+//------------------------------------------------------------------------
+// BaseStream
+//
+// This is the base class for all streams that read directly from a file.
+//------------------------------------------------------------------------
+
+class BaseStream: public Stream {
+public:
+
+ BaseStream(Object *dict);
+ virtual ~BaseStream();
+ virtual Stream *makeSubStream(int start, int length, Object *dict) = 0;
+ virtual void setPos(int pos1) = 0;
+ virtual BaseStream *getBaseStream() { return this; }
+ virtual Dict *getDict() { return dict.getDict(); }
+
+ // Get/set position of first byte of stream within the file.
+ virtual int getStart() = 0;
+ virtual void moveStart(int delta) = 0;
+
+private:
+
+ Object dict;
+};
+
+//------------------------------------------------------------------------
+// FilterStream
+//
+// This is the base class for all streams that filter another stream.
+//------------------------------------------------------------------------
+
+class FilterStream: public Stream {
+public:
+
+ FilterStream(Stream *str);
+ virtual ~FilterStream();
+ virtual int getPos() { return str->getPos(); }
+ virtual void setPos(int pos);
+ virtual BaseStream *getBaseStream() { return str->getBaseStream(); }
+ virtual Dict *getDict() { return str->getDict(); }
+
+protected:
+
+ Stream *str;
+};
+