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------------------------------------------------------------------------------
-- --
-- GNAT LIBRARY COMPONENTS --
-- --
-- ADA.CONTAINERS.BOUNDED_PRIORITY_QUEUES --
-- --
-- S p e c --
-- --
-- Copyright (C) 2011, Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
-- apply solely to the contents of the part following the private keyword. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- This unit was originally developed by Matthew J Heaney. --
------------------------------------------------------------------------------
with System;
with Ada.Containers.Synchronized_Queue_Interfaces;
with Ada.Containers.Bounded_Doubly_Linked_Lists;
generic
with package Queue_Interfaces is
new Ada.Containers.Synchronized_Queue_Interfaces (<>);
type Queue_Priority is private;
with function Get_Priority
(Element : Queue_Interfaces.Element_Type) return Queue_Priority is <>;
with function Before
(Left, Right : Queue_Priority) return Boolean is <>;
Default_Capacity : Count_Type;
Default_Ceiling : System.Any_Priority := System.Priority'Last;
package Ada.Containers.Bounded_Priority_Queues is
pragma Preelaborate;
package Implementation is
-- All identifiers in this unit are implementation defined
pragma Implementation_Defined;
type List_Type (Capacity : Count_Type) is tagged limited private;
procedure Enqueue
(List : in out List_Type;
New_Item : Queue_Interfaces.Element_Type);
procedure Dequeue
(List : in out List_Type;
Element : out Queue_Interfaces.Element_Type);
procedure Dequeue
(List : in out List_Type;
At_Least : Queue_Priority;
Element : in out Queue_Interfaces.Element_Type;
Success : out Boolean);
function First_Element
(List : List_Type) return Queue_Interfaces.Element_Type;
function Length (List : List_Type) return Count_Type;
function Max_Length (List : List_Type) return Count_Type;
private
-- We need a better data structure here, such as a proper heap. ???
package List_Types is new Bounded_Doubly_Linked_Lists
(Element_Type => Queue_Interfaces.Element_Type,
"=" => Queue_Interfaces."=");
type List_Type (Capacity : Count_Type) is tagged limited record
Container : List_Types.List (Capacity);
Max_Length : Count_Type := 0;
end record;
end Implementation;
protected type Queue
(Capacity : Count_Type := Default_Capacity;
Ceiling : System.Any_Priority := Default_Ceiling)
with Priority => Ceiling is new Queue_Interfaces.Queue with
overriding
entry Enqueue (New_Item : Queue_Interfaces.Element_Type);
overriding
entry Dequeue (Element : out Queue_Interfaces.Element_Type);
-- The priority queue operation Dequeue_Only_High_Priority had been a
-- protected entry in early drafts of AI05-0159, but it was discovered
-- that that operation as specified was not in fact implementable. The
-- operation was changed from an entry to a protected procedure per the
-- ARG meeting in Edinburgh (June 2011), with a different signature and
-- semantics.
not overriding
procedure Dequeue_Only_High_Priority
(At_Least : Queue_Priority;
Element : in out Queue_Interfaces.Element_Type;
Success : out Boolean);
overriding
function Current_Use return Count_Type;
overriding
function Peak_Use return Count_Type;
private
List : Implementation.List_Type (Capacity);
end Queue;
end Ada.Containers.Bounded_Priority_Queues;
|
