62d9a4c2f7
git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@7072 212acab6-be3b-0410-9dea-997c60f758d6
102 lines
2.9 KiB
C++
102 lines
2.9 KiB
C++
/*
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* LZInWindow.h
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*
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* This file is a part of LZMA compression module for NSIS.
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*
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* Original LZMA SDK Copyright (C) 1999-2006 Igor Pavlov
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* Modifications Copyright (C) 2003-2019 Amir Szekely <kichik@netvision.net.il>
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*
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* Licensed under the Common Public License version 1.0 (the "License");
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* you may not use this file except in compliance with the License.
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*
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* Licence details can be found in the file COPYING.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty.
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*/
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#ifndef __LZ_IN_WINDOW_H
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#define __LZ_IN_WINDOW_H
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#include "../../IStream.h"
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class CLZInWindow
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{
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Byte *_bufferBase; // pointer to buffer with data
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ISequentialInStream *_stream;
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UInt32 _posLimit; // offset (from _buffer) when new block reading must be done
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bool _streamEndWasReached; // if (true) then _streamPos shows real end of stream
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const Byte *_pointerToLastSafePosition;
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protected:
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Byte *_buffer; // Pointer to virtual Buffer begin
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UInt32 _blockSize; // Size of Allocated memory block
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UInt32 _pos; // offset (from _buffer) of curent byte
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UInt32 _keepSizeBefore; // how many BYTEs must be kept in buffer before _pos
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UInt32 _keepSizeAfter; // how many BYTEs must be kept buffer after _pos
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UInt32 _streamPos; // offset (from _buffer) of first not read byte from Stream
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void MoveBlock();
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HRESULT ReadBlock();
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void Free();
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public:
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CLZInWindow(): _bufferBase(0) {}
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virtual ~CLZInWindow() { Free(); }
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// keepSizeBefore + keepSizeAfter + keepSizeReserv < 4G)
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bool Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter, UInt32 keepSizeReserv = (1<<17));
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void SetStream(ISequentialInStream *stream);
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HRESULT Init();
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// void ReleaseStream();
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Byte *GetBuffer() const { return _buffer; }
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const Byte *GetPointerToCurrentPos() const { return _buffer + _pos; }
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HRESULT MovePos()
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{
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_pos++;
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if (_pos > _posLimit)
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{
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const Byte *pointerToPostion = _buffer + _pos;
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if(pointerToPostion > _pointerToLastSafePosition)
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MoveBlock();
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return ReadBlock();
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}
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else
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return S_OK;
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}
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Byte GetIndexByte(Int32 index) const { return _buffer[(size_t)_pos + index]; }
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// index + limit have not to exceed _keepSizeAfter;
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// -2G <= index < 2G
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UInt32 GetMatchLen(Int32 index, UInt32 distance, UInt32 limit) const
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{
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if(_streamEndWasReached)
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if ((_pos + index) + limit > _streamPos)
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limit = _streamPos - (_pos + index);
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distance++;
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const Byte *pby = _buffer + (size_t)_pos + index;
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UInt32 i;
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for(i = 0; i < limit && pby[i] == pby[(size_t)i - distance]; i++);
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return i;
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}
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UInt32 GetNumAvailableBytes() const { return _streamPos - _pos; }
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void ReduceOffsets(Int32 subValue)
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{
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_buffer += subValue;
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_posLimit -= subValue;
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_pos -= subValue;
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_streamPos -= subValue;
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}
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bool NeedMove(size_t numCheckBytes)
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{
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size_t reserv = _pointerToLastSafePosition - (_buffer + _pos);
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return (reserv <= numCheckBytes);
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}
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};
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#endif
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