A filter stream has the capability of a normal stream but it can be placed on top of another stream. So, for example, it can uncompress or decrypt the data which are read from another stream and pass it to the requester.
The interface of this class is the same as that of wxInputStream. Only a constructor differs and it is documented below.
Initializes a "filter" stream.
If the parent stream is passed as a pointer then the new filter stream takes ownership of it. If it is passed by reference then it does not.