File : bc-containers-maps-unbounded-synchronized.ads


-- Copyright (C) 1994-2000 Grady Booch and Simon Wright.
-- All Rights Reserved.
--
--      This program is free software; you can redistribute it
--      and/or modify it under the terms of the Ada Community
--      License which comes with this Library.
--
--      This program is distributed in the hope that it will be
--      useful, but WITHOUT ANY WARRANTY; without even the implied
--      warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
--      PURPOSE. See the Ada Community License for more details.
--      You should have received a copy of the Ada Community
--      License with this library, in the file named "Ada Community
--      License" or "ACL". If not, contact the author of this library
--      for a copy.
--

-- $Id: bc-containers-maps-unbounded-synchronized.ads,v 1.1.2.1 2000/02/12 14:37:57 simon Exp $

with BC.Support.Synchronization;

generic
  type Monitor is new BC.Support.Synchronization.Monitor_Base with private;
package BC.Containers.Maps.Unbounded.Synchronized is

  pragma Elaborate_Body;

  -- A map denotes a collection forming a dictionary of domain/range
  -- pairs. Maps are cached, so that the most recently accessed
  -- domain/range pair can be found on the order of O(1).

  -- The hash function (the generic parameter Hash) determines the
  -- allocation of pairs to hash buckets. The value returned must not
  -- change during the lifetime of a given Item. The range of hash values
  -- need not be constrained to the number of buckets in the map.

  -- The hash function must satisfy the condition that, for objects A and
  -- B, if A = B, then Hash (A) must equal Hash (B). The hash function
  -- should attempt to spread the set of possible items uniformly across
  -- the number of buckets. The quality of the hash function has a
  -- significant impact upon performance.

  -- XXX A problem in GNAT (3.11p, 3.12a2) means we have to refer to
  -- the type Value as Maps.Value.

  type Synchronized_Unbounded_Map is new Unbounded_Map with private;

  procedure Clear (M : in out Synchronized_Unbounded_Map);
  -- Empty the map of all item/value pairs. The cached item/value pair is
  -- cleared.

  procedure Bind
     (M : in out Synchronized_Unbounded_Map; I : Item; V : Maps.Value);
  -- If the item already exists in the map, raise BC.Duplicate. Otherwise,
  -- add the item/value pair to the map. The cached item/value pair is set
  -- to this new binding.

  procedure Rebind
     (M : in out Synchronized_Unbounded_Map; I : Item; V : Maps.Value);
  -- If the item does not exist in the map, raise BC.Not_Found. Otherwise,
  -- change the item's binding to the given value. The cached item/value
  -- pair is set to this new binding.

  procedure Unbind (M : in out Synchronized_Unbounded_Map; I : Item);
  -- If the item does not exist in the map, raise BC.Not_Found. Otherwise,
  -- remove the item/value binding. The cached item/value pair is cleared.

  function Extent (M : Synchronized_Unbounded_Map) return Natural;
  -- Return the number of item/value bindings in the map.

  function Is_Empty (M : Synchronized_Unbounded_Map) return Boolean;
  -- Return True if and only if there are no item/value bindings in the
  -- map; otherwise, return False.

  function Is_Bound (M : Synchronized_Unbounded_Map; I : Item) return Boolean;
  -- Return True if and only if there is a binding for the given item in
  -- the map; otherwise, return False. The cached item/value pair is used
  -- to accelerate the search; if there is a cache hit, the time complexity
  -- of this operation is O(1).

  function Value_Of
     (M : Synchronized_Unbounded_Map; I : Item) return Maps.Value;
  -- If the item does not exist in the map, raises BC.Not_Found. Otherwise,
  -- return a constant pointer to the value bound to the given item. The
  -- cached item/value pair is used to accelerate the search; if there is a
  -- cache hit, the time complexity of this operation is O(1).

private

  procedure Lock (M : in out Synchronized_Unbounded_Map);
  procedure Unlock (M : in out Synchronized_Unbounded_Map);

  type Synchronized_Unbounded_Map is new Unbounded_Map with record
    The_Monitor : BC.Support.Synchronization.Monitor_P;
  end record;

  procedure Initialize (M : in out Synchronized_Unbounded_Map);
  procedure Adjust (M : in out Synchronized_Unbounded_Map);
  procedure Finalize (M : in out Synchronized_Unbounded_Map);

end BC.Containers.Maps.Unbounded.Synchronized;