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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 _ S E T S --
-- --
-- B o d y --
-- --
-- Copyright (C) 2004-2021, 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 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 Ada.Unchecked_Deallocation;
with Ada.Containers.Hash_Tables.Generic_Operations;
pragma Elaborate_All (Ada.Containers.Hash_Tables.Generic_Operations);
with Ada.Containers.Hash_Tables.Generic_Keys;
pragma Elaborate_All (Ada.Containers.Hash_Tables.Generic_Keys);
with Ada.Containers.Helpers; use Ada.Containers.Helpers;
with Ada.Containers.Prime_Numbers;
with System; use type System.Address;
with System.Put_Images;
package body Ada.Containers.Hashed_Sets with
SPARK_Mode => Off
is
pragma Warnings (Off, "variable ""Busy*"" is not referenced");
pragma Warnings (Off, "variable ""Lock*"" is not referenced");
-- See comment in Ada.Containers.Helpers
-----------------------
-- Local Subprograms --
-----------------------
procedure Assign (Node : Node_Access; Item : Element_Type);
pragma Inline (Assign);
function Copy_Node (Source : Node_Access) return Node_Access;
pragma Inline (Copy_Node);
function Equivalent_Keys
(Key : Element_Type;
Node : Node_Access) return Boolean;
pragma Inline (Equivalent_Keys);
function Find_Equal_Key
(R_HT : Hash_Table_Type;
L_Node : Node_Access) return Boolean;
function Find_Equivalent_Key
(R_HT : Hash_Table_Type;
L_Node : Node_Access) return Boolean;
procedure Free (X : in out Node_Access);
function Hash_Node (Node : Node_Access) return Hash_Type;
pragma Inline (Hash_Node);
procedure Insert
(HT : in out Hash_Table_Type;
New_Item : Element_Type;
Node : out Node_Access;
Inserted : out Boolean);
function Is_In
(HT : aliased in out Hash_Table_Type;
Key : Node_Access) return Boolean;
pragma Inline (Is_In);
function Next (Node : Node_Access) return Node_Access;
pragma Inline (Next);
function Read_Node (Stream : not null access Root_Stream_Type'Class)
return Node_Access;
pragma Inline (Read_Node);
procedure Set_Next (Node : Node_Access; Next : Node_Access);
pragma Inline (Set_Next);
function Vet (Position : Cursor) return Boolean;
procedure Write_Node
(Stream : not null access Root_Stream_Type'Class;
Node : Node_Access);
pragma Inline (Write_Node);
--------------------------
-- Local Instantiations --
--------------------------
package HT_Ops is new Hash_Tables.Generic_Operations
(HT_Types => HT_Types,
Hash_Node => Hash_Node,
Next => Next,
Set_Next => Set_Next,
Copy_Node => Copy_Node,
Free => Free);
package Element_Keys is new Hash_Tables.Generic_Keys
(HT_Types => HT_Types,
Next => Next,
Set_Next => Set_Next,
Key_Type => Element_Type,
Hash => Hash,
Equivalent_Keys => Equivalent_Keys);
function Is_Equal is
new HT_Ops.Generic_Equal (Find_Equal_Key);
function Is_Equivalent is
new HT_Ops.Generic_Equal (Find_Equivalent_Key);
procedure Read_Nodes is
new HT_Ops.Generic_Read (Read_Node);
procedure Replace_Element is
new Element_Keys.Generic_Replace_Element (Hash_Node, Assign);
procedure Write_Nodes is
new HT_Ops.Generic_Write (Write_Node);
---------
-- "=" --
---------
function "=" (Left, Right : Cursor) return Boolean is
begin
return
Left.Container = Right.Container
and then Left.Node = Right.Node;
end "=";
function "=" (Left, Right : Set) return Boolean is
begin
return Is_Equal (Left.HT, Right.HT);
end "=";
------------
-- Adjust --
------------
procedure Adjust (Container : in out Set) is
begin
HT_Ops.Adjust (Container.HT);
end Adjust;
------------
-- Assign --
------------
procedure Assign (Node : Node_Access; Item : Element_Type) is
begin
Node.Element := Item;
end Assign;
procedure Assign (Target : in out Set; Source : Set) is
begin
if Target'Address = Source'Address then
return;
end if;
Target.Clear;
Target.Union (Source);
end Assign;
--------------
-- Capacity --
--------------
function Capacity (Container : Set) return Count_Type is
begin
return HT_Ops.Capacity (Container.HT);
end Capacity;
-----------
-- Clear --
-----------
procedure Clear (Container : in out Set) is
begin
HT_Ops.Clear (Container.HT);
end Clear;
------------------------
-- Constant_Reference --
------------------------
function Constant_Reference
(Container : aliased Set;
Position : Cursor) return Constant_Reference_Type
is
begin
if Checks and then Position.Container = null then
raise Constraint_Error with "Position cursor has no element";
end if;
if Checks and then Position.Container /= Container'Unrestricted_Access
then
raise Program_Error with
"Position cursor designates wrong container";
end if;
pragma Assert (Vet (Position), "bad cursor in Constant_Reference");
declare
HT : Hash_Table_Type renames Position.Container.all.HT;
TC : constant Tamper_Counts_Access :=
HT.TC'Unrestricted_Access;
begin
return R : constant Constant_Reference_Type :=
(Element => Position.Node.Element'Access,
Control => (Controlled with TC))
do
Busy (TC.all);
end return;
end;
end Constant_Reference;
--------------
-- Contains --
--------------
function Contains (Container : Set; Item : Element_Type) return Boolean is
begin
return Find (Container, Item) /= No_Element;
end Contains;
----------
-- Copy --
----------
function Copy
(Source : Set;
Capacity : Count_Type := 0) return Set
is
C : Count_Type;
begin
if Capacity < Source.Length then
if Checks and then Capacity /= 0 then
raise Capacity_Error
with "Requested capacity is less than Source length";
end if;
C := Source.Length;
else
C := Capacity;
end if;
return Target : Set do
Target.Reserve_Capacity (C);
Target.Assign (Source);
end return;
end Copy;
---------------
-- Copy_Node --
---------------
function Copy_Node (Source : Node_Access) return Node_Access is
begin
return new Node_Type'(Element => Source.Element, Next => null);
end Copy_Node;
------------
-- Delete --
------------
procedure Delete
(Container : in out Set;
Item : Element_Type)
is
X : Node_Access;
begin
Element_Keys.Delete_Key_Sans_Free (Container.HT, Item, X);
if Checks and then X = null then
raise Constraint_Error with "attempt to delete element not in set";
end if;
Free (X);
end Delete;
procedure Delete
(Container : in out Set;
Position : in out Cursor)
is
begin
TC_Check (Container.HT.TC);
if Checks and then Position.Node = null then
raise Constraint_Error with "Position cursor equals No_Element";
end if;
if Checks and then Position.Container /= Container'Unrestricted_Access
then
raise Program_Error with "Position cursor designates wrong set";
end if;
pragma Assert (Vet (Position), "bad cursor in Delete");
HT_Ops.Delete_Node_Sans_Free (Container.HT, Position.Node);
Free (Position.Node);
Position.Container := null;
Position.Position := No_Element.Position;
pragma Assert (Position = No_Element);
end Delete;
----------------
-- Difference --
----------------
procedure Difference
(Target : in out Set;
Source : Set)
is
Tgt_Node : Node_Access;
Src_HT : Hash_Table_Type renames Source'Unrestricted_Access.HT;
begin
if Target'Address = Source'Address then
Clear (Target);
return;
end if;
if Src_HT.Length = 0 then
return;
end if;
TC_Check (Target.HT.TC);
if Src_HT.Length < Target.HT.Length then
declare
Src_Node : Node_Access;
begin
Src_Node := HT_Ops.First (Src_HT);
while Src_Node /= null loop
Tgt_Node := Element_Keys.Find (Target.HT, Src_Node.Element);
if Tgt_Node /= null then
HT_Ops.Delete_Node_Sans_Free (Target.HT, Tgt_Node);
Free (Tgt_Node);
end if;
Src_Node := HT_Ops.Next (Src_HT, Src_Node);
end loop;
end;
else
Tgt_Node := HT_Ops.First (Target.HT);
while Tgt_Node /= null loop
if Is_In (Src_HT, Tgt_Node) then
declare
X : Node_Access := Tgt_Node;
begin
Tgt_Node := HT_Ops.Next (Target.HT, Tgt_Node);
HT_Ops.Delete_Node_Sans_Free (Target.HT, X);
Free (X);
end;
else
Tgt_Node := HT_Ops.Next (Target.HT, Tgt_Node);
end if;
end loop;
end if;
end Difference;
function Difference (Left, Right : Set) return Set is
Left_HT : Hash_Table_Type renames Left'Unrestricted_Access.HT;
Right_HT : Hash_Table_Type renames Right'Unrestricted_Access.HT;
Buckets : HT_Types.Buckets_Access;
Length : Count_Type;
begin
if Left'Address = Right'Address then
return Empty_Set;
end if;
if Left_HT.Length = 0 then
return Empty_Set;
end if;
if Right_HT.Length = 0 then
return Left;
end if;
declare
Size : constant Hash_Type := Prime_Numbers.To_Prime (Left.Length);
begin
Buckets := HT_Ops.New_Buckets (Length => Size);
end;
Length := 0;
Iterate_Left : declare
procedure Process (L_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (L_Node : Node_Access) is
begin
if not Is_In (Right_HT, L_Node) then
declare
-- Per AI05-0022, the container implementation is required
-- to detect element tampering by a generic actual
-- subprogram, hence the use of Checked_Index instead of a
-- simple invocation of generic formal Hash.
J : constant Hash_Type :=
HT_Ops.Checked_Index (Left_HT, Buckets.all, L_Node);
Bucket : Node_Access renames Buckets (J);
begin
Bucket := new Node_Type'(L_Node.Element, Bucket);
end;
Length := Length + 1;
end if;
end Process;
-- Start of processing for Iterate_Left
begin
Iterate (Left_HT);
exception
when others =>
HT_Ops.Free_Hash_Table (Buckets);
raise;
end Iterate_Left;
return (Controlled with HT => (Buckets, Length, (Busy => 0, Lock => 0)));
end Difference;
-------------
-- Element --
-------------
function Element (Position : Cursor) return Element_Type is
begin
if Checks and then Position.Node = null then
raise Constraint_Error with "Position cursor equals No_Element";
end if;
pragma Assert (Vet (Position), "bad cursor in function Element");
return Position.Node.Element;
end Element;
-----------
-- Empty --
-----------
function Empty (Capacity : Count_Type := 1000) return Set is
begin
return Result : Set do
Reserve_Capacity (Result, Capacity);
end return;
end Empty;
---------------------
-- Equivalent_Sets --
---------------------
function Equivalent_Sets (Left, Right : Set) return Boolean is
begin
return Is_Equivalent (Left.HT, Right.HT);
end Equivalent_Sets;
-------------------------
-- Equivalent_Elements --
-------------------------
function Equivalent_Elements (Left, Right : Cursor)
return Boolean is
begin
if Checks and then Left.Node = null then
raise Constraint_Error with
"Left cursor of Equivalent_Elements equals No_Element";
end if;
if Checks and then Right.Node = null then
raise Constraint_Error with
"Right cursor of Equivalent_Elements equals No_Element";
end if;
pragma Assert (Vet (Left), "bad Left cursor in Equivalent_Elements");
pragma Assert (Vet (Right), "bad Right cursor in Equivalent_Elements");
-- AI05-0022 requires that a container implementation detect element
-- tampering by a generic actual subprogram. However, the following case
-- falls outside the scope of that AI. Randy Brukardt explained on the
-- ARG list on 2013/02/07 that:
-- (Begin Quote):
-- But for an operation like "<" [the ordered set analog of
-- Equivalent_Elements], there is no need to "dereference" a cursor
-- after the call to the generic formal parameter function, so nothing
-- bad could happen if tampering is undetected. And the operation can
-- safely return a result without a problem even if an element is
-- deleted from the container.
-- (End Quote).
return Equivalent_Elements (Left.Node.Element, Right.Node.Element);
end Equivalent_Elements;
function Equivalent_Elements (Left : Cursor; Right : Element_Type)
return Boolean is
begin
if Checks and then Left.Node = null then
raise Constraint_Error with
"Left cursor of Equivalent_Elements equals No_Element";
end if;
pragma Assert (Vet (Left), "Left cursor in Equivalent_Elements is bad");
return Equivalent_Elements (Left.Node.Element, Right);
end Equivalent_Elements;
function Equivalent_Elements (Left : Element_Type; Right : Cursor)
return Boolean is
begin
if Checks and then Right.Node = null then
raise Constraint_Error with
"Right cursor of Equivalent_Elements equals No_Element";
end if;
pragma Assert
(Vet (Right),
"Right cursor of Equivalent_Elements is bad");
return Equivalent_Elements (Left, Right.Node.Element);
end Equivalent_Elements;
---------------------
-- Equivalent_Keys --
---------------------
function Equivalent_Keys (Key : Element_Type; Node : Node_Access)
return Boolean is
begin
return Equivalent_Elements (Key, Node.Element);
end Equivalent_Keys;
-------------
-- Exclude --
-------------
procedure Exclude
(Container : in out Set;
Item : Element_Type)
is
X : Node_Access;
begin
Element_Keys.Delete_Key_Sans_Free (Container.HT, Item, X);
Free (X);
end Exclude;
--------------
-- Finalize --
--------------
procedure Finalize (Container : in out Set) is
begin
HT_Ops.Finalize (Container.HT);
end Finalize;
procedure Finalize (Object : in out Iterator) is
begin
if Object.Container /= null then
Unbusy (Object.Container.HT.TC);
end if;
end Finalize;
----------
-- Find --
----------
function Find
(Container : Set;
Item : Element_Type) return Cursor
is
HT : Hash_Table_Type renames Container'Unrestricted_Access.HT;
Node : constant Node_Access := Element_Keys.Find (HT, Item);
begin
if Node = null then
return No_Element;
end if;
return Cursor'
(Container'Unrestricted_Access, Node, HT_Ops.Index (HT, Node));
end Find;
--------------------
-- Find_Equal_Key --
--------------------
function Find_Equal_Key
(R_HT : Hash_Table_Type;
L_Node : Node_Access) return Boolean
is
R_Index : constant Hash_Type :=
Element_Keys.Index (R_HT, L_Node.Element);
R_Node : Node_Access := R_HT.Buckets (R_Index);
begin
loop
if R_Node = null then
return False;
end if;
if L_Node.Element = R_Node.Element then
return True;
end if;
R_Node := Next (R_Node);
end loop;
end Find_Equal_Key;
-------------------------
-- Find_Equivalent_Key --
-------------------------
function Find_Equivalent_Key
(R_HT : Hash_Table_Type;
L_Node : Node_Access) return Boolean
is
R_Index : constant Hash_Type :=
Element_Keys.Index (R_HT, L_Node.Element);
R_Node : Node_Access := R_HT.Buckets (R_Index);
begin
loop
if R_Node = null then
return False;
end if;
if Equivalent_Elements (L_Node.Element, R_Node.Element) then
return True;
end if;
R_Node := Next (R_Node);
end loop;
end Find_Equivalent_Key;
-----------
-- First --
-----------
function First (Container : Set) return Cursor is
Pos : Hash_Type;
Node : constant Node_Access := HT_Ops.First (Container.HT, Pos);
begin
if Node = null then
return No_Element;
end if;
return Cursor'(Container'Unrestricted_Access, Node, Pos);
end First;
function First (Object : Iterator) return Cursor is
begin
return Object.Container.First;
end First;
----------
-- Free --
----------
procedure Free (X : in out Node_Access) is
procedure Deallocate is
new Ada.Unchecked_Deallocation (Node_Type, Node_Access);
begin
if X /= null then
X.Next := X; -- detect mischief (in Vet)
Deallocate (X);
end if;
end Free;
------------------------
-- Get_Element_Access --
------------------------
function Get_Element_Access
(Position : Cursor) return not null Element_Access is
begin
return Position.Node.Element'Access;
end Get_Element_Access;
-----------------
-- Has_Element --
-----------------
function Has_Element (Position : Cursor) return Boolean is
begin
pragma Assert (Vet (Position), "bad cursor in Has_Element");
return Position.Node /= null;
end Has_Element;
---------------
-- Hash_Node --
---------------
function Hash_Node (Node : Node_Access) return Hash_Type is
begin
return Hash (Node.Element);
end Hash_Node;
-------------
-- Include --
-------------
procedure Include
(Container : in out Set;
New_Item : Element_Type)
is
Position : Cursor;
Inserted : Boolean;
begin
Insert (Container, New_Item, Position, Inserted);
if not Inserted then
TE_Check (Container.HT.TC);
Position.Node.Element := New_Item;
end if;
end Include;
------------
-- Insert --
------------
procedure Insert
(Container : in out Set;
New_Item : Element_Type;
Position : out Cursor;
Inserted : out Boolean)
is
begin
Insert (Container.HT, New_Item, Position.Node, Inserted);
Position.Container := Container'Unchecked_Access;
-- Note that we do not set the Position component of the cursor,
-- because it may become incorrect on subsequent insertions/deletions
-- from the container. This will lose some optimizations but prevents
-- anomalies when the underlying hash-table is expanded or shrunk.
end Insert;
procedure Insert
(Container : in out Set;
New_Item : Element_Type)
is
Position : Cursor;
pragma Unreferenced (Position);
Inserted : Boolean;
begin
Insert (Container, New_Item, Position, Inserted);
if Checks and then not Inserted then
raise Constraint_Error with
"attempt to insert element already in set";
end if;
end Insert;
procedure Insert
(HT : in out Hash_Table_Type;
New_Item : Element_Type;
Node : out Node_Access;
Inserted : out Boolean)
is
function New_Node (Next : Node_Access) return Node_Access;
pragma Inline (New_Node);
procedure Local_Insert is
new Element_Keys.Generic_Conditional_Insert (New_Node);
--------------
-- New_Node --
--------------
function New_Node (Next : Node_Access) return Node_Access is
begin
return new Node_Type'(New_Item, Next);
end New_Node;
-- Start of processing for Insert
begin
if HT_Ops.Capacity (HT) = 0 then
HT_Ops.Reserve_Capacity (HT, 1);
end if;
TC_Check (HT.TC);
Local_Insert (HT, New_Item, Node, Inserted);
if Inserted
and then HT.Length > HT_Ops.Capacity (HT)
then
HT_Ops.Reserve_Capacity (HT, HT.Length);
end if;
end Insert;
------------------
-- Intersection --
------------------
procedure Intersection
(Target : in out Set;
Source : Set)
is
Src_HT : Hash_Table_Type renames Source'Unrestricted_Access.HT;
Tgt_Node : Node_Access;
begin
if Target'Address = Source'Address then
return;
end if;
if Source.HT.Length = 0 then
Clear (Target);
return;
end if;
TC_Check (Target.HT.TC);
Tgt_Node := HT_Ops.First (Target.HT);
while Tgt_Node /= null loop
if Is_In (Src_HT, Tgt_Node) then
Tgt_Node := HT_Ops.Next (Target.HT, Tgt_Node);
else
declare
X : Node_Access := Tgt_Node;
begin
Tgt_Node := HT_Ops.Next (Target.HT, Tgt_Node);
HT_Ops.Delete_Node_Sans_Free (Target.HT, X);
Free (X);
end;
end if;
end loop;
end Intersection;
function Intersection (Left, Right : Set) return Set is
Left_HT : Hash_Table_Type renames Left'Unrestricted_Access.HT;
Right_HT : Hash_Table_Type renames Right'Unrestricted_Access.HT;
Buckets : HT_Types.Buckets_Access;
Length : Count_Type;
begin
if Left'Address = Right'Address then
return Left;
end if;
Length := Count_Type'Min (Left.Length, Right.Length);
if Length = 0 then
return Empty_Set;
end if;
declare
Size : constant Hash_Type := Prime_Numbers.To_Prime (Length);
begin
Buckets := HT_Ops.New_Buckets (Length => Size);
end;
Length := 0;
Iterate_Left : declare
procedure Process (L_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (L_Node : Node_Access) is
begin
if Is_In (Right_HT, L_Node) then
declare
-- Per AI05-0022, the container implementation is required
-- to detect element tampering by a generic actual
-- subprogram, hence the use of Checked_Index instead of a
-- simple invocation of generic formal Hash.
J : constant Hash_Type :=
HT_Ops.Checked_Index (Left_HT, Buckets.all, L_Node);
Bucket : Node_Access renames Buckets (J);
begin
Bucket := new Node_Type'(L_Node.Element, Bucket);
end;
Length := Length + 1;
end if;
end Process;
-- Start of processing for Iterate_Left
begin
Iterate (Left_HT);
exception
when others =>
HT_Ops.Free_Hash_Table (Buckets);
raise;
end Iterate_Left;
return (Controlled with HT => (Buckets, Length, (Busy => 0, Lock => 0)));
end Intersection;
--------------
-- Is_Empty --
--------------
function Is_Empty (Container : Set) return Boolean is
begin
return Container.HT.Length = 0;
end Is_Empty;
-----------
-- Is_In --
-----------
function Is_In
(HT : aliased in out Hash_Table_Type;
Key : Node_Access) return Boolean
is
begin
return Element_Keys.Find (HT, Key.Element) /= null;
end Is_In;
---------------
-- Is_Subset --
---------------
function Is_Subset (Subset : Set; Of_Set : Set) return Boolean is
Subset_HT : Hash_Table_Type renames Subset'Unrestricted_Access.HT;
Of_Set_HT : Hash_Table_Type renames Of_Set'Unrestricted_Access.HT;
Subset_Node : Node_Access;
begin
if Subset'Address = Of_Set'Address then
return True;
end if;
if Subset.Length > Of_Set.Length then
return False;
end if;
Subset_Node := HT_Ops.First (Subset_HT);
while Subset_Node /= null loop
if not Is_In (Of_Set_HT, Subset_Node) then
return False;
end if;
Subset_Node := HT_Ops.Next (Subset_HT, Subset_Node);
end loop;
return True;
end Is_Subset;
-------------
-- Iterate --
-------------
procedure Iterate
(Container : Set;
Process : not null access procedure (Position : Cursor))
is
procedure Process_Node (Node : Node_Access; Position : Hash_Type);
pragma Inline (Process_Node);
procedure Iterate is
new HT_Ops.Generic_Iteration_With_Position (Process_Node);
------------------
-- Process_Node --
------------------
procedure Process_Node (Node : Node_Access; Position : Hash_Type) is
begin
Process (Cursor'(Container'Unrestricted_Access, Node, Position));
end Process_Node;
Busy : With_Busy (Container.HT.TC'Unrestricted_Access);
-- Start of processing for Iterate
begin
Iterate (Container.HT);
end Iterate;
function Iterate
(Container : Set) return Set_Iterator_Interfaces.Forward_Iterator'Class
is
begin
Busy (Container.HT.TC'Unrestricted_Access.all);
return It : constant Iterator :=
Iterator'(Limited_Controlled with
Container => Container'Unrestricted_Access);
end Iterate;
------------
-- Length --
------------
function Length (Container : Set) return Count_Type is
begin
return Container.HT.Length;
end Length;
----------
-- Move --
----------
procedure Move (Target : in out Set; Source : in out Set) is
begin
HT_Ops.Move (Target => Target.HT, Source => Source.HT);
end Move;
----------
-- Next --
----------
function Next (Node : Node_Access) return Node_Access is
begin
return Node.Next;
end Next;
function Next (Position : Cursor) return Cursor is
Node : Node_Access;
Pos : Hash_Type;
begin
if Position.Node = null then
return No_Element;
end if;
pragma Assert (Vet (Position), "bad cursor in Next");
Pos := Position.Position;
Node := HT_Ops.Next (Position.Container.HT, Position.Node, Pos);
if Node = null then
return No_Element;
end if;
return Cursor'(Position.Container, Node, Pos);
end Next;
procedure Next (Position : in out Cursor) is
begin
Position := Next (Position);
end Next;
function Next
(Object : Iterator;
Position : Cursor) return Cursor
is
begin
if Position.Container = null then
return No_Element;
end if;
if Checks and then Position.Container /= Object.Container then
raise Program_Error with
"Position cursor of Next designates wrong set";
end if;
return Next (Position);
end Next;
-------------
-- Overlap --
-------------
function Overlap (Left, Right : Set) return Boolean is
Left_HT : Hash_Table_Type renames Left'Unrestricted_Access.HT;
Right_HT : Hash_Table_Type renames Right'Unrestricted_Access.HT;
Left_Node : Node_Access;
begin
if Right.Length = 0 then
return False;
end if;
if Left'Address = Right'Address then
return True;
end if;
Left_Node := HT_Ops.First (Left_HT);
while Left_Node /= null loop
if Is_In (Right_HT, Left_Node) then
return True;
end if;
Left_Node := HT_Ops.Next (Left_HT, Left_Node);
end loop;
return False;
end Overlap;
----------------------
-- Pseudo_Reference --
----------------------
function Pseudo_Reference
(Container : aliased Set'Class) return Reference_Control_Type
is
TC : constant Tamper_Counts_Access :=
Container.HT.TC'Unrestricted_Access;
begin
return R : constant Reference_Control_Type := (Controlled with TC) do
Busy (TC.all);
end return;
end Pseudo_Reference;
-------------------
-- Query_Element --
-------------------
procedure Query_Element
(Position : Cursor;
Process : not null access procedure (Element : Element_Type))
is
begin
if Checks and then Position.Node = null then
raise Constraint_Error with
"Position cursor of Query_Element equals No_Element";
end if;
pragma Assert (Vet (Position), "bad cursor in Query_Element");
declare
HT : Hash_Table_Type renames Position.Container.HT;
Lock : With_Lock (HT.TC'Unrestricted_Access);
begin
Process (Position.Node.Element);
end;
end Query_Element;
---------------
-- Put_Image --
---------------
procedure Put_Image
(S : in out Ada.Strings.Text_Buffers.Root_Buffer_Type'Class; V : Set)
is
First_Time : Boolean := True;
use System.Put_Images;
begin
Array_Before (S);
for X of V loop
if First_Time then
First_Time := False;
else
Simple_Array_Between (S);
end if;
Element_Type'Put_Image (S, X);
end loop;
Array_After (S);
end Put_Image;
----------
-- Read --
----------
procedure Read
(Stream : not null access Root_Stream_Type'Class;
Container : out Set)
is
begin
Read_Nodes (Stream, Container.HT);
end Read;
procedure Read
(Stream : not null access Root_Stream_Type'Class;
Item : out Cursor)
is
begin
raise Program_Error with "attempt to stream set cursor";
end Read;
procedure Read
(Stream : not null access Root_Stream_Type'Class;
Item : out Constant_Reference_Type)
is
begin
raise Program_Error with "attempt to stream reference";
end Read;
---------------
-- Read_Node --
---------------
function Read_Node (Stream : not null access Root_Stream_Type'Class)
return Node_Access
is
Node : Node_Access := new Node_Type;
begin
Element_Type'Read (Stream, Node.Element);
return Node;
exception
when others =>
Free (Node);
raise;
end Read_Node;
-------------
-- Replace --
-------------
procedure Replace
(Container : in out Set;
New_Item : Element_Type)
is
Node : constant Node_Access :=
Element_Keys.Find (Container.HT, New_Item);
begin
TE_Check (Container.HT.TC);
if Checks and then Node = null then
raise Constraint_Error with
"attempt to replace element not in set";
end if;
Node.Element := New_Item;
end Replace;
procedure Replace_Element
(Container : in out Set;
Position : Cursor;
New_Item : Element_Type)
is
begin
if Checks and then Position.Node = null then
raise Constraint_Error with
"Position cursor equals No_Element";
end if;
if Checks and then Position.Container /= Container'Unrestricted_Access
then
raise Program_Error with
"Position cursor designates wrong set";
end if;
pragma Assert (Vet (Position), "bad cursor in Replace_Element");
Replace_Element (Container.HT, Position.Node, New_Item);
end Replace_Element;
----------------------
-- Reserve_Capacity --
----------------------
procedure Reserve_Capacity
(Container : in out Set;
Capacity : Count_Type)
is
begin
HT_Ops.Reserve_Capacity (Container.HT, Capacity);
end Reserve_Capacity;
--------------
-- Set_Next --
--------------
procedure Set_Next (Node : Node_Access; Next : Node_Access) is
begin
Node.Next := Next;
end Set_Next;
--------------------------
-- Symmetric_Difference --
--------------------------
procedure Symmetric_Difference
(Target : in out Set;
Source : Set)
is
Tgt_HT : Hash_Table_Type renames Target.HT;
Src_HT : Hash_Table_Type renames Source.HT'Unrestricted_Access.all;
begin
if Target'Address = Source'Address then
Clear (Target);
return;
end if;
TC_Check (Tgt_HT.TC);
declare
N : constant Count_Type := Target.Length + Source.Length;
begin
if N > HT_Ops.Capacity (Tgt_HT) then
HT_Ops.Reserve_Capacity (Tgt_HT, N);
end if;
end;
if Target.Length = 0 then
Iterate_Source_When_Empty_Target : declare
procedure Process (Src_Node : Node_Access);
procedure Iterate is new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (Src_Node : Node_Access) is
E : Element_Type renames Src_Node.Element;
B : Buckets_Type renames Tgt_HT.Buckets.all;
J : constant Hash_Type := Hash (E) mod B'Length;
N : Count_Type renames Tgt_HT.Length;
begin
B (J) := new Node_Type'(E, B (J));
N := N + 1;
end Process;
-- Per AI05-0022, the container implementation is required to
-- detect element tampering by a generic actual subprogram.
Lock_Tgt : With_Lock (Tgt_HT.TC'Unrestricted_Access);
Lock_Src : With_Lock (Src_HT.TC'Unrestricted_Access);
-- Start of processing for Iterate_Source_When_Empty_Target
begin
Iterate (Src_HT);
end Iterate_Source_When_Empty_Target;
else
Iterate_Source : declare
procedure Process (Src_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (Src_Node : Node_Access) is
E : Element_Type renames Src_Node.Element;
B : Buckets_Type renames Tgt_HT.Buckets.all;
J : constant Hash_Type := Hash (E) mod B'Length;
N : Count_Type renames Tgt_HT.Length;
begin
if B (J) = null then
B (J) := new Node_Type'(E, null);
N := N + 1;
elsif Equivalent_Elements (E, B (J).Element) then
declare
X : Node_Access := B (J);
begin
B (J) := B (J).Next;
N := N - 1;
Free (X);
end;
else
declare
Prev : Node_Access := B (J);
Curr : Node_Access := Prev.Next;
begin
while Curr /= null loop
if Equivalent_Elements (E, Curr.Element) then
Prev.Next := Curr.Next;
N := N - 1;
Free (Curr);
return;
end if;
Prev := Curr;
Curr := Prev.Next;
end loop;
B (J) := new Node_Type'(E, B (J));
N := N + 1;
end;
end if;
end Process;
-- Per AI05-0022, the container implementation is required to
-- detect element tampering by a generic actual subprogram.
Lock_Tgt : With_Lock (Tgt_HT.TC'Unrestricted_Access);
Lock_Src : With_Lock (Src_HT.TC'Unrestricted_Access);
-- Start of processing for Iterate_Source
begin
Iterate (Src_HT);
end Iterate_Source;
end if;
end Symmetric_Difference;
function Symmetric_Difference (Left, Right : Set) return Set is
Left_HT : Hash_Table_Type renames Left'Unrestricted_Access.HT;
Right_HT : Hash_Table_Type renames Right'Unrestricted_Access.HT;
Buckets : HT_Types.Buckets_Access;
Length : Count_Type;
begin
if Left'Address = Right'Address then
return Empty_Set;
end if;
if Right.Length = 0 then
return Left;
end if;
if Left.Length = 0 then
return Right;
end if;
declare
Size : constant Hash_Type :=
Prime_Numbers.To_Prime (Left.Length + Right.Length);
begin
Buckets := HT_Ops.New_Buckets (Length => Size);
end;
Length := 0;
Iterate_Left : declare
procedure Process (L_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (L_Node : Node_Access) is
begin
if not Is_In (Right_HT, L_Node) then
declare
E : Element_Type renames L_Node.Element;
-- Per AI05-0022, the container implementation is required
-- to detect element tampering by a generic actual
-- subprogram, hence the use of Checked_Index instead of a
-- simple invocation of generic formal Hash.
J : constant Hash_Type :=
HT_Ops.Checked_Index (Left_HT, Buckets.all, L_Node);
begin
Buckets (J) := new Node_Type'(E, Buckets (J));
Length := Length + 1;
end;
end if;
end Process;
-- Start of processing for Iterate_Left
begin
Iterate (Left_HT);
exception
when others =>
HT_Ops.Free_Hash_Table (Buckets);
raise;
end Iterate_Left;
Iterate_Right : declare
procedure Process (R_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (R_Node : Node_Access) is
begin
if not Is_In (Left_HT, R_Node) then
declare
E : Element_Type renames R_Node.Element;
-- Per AI05-0022, the container implementation is required
-- to detect element tampering by a generic actual
-- subprogram, hence the use of Checked_Index instead of a
-- simple invocation of generic formal Hash.
J : constant Hash_Type :=
HT_Ops.Checked_Index (Right_HT, Buckets.all, R_Node);
begin
Buckets (J) := new Node_Type'(E, Buckets (J));
Length := Length + 1;
end;
end if;
end Process;
-- Start of processing for Iterate_Right
begin
Iterate (Right_HT);
exception
when others =>
HT_Ops.Free_Hash_Table (Buckets);
raise;
end Iterate_Right;
return (Controlled with HT => (Buckets, Length, (Busy => 0, Lock => 0)));
end Symmetric_Difference;
------------
-- To_Set --
------------
function To_Set (New_Item : Element_Type) return Set is
HT : Hash_Table_Type;
Node : Node_Access;
Inserted : Boolean;
pragma Unreferenced (Node, Inserted);
begin
Insert (HT, New_Item, Node, Inserted);
return Set'(Controlled with HT);
end To_Set;
-----------
-- Union --
-----------
procedure Union
(Target : in out Set;
Source : Set)
is
procedure Process (Src_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (Src_Node : Node_Access) is
function New_Node (Next : Node_Access) return Node_Access;
pragma Inline (New_Node);
procedure Insert is
new Element_Keys.Generic_Conditional_Insert (New_Node);
--------------
-- New_Node --
--------------
function New_Node (Next : Node_Access) return Node_Access is
Node : constant Node_Access :=
new Node_Type'(Src_Node.Element, Next);
begin
return Node;
end New_Node;
Tgt_Node : Node_Access;
Success : Boolean;
pragma Unreferenced (Tgt_Node, Success);
-- Start of processing for Process
begin
Insert (Target.HT, Src_Node.Element, Tgt_Node, Success);
end Process;
-- Start of processing for Union
begin
if Target'Address = Source'Address then
return;
end if;
TC_Check (Target.HT.TC);
declare
N : constant Count_Type := Target.Length + Source.Length;
begin
if N > HT_Ops.Capacity (Target.HT) then
HT_Ops.Reserve_Capacity (Target.HT, N);
end if;
end;
Iterate (Source.HT);
end Union;
function Union (Left, Right : Set) return Set is
Left_HT : Hash_Table_Type renames Left.HT'Unrestricted_Access.all;
Right_HT : Hash_Table_Type renames Right.HT'Unrestricted_Access.all;
Buckets : HT_Types.Buckets_Access;
Length : Count_Type;
begin
if Left'Address = Right'Address then
return Left;
end if;
if Right.Length = 0 then
return Left;
end if;
if Left.Length = 0 then
return Right;
end if;
declare
Size : constant Hash_Type :=
Prime_Numbers.To_Prime (Left.Length + Right.Length);
begin
Buckets := HT_Ops.New_Buckets (Length => Size);
end;
Iterate_Left : declare
procedure Process (L_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (L_Node : Node_Access) is
J : constant Hash_Type :=
Hash (L_Node.Element) mod Buckets'Length;
begin
Buckets (J) := new Node_Type'(L_Node.Element, Buckets (J));
end Process;
-- Per AI05-0022, the container implementation is required to detect
-- element tampering by a generic actual subprogram, hence the use of
-- Checked_Index instead of a simple invocation of generic formal
-- Hash.
Lock_Left : With_Lock (Left_HT.TC'Unrestricted_Access);
-- Start of processing for Iterate_Left
begin
Iterate (Left_HT);
exception
when others =>
HT_Ops.Free_Hash_Table (Buckets);
raise;
end Iterate_Left;
Length := Left.Length;
Iterate_Right : declare
procedure Process (Src_Node : Node_Access);
procedure Iterate is
new HT_Ops.Generic_Iteration (Process);
-------------
-- Process --
-------------
procedure Process (Src_Node : Node_Access) is
J : constant Hash_Type :=
Hash (Src_Node.Element) mod Buckets'Length;
Tgt_Node : Node_Access := Buckets (J);
begin
while Tgt_Node /= null loop
if Equivalent_Elements (Src_Node.Element, Tgt_Node.Element) then
return;
end if;
Tgt_Node := Next (Tgt_Node);
end loop;
Buckets (J) := new Node_Type'(Src_Node.Element, Buckets (J));
Length := Length + 1;
end Process;
-- Per AI05-0022, the container implementation is required to detect
-- element tampering by a generic actual subprogram, hence the use of
-- Checked_Index instead of a simple invocation of generic formal
-- Hash.
Lock_Left : With_Lock (Left_HT.TC'Unrestricted_Access);
Lock_Right : With_Lock (Right_HT.TC'Unrestricted_Access);
-- Start of processing for Iterate_Right
begin
Iterate (Right_HT);
exception
when others =>
HT_Ops.Free_Hash_Table (Buckets);
raise;
end Iterate_Right;
return (Controlled with HT => (Buckets, Length, (Busy => 0, Lock => 0)));
end Union;
---------
-- Vet --
---------
function Vet (Position : Cursor) return Boolean is
begin
if Position.Node = null then
return Position.Container = null;
end if;
if Position.Container = null then
return False;
end if;
if Position.Node.Next = Position.Node then
return False;
end if;
declare
HT : Hash_Table_Type renames Position.Container.HT;
X : Node_Access;
begin
if HT.Length = 0 then
return False;
end if;
if HT.Buckets = null
or else HT.Buckets'Length = 0
then
return False;
end if;
X := HT.Buckets (Element_Keys.Checked_Index
(HT,
Position.Node.Element));
for J in 1 .. HT.Length loop
if X = Position.Node then
return True;
end if;
if X = null then
return False;
end if;
if X = X.Next then -- to prevent unnecessary looping
return False;
end if;
X := X.Next;
end loop;
return False;
end;
end Vet;
-----------
-- Write --
-----------
procedure Write
(Stream : not null access Root_Stream_Type'Class;
Container : Set)
is
begin
Write_Nodes (Stream, Container.HT);
end Write;
procedure Write
(Stream : not null access Root_Stream_Type'Class;
Item : Cursor)
is
begin
raise Program_Error with "attempt to stream set cursor";
end Write;
procedure Write
(Stream : not null access Root_Stream_Type'Class;
Item : Constant_Reference_Type)
is
begin
raise Program_Error with "attempt to stream reference";
end Write;
----------------
-- Write_Node --
----------------
procedure Write_Node
(Stream : not null access Root_Stream_Type'Class;
Node : Node_Access)
is
begin
Element_Type'Write (Stream, Node.Element);
end Write_Node;
package body Generic_Keys is
-----------------------
-- Local Subprograms --
-----------------------
function Equivalent_Key_Node
(Key : Key_Type;
Node : Node_Access) return Boolean;
pragma Inline (Equivalent_Key_Node);
--------------------------
-- Local Instantiations --
--------------------------
package Key_Keys is
new Hash_Tables.Generic_Keys
(HT_Types => HT_Types,
Next => Next,
Set_Next => Set_Next,
Key_Type => Key_Type,
Hash => Hash,
Equivalent_Keys => Equivalent_Key_Node);
------------------------
-- Constant_Reference --
------------------------
function Constant_Reference
(Container : aliased Set;
Key : Key_Type) return Constant_Reference_Type
is
HT : Hash_Table_Type renames Container'Unrestricted_Access.HT;
Node : constant Node_Access := Key_Keys.Find (HT, Key);
begin
if Checks and then Node = null then
raise Constraint_Error with "Key not in set";
end if;
declare
TC : constant Tamper_Counts_Access :=
HT.TC'Unrestricted_Access;
begin
return R : constant Constant_Reference_Type :=
(Element => Node.Element'Access,
Control => (Controlled with TC))
do
Busy (TC.all);
end return;
end;
end Constant_Reference;
--------------
-- Contains --
--------------
function Contains
(Container : Set;
Key : Key_Type) return Boolean
is
begin
return Find (Container, Key) /= No_Element;
end Contains;
------------
-- Delete --
------------
procedure Delete
(Container : in out Set;
Key : Key_Type)
is
X : Node_Access;
begin
Key_Keys.Delete_Key_Sans_Free (Container.HT, Key, X);
if Checks and then X = null then
raise Constraint_Error with "attempt to delete key not in set";
end if;
Free (X);
end Delete;
-------------
-- Element --
-------------
function Element
(Container : Set;
Key : Key_Type) return Element_Type
is
HT : Hash_Table_Type renames Container'Unrestricted_Access.HT;
Node : constant Node_Access := Key_Keys.Find (HT, Key);
begin
if Checks and then Node = null then
raise Constraint_Error with "key not in set";
end if;
return Node.Element;
end Element;
-------------------------
-- Equivalent_Key_Node --
-------------------------
function Equivalent_Key_Node
(Key : Key_Type;
Node : Node_Access) return Boolean
is
begin
return Equivalent_Keys (Key, Generic_Keys.Key (Node.Element));
end Equivalent_Key_Node;
-------------
-- Exclude --
-------------
procedure Exclude
(Container : in out Set;
Key : Key_Type)
is
X : Node_Access;
begin
Key_Keys.Delete_Key_Sans_Free (Container.HT, Key, X);
Free (X);
end Exclude;
--------------
-- Finalize --
--------------
procedure Finalize (Control : in out Reference_Control_Type) is
begin
if Control.Container /= null then
Impl.Reference_Control_Type (Control).Finalize;
if Checks and then
Hash (Key (Element (Control.Old_Pos))) /= Control.Old_Hash
then
HT_Ops.Delete_Node_At_Index
(Control.Container.HT, Control.Index, Control.Old_Pos.Node);
raise Program_Error with "key not preserved in reference";
end if;
Control.Container := null;
end if;
end Finalize;
----------
-- Find --
----------
function Find
(Container : Set;
Key : Key_Type) return Cursor
is
HT : Hash_Table_Type renames Container'Unrestricted_Access.HT;
Node : constant Node_Access := Key_Keys.Find (HT, Key);
begin
if Node = null then
return No_Element;
else
return Cursor'
(Container'Unrestricted_Access, Node, HT_Ops.Index (HT, Node));
end if;
end Find;
---------
-- Key --
---------
function Key (Position : Cursor) return Key_Type is
begin
if Checks and then Position.Node = null then
raise Constraint_Error with
"Position cursor equals No_Element";
end if;
pragma Assert (Vet (Position), "bad cursor in function Key");
return Key (Position.Node.Element);
end Key;
----------
-- Read --
----------
procedure Read
(Stream : not null access Root_Stream_Type'Class;
Item : out Reference_Type)
is
begin
raise Program_Error with "attempt to stream reference";
end Read;
------------------------------
-- Reference_Preserving_Key --
------------------------------
function Reference_Preserving_Key
(Container : aliased in out Set;
Position : Cursor) return Reference_Type
is
begin
if Checks and then Position.Container = null then
raise Constraint_Error with "Position cursor has no element";
end if;
if Checks and then Position.Container /= Container'Unrestricted_Access
then
raise Program_Error with
"Position cursor designates wrong container";
end if;
pragma Assert
(Vet (Position),
"bad cursor in function Reference_Preserving_Key");
declare
HT : Hash_Table_Type renames Position.Container.all.HT;
begin
return R : constant Reference_Type :=
(Element => Position.Node.Element'Access,
Control =>
(Controlled with
HT.TC'Unrestricted_Access,
Container'Unrestricted_Access,
Index => HT_Ops.Index (HT, Position.Node),
Old_Pos => Position,
Old_Hash => Hash (Key (Position))))
do
Busy (HT.TC);
end return;
end;
end Reference_Preserving_Key;
function Reference_Preserving_Key
(Container : aliased in out Set;
Key : Key_Type) return Reference_Type
is
Node : constant Node_Access := Key_Keys.Find (Container.HT, Key);
begin
if Checks and then Node = null then
raise Constraint_Error with "key not in set";
end if;
declare
HT : Hash_Table_Type renames Container.HT;
P : constant Cursor := Find (Container, Key);
begin
return R : constant Reference_Type :=
(Element => Node.Element'Access,
Control =>
(Controlled with
HT.TC'Unrestricted_Access,
Container'Unrestricted_Access,
Index => HT_Ops.Index (HT, P.Node),
Old_Pos => P,
Old_Hash => Hash (Key)))
do
Busy (HT.TC);
end return;
end;
end Reference_Preserving_Key;
-------------
-- Replace --
-------------
procedure Replace
(Container : in out Set;
Key : Key_Type;
New_Item : Element_Type)
is
Node : constant Node_Access := Key_Keys.Find (Container.HT, Key);
begin
if Checks and then Node = null then
raise Constraint_Error with
"attempt to replace key not in set";
end if;
Replace_Element (Container.HT, Node, New_Item);
end Replace;
-----------------------------------
-- Update_Element_Preserving_Key --
-----------------------------------
procedure Update_Element_Preserving_Key
(Container : in out Set;
Position : Cursor;
Process : not null access
procedure (Element : in out Element_Type))
is
HT : Hash_Table_Type renames Container.HT;
Indx : Hash_Type;
begin
if Checks and then Position.Node = null then
raise Constraint_Error with
"Position cursor equals No_Element";
end if;
if Checks and then Position.Container /= Container'Unrestricted_Access
then
raise Program_Error with
"Position cursor designates wrong set";
end if;
if Checks and then
(HT.Buckets = null
or else HT.Buckets'Length = 0
or else HT.Length = 0
or else Position.Node.Next = Position.Node)
then
raise Program_Error with "Position cursor is bad (set is empty)";
end if;
pragma Assert
(Vet (Position),
"bad cursor in Update_Element_Preserving_Key");
-- Per AI05-0022, the container implementation is required to detect
-- element tampering by a generic actual subprogram.
declare
E : Element_Type renames Position.Node.Element;
K : constant Key_Type := Key (E);
Lock : With_Lock (HT.TC'Unrestricted_Access);
begin
Indx := HT_Ops.Index (HT, Position.Node);
Process (E);
if Equivalent_Keys (K, Key (E)) then
return;
end if;
end;
if HT.Buckets (Indx) = Position.Node then
HT.Buckets (Indx) := Position.Node.Next;
else
declare
Prev : Node_Access := HT.Buckets (Indx);
begin
while Prev.Next /= Position.Node loop
Prev := Prev.Next;
if Checks and then Prev = null then
raise Program_Error with
"Position cursor is bad (node not found)";
end if;
end loop;
Prev.Next := Position.Node.Next;
end;
end if;
HT.Length := HT.Length - 1;
declare
X : Node_Access := Position.Node;
begin
Free (X);
end;
raise Program_Error with "key was modified";
end Update_Element_Preserving_Key;
-----------
-- Write --
-----------
procedure Write
(Stream : not null access Root_Stream_Type'Class;
Item : Reference_Type)
is
begin
raise Program_Error with "attempt to stream reference";
end Write;
end Generic_Keys;
end Ada.Containers.Hashed_Sets;