public Win32MemoryMapPager(string file,
long?initialFileSize = null,
NativeFileAttributes options = NativeFileAttributes.Normal,
NativeFileAccess access = NativeFileAccess.GenericRead | NativeFileAccess.GenericWrite)
{
NativeMethods.SYSTEM_INFO systemInfo;
NativeMethods.GetSystemInfo(out systemInfo);
AllocationGranularity = systemInfo.allocationGranularity;
_access = access;
_memoryMappedFileAccess = _access == NativeFileAccess.GenericRead
? MemoryMappedFileAccess.Read
: MemoryMappedFileAccess.ReadWrite;
_handle = NativeFileMethods.CreateFile(file, access,
NativeFileShare.Read | NativeFileShare.Write | NativeFileShare.Delete, IntPtr.Zero,
NativeFileCreationDisposition.OpenAlways, options, IntPtr.Zero);
if (_handle.IsInvalid)
{
int lastWin32ErrorCode = Marshal.GetLastWin32Error();
throw new IOException("Failed to open file storage of Win32MemoryMapPager",
new Win32Exception(lastWin32ErrorCode));
}
_fileInfo = new FileInfo(file);
var streamAccessType = _access == NativeFileAccess.GenericRead
? FileAccess.Read
: FileAccess.ReadWrite;
_fileStream = new FileStream(_handle, streamAccessType);
_totalAllocationSize = _fileInfo.Length;
if (_access.HasFlag(NativeFileAccess.GenericWrite) ||
_access.HasFlag(NativeFileAccess.GenericAll) ||
_access.HasFlag(NativeFileAccess.FILE_GENERIC_WRITE))
{
var fileLength = _fileStream.Length;
if (fileLength == 0 && initialFileSize.HasValue)
{
fileLength = initialFileSize.Value;
}
if (_fileStream.Length == 0 || (fileLength % AllocationGranularity != 0))
{
fileLength = NearestSizeToAllocationGranularity(fileLength);
_fileStream.SetLength(fileLength);
}
_totalAllocationSize = fileLength;
}
NumberOfAllocatedPages = _totalAllocationSize / PageSize;
PagerState.Release();
PagerState = CreatePagerState();
}
public Win32MemoryMapPager(string file,
long? initialFileSize = null,
NativeFileAttributes options = NativeFileAttributes.Normal,
NativeFileAccess access = NativeFileAccess.GenericRead | NativeFileAccess.GenericWrite)
{
NativeMethods.SYSTEM_INFO systemInfo;
NativeMethods.GetSystemInfo(out systemInfo);
AllocationGranularity = systemInfo.allocationGranularity;
_access = access;
_memoryMappedFileAccess = _access == NativeFileAccess.GenericRead
? MemoryMappedFileAccess.Read
: MemoryMappedFileAccess.ReadWrite;
_handle = NativeFileMethods.CreateFile(file, access,
NativeFileShare.Read | NativeFileShare.Write | NativeFileShare.Delete, IntPtr.Zero,
NativeFileCreationDisposition.OpenAlways, options, IntPtr.Zero);
if (_handle.IsInvalid)
{
int lastWin32ErrorCode = Marshal.GetLastWin32Error();
throw new IOException("Failed to open file storage of Win32MemoryMapPager",
new Win32Exception(lastWin32ErrorCode));
}
_fileInfo = new FileInfo(file);
var streamAccessType = _access == NativeFileAccess.GenericRead
? FileAccess.Read
: FileAccess.ReadWrite;
_fileStream = new FileStream(_handle, streamAccessType);
_totalAllocationSize = _fileInfo.Length;
if (_access.HasFlag(NativeFileAccess.GenericWrite) ||
_access.HasFlag(NativeFileAccess.GenericAll) ||
_access.HasFlag(NativeFileAccess.FILE_GENERIC_WRITE))
{
var fileLength = _fileStream.Length;
if (fileLength == 0 && initialFileSize.HasValue)
fileLength = initialFileSize.Value;
if (_fileStream.Length == 0 || (fileLength % AllocationGranularity != 0))
{
fileLength = NearestSizeToAllocationGranularity(fileLength);
_fileStream.SetLength(fileLength);
}
_totalAllocationSize = fileLength;
}
NumberOfAllocatedPages = _totalAllocationSize / PageSize;
PagerState.Release();
PagerState = CreatePagerState();
}
