protected virtual void Dispose(bool disposing)
{
if (IsOpen)
{
Win32MapApis.CloseHandle(_hMap);
}
_hMap = NULL_HANDLE;
if (disposing)
{
GC.SuppressFinalize(this);
}
}
Create(string fileName, MapProtection protection,
long maxSize, String name)
{
MemoryMappedFile map = new MemoryMappedFile();
// open file first
IntPtr hFile = INVALID_HANDLE_VALUE;
if (fileName != null)
{
// 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());
}
// FIX: Is support neede for zero-length files!?!
}
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());
}
return(map);
}
