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#ifndef __STREAM_WINDOWIN_H
#define __STREAM_WINDOWIN_H
#include "IInOutStreams.h"
#include <stdio.h>
namespace NStream {
namespace NWindow {
class CIn
{
BYTE *m_BufferBase; // pointer to buffer with data
ISequentialInStream* m_Stream;
INT m_PosLimit; // offset (from m_Buffer) of first byte when new block reading must be done
bool m_StreamEndWasReached; // if (true) then m_StreamPos shows real end of stream
const BYTE *m_PointerToLastSafePosition;
protected:
BYTE *m_Buffer; // Pointer to virtual Buffer begin
INT m_BlockSize; // Size of Allocated memory block
INT m_Pos; // offset (from m_Buffer) of curent byte
INT m_KeepSizeBefore; // how many BYTEs must be kept in buffer before m_Pos
INT m_KeepSizeAfter; // how many BYTEs must be kept buffer after m_Pos
INT m_KeepSizeReserv; // how many BYTEs must be kept as reserv
INT m_StreamPos; // offset (from m_Buffer) of first not read byte from Stream
virtual void BeforeMoveBlock() {};
virtual void AfterMoveBlock() {};
void MoveBlock();
virtual HRESULT ReadBlock();
void Free();
public:
CIn();
void Create(INT aKeepSizeBefore, INT aKeepSizeAfter,
INT aKeepSizeReserv = (1<<17));
virtual ~CIn();
HRESULT Init(ISequentialInStream *aStream);
BYTE *GetBuffer() const { return m_Buffer; }
const BYTE *GetPointerToCurrentPos() const { return m_Buffer + m_Pos; }
HRESULT MovePos()
{
m_Pos++;
if (m_Pos > m_PosLimit)
{
const BYTE *aPointerToPostion = m_Buffer + m_Pos;
if(aPointerToPostion > m_PointerToLastSafePosition)
MoveBlock();
return ReadBlock();
}
else
return S_OK;
}
// BYTE GetCurrentByte()const;
BYTE GetIndexByte(INT anIndex)const
{ return m_Buffer[m_Pos + anIndex]; }
// INT GetCurPos()const { return m_Pos;};
// BYTE *GetBufferBeg()const { return m_Buffer;};
// aIndex + aLimit have not to exceed m_KeepSizeAfter;
INT GetMatchLen(INT aIndex, INT aBack, INT aLimit) const
{
if(m_StreamEndWasReached)
if ((m_Pos + aIndex) + aLimit > m_StreamPos)
aLimit = m_StreamPos - (m_Pos + aIndex);
aBack++;
BYTE *pby = m_Buffer + m_Pos + aIndex;
INT i;
for(i = 0; i < aLimit && pby[i] == pby[i - aBack]; i++);
return i;
}
INT GetNumAvailableBytes() const { return m_StreamPos - m_Pos; }
void ReduceOffsets(INT aSubValue)
{
m_Buffer += aSubValue;
m_PosLimit -= aSubValue;
m_Pos -= aSubValue;
m_StreamPos -= aSubValue;
}
};
}}
#endif
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