September Morn Update

Task/Queue-Definition/Component-Pascal/queue-definition-1.component

@@ -1,63 +1,81 @@
 MODULE Queue;
-IMPORT StdLog,Boxes;
-
+IMPORT
+	Boxes;
 TYPE
-    Queue* = POINTER TO RECORD
-        first,last: LONGINT;
-        queue: POINTER TO ARRAY OF Boxes.Object;
-    END;
-
-    PROCEDURE NewQueue*(cap: LONGINT): Queue;
-    VAR
-        q: Queue;
-    BEGIN
-        NEW(q);q.first := 0; q.last := 0;
-        NEW(q.queue,cap);
-        RETURN q
-    END NewQueue;
-
-    PROCEDURE (q: Queue) IsEmpty*(): BOOLEAN, NEW;
-    VAR
-    BEGIN
-        RETURN (q.first = q.last)
-    END IsEmpty;
-
-    PROCEDURE (q: Queue) Push*(o: Boxes.Object),NEW;
-    VAR
-        i,j,oldSize,newSize: LONGINT;
-        queue: POINTER TO ARRAY OF Boxes.Object;
-    BEGIN
-        IF q.IsEmpty() THEN
-            q.queue[q.last] := o;
-            q.last := (q.last + 1) MOD LEN(q.queue)
-        ELSE
-            q.queue[q.last] := o;
-            q.last := (q.last + 1) MOD LEN(q.queue);
-            IF q.first = q.last THEN
-                (* grow queue *)
-                newSize := LEN(q.queue) + (LEN(q.queue) DIV 2);
-                (* new queue*)
-                NEW(queue,newSize);
-                (* move data from old queue to new queue *)
-                i := q.first; j := 0;oldSize := LEN(q.queue) - q.first + q.last;
-                WHILE (j < oldSize ) & (j < LEN(queue) - 1) DO
-                    queue[j] := q.queue[i];
-                    i := (i + 1) MOD LEN(q.queue);INC(j)
-                END;
-                q.queue := queue;q.first := 0;q.last := j
-            END
-        END;
-    END Push;
-
-    PROCEDURE (q: Queue) Pop*(): Boxes.Object, NEW;
-    VAR
-        o: Boxes.Object;
-    BEGIN
-        ASSERT(~q.IsEmpty());
-        o := q.queue[q.first];
-        q.queue[q.first] := NIL;
-        q.first := (q.first + 1) MOD LEN(q.queue);
-        RETURN o;
-    END Pop;
-
+	Instance* = POINTER TO LIMITED RECORD
+		size: LONGINT;
+		first,last: LONGINT;
+		_queue: POINTER TO ARRAY OF Boxes.Box;
+	END;
+	
+	PROCEDURE (self: Instance) Initialize(capacity: LONGINT),NEW;
+	BEGIN
+		self.size := 0;
+		self.first := 0;
+		self.last := 0;
+		NEW(self._queue,capacity)
+	END Initialize;
+	
+	PROCEDURE New*(capacity: LONGINT): Instance;
+	VAR
+		aQueue: Instance;
+	BEGIN
+		NEW(aQueue);aQueue.Initialize(capacity);RETURN aQueue
+	END New;
+	
+	PROCEDURE (self: Instance) IsEmpty*(): BOOLEAN, NEW;
+	BEGIN
+		RETURN self.size = 0;
+	END IsEmpty;
+	
+	PROCEDURE (self: Instance) Capacity*(): LONGINT, NEW;
+	BEGIN
+		RETURN LEN(self._queue)
+	END Capacity;
+	
+	PROCEDURE (self: Instance) Size*(): LONGINT, NEW;
+	BEGIN
+		RETURN self.size
+	END Size;
+	
+	PROCEDURE (self: Instance) IsFull*(): BOOLEAN, NEW;
+	BEGIN
+		RETURN self.size = self.Capacity()
+	END IsFull;
+	
+	PROCEDURE (self: Instance) Push*(b: Boxes.Box), NEW;
+	VAR
+		i, j, newCapacity, oldSize: LONGINT;
+		queue: POINTER TO ARRAY OF Boxes.Box;
+	BEGIN
+		INC(self.size);
+		self._queue[self.last] := b;
+		self.last := (self.last + 1) MOD self.Capacity();
+		IF self.IsFull() THEN
+			(* grow queue *)
+			newCapacity := self.Capacity() + (self.Capacity() DIV 2);
+			(* new queue *)
+			NEW(queue,newCapacity);
+			(* move data from old to new queue *)
+			i := self.first; j := 0; oldSize := self.Capacity() - self.first + self.last;
+			WHILE (j < oldSize) & (j < newCapacity - 1) DO
+				queue[j] := self._queue[i];
+				i := (i + 1) MOD newCapacity;INC(j)
+			END;
+			self._queue := queue;self.first := 0;self.last := j
+		END
+	END Push;
+	
+	PROCEDURE (self: Instance) Pop*(): Boxes.Box, NEW;
+	VAR
+		b: Boxes.Box;
+	BEGIN
+		ASSERT(~self.IsEmpty());
+		DEC(self.size);
+		b := self._queue[self.first];
+		self._queue[self.first] := NIL;
+		self.first := (self.first + 1) MOD self.Capacity();
+		RETURN b
+	END Pop;
+	
 END Queue.