File : pragmarc-queue_bounded_unprotected.ads
-- PragmAda Reusable Component (PragmARC)
-- Copyright (C) 2002 by PragmAda Software Engineering. All rights reserved.
-- **************************************************************************
--
-- Bounded queue ADT for sequential use only
-- Each queue has a preset maximum size
--
-- History:
-- 2002 Oct 01 J. Carter V2.1--Added Context to Iterate; use mode out to allow scalars
-- 2002 May 01 J. Carter V2.0--Added Assign; implemented using PragmARC.List_Bounded_Unprotected
-- 2001 Jun 01 J. Carter V1.1--Added Peek
-- 2000 May 01 J. Carter V1.0--Initial release
--
with PragmARC.List_Bounded_Unprotected;
generic -- PragmARC.Queue_Bounded_Unprotected
type Element is limited private;
with procedure Assign (To : out Element; From : in Element) is <>;
package PragmARC.Queue_Bounded_Unprotected is
pragma Preelaborate;
type Handle (Max_Size : Positive) is limited private; -- Initial value: emtpy
procedure Clear (Queue : in out Handle);
-- Makes Queue empty
-- Contents of Queue are lost
-- All queues are initially empty
--
-- Time: O(1)
--
-- Postcondition: Is_Empty (Queue)
procedure Assign (To : out Handle; From : in Handle);
-- Makes To a copy of From
-- Raises Too_Short if To.Max_Size < Length (From)
-- To is unchanged if Too_Short is Raised
--
-- Time: O(N)
--
-- Precondition: To.Max_Size >= Length (From) raise Too_Short if violated
procedure Put (Into : in out Handle; Item : in Element); -- raise Full
-- Adds Item to Into
-- Raises Full if Into is already full
-- Into is unchanged if Full is raised
--
-- Time: O(1)
--
-- Precondition: not Is_Full (Into) raise Full if violated
--
-- Postcondition: not Is_Empty (Into)
procedure Get (From : in out Handle; Item : out Element); -- raise Empty
-- Removes the next Element from From and puts it in Item
-- Raises Empty if From is empty
-- From is unchanged if Empty is raised
-- Contents of Item are undefined if Empty is raised
--
-- Time: O(1)
--
-- Precondition: not Is_Empty (From) raise Empty if violated
--
-- Postcondition: not Is_Full (From)
function Is_Full (Queue : Handle) return Boolean;
-- Returns True if Queue is full; False otherwise
--
-- Time: O(1)
function Is_Empty (Queue : Handle) return Boolean;
-- Returns True if Queue is empty; False otherwise
--
-- Time: O(1)
function Length (Queue : Handle) return Natural;
-- Returns the number of Elements in Queue
--
-- Time: O(N)
function Peek (Queue : Handle) return Element;
-- Returnss the Element at the head of Queue without altering Queue
--
-- Raises Empty if Queue is empty
--
-- Time: O(1)
--
-- Precondition: not Is_Empty (Queue) raise Empty if violated
generic -- Iterate
type Context_Data (<>) is limited private;
with procedure Action (Item : in out Element; Context : in out Context_Data; Continue : out Boolean);
procedure Iterate (Over : in out Handle; Context : in out Context_Data);
-- Applies Action to each Element in Over, from head to tail
-- Iterate terminates immediately if Continue is set to False (remainder of Over is not processed)
private -- PragmARC.Queue_Bounded_Unprotected
package Implementation is new PragmARC.List_Bounded_Unprotected (Element => Element);
type Handle (Max_Size : Positive) is record
List : Implementation.Handle (Max_Size => Max_Size);
end record;
end PragmARC.Queue_Bounded_Unprotected;
--
-- This is free software; you can redistribute it and/or modify it under
-- terms of the GNU General Public License as published by the Free Software
-- Foundation; either version 2, or (at your option) any later version.
-- This software is distributed in the hope that it will be useful, but WITH
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details. Free Software Foundation, 59 Temple Place - Suite
-- 330, Boston, MA 02111-1307, USA.
--
-- As a special exception, if other files instantiate generics from this
-- unit, or you link this unit with other files to produce an executable,
-- this unit does not by itself cause the resulting executable to be
-- covered by the GNU General Public License. This exception does not
-- however invalidate any other reasons why the executable file might be
-- covered by the GNU Public License