Source code of Windows XP (NT5)
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//+-------------------------------------------------------------------
//
// File: stream.cxx
//
// Contents: Stream interface on flat File.
//
// Classes: CStreamOnFile
//
// Macros: DEFINE_INTERFACE_XMIT_ROUTINES
//
// History: 08-08-95 Rickhi Created
//
//--------------------------------------------------------------------
#include <ole2.h>
#include <stream.hxx>
CStreamOnFile::CStreamOnFile(const WCHAR *pwszFileName, SCODE &sc, BOOL fRead) :
_clRefs(1),
_hFile(NULL),
_lOffset(0),
_cSize(0),
_cbData(0),
_fRead(fRead)
{
_pbData = new BYTE[2048]; // should be big enough
if (!_pbData)
{
sc = E_OUTOFMEMORY;
return;
}
_cbData = 2048;
// open the file.
DWORD fdwCreate = (_fRead) ? OPEN_EXISTING : CREATE_ALWAYS;
_hFile = CreateFile(pwszFileName,
GENERIC_READ | GENERIC_WRITE, // fdwAccess
FILE_SHARE_READ | FILE_SHARE_WRITE, // fdwShareMode
NULL, // lpsaSecurity
fdwCreate, // creation options
FILE_ATTRIBUTE_NORMAL, // attributes & flags
NULL // hTemplateFile
);
if (_hFile == INVALID_HANDLE_VALUE)
{
sc = HRESULT_FROM_WIN32(GetLastError());
return;
}
// read the file into the memory block
DWORD cbRead = 0;
if (_fRead && ! ReadFile(_hFile,
_pbData,
_cbData,
&cbRead,
NULL))
{
sc = HRESULT_FROM_WIN32(GetLastError());
return;
}
if (_fRead)
{
_cSize = _cbData;
}
sc = S_OK;
}
CStreamOnFile::~CStreamOnFile(void)
{
if (_hFile)
{
if (!_fRead)
{
// write the data to the file
DWORD cbWritten = 0;
if (!WriteFile(_hFile,
_pbData,
_cbData,
&cbWritten,
NULL))
{
SCODE sc = HRESULT_FROM_WIN32(GetLastError());
}
}
CloseHandle(_hFile);
}
}
STDMETHODIMP CStreamOnFile::QueryInterface(
REFIID iidInterface,
void FAR* FAR* ppvObj)
{
HRESULT hresult = S_OK;
// We only support IUnknown and IStream
if (IsEqualIID(iidInterface, IID_IUnknown) ||
IsEqualIID(iidInterface, IID_IStream))
{
*ppvObj = this;
AddRef();
}
else
{
*ppvObj = NULL;
hresult = E_NOINTERFACE;
}
return hresult;
}
STDMETHODIMP_(ULONG) CStreamOnFile::AddRef(void)
{
InterlockedIncrement(&_clRefs);
return _clRefs;
}
STDMETHODIMP_(ULONG) CStreamOnFile::Release(void)
{
if (InterlockedDecrement(&_clRefs) == 0)
{
delete this;
return 0;
}
return _clRefs;
}
STDMETHODIMP CStreamOnFile::Read(
VOID HUGEP* pv,
ULONG cb,
ULONG FAR* pcbRead)
{
HRESULT hresult = S_OK;
if (pcbRead)
{
*pcbRead = 0L;
}
if ((LONG)cb + _lOffset > _cSize)
{
cb = _cSize - _lOffset;
hresult = STG_E_READFAULT;
}
memcpy(pv, _pbData + _lOffset, (size_t) cb);
_lOffset += cb;
if (pcbRead != NULL)
{
*pcbRead = cb;
}
return hresult;
}
STDMETHODIMP CStreamOnFile::Write(
VOID const HUGEP* pv,
ULONG cbToWrite,
ULONG FAR* pcbWritten)
{
HRESULT hresult = S_OK;
if (pcbWritten)
{
*pcbWritten = 0L;
}
if (cbToWrite + _lOffset > _cbData)
{
return E_OUTOFMEMORY;
}
// copy in the new data
memcpy(_pbData + _lOffset, pv, (size_t) cbToWrite);
_lOffset += cbToWrite;
if (pcbWritten != NULL)
{
*pcbWritten = cbToWrite;
}
// We assume maxium size of buffer is the size to send on the network.
if (_cSize < _lOffset)
{
_cSize = _lOffset;
}
return hresult;
}
STDMETHODIMP CStreamOnFile::Seek(
LARGE_INTEGER dlibMoveIN,
DWORD dwOrigin,
ULARGE_INTEGER FAR* plibNewPosition)
{
HRESULT hresult = S_OK;
LONG dlibMove = dlibMoveIN.LowPart;
ULONG cbNewPos = dlibMove;
switch(dwOrigin)
{
case STREAM_SEEK_SET:
if (dlibMove >= 0)
{
_lOffset = dlibMove;
}
else
{
hresult = STG_E_SEEKERROR;
}
break;
case STREAM_SEEK_CUR:
if (!(dlibMove < 0 && (-dlibMove > _lOffset)))
{
_lOffset += (ULONG) dlibMove;
}
else
{
hresult = STG_E_SEEKERROR;
}
break;
case STREAM_SEEK_END:
if (!(dlibMove < 0 && ((ULONG) -dlibMove) > _cbData))
{
_lOffset = _cbData + dlibMove;
}
else
{
hresult = STG_E_SEEKERROR;
}
break;
default:
hresult = STG_E_SEEKERROR;
}
if (plibNewPosition != NULL)
{
ULISet32(*plibNewPosition, _lOffset);
}
return hresult;
}
STDMETHODIMP CStreamOnFile::SetSize(ULARGE_INTEGER cb)
{
return E_NOTIMPL;
}
STDMETHODIMP CStreamOnFile::CopyTo(
IStream FAR* pstm,
ULARGE_INTEGER cb,
ULARGE_INTEGER FAR* pcbRead,
ULARGE_INTEGER FAR* pcbWritten)
{
return E_NOTIMPL;
}
STDMETHODIMP CStreamOnFile::Commit(DWORD grfCommitFlags)
{
return NOERROR;
}
STDMETHODIMP CStreamOnFile::Revert(void)
{
return NOERROR;
}
STDMETHODIMP CStreamOnFile::LockRegion(
ULARGE_INTEGER libOffset,
ULARGE_INTEGER cb,
DWORD dwLockType)
{
return STG_E_INVALIDFUNCTION;
}
STDMETHODIMP CStreamOnFile::UnlockRegion(
ULARGE_INTEGER libOffset,
ULARGE_INTEGER cb,
DWORD dwLockType)
{
return STG_E_INVALIDFUNCTION;
}
STDMETHODIMP CStreamOnFile::Stat(
STATSTG FAR* pstatstg,
DWORD statflag)
{
memset(pstatstg, 0, sizeof(STATSTG));
return E_NOTIMPL;
}
STDMETHODIMP CStreamOnFile::Clone(IStream FAR * FAR *ppstm)
{
return E_NOTIMPL;
}