More exactly TMemoryStream:

[code=Pascal]

FS:= TFileStream.Create(FileName, fmOpenRead);

Stream:= TMemoryStream.Create;
Stream.Size:= FS.Size;
Stream.CopyFrom(FS, FS.Size);
FS.Free;

// loaded into memory
Stream.Position:=0;
Stream.Read(value, sizeof(Integer));
...
Stream.Free;

[/code]