SYM &s );
	void   EncodeSymbol( ByteWriter &writer, ARI_SYM sym );
	void   FlushEncoder( ByteWriter &writer );
	void   GetSymbolScale( PARI_SYM pSym );
	DWORD  GetCurrentCount( ARI_SYM s );
	UINT   SymbolToIndex( DWORD dwCount, PARI_SYM sym );
	void   RemoveSymbolFromStream( ByteReader &reader, ARI_SYM sym );
};

typedef AriCoder *PAriCoder;