File : average_queue.adb


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--                         ADAGIO - ADALID - AENEA.                         --

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--                            Copyright (C) 2003                            --

--                                 A. Mosteo.                               --

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--  Authors: A. Mosteo. (adagio@mosteo.com)                                 --

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--  $Id: average_queue.adb,v 1.3 2004/01/21 21:05:43 Jano Exp $


package body Average_queue is

   -- Add a new item

   -- Will lost olders when size exceeded

   procedure Push(this: in out Object; New_item: in Item) is
   begin
      this.Data(this.Pos):= New_item;
      this.Pos:= this.Pos + 1;
      if this.Pos > this.Data'Last then
         this.Pos:= this.Data'First;
      end if;
      if this.Length < this.Data'Length then
         this.Length:= this.Length + 1;
      end if;
   end;

   -- Returns the average of pushed objects

   function Average(this: in Object) return float is
      Acum: Item:= this.Data(this.Data'First);
   begin
      if this.Length = 0 then
         raise No_data;
      end if;

      for n in this.Data'First + 1 .. this.Data'First + this.Length - 1 loop
         Acum:= Acum + this.Data(n);
      end loop;
      return Acum / this.Length;
   end;

   -- Says if there is no data to average.

   function Is_empty (This : in Object) return Boolean is
   begin
      return This.Length = 0;
   end Is_empty;

end Average_queue;