------------------------------------------------------------------------------ -- -- -- 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) 2004-2008, 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 2, 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. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, 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. -- -- -- -- 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;