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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT LIBRARY COMPONENTS                          --

--                                                                          --

--            A D A . C O N T A I N E R S . H A S H E D _ M A P S           --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 2004-2009, 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.                  --

------------------------------------------------------------------------------

private with Ada.Containers.Hash_Tables;

private with Ada.Streams;

private with Ada.Finalization;

generic

   type Key_Type is private;

   type Element_Type is private;

   with function Hash (Key : Key_Type) return Hash_Type;

   with function Equivalent_Keys (Left, Right : Key_Type) return Boolean;

   with function "=" (Left, Right : Element_Type) return Boolean is <>;

package Ada.Containers.Hashed_Maps is

   pragma Preelaborate;

   pragma Remote_Types;

   type Map is tagged private;

   pragma Preelaborable_Initialization (Map);

   type Cursor is private;

   pragma Preelaborable_Initialization (Cursor);

   Empty_Map : constant Map;

   --  Map objects declared without an initialization expression are

   --  initialized to the value Empty_Map.

   No_Element : constant Cursor;

   --  Cursor objects declared without an initialization expression are

   --  initialized to the value No_Element.

   function "=" (Left, Right : Map) return Boolean;

   --  For each key/element pair in Left, equality attempts to find the key in

   --  Right; if a search fails the equality returns False. The search works by

   --  calling Hash to find the bucket in the Right map that corresponds to the

   --  Left key. If bucket is non-empty, then equality calls Equivalent_Keys

   --  to compare the key (in Left) to the key of each node in the bucket (in

   --  Right); if the keys are equivalent, then the equality test for this

   --  key/element pair (in Left) completes by calling the element equality

   --  operator to compare the element (in Left) to the element of the node

   --  (in Right) whose key matched.

   function Capacity (Container : Map) return Count_Type;

   --  Returns the current capacity of the map. Capacity is the maximum length

   --  before which rehashing in guaranteed not to occur.

   procedure Reserve_Capacity (Container : in out Map; Capacity : Count_Type);

   --  Adjusts the current capacity, by allocating a new buckets array. If the

   --  requested capacity is less than the current capacity, then the capacity

   --  is contracted (to a value not less than the current length). If the

   --  requested capacity is greater than the current capacity, then the

   --  capacity is expanded (to a value not less than what is requested). In

   --  either case, the nodes are rehashed from the old buckets array onto the

   --  new buckets array (Hash is called once for each existing key in order to

   --  compute the new index), and then the old buckets array is deallocated.

   function Length (Container : Map) return Count_Type;

   --  Returns the number of items in the map

   function Is_Empty (Container : Map) return Boolean;

   --  Equivalent to Length (Container) = 0

   procedure Clear (Container : in out Map);

   --  Removes all of the items from the map

   function Key (Position : Cursor) return Key_Type;

   --  Returns the key of the node designated by the cursor

   function Element (Position : Cursor) return Element_Type;

   --  Returns the element of the node designated by the cursor

   procedure Replace_Element

     (Container : in out Map;

      Position  : Cursor;

      New_Item  : Element_Type);

   --  Assigns the value New_Item to the element designated by the cursor

   procedure Query_Element

     (Position : Cursor;

      Process  : not null access

                   procedure (Key : Key_Type; Element : Element_Type));

   --  Calls Process with the key and element (both having only a constant

   --  view) of the node designed by the cursor.

   procedure Update_Element

     (Container : in out Map;

      Position  : Cursor;

      Process   : not null access

                    procedure (Key : Key_Type; Element : in out Element_Type));

   --  Calls Process with the key (with only a constant view) and element (with

   --  a variable view) of the node designed by the cursor.

   procedure Move (Target : in out Map; Source : in out Map);

   --  Clears Target (if it's not empty), and then moves (not copies) the

   --  buckets array and nodes from Source to Target.

   procedure Insert

     (Container : in out Map;

      Key       : Key_Type;

      New_Item  : Element_Type;

      Position  : out Cursor;

      Inserted  : out Boolean);

   --  Conditionally inserts New_Item into the map. If Key is already in the

   --  map, then Inserted returns False and Position designates the node

   --  containing the existing key/element pair (neither of which is modified).

   --  If Key is not already in the map, the Inserted returns True and Position

   --  designates the newly-inserted node container Key and New_Item. The

   --  search for the key works as follows. Hash is called to determine Key's

   --  bucket; if the bucket is non-empty, then Equivalent_Keys is called to

   --  compare Key to each node in that bucket. If the bucket is empty, or

   --  there were no matching keys in the bucket, the search "fails" and the

   --  key/item pair is inserted in the map (and Inserted returns True);

   --  otherwise, the search "succeeds" (and Inserted returns False).

   procedure Insert

     (Container : in out Map;

      Key       : Key_Type;

      Position  : out Cursor;

      Inserted  : out Boolean);

   --  The same as the (conditional) Insert that accepts an element parameter,

   --  with the difference that if Inserted returns True, then the element of

   --  the newly-inserted node is initialized to its default value.

   procedure Insert

     (Container : in out Map;

      Key       : Key_Type;

      New_Item  : Element_Type);

   --  Attempts to insert Key into the map, performing the usual search (which

   --  involves calling both Hash and Equivalent_Keys); if the search succeeds

   --  (because Key is already in the map), then it raises Constraint_Error.

   --  (This version of Insert is similar to Replace, but having the opposite

   --  exception behavior. It is intended for use when you want to assert that

   --  Key is not already in the map.)

   procedure Include

     (Container : in out Map;

      Key       : Key_Type;

      New_Item  : Element_Type);

   --  Attempts to insert Key into the map. If Key is already in the map, then

   --  both the existing key and element are assigned the values of Key and

   --  New_Item, respectively. (This version of Insert only raises an exception

   --  if cursor tampering occurs. It is intended for use when you want to

   --  insert the key/element pair in the map, and you don't care whether Key

   --  is already present.)

   procedure Replace

     (Container : in out Map;

      Key       : Key_Type;

      New_Item  : Element_Type);

   --  Searches for Key in the map; if the search fails (because Key was not in

   --  the map), then it raises Constraint_Error. Otherwise, both the existing

   --  key and element are assigned the values of Key and New_Item rsp. (This

   --  is similar to Insert, but with the opposite exception behavior. It is to

   --  be used when you want to assert that Key is already in the map.)

   procedure Exclude (Container : in out Map; Key : Key_Type);

   --  Searches for Key in the map, and if found, removes its node from the map

   --  and then deallocates it. The search works as follows. The operation

   --  calls Hash to determine the key's bucket; if the bucket is not empty, it

   --  calls Equivalent_Keys to compare Key to each key in the bucket. (This is

   --  the deletion analog of Include. It is intended for use when you want to

   --  remove the item from the map, but don't care whether the key is already

   --  in the map.)

   procedure Delete (Container : in out Map; Key : Key_Type);

   --  Searches for Key in the map (which involves calling both Hash and

   --  Equivalent_Keys). If the search fails, then the operation raises

   --  Constraint_Error. Otherwise it removes the node from the map and then

   --  deallocates it. (This is the deletion analog of non-conditional

   --  Insert. It is intended for use when you want to assert that the item is

   --  already in the map.)

   procedure Delete (Container : in out Map; Position : in out Cursor);

   --  Removes the node designated by Position from the map, and then

   --  deallocates the node. The operation calls Hash to determine the bucket,

   --  and then compares Position to each node in the bucket until there's a

   --  match (it does not call Equivalent_Keys).

   function First (Container : Map) return Cursor;

   --  Returns a cursor that designates the first non-empty bucket, by

   --  searching from the beginning of the buckets array.

   function Next (Position : Cursor) return Cursor;

   --  Returns a cursor that designates the node that follows the current one

   --  designated by Position. If Position designates the last node in its

   --  bucket, the operation calls Hash to compute the index of this bucket,

   --  and searches the buckets array for the first non-empty bucket, starting

   --  from that index; otherwise, it simply follows the link to the next node

   --  in the same bucket.

   procedure Next (Position : in out Cursor);

   --  Equivalent to Position := Next (Position)

   function Find (Container : Map; Key : Key_Type) return Cursor;

   --  Searches for Key in the map. Find calls Hash to determine the key's

   --  bucket; if the bucket is not empty, it calls Equivalent_Keys to compare

   --  Key to each key in the bucket. If the search succeeds, Find returns a

   --  cursor designating the matching node; otherwise, it returns No_Element.

   function Contains (Container : Map; Key : Key_Type) return Boolean;

   --  Equivalent to Find (Container, Key) /= No_Element

   function Element (Container : Map; Key : Key_Type) return Element_Type;

   --  Equivalent to Element (Find (Container, Key))

   function Has_Element (Position : Cursor) return Boolean;

   --  Equivalent to Position /= No_Element

   function Equivalent_Keys (Left, Right : Cursor) return Boolean;

   --  Returns the result of calling Equivalent_Keys with the keys of the nodes

   --  designated by cursors Left and Right.

   function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean;

   --  Returns the result of calling Equivalent_Keys with key of the node

   --  designated by Left and key Right.

   function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean;

   --  Returns the result of calling Equivalent_Keys with key Left and the node

   --  designated by Right.

   procedure Iterate

     (Container : Map;

      Process   : not null access procedure (Position : Cursor));

   --  Calls Process for each node in the map

private

   pragma Inline ("=");

   pragma Inline (Length);

   pragma Inline (Is_Empty);

   pragma Inline (Clear);

   pragma Inline (Key);

   pragma Inline (Element);

   pragma Inline (Move);

   pragma Inline (Contains);

   pragma Inline (Capacity);

   pragma Inline (Reserve_Capacity);

   pragma Inline (Has_Element);

   pragma Inline (Equivalent_Keys);

   pragma Inline (Next);

   type Node_Type;

   type Node_Access is access Node_Type;

   type Node_Type is limited record

      Key     : Key_Type;

      Element : Element_Type;

      Next    : Node_Access;

   end record;

   package HT_Types is

     new Hash_Tables.Generic_Hash_Table_Types (Node_Type, Node_Access);

   type Map is new Ada.Finalization.Controlled with record

      HT : HT_Types.Hash_Table_Type;

   end record;

   use HT_Types;

   use Ada.Finalization;

   overriding

   procedure Adjust (Container : in out Map);

   overriding

   procedure Finalize (Container : in out Map);

   use Ada.Streams;

   procedure Write

     (Stream    : not null access Root_Stream_Type'Class;

      Container : Map);

   for Map'Write use Write;

   procedure Read

     (Stream    : not null access Root_Stream_Type'Class;

      Container : out Map);

   for Map'Read use Read;

   type Map_Access is access constant Map;

   for Map_Access'Storage_Size use 0;

   type Cursor is record

      Container : Map_Access;

      Node      : Node_Access;

   end record;

   procedure Read

     (Stream : not null access Root_Stream_Type'Class;

      Item   : out Cursor);

   for Cursor'Read use Read;

   procedure Write

     (Stream : not null access Root_Stream_Type'Class;

      Item   : Cursor);

   for Cursor'Write use Write;

   Empty_Map : constant Map := (Controlled with HT => (null, 0, 0, 0));

   No_Element : constant Cursor := (Container => null, Node => null);

end Ada.Containers.Hashed_Maps;