mirror of
https://github.com/Xevion/easy7zip.git
synced 2025-12-08 14:07:00 -06:00
85 lines
2.4 KiB
C++
Executable File
85 lines
2.4 KiB
C++
Executable File
// LZInWindow.h
|
|
|
|
#ifndef __LZ_IN_WINDOW_H
|
|
#define __LZ_IN_WINDOW_H
|
|
|
|
#include "../../IStream.h"
|
|
|
|
class CLZInWindow
|
|
{
|
|
Byte *_bufferBase; // pointer to buffer with data
|
|
ISequentialInStream *_stream;
|
|
UInt32 _posLimit; // offset (from _buffer) of first byte when new block reading must be done
|
|
bool _streamEndWasReached; // if (true) then _streamPos shows real end of stream
|
|
const Byte *_pointerToLastSafePosition;
|
|
protected:
|
|
Byte *_buffer; // Pointer to virtual Buffer begin
|
|
UInt32 _blockSize; // Size of Allocated memory block
|
|
UInt32 _pos; // offset (from _buffer) of curent byte
|
|
UInt32 _keepSizeBefore; // how many BYTEs must be kept in buffer before _pos
|
|
UInt32 _keepSizeAfter; // how many BYTEs must be kept buffer after _pos
|
|
UInt32 _keepSizeReserv; // how many BYTEs must be kept as reserv
|
|
UInt32 _streamPos; // offset (from _buffer) of first not read byte from Stream
|
|
|
|
virtual void BeforeMoveBlock() {};
|
|
virtual void AfterMoveBlock() {};
|
|
void MoveBlock();
|
|
virtual HRESULT ReadBlock();
|
|
void Free();
|
|
public:
|
|
CLZInWindow(): _bufferBase(0) {}
|
|
virtual ~CLZInWindow() { Free(); }
|
|
|
|
bool Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter,
|
|
UInt32 keepSizeReserv = (1<<17));
|
|
|
|
HRESULT Init(ISequentialInStream *stream);
|
|
// void ReleaseStream();
|
|
|
|
Byte *GetBuffer() const { return _buffer; }
|
|
|
|
const Byte *GetPointerToCurrentPos() const { return _buffer + _pos; }
|
|
|
|
HRESULT MovePos()
|
|
{
|
|
_pos++;
|
|
if (_pos > _posLimit)
|
|
{
|
|
const Byte *pointerToPostion = _buffer + _pos;
|
|
if(pointerToPostion > _pointerToLastSafePosition)
|
|
MoveBlock();
|
|
return ReadBlock();
|
|
}
|
|
else
|
|
return S_OK;
|
|
}
|
|
Byte GetIndexByte(Int32 index)const
|
|
{ return _buffer[(size_t)_pos + index]; }
|
|
|
|
// index + limit have not to exceed _keepSizeAfter;
|
|
UInt32 GetMatchLen(Int32 index, UInt32 distance, UInt32 limit) const
|
|
{
|
|
if(_streamEndWasReached)
|
|
if ((_pos + index) + limit > _streamPos)
|
|
limit = _streamPos - (_pos + index);
|
|
distance++;
|
|
Byte *pby = _buffer + (size_t)_pos + index;
|
|
UInt32 i;
|
|
for(i = 0; i < limit && pby[i] == pby[(size_t)i - distance]; i++);
|
|
return i;
|
|
}
|
|
|
|
UInt32 GetNumAvailableBytes() const { return _streamPos - _pos; }
|
|
|
|
void ReduceOffsets(Int32 subValue)
|
|
{
|
|
_buffer += subValue;
|
|
_posLimit -= subValue;
|
|
_pos -= subValue;
|
|
_streamPos -= subValue;
|
|
}
|
|
|
|
};
|
|
|
|
#endif
|