public void Flush(IntPtr viewBaseAddr)
{
// Throws OverflowException if (a) this is a 32-bit platform AND (b) size is out of bounds (ie. int bounds) with respect to this platform
IntPtr flushLength = new IntPtr(MaxSize);
Win32MapApis.FlushViewOfFile(viewBaseAddr, flushLength);
}
protected virtual void Dispose(bool disposing)
{
if (IsOpen)
{
Win32MapApis.CloseHandle(_hMap);
}
_hMap = NULL_HANDLE;
if (disposing)
{
GC.SuppressFinalize(this);
}
}
/// <summary>
/// Open an existing named File Mapping object
/// </summary>
/// <param name="access">desired access to the map</param>
/// <param name="name">name of object</param>
/// <returns>The memory mapped file instance</returns>
public static MemoryMappedFile Open(MapAccess access, String name)
{
MemoryMappedFile map = new MemoryMappedFile
{
_hMap = Win32MapApis.OpenFileMapping((int)access, false, name)
};
if (map._hMap == NULL_HANDLE)
{
throw new FileMapIOException(Marshal.GetHRForLastWin32Error());
}
map._maxSize = -1; // debug unknown
return(map);
}
public IntPtr MapView(MapAccess access, long offset, long size)
{
if (!IsOpen)
{
throw new ObjectDisposedException("Winterdom.IO.FileMap.MemoryMappedFile.MapView - MMF already closed");
}
// Throws OverflowException if (a) this is a 32-bit platform AND (b) size is out of bounds (ie. int bounds) with respect to this platform
IntPtr mapSize = new IntPtr(size);
IntPtr baseAddress = Win32MapApis.MapViewOfFile(
_hMap, (int)access,
(int)((offset >> 32) & 0xFFFFFFFF),
(int)(offset & 0xFFFFFFFF), mapSize
);
if (baseAddress == IntPtr.Zero)
{
throw new FileMapIOException(Marshal.GetHRForLastWin32Error());
}
return(baseAddress);
}
public void UnMapView(IntPtr mapBaseAddr)
{
Win32MapApis.UnmapViewOfFile(mapBaseAddr);
}
Create(string fileName, MapProtection protection,
long maxSize, String name)
{
MemoryMappedFile map = new MemoryMappedFile();
if (!map.Is64bit && maxSize > uint.MaxValue)
{
throw new ConstraintException("32bit systems support max size of 4gb.");
}
// open file first
IntPtr hFile = INVALID_HANDLE_VALUE;
if (!string.IsNullOrEmpty(fileName))
{
if (maxSize == 0)
{
if (!File.Exists(fileName))
{
throw new Exception(string.Format("Winterdom.IO.FileMap.MemoryMappedFile.Create - \"{0}\" does not exist ==> Unable to map entire file", fileName));
}
FileInfo backingFileInfo = new FileInfo(fileName);
maxSize = backingFileInfo.Length;
if (maxSize == 0)
{
throw new Exception(string.Format("Winterdom.IO.FileMap.MemoryMappedFile.Create - \"{0}\" is zero bytes ==> Unable to map entire file", fileName));
}
}
// determine file access needed
// we'll always need generic read access
int desiredAccess = GENERIC_READ;
if ((protection == MapProtection.PageReadWrite) ||
(protection == MapProtection.PageWriteCopy))
{
desiredAccess |= GENERIC_WRITE;
}
// open or create the file
// if it doesn't exist, it gets created
hFile = Win32MapApis.CreateFile(
fileName, desiredAccess, 0,
IntPtr.Zero, OPEN_ALWAYS, 0, IntPtr.Zero
);
if (hFile == INVALID_HANDLE_VALUE)
{
throw new FileMapIOException(Marshal.GetHRForLastWin32Error());
}
map._fileName = fileName;
}
map._hMap = Win32MapApis.CreateFileMapping(
hFile, IntPtr.Zero, (int)protection,
(int)((maxSize >> 32) & 0xFFFFFFFF),
(int)(maxSize & 0xFFFFFFFF), name
);
// close file handle, we don't need it
if (hFile != INVALID_HANDLE_VALUE)
{
Win32MapApis.CloseHandle(hFile);
}
if (map._hMap == NULL_HANDLE)
{
throw new FileMapIOException(Marshal.GetHRForLastWin32Error());
}
map._protection = protection;
map._maxSize = maxSize;
return(map);
}
