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Fix the semantics of SetFilePointer as described by Raymond Chen on http://blogs.msdn.com/oldnewthing/archive/2007/07/11/3805135.aspx

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svn path=/trunk/; revision=27612
This commit is contained in:
Thomas Bluemel 2007-07-12 10:56:00 +00:00
parent 87d4c1e2b4
commit e0bf78bad7
1 changed files with 26 additions and 8 deletions
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34
reactos/dll/win32/kernel32/file/file.c
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@ -394,18 +394,14 @@ SetFilePointer(HANDLE hFile,
return -1;
}
Distance.u.LowPart = lDistanceToMove;
if (lpDistanceToMoveHigh)
{
Distance.u.HighPart = *lpDistanceToMoveHigh;
}
else if (lDistanceToMove >= 0)
{
Distance.u.HighPart = 0;
Distance.u.LowPart = lDistanceToMove;
}
else
{
Distance.u.HighPart = -1;
Distance.QuadPart = lDistanceToMove;
}
switch(dwMoveMethod)
@ -441,6 +437,14 @@ SetFilePointer(HANDLE hFile,
return -1;
}
if (lpDistanceToMoveHigh == NULL && FilePosition.CurrentByteOffset.HighPart != 0)
{
/* If we're moving the pointer outside of the 32 bit boundaries but
the application only passed a 32 bit value we need to bail out! */
SetLastError(ERROR_INVALID_PARAMETER);
return -1;
}
errCode = NtSetInformationFile(hFile,
&IoStatusBlock,
&FilePosition,
@ -448,14 +452,28 @@ SetFilePointer(HANDLE hFile,
FilePositionInformation);
if (!NT_SUCCESS(errCode))
{
SetLastErrorByStatus(errCode);
return -1;
if (lpDistanceToMoveHigh != NULL)
*lpDistanceToMoveHigh = -1;
SetLastErrorByStatus(errCode);
return -1;
}
if (lpDistanceToMoveHigh != NULL)
{
*lpDistanceToMoveHigh = FilePosition.CurrentByteOffset.u.HighPart;
}
if (FilePosition.CurrentByteOffset.u.LowPart == -1)
{
/* The value of -1 is valid here, especially when the new
file position is greater than 4 GB. Since NtSetInformationFile
succeeded we never set an error code and we explicitly need
to clear a previously set error code in this case, which
an application will check if INVALID_SET_FILE_POINTER is returned! */
SetLastError(ERROR_SUCCESS);
}
return FilePosition.CurrentByteOffset.u.LowPart;
}