-- --
-- GNAT LIBRARY COMPONENTS --
-- --
--- A D A . C O N T A I N E R S . --
--- H A S H _ T A B L E S . G E N E R I C _ K E Y S --
+-- ADA.CONTAINERS.HASH_TABLES.GENERIC_KEYS --
-- --
-- B o d y --
-- --
--- Copyright (C) 2004-2005, 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. --
+-- Copyright (C) 2004-2010, Free Software Foundation, Inc. --
-- --
-- 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- --
+-- 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. 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. --
+-- 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. --
-- --
--- 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. --
+-- 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. --
------------------------------------------------------------------------------
--------------------------
procedure Delete_Key_Sans_Free
- (HT : in out Hash_Table_Type;
- Key : Key_Type;
- X : out Node_Access)
+ (HT : in out Hash_Table_Type;
+ Key : Key_Type;
+ X : out Node_Access)
is
Indx : Hash_Type;
Prev : Node_Access;
if Equivalent_Keys (Key, X) then
if HT.Busy > 0 then
- raise Program_Error;
+ raise Program_Error with
+ "attempt to tamper with cursors (container is busy)";
end if;
HT.Buckets (Indx) := Next (X);
HT.Length := HT.Length - 1;
if Equivalent_Keys (Key, X) then
if HT.Busy > 0 then
- raise Program_Error;
+ raise Program_Error with
+ "attempt to tamper with cursors (container is busy)";
end if;
Set_Next (Node => Prev, Next => Next (X));
HT.Length := HT.Length - 1;
Indx : constant Hash_Type := Index (HT, Key);
B : Node_Access renames HT.Buckets (Indx);
- subtype Length_Subtype is Count_Type range 0 .. Count_Type'Last - 1;
-
begin
if B = null then
if HT.Busy > 0 then
- raise Program_Error;
+ raise Program_Error with
+ "attempt to tamper with cursors (container is busy)";
end if;
- declare
- Length : constant Length_Subtype := HT.Length;
- begin
- Node := New_Node (Next => null);
- Inserted := True;
+ if HT.Length = Count_Type'Last then
+ raise Constraint_Error;
+ end if;
+
+ Node := New_Node (Next => null);
+ Inserted := True;
- B := Node;
- HT.Length := Length + 1;
- end;
+ B := Node;
+ HT.Length := HT.Length + 1;
return;
end if;
end loop;
if HT.Busy > 0 then
- raise Program_Error;
+ raise Program_Error with
+ "attempt to tamper with cursors (container is busy)";
end if;
- declare
- Length : constant Length_Subtype := HT.Length;
- begin
- Node := New_Node (Next => B);
- Inserted := True;
+ if HT.Length = Count_Type'Last then
+ raise Constraint_Error;
+ end if;
- B := Node;
- HT.Length := Length + 1;
- end;
+ Node := New_Node (Next => B);
+ Inserted := True;
+
+ B := Node;
+ HT.Length := HT.Length + 1;
end Generic_Conditional_Insert;
-----------
return Hash (Key) mod HT.Buckets'Length;
end Index;
+ -----------------------------
+ -- Generic_Replace_Element --
+ -----------------------------
+
+ procedure Generic_Replace_Element
+ (HT : in out Hash_Table_Type;
+ Node : Node_Access;
+ Key : Key_Type)
+ is
+ pragma Assert (HT.Length > 0);
+ pragma Assert (Node /= null);
+
+ Old_Hash : constant Hash_Type := Hash (Node);
+ Old_Indx : constant Hash_Type := Old_Hash mod HT.Buckets'Length;
+
+ New_Hash : constant Hash_Type := Hash (Key);
+ New_Indx : constant Hash_Type := New_Hash mod HT.Buckets'Length;
+
+ New_Bucket : Node_Access renames HT.Buckets (New_Indx);
+ N, M : Node_Access;
+
+ begin
+ if Equivalent_Keys (Key, Node) then
+ pragma Assert (New_Hash = Old_Hash);
+
+ if HT.Lock > 0 then
+ raise Program_Error with
+ "attempt to tamper with elements (container is locked)";
+ end if;
+
+ -- We can change a node's key to Key (that's what Assign is for), but
+ -- only if Key is not already in the hash table. (In a unique-key
+ -- hash table as this one a key is mapped to exactly one node only.)
+ -- The exception is when Key is mapped to Node, in which case the
+ -- change is allowed.
+
+ Assign (Node, Key);
+ pragma Assert (Hash (Node) = New_Hash);
+ pragma Assert (Equivalent_Keys (Key, Node));
+ return;
+ end if;
+
+ -- Key is not equivalent to Node, so we now have to determine if it's
+ -- equivalent to some other node in the hash table. This is the case
+ -- irrespective of whether Key is in the same or a different bucket from
+ -- Node.
+
+ N := New_Bucket;
+ while N /= null loop
+ if Equivalent_Keys (Key, N) then
+ pragma Assert (N /= Node);
+ raise Program_Error with
+ "attempt to replace existing element";
+ end if;
+
+ N := Next (N);
+ end loop;
+
+ -- We have determined that Key is not already in the hash table, so
+ -- the change is tentatively allowed. We now perform the standard
+ -- checks to determine whether the hash table is locked (because you
+ -- cannot change an element while it's in use by Query_Element or
+ -- Update_Element), or if the container is busy (because moving a
+ -- node to a different bucket would interfere with iteration).
+
+ if Old_Indx = New_Indx then
+ -- The node is already in the bucket implied by Key. In this case
+ -- we merely change its value without moving it.
+
+ if HT.Lock > 0 then
+ raise Program_Error with
+ "attempt to tamper with elements (container is locked)";
+ end if;
+
+ Assign (Node, Key);
+ pragma Assert (Hash (Node) = New_Hash);
+ pragma Assert (Equivalent_Keys (Key, Node));
+ return;
+ end if;
+
+ -- The node is a bucket different from the bucket implied by Key
+
+ if HT.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (container is busy)";
+ end if;
+
+ -- Do the assignment first, before moving the node, so that if Assign
+ -- propagates an exception, then the hash table will not have been
+ -- modified (except for any possible side-effect Assign had on Node).
+
+ Assign (Node, Key);
+ pragma Assert (Hash (Node) = New_Hash);
+ pragma Assert (Equivalent_Keys (Key, Node));
+
+ -- Now we can safely remove the node from its current bucket
+
+ N := HT.Buckets (Old_Indx);
+ pragma Assert (N /= null);
+
+ if N = Node then
+ HT.Buckets (Old_Indx) := Next (Node);
+
+ else
+ pragma Assert (HT.Length > 1);
+
+ loop
+ M := Next (N);
+ pragma Assert (M /= null);
+
+ if M = Node then
+ Set_Next (Node => N, Next => Next (Node));
+ exit;
+ end if;
+
+ N := M;
+ end loop;
+ end if;
+
+ -- Now we link the node into its new bucket (corresponding to Key)
+
+ Set_Next (Node => Node, Next => New_Bucket);
+ New_Bucket := Node;
+ end Generic_Replace_Element;
+
end Ada.Containers.Hash_Tables.Generic_Keys;
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