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121 lines
2.3 KiB
121 lines
2.3 KiB
// IOStream.cpp -- Implementation for class CIOStream
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#include "stdafx.h"
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#include "IOStream.h"
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CIOStream *CIOStream::NewIOStream(CUnbufferedIO *puio)
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{
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ASSERT(puio);
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CIOStream *pios= NULL;
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__try
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{
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pios= New CIOStream;
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pios->InitialIOStream(puio);
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}
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__finally
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{
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if (_abnormal_termination() && pios)
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{
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delete pios; pios= NULL;
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}
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}
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return pios;
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}
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CIOStream::CIOStream()
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{
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m_cdw = 0;
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m_cBlocks = 0;
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m_ibFileNextLow = 0;
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m_ibFileNextHigh = 0;
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}
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CIOStream::~CIOStream()
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{
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if (Writable()) FlushOutput(TRUE);
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}
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BOOL CIOStream::InitialIOStream(CUnbufferedIO *puio)
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{
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ASSERT(puio);
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if (!InitialIOQueue(puio)) return FALSE;
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return TRUE;
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}
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void CIOStream::AttachStream(BOOL fOut, UINT cdwStream,
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UINT ibFileLow, UINT ibFileHigh
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)
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{
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ASSERT(Initialed());
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if (Writable()) FlushOutput(TRUE);
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ASSERT(fOut || cdwStream);
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if (fOut) m_cdw= 0;
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else
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{
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m_cdw = cdwStream;
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m_cBlocks = BlocksFor(cdwStream * sizeof(UINT), CbBlockSize());
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}
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m_ibFileNextLow = ibFileLow;
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m_ibFileNextHigh = ibFileHigh;
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EnableStream(fOut);
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}
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BOOL CIOStream::NextFileAddress(PUINT pibFileLow, PUINT pibFileHigh, PUINT pcdw)
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{
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if (*pcdw > CbBlockSize() / sizeof(UINT))
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*pcdw = CbBlockSize() / sizeof(UINT);
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ASSERT(!(m_ibFileNextLow % CbBlockSize()));
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ASSERT(! m_ibFileNextHigh);
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*pibFileLow = m_ibFileNextLow;
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*pibFileHigh = m_ibFileNextHigh;
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if (Writable())
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{
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m_cdw += *pcdw;
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m_ibFileNextLow += (*pcdw) * sizeof(UINT);
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return FALSE;
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}
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if (!m_cBlocks)
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{
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*pcdw= 0; return TRUE;
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}
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if (--m_cBlocks)
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{
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*pcdw = CbBlockSize() / sizeof(UINT);
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m_cdw -= CbBlockSize() / sizeof(UINT);
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m_ibFileNextLow += *pcdw * sizeof(UINT);
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return FALSE;
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}
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else // The last block won't necessarily be full.
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{
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*pcdw= m_cdw; m_cdw= 0;
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m_ibFileNextLow += *pcdw * sizeof(UINT);
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return TRUE;
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}
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}
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void CIOStream::ReleaseFileBlock(UINT ibFileLow, UINT ibFileHigh)
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{
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ASSERT(!ibFileHigh);
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}
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