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Annotation of elwix/tools/oldlzma/SRC/7zip/Compress/LZ/LZInWindow.cpp, revision 1.1

1.1     ! misho       1: // LZInWindow.cpp
        !             2: 
        !             3: #include "StdAfx.h"
        !             4: 
        !             5: #include "LZInWindow.h"
        !             6: #include "../../../Common/MyCom.h"
        !             7: #include "../../../Common/Alloc.h"
        !             8: 
        !             9: void CLZInWindow::Free()
        !            10: {
        !            11:   ::BigFree(_bufferBase);
        !            12:   _bufferBase = 0;
        !            13: }
        !            14: 
        !            15: bool CLZInWindow::Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter, UInt32 keepSizeReserv)
        !            16: {
        !            17:   _keepSizeBefore = keepSizeBefore;
        !            18:   _keepSizeAfter = keepSizeAfter;
        !            19:   _keepSizeReserv = keepSizeReserv;
        !            20:   UInt32 blockSize = keepSizeBefore + keepSizeAfter + keepSizeReserv;
        !            21:   if (_bufferBase == 0 || _blockSize != blockSize)
        !            22:   {
        !            23:     Free();
        !            24:     _blockSize = blockSize;
        !            25:     _bufferBase = (Byte *)::BigAlloc(_blockSize);
        !            26:   }
        !            27:   _pointerToLastSafePosition = _bufferBase + _blockSize - keepSizeAfter;
        !            28:   return (_bufferBase != 0);
        !            29: }
        !            30: 
        !            31: 
        !            32: HRESULT CLZInWindow::Init(ISequentialInStream *stream)
        !            33: {
        !            34:   _stream = stream;
        !            35:   _buffer = _bufferBase;
        !            36:   _pos = 0;
        !            37:   _streamPos = 0;
        !            38:   _streamEndWasReached = false;
        !            39:   return ReadBlock();
        !            40: }
        !            41: 
        !            42: /*
        !            43: void CLZInWindow::ReleaseStream()
        !            44: {
        !            45:   _stream.Release();
        !            46: }
        !            47: */
        !            48: 
        !            49: ///////////////////////////////////////////
        !            50: // ReadBlock
        !            51: 
        !            52: // In State:
        !            53: //   (_buffer + _streamPos) <= (_bufferBase + _blockSize)
        !            54: // Out State:
        !            55: //   _posLimit <= _blockSize - _keepSizeAfter;
        !            56: //   if(_streamEndWasReached == false):
        !            57: //     _streamPos >= _pos + _keepSizeAfter
        !            58: //     _posLimit = _streamPos - _keepSizeAfter;
        !            59: //   else
        !            60: //          
        !            61:   
        !            62: HRESULT CLZInWindow::ReadBlock()
        !            63: {
        !            64:   if(_streamEndWasReached)
        !            65:     return S_OK;
        !            66:   while(true)
        !            67:   {
        !            68:     UInt32 size = UInt32(_bufferBase - _buffer) + _blockSize - _streamPos;
        !            69:     if(size == 0)
        !            70:       return S_OK;
        !            71:     UInt32 numReadBytes;
        !            72:     RINOK(_stream->ReadPart(_buffer + _streamPos, size, &numReadBytes));
        !            73:     if(numReadBytes == 0)
        !            74:     {
        !            75:       _posLimit = _streamPos;
        !            76:       const Byte *pointerToPostion = _buffer + _posLimit;
        !            77:       if(pointerToPostion > _pointerToLastSafePosition)
        !            78:         _posLimit = (UInt32)(_pointerToLastSafePosition - _buffer);
        !            79:       _streamEndWasReached = true;
        !            80:       return S_OK;
        !            81:     }
        !            82:     _streamPos += numReadBytes;
        !            83:     if(_streamPos >= _pos + _keepSizeAfter)
        !            84:     {
        !            85:       _posLimit = _streamPos - _keepSizeAfter;
        !            86:       return S_OK;
        !            87:     }
        !            88:   }
        !            89: }
        !            90: 
        !            91: void CLZInWindow::MoveBlock()
        !            92: {
        !            93:   BeforeMoveBlock();
        !            94:   UInt32 offset = UInt32(_buffer - _bufferBase) + _pos - _keepSizeBefore;
        !            95:   UInt32 numBytes = UInt32(_buffer - _bufferBase) + _streamPos -  offset;
        !            96:   memmove(_bufferBase, _bufferBase + offset, numBytes);
        !            97:   _buffer -= offset;
        !            98:   AfterMoveBlock();
        !            99: }