Source code of Windows XP (NT5)
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/*++
Copyright (C) Microsoft Corporation, 1998 - 1999
All rights reserved.
Module Name:
Stream.cxx
Abstract:
implements TStream class methods
Author:
Adina Trufinescu (AdinaTru) 4-Nov-1998
Revision History:
--*/
#include "precomp.h"
#pragma hdrstop
#include "stream.hxx"
/*++
Title:
TStream
Routine Description:
Initialize the TStream class; note the class is initaliy
in an in valid state until a read or write occurs in which
case the file handle is created and then the class becomes valid.
Arguments:
None
Return Value:
Nothing
--*/
TStream::
TStream(
IN TString& strFileName
) : m_strFileName(strFileName),
m_hFileHandle(INVALID_HANDLE_VALUE),
m_dwAccess(0),
m_bCreated(FALSE)
{
m_uliStreamSize.QuadPart = 0;
}
/*++
Title:
~TStream
Routine Description:
Releases the stream file handle.
Arguments:
None
Return Value:
Nothing
--*/
TStream::
~TStream(
VOID
)
{
if(m_hFileHandle != INVALID_HANDLE_VALUE)
{
CloseHandle(m_hFileHandle);
}
}
/*++
Title:
bValid
Routine Description:
check class member validity : file handle invalid
Arguments:
None
Return Value:
TRUE if class is in a valid state.
--*/
BOOL
TStream::
bValid(
VOID
)
{
return (m_hFileHandle != INVALID_HANDLE_VALUE);
}
/*++
Title:
Read
Routine Description:
Reads cb bytes into pv , from current position of file.
Number of actual reded bytes stored in pbcRead
Arguments:
Return Value:
The error code from ReadFile API is converted to HRESULT
--*/
HRESULT
TStream::
Read(
VOID *pv,
ULONG cb,
ULONG *pcbRead
)
{
TStatusH hr;
if(!bValid())
{
m_hFileHandle = PCreateFile(&m_dwAccess);
if(!bValid())
{
hr DBGCHK = E_UNEXPECTED;
goto End;
}
}
if(bValid())
{
if(pv)
{
if(!ReadFile( m_hFileHandle,
reinterpret_cast<LPDWORD>(pv),
static_cast<DWORD>(cb),
reinterpret_cast<LPDWORD>(pcbRead),
NULL))
{
*pcbRead = 0;
hr DBGCHK = MapWin32ErrorCodeToHRes(GetLastError());
goto End;
}
hr DBGCHK = ((*pcbRead) == cb) && (*pcbRead != 0 && cb != 0) ? S_OK : E_FAIL;
}
else
{
hr DBGCHK = STG_E_INVALIDPOINTER;
}
}
End:
return hr;
}
/*++
Title:
Write
Routine Description:
Writes cb bytes from pv , at current position of file.
Number of actual written bytes stored in pcbWritten
Arguments:
Return Value:
The error code from WriteFile API is converted to HRESULT
--*/
HRESULT
TStream::
Write(
VOID const* pv,
ULONG cb,
ULONG * pcbWritten
)
{
HRESULT hr = E_UNEXPECTED;
if(!bValid())
{
m_hFileHandle = PCreateFile(&m_dwAccess);
if(!bValid())
{
goto End;
}
}
if(bValid())
{
if(pv)
{
if(!WriteFile(m_hFileHandle,
static_cast<LPCVOID>(pv),
static_cast<DWORD>(cb),
reinterpret_cast<LPDWORD>(pcbWritten),
NULL))
{
if (pcbWritten)
{
*pcbWritten = 0;
}
hr = MapWin32ErrorCodeToHRes(GetLastError());
}
if (pcbWritten)
{
hr = (*pcbWritten == cb) ? S_OK : hr;
}
else
{
hr = STG_E_INVALIDPOINTER;
}
if(SUCCEEDED(hr))
{
DBGMSG( DBG_NONE, ( "TPrnStream::Write OK !!!\n" ));
}
}
else
{
hr = STG_E_INVALIDPOINTER;
}
}
End:
return hr;
}
/*++
Title:
Seek
Routine Description:
Set stream pointer
Arguments:
dlibMove - Offset relative to dwOrigin
dwOrigin - Specifies the origin for the offset
plibNewPosition - Pointer to location containing new seek
Return Value:
The error code from SetFilePointer API is converted to HRESULT
--*/
HRESULT
TStream::
Seek(
LARGE_INTEGER dlibMove,
DWORD dwOrigin,
ULARGE_INTEGER * plibNewPosition
)
{
DWORD dwMoveMethod;
DWORD dwCurrentFilePosition ;
LONG lDistanceToMoveHigh;
TStatusB bStatus;
TStatusH hr;
DWORD dwError;
static const DWORD adwMoveMethode[] =
{
FILE_BEGIN,
FILE_CURRENT,
FILE_END,
};
dwMoveMethod = adwMoveMethode[dwOrigin];
if(!bValid())
{
m_hFileHandle = PCreateFile(&m_dwAccess);
if(!bValid())
{
hr DBGCHK = E_UNEXPECTED;
goto End;
}
}
lDistanceToMoveHigh = dlibMove.HighPart;
dwCurrentFilePosition = SetFilePointer( m_hFileHandle,
static_cast<LONG>(dlibMove.LowPart),
&lDistanceToMoveHigh,
dwMoveMethod );
DBGMSG( DBG_NONE, ( "Seek: Current pos: high %d low %d\n" ,lDistanceToMoveHigh, dwCurrentFilePosition) );
if (dwCurrentFilePosition == 0xFFFFFFFF && (dwError = GetLastError()) != NO_ERROR )
{
hr DBGCHK = MapWin32ErrorCodeToHRes(dwError);
}
else
{
if(plibNewPosition)
{
plibNewPosition->HighPart = static_cast<DWORD>(lDistanceToMoveHigh);
plibNewPosition->LowPart = dwCurrentFilePosition;
}
hr DBGNOCHK = S_OK;
}
End:
return hr;
}
/*++
Title:
PCreateFile
Routine Description:
If file doesn't exists , create it with write / read access
If file exists , try open it with read wrire access ; if fail , try to open with read
Arguments:
pdwAccess - access rights if succeeded , 0 if failed
Return Value:
The error code from SetFilePointer API is converted to HRESULT
--*/
HANDLE
TStream::
PCreateFile(
OUT LPDWORD pdwAccess
)
{
HANDLE hFileHandle;
DWORD dwAccess;
*pdwAccess = 0;
//
// try to open an existing file with read/write access
//
dwAccess = GENERIC_WRITE | GENERIC_READ;
hFileHandle = CreateFile( m_strFileName,
dwAccess,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
if(hFileHandle == INVALID_HANDLE_VALUE)
{
//
// if last error is access denied , try to open only with read access
//
if(GetLastError() == ERROR_ACCESS_DENIED)
{
dwAccess = GENERIC_READ;
hFileHandle = CreateFile( m_strFileName,
GENERIC_READ,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
}
else if(GetLastError() == ERROR_FILE_NOT_FOUND)
{
dwAccess = GENERIC_WRITE | GENERIC_READ;
//
// if last error was file don't exist , try to create it
//
hFileHandle = CreateFile( m_strFileName,
dwAccess,
0,
NULL,
OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL,
NULL);
m_bCreated = TRUE;
}
}
if(hFileHandle != INVALID_HANDLE_VALUE)
{
*pdwAccess = dwAccess;
m_uliStreamSize.LowPart = GetFileSize(hFileHandle, &m_uliStreamSize.HighPart);
}
return hFileHandle;
}
/*++
Title:
DestroyFile
Routine Description:
If file handle is invalid , it means that file wasn't creaded - return TRUE
If file handle is valid , close it and delete file
Arguments:
None
Return Value:
TRUE if succeeded
--*/
HRESULT
TStream::
DestroyFile(
VOID
)
{
TStatusB bStatus;
bStatus DBGNOCHK = TRUE;
if(m_hFileHandle != INVALID_HANDLE_VALUE)
{
CloseHandle(m_hFileHandle);
m_hFileHandle = INVALID_HANDLE_VALUE;
bStatus DBGCHK = DeleteFile(m_strFileName);
}
return bStatus ? S_OK : MapWin32ErrorCodeToHRes(GetLastError());
}
/*++
Title:
bSetEndOfFile
Routine Description:
If file handle is valid , set end of file
Needed it for truncating the file in case of overwritting
Called at the end of every successfull storing
Arguments:
None
Return Value:
TRUE if succeeded
--*/
BOOL
TStream::
bSetEndOfFile(
VOID
)
{
TStatusB bStatus;
bStatus DBGCHK = (m_hFileHandle != INVALID_HANDLE_VALUE);
if(bStatus)
{
bStatus DBGCHK = SetEndOfFile(m_hFileHandle);
}
return bStatus;
}
/*++
Title:
MapWin32ErrorCodeToHRes
Routine Description:
maps file error codes to HRESULT errors
Arguments:
Error value to convert
Return Value:
Converted error value to an HRESULT
Last Error:
--*/
HRESULT
TStream::
MapWin32ErrorCodeToHRes(
IN DWORD dwErrorCode
)
{
return MAKE_HRESULT( SEVERITY_ERROR, FACILITY_STORAGE, dwErrorCode);
}