Not a bug so much as a request.  Replace the block:

const HANDLE INVALID_HANDLE_VALUE = cast(HANDLE)-1;
const DWORD INVALID_FILE_SIZE = cast(DWORD)0xFFFFFFFF;

with:

const HANDLE INVALID_HANDLE_VALUE = cast(HANDLE)-1;
const DWORD INVALID_SET_FILE_POINTER = cast(DWORD)-1;
const DWORD INVALID_FILE_SIZE = cast(DWORD)0xFFFFFFFF;

ie. I need INVALID_SET_FILE_POINTER to be defined.