2291 lines
62 KiB
Ada
2291 lines
62 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT LIBRARY COMPONENTS --
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-- --
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-- ADA.CONTAINERS.INDEFINITE_DOUBLY_LINKED_LISTS --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 2004-2015, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- This unit was originally developed by Matthew J Heaney. --
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------------------------------------------------------------------------------
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with Ada.Unchecked_Deallocation;
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with System; use type System.Address;
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package body Ada.Containers.Indefinite_Doubly_Linked_Lists is
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pragma Warnings (Off, "variable ""Busy*"" is not referenced");
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pragma Warnings (Off, "variable ""Lock*"" is not referenced");
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-- See comment in Ada.Containers.Helpers
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procedure Free is
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new Ada.Unchecked_Deallocation (Element_Type, Element_Access);
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-----------------------
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-- Local Subprograms --
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-----------------------
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procedure Free (X : in out Node_Access);
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procedure Insert_Internal
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(Container : in out List;
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Before : Node_Access;
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New_Node : Node_Access);
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procedure Splice_Internal
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(Target : in out List;
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Before : Node_Access;
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Source : in out List);
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procedure Splice_Internal
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(Target : in out List;
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Before : Node_Access;
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Source : in out List;
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Position : Node_Access);
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function Vet (Position : Cursor) return Boolean;
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-- Checks invariants of the cursor and its designated container, as a
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-- simple way of detecting dangling references (see operation Free for a
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-- description of the detection mechanism), returning True if all checks
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-- pass. Invocations of Vet are used here as the argument of pragma Assert,
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-- so the checks are performed only when assertions are enabled.
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---------
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-- "=" --
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---------
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function "=" (Left, Right : List) return Boolean is
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begin
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if Left.Length /= Right.Length then
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return False;
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end if;
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if Left.Length = 0 then
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return True;
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end if;
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declare
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-- Per AI05-0022, the container implementation is required to detect
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-- element tampering by a generic actual subprogram.
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Lock_Left : With_Lock (Left.TC'Unrestricted_Access);
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Lock_Right : With_Lock (Right.TC'Unrestricted_Access);
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L : Node_Access := Left.First;
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R : Node_Access := Right.First;
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begin
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for J in 1 .. Left.Length loop
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if L.Element.all /= R.Element.all then
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return False;
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end if;
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L := L.Next;
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R := R.Next;
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end loop;
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end;
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return True;
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end "=";
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------------
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-- Adjust --
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------------
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procedure Adjust (Container : in out List) is
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Src : Node_Access := Container.First;
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Dst : Node_Access;
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begin
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-- If the counts are nonzero, execution is technically erroneous, but
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-- it seems friendly to allow things like concurrent "=" on shared
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-- constants.
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Zero_Counts (Container.TC);
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if Src = null then
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pragma Assert (Container.Last = null);
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pragma Assert (Container.Length = 0);
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return;
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end if;
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pragma Assert (Container.First.Prev = null);
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pragma Assert (Container.Last.Next = null);
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pragma Assert (Container.Length > 0);
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Container.First := null;
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Container.Last := null;
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Container.Length := 0;
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declare
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Element : Element_Access := new Element_Type'(Src.Element.all);
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begin
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Dst := new Node_Type'(Element, null, null);
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exception
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when others =>
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Free (Element);
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raise;
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end;
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Container.First := Dst;
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Container.Last := Dst;
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Container.Length := 1;
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Src := Src.Next;
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while Src /= null loop
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declare
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Element : Element_Access := new Element_Type'(Src.Element.all);
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begin
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Dst := new Node_Type'(Element, null, Prev => Container.Last);
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exception
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when others =>
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Free (Element);
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raise;
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end;
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Container.Last.Next := Dst;
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Container.Last := Dst;
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Container.Length := Container.Length + 1;
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Src := Src.Next;
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end loop;
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end Adjust;
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------------
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-- Append --
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------------
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procedure Append
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(Container : in out List;
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New_Item : Element_Type;
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Count : Count_Type := 1)
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is
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begin
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Insert (Container, No_Element, New_Item, Count);
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end Append;
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------------
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-- Assign --
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------------
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procedure Assign (Target : in out List; Source : List) is
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Node : Node_Access;
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begin
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if Target'Address = Source'Address then
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return;
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else
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Target.Clear;
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Node := Source.First;
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while Node /= null loop
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Target.Append (Node.Element.all);
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Node := Node.Next;
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end loop;
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end if;
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end Assign;
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-----------
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-- Clear --
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-----------
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procedure Clear (Container : in out List) is
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X : Node_Access;
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pragma Warnings (Off, X);
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begin
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if Container.Length = 0 then
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pragma Assert (Container.First = null);
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pragma Assert (Container.Last = null);
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pragma Assert (Container.TC = (Busy => 0, Lock => 0));
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return;
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end if;
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pragma Assert (Container.First.Prev = null);
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pragma Assert (Container.Last.Next = null);
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TC_Check (Container.TC);
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while Container.Length > 1 loop
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X := Container.First;
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pragma Assert (X.Next.Prev = Container.First);
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Container.First := X.Next;
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Container.First.Prev := null;
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Container.Length := Container.Length - 1;
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Free (X);
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end loop;
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X := Container.First;
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pragma Assert (X = Container.Last);
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Container.First := null;
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Container.Last := null;
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Container.Length := 0;
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Free (X);
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end Clear;
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------------------------
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-- Constant_Reference --
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------------------------
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function Constant_Reference
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(Container : aliased List;
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Position : Cursor) return Constant_Reference_Type
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is
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begin
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if Checks and then Position.Container = null then
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raise Constraint_Error with "Position cursor has no element";
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end if;
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if Checks and then Position.Container /= Container'Unrestricted_Access
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then
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raise Program_Error with
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"Position cursor designates wrong container";
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end if;
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if Checks and then Position.Node.Element = null then
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raise Program_Error with "Node has no element";
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end if;
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pragma Assert (Vet (Position), "bad cursor in Constant_Reference");
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declare
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TC : constant Tamper_Counts_Access :=
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Container.TC'Unrestricted_Access;
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begin
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return R : constant Constant_Reference_Type :=
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(Element => Position.Node.Element,
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Control => (Controlled with TC))
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do
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Lock (TC.all);
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end return;
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end;
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end Constant_Reference;
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--------------
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-- Contains --
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--------------
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function Contains
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(Container : List;
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Item : Element_Type) return Boolean
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is
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begin
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return Find (Container, Item) /= No_Element;
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end Contains;
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----------
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-- Copy --
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----------
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function Copy (Source : List) return List is
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begin
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return Target : List do
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Target.Assign (Source);
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end return;
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end Copy;
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------------
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-- Delete --
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------------
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procedure Delete
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(Container : in out List;
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Position : in out Cursor;
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Count : Count_Type := 1)
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is
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X : Node_Access;
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begin
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if Checks and then Position.Node = null then
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raise Constraint_Error with
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"Position cursor has no element";
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end if;
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if Checks and then Position.Node.Element = null then
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raise Program_Error with
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"Position cursor has no element";
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end if;
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if Checks and then Position.Container /= Container'Unrestricted_Access
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then
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raise Program_Error with
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"Position cursor designates wrong container";
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end if;
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pragma Assert (Vet (Position), "bad cursor in Delete");
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if Position.Node = Container.First then
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Delete_First (Container, Count);
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Position := No_Element; -- Post-York behavior
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return;
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end if;
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if Count = 0 then
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Position := No_Element; -- Post-York behavior
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return;
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end if;
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TC_Check (Container.TC);
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for Index in 1 .. Count loop
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X := Position.Node;
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Container.Length := Container.Length - 1;
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if X = Container.Last then
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Position := No_Element;
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Container.Last := X.Prev;
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Container.Last.Next := null;
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Free (X);
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return;
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end if;
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Position.Node := X.Next;
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X.Next.Prev := X.Prev;
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X.Prev.Next := X.Next;
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Free (X);
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end loop;
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-- Fix this junk comment ???
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Position := No_Element; -- Post-York behavior
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end Delete;
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------------------
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-- Delete_First --
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------------------
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procedure Delete_First
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(Container : in out List;
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Count : Count_Type := 1)
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is
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X : Node_Access;
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begin
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if Count >= Container.Length then
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Clear (Container);
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return;
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end if;
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if Count = 0 then
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return;
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end if;
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TC_Check (Container.TC);
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for J in 1 .. Count loop
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X := Container.First;
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pragma Assert (X.Next.Prev = Container.First);
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Container.First := X.Next;
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Container.First.Prev := null;
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Container.Length := Container.Length - 1;
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Free (X);
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end loop;
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end Delete_First;
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-----------------
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-- Delete_Last --
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-----------------
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procedure Delete_Last
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(Container : in out List;
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Count : Count_Type := 1)
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is
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X : Node_Access;
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begin
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if Count >= Container.Length then
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Clear (Container);
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return;
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end if;
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if Count = 0 then
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return;
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end if;
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TC_Check (Container.TC);
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for J in 1 .. Count loop
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X := Container.Last;
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pragma Assert (X.Prev.Next = Container.Last);
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Container.Last := X.Prev;
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Container.Last.Next := null;
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Container.Length := Container.Length - 1;
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Free (X);
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end loop;
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end Delete_Last;
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-------------
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-- Element --
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-------------
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function Element (Position : Cursor) return Element_Type is
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begin
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if Checks and then Position.Node = null then
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raise Constraint_Error with
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"Position cursor has no element";
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end if;
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if Checks and then Position.Node.Element = null then
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raise Program_Error with
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"Position cursor has no element";
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end if;
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pragma Assert (Vet (Position), "bad cursor in Element");
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return Position.Node.Element.all;
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end Element;
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--------------
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-- Finalize --
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--------------
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procedure Finalize (Object : in out Iterator) is
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begin
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if Object.Container /= null then
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Unbusy (Object.Container.TC);
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end if;
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end Finalize;
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----------
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-- Find --
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----------
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function Find
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(Container : List;
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Item : Element_Type;
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Position : Cursor := No_Element) return Cursor
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is
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Node : Node_Access := Position.Node;
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begin
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if Node = null then
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Node := Container.First;
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else
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if Checks and then Node.Element = null then
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raise Program_Error;
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end if;
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if Checks and then Position.Container /= Container'Unrestricted_Access
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then
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raise Program_Error with
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"Position cursor designates wrong container";
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end if;
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pragma Assert (Vet (Position), "bad cursor in Find");
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end if;
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|
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-- Per AI05-0022, the container implementation is required to detect
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-- element tampering by a generic actual subprogram.
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declare
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Lock : With_Lock (Container.TC'Unrestricted_Access);
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begin
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while Node /= null loop
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if Node.Element.all = Item then
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return Cursor'(Container'Unrestricted_Access, Node);
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end if;
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Node := Node.Next;
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end loop;
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return No_Element;
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end;
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end Find;
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-----------
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-- First --
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-----------
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function First (Container : List) return Cursor is
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begin
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if Container.First = null then
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return No_Element;
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else
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return Cursor'(Container'Unrestricted_Access, Container.First);
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end if;
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end First;
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function First (Object : Iterator) return Cursor is
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begin
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-- The value of the iterator object's Node component influences the
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-- behavior of the First (and Last) selector function.
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-- When the Node component is null, this means the iterator object was
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-- constructed without a start expression, in which case the (forward)
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-- iteration starts from the (logical) beginning of the entire sequence
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-- of items (corresponding to Container.First, for a forward iterator).
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-- Otherwise, this is iteration over a partial sequence of items. When
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-- the Node component is non-null, the iterator object was constructed
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-- with a start expression, that specifies the position from which the
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-- (forward) partial iteration begins.
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if Object.Node = null then
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return Indefinite_Doubly_Linked_Lists.First (Object.Container.all);
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else
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return Cursor'(Object.Container, Object.Node);
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end if;
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end First;
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|
|
-------------------
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-- First_Element --
|
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-------------------
|
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|
|
function First_Element (Container : List) return Element_Type is
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begin
|
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if Checks and then Container.First = null then
|
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raise Constraint_Error with "list is empty";
|
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end if;
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return Container.First.Element.all;
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end First_Element;
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|
|
----------
|
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-- Free --
|
|
----------
|
|
|
|
procedure Free (X : in out Node_Access) is
|
|
procedure Deallocate is
|
|
new Ada.Unchecked_Deallocation (Node_Type, Node_Access);
|
|
|
|
begin
|
|
-- While a node is in use, as an active link in a list, its Previous and
|
|
-- Next components must be null, or designate a different node; this is
|
|
-- a node invariant. For this indefinite list, there is an additional
|
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-- invariant: that the element access value be non-null. Before actually
|
|
-- deallocating the node, we set the node access value components of the
|
|
-- node to point to the node itself, and set the element access value to
|
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-- null (by deallocating the node's element), thus falsifying the node
|
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-- invariant. Subprogram Vet inspects the value of the node components
|
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-- when interrogating the node, in order to detect whether the cursor's
|
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-- node access value is dangling.
|
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|
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-- Note that we have no guarantee that the storage for the node isn't
|
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-- modified when it is deallocated, but there are other tests that Vet
|
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-- does if node invariants appear to be satisifed. However, in practice
|
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-- this simple test works well enough, detecting dangling references
|
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-- immediately, without needing further interrogation.
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|
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X.Next := X;
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X.Prev := X;
|
|
|
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begin
|
|
Free (X.Element);
|
|
exception
|
|
when others =>
|
|
X.Element := null;
|
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Deallocate (X);
|
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raise;
|
|
end;
|
|
|
|
Deallocate (X);
|
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end Free;
|
|
|
|
---------------------
|
|
-- Generic_Sorting --
|
|
---------------------
|
|
|
|
package body Generic_Sorting is
|
|
|
|
---------------
|
|
-- Is_Sorted --
|
|
---------------
|
|
|
|
function Is_Sorted (Container : List) return Boolean is
|
|
-- Per AI05-0022, the container implementation is required to detect
|
|
-- element tampering by a generic actual subprogram.
|
|
|
|
Lock : With_Lock (Container.TC'Unrestricted_Access);
|
|
|
|
Node : Node_Access;
|
|
begin
|
|
Node := Container.First;
|
|
for J in 2 .. Container.Length loop
|
|
if Node.Next.Element.all < Node.Element.all then
|
|
return False;
|
|
end if;
|
|
|
|
Node := Node.Next;
|
|
end loop;
|
|
|
|
return True;
|
|
end Is_Sorted;
|
|
|
|
-----------
|
|
-- Merge --
|
|
-----------
|
|
|
|
procedure Merge
|
|
(Target : in out List;
|
|
Source : in out List)
|
|
is
|
|
begin
|
|
-- The semantics of Merge changed slightly per AI05-0021. It was
|
|
-- originally the case that if Target and Source denoted the same
|
|
-- container object, then the GNAT implementation of Merge did
|
|
-- nothing. However, it was argued that RM05 did not precisely
|
|
-- specify the semantics for this corner case. The decision of the
|
|
-- ARG was that if Target and Source denote the same non-empty
|
|
-- container object, then Program_Error is raised.
|
|
|
|
if Source.Is_Empty then
|
|
return;
|
|
end if;
|
|
|
|
if Checks and then Target'Address = Source'Address then
|
|
raise Program_Error with
|
|
"Target and Source denote same non-empty container";
|
|
end if;
|
|
|
|
if Checks and then Target.Length > Count_Type'Last - Source.Length
|
|
then
|
|
raise Constraint_Error with "new length exceeds maximum";
|
|
end if;
|
|
|
|
TC_Check (Target.TC);
|
|
TC_Check (Source.TC);
|
|
|
|
declare
|
|
Lock_Target : With_Lock (Target.TC'Unchecked_Access);
|
|
Lock_Source : With_Lock (Source.TC'Unchecked_Access);
|
|
|
|
LI, RI, RJ : Node_Access;
|
|
|
|
begin
|
|
LI := Target.First;
|
|
RI := Source.First;
|
|
while RI /= null loop
|
|
pragma Assert (RI.Next = null
|
|
or else not (RI.Next.Element.all <
|
|
RI.Element.all));
|
|
|
|
if LI = null then
|
|
Splice_Internal (Target, null, Source);
|
|
exit;
|
|
end if;
|
|
|
|
pragma Assert (LI.Next = null
|
|
or else not (LI.Next.Element.all <
|
|
LI.Element.all));
|
|
|
|
if RI.Element.all < LI.Element.all then
|
|
RJ := RI;
|
|
RI := RI.Next;
|
|
Splice_Internal (Target, LI, Source, RJ);
|
|
|
|
else
|
|
LI := LI.Next;
|
|
end if;
|
|
end loop;
|
|
end;
|
|
end Merge;
|
|
|
|
----------
|
|
-- Sort --
|
|
----------
|
|
|
|
procedure Sort (Container : in out List) is
|
|
procedure Partition (Pivot : Node_Access; Back : Node_Access);
|
|
-- Comment ???
|
|
|
|
procedure Sort (Front, Back : Node_Access);
|
|
-- Comment??? Confusing name??? change name???
|
|
|
|
---------------
|
|
-- Partition --
|
|
---------------
|
|
|
|
procedure Partition (Pivot : Node_Access; Back : Node_Access) is
|
|
Node : Node_Access;
|
|
|
|
begin
|
|
Node := Pivot.Next;
|
|
while Node /= Back loop
|
|
if Node.Element.all < Pivot.Element.all then
|
|
declare
|
|
Prev : constant Node_Access := Node.Prev;
|
|
Next : constant Node_Access := Node.Next;
|
|
|
|
begin
|
|
Prev.Next := Next;
|
|
|
|
if Next = null then
|
|
Container.Last := Prev;
|
|
else
|
|
Next.Prev := Prev;
|
|
end if;
|
|
|
|
Node.Next := Pivot;
|
|
Node.Prev := Pivot.Prev;
|
|
|
|
Pivot.Prev := Node;
|
|
|
|
if Node.Prev = null then
|
|
Container.First := Node;
|
|
else
|
|
Node.Prev.Next := Node;
|
|
end if;
|
|
|
|
Node := Next;
|
|
end;
|
|
|
|
else
|
|
Node := Node.Next;
|
|
end if;
|
|
end loop;
|
|
end Partition;
|
|
|
|
----------
|
|
-- Sort --
|
|
----------
|
|
|
|
procedure Sort (Front, Back : Node_Access) is
|
|
Pivot : constant Node_Access :=
|
|
(if Front = null then Container.First else Front.Next);
|
|
begin
|
|
if Pivot /= Back then
|
|
Partition (Pivot, Back);
|
|
Sort (Front, Pivot);
|
|
Sort (Pivot, Back);
|
|
end if;
|
|
end Sort;
|
|
|
|
-- Start of processing for Sort
|
|
|
|
begin
|
|
if Container.Length <= 1 then
|
|
return;
|
|
end if;
|
|
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
|
|
TC_Check (Container.TC);
|
|
|
|
-- Per AI05-0022, the container implementation is required to detect
|
|
-- element tampering by a generic actual subprogram.
|
|
|
|
declare
|
|
Lock : With_Lock (Container.TC'Unchecked_Access);
|
|
begin
|
|
Sort (Front => null, Back => null);
|
|
end;
|
|
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
end Sort;
|
|
|
|
end Generic_Sorting;
|
|
|
|
------------------------
|
|
-- Get_Element_Access --
|
|
------------------------
|
|
|
|
function Get_Element_Access
|
|
(Position : Cursor) return not null Element_Access is
|
|
begin
|
|
return Position.Node.Element;
|
|
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;
|
|
|
|
------------
|
|
-- Insert --
|
|
------------
|
|
|
|
procedure Insert
|
|
(Container : in out List;
|
|
Before : Cursor;
|
|
New_Item : Element_Type;
|
|
Position : out Cursor;
|
|
Count : Count_Type := 1)
|
|
is
|
|
First_Node : Node_Access;
|
|
New_Node : Node_Access;
|
|
|
|
begin
|
|
if Before.Container /= null then
|
|
if Checks and then Before.Container /= Container'Unrestricted_Access
|
|
then
|
|
raise Program_Error with
|
|
"Before cursor designates wrong list";
|
|
end if;
|
|
|
|
if Checks and then
|
|
(Before.Node = null or else Before.Node.Element = null)
|
|
then
|
|
raise Program_Error with
|
|
"Before cursor has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Before), "bad cursor in Insert");
|
|
end if;
|
|
|
|
if Count = 0 then
|
|
Position := Before;
|
|
return;
|
|
end if;
|
|
|
|
if Checks and then Container.Length > Count_Type'Last - Count then
|
|
raise Constraint_Error with "new length exceeds maximum";
|
|
end if;
|
|
|
|
TC_Check (Container.TC);
|
|
|
|
declare
|
|
-- The element allocator may need an accessibility check in the case
|
|
-- the actual type is class-wide or has access discriminants (see
|
|
-- RM 4.8(10.1) and AI12-0035). We don't unsuppress the check on the
|
|
-- allocator in the loop below, because the one in this block would
|
|
-- have failed already.
|
|
|
|
pragma Unsuppress (Accessibility_Check);
|
|
|
|
Element : Element_Access := new Element_Type'(New_Item);
|
|
|
|
begin
|
|
New_Node := new Node_Type'(Element, null, null);
|
|
First_Node := New_Node;
|
|
|
|
exception
|
|
when others =>
|
|
Free (Element);
|
|
raise;
|
|
end;
|
|
|
|
Insert_Internal (Container, Before.Node, New_Node);
|
|
|
|
for J in 2 .. Count loop
|
|
declare
|
|
Element : Element_Access := new Element_Type'(New_Item);
|
|
begin
|
|
New_Node := new Node_Type'(Element, null, null);
|
|
exception
|
|
when others =>
|
|
Free (Element);
|
|
raise;
|
|
end;
|
|
|
|
Insert_Internal (Container, Before.Node, New_Node);
|
|
end loop;
|
|
|
|
Position := Cursor'(Container'Unchecked_Access, First_Node);
|
|
end Insert;
|
|
|
|
procedure Insert
|
|
(Container : in out List;
|
|
Before : Cursor;
|
|
New_Item : Element_Type;
|
|
Count : Count_Type := 1)
|
|
is
|
|
Position : Cursor;
|
|
pragma Unreferenced (Position);
|
|
begin
|
|
Insert (Container, Before, New_Item, Position, Count);
|
|
end Insert;
|
|
|
|
---------------------
|
|
-- Insert_Internal --
|
|
---------------------
|
|
|
|
procedure Insert_Internal
|
|
(Container : in out List;
|
|
Before : Node_Access;
|
|
New_Node : Node_Access)
|
|
is
|
|
begin
|
|
if Container.Length = 0 then
|
|
pragma Assert (Before = null);
|
|
pragma Assert (Container.First = null);
|
|
pragma Assert (Container.Last = null);
|
|
|
|
Container.First := New_Node;
|
|
Container.Last := New_Node;
|
|
|
|
elsif Before = null then
|
|
pragma Assert (Container.Last.Next = null);
|
|
|
|
Container.Last.Next := New_Node;
|
|
New_Node.Prev := Container.Last;
|
|
|
|
Container.Last := New_Node;
|
|
|
|
elsif Before = Container.First then
|
|
pragma Assert (Container.First.Prev = null);
|
|
|
|
Container.First.Prev := New_Node;
|
|
New_Node.Next := Container.First;
|
|
|
|
Container.First := New_Node;
|
|
|
|
else
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
|
|
New_Node.Next := Before;
|
|
New_Node.Prev := Before.Prev;
|
|
|
|
Before.Prev.Next := New_Node;
|
|
Before.Prev := New_Node;
|
|
end if;
|
|
|
|
Container.Length := Container.Length + 1;
|
|
end Insert_Internal;
|
|
|
|
--------------
|
|
-- Is_Empty --
|
|
--------------
|
|
|
|
function Is_Empty (Container : List) return Boolean is
|
|
begin
|
|
return Container.Length = 0;
|
|
end Is_Empty;
|
|
|
|
-------------
|
|
-- Iterate --
|
|
-------------
|
|
|
|
procedure Iterate
|
|
(Container : List;
|
|
Process : not null access procedure (Position : Cursor))
|
|
is
|
|
Busy : With_Busy (Container.TC'Unrestricted_Access);
|
|
Node : Node_Access := Container.First;
|
|
|
|
begin
|
|
while Node /= null loop
|
|
Process (Cursor'(Container'Unrestricted_Access, Node));
|
|
Node := Node.Next;
|
|
end loop;
|
|
end Iterate;
|
|
|
|
function Iterate
|
|
(Container : List)
|
|
return List_Iterator_Interfaces.Reversible_Iterator'class
|
|
is
|
|
begin
|
|
-- The value of the Node component influences the behavior of the First
|
|
-- and Last selector functions of the iterator object. When the Node
|
|
-- component is null (as is the case here), this means the iterator
|
|
-- object was constructed without a start expression. This is a
|
|
-- complete iterator, meaning that the iteration starts from the
|
|
-- (logical) beginning of the sequence of items.
|
|
|
|
-- Note: For a forward iterator, Container.First is the beginning, and
|
|
-- for a reverse iterator, Container.Last is the beginning.
|
|
|
|
return It : constant Iterator :=
|
|
Iterator'(Limited_Controlled with
|
|
Container => Container'Unrestricted_Access,
|
|
Node => null)
|
|
do
|
|
Busy (Container.TC'Unrestricted_Access.all);
|
|
end return;
|
|
end Iterate;
|
|
|
|
function Iterate
|
|
(Container : List;
|
|
Start : Cursor)
|
|
return List_Iterator_Interfaces.Reversible_Iterator'Class
|
|
is
|
|
begin
|
|
-- It was formerly the case that when Start = No_Element, the partial
|
|
-- iterator was defined to behave the same as for a complete iterator,
|
|
-- and iterate over the entire sequence of items. However, those
|
|
-- semantics were unintuitive and arguably error-prone (it is too easy
|
|
-- to accidentally create an endless loop), and so they were changed,
|
|
-- per the ARG meeting in Denver on 2011/11. However, there was no
|
|
-- consensus about what positive meaning this corner case should have,
|
|
-- and so it was decided to simply raise an exception. This does imply,
|
|
-- however, that it is not possible to use a partial iterator to specify
|
|
-- an empty sequence of items.
|
|
|
|
if Checks and then Start = No_Element then
|
|
raise Constraint_Error with
|
|
"Start position for iterator equals No_Element";
|
|
end if;
|
|
|
|
if Checks and then Start.Container /= Container'Unrestricted_Access then
|
|
raise Program_Error with
|
|
"Start cursor of Iterate designates wrong list";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Start), "Start cursor of Iterate is bad");
|
|
|
|
-- The value of the Node component influences the behavior of the
|
|
-- First and Last selector functions of the iterator object. When
|
|
-- the Node component is non-null (as is the case here), it means
|
|
-- that this is a partial iteration, over a subset of the complete
|
|
-- sequence of items. The iterator object was constructed with
|
|
-- a start expression, indicating the position from which the
|
|
-- iteration begins. Note that the start position has the same value
|
|
-- irrespective of whether this is a forward or reverse iteration.
|
|
|
|
return It : constant Iterator :=
|
|
Iterator'(Limited_Controlled with
|
|
Container => Container'Unrestricted_Access,
|
|
Node => Start.Node)
|
|
do
|
|
Busy (Container.TC'Unrestricted_Access.all);
|
|
end return;
|
|
end Iterate;
|
|
|
|
----------
|
|
-- Last --
|
|
----------
|
|
|
|
function Last (Container : List) return Cursor is
|
|
begin
|
|
if Container.Last = null then
|
|
return No_Element;
|
|
else
|
|
return Cursor'(Container'Unrestricted_Access, Container.Last);
|
|
end if;
|
|
end Last;
|
|
|
|
function Last (Object : Iterator) return Cursor is
|
|
begin
|
|
-- The value of the iterator object's Node component influences the
|
|
-- behavior of the Last (and First) selector function.
|
|
|
|
-- When the Node component is null, this means the iterator object was
|
|
-- constructed without a start expression, in which case the (reverse)
|
|
-- iteration starts from the (logical) beginning of the entire sequence
|
|
-- (corresponding to Container.Last, for a reverse iterator).
|
|
|
|
-- Otherwise, this is iteration over a partial sequence of items. When
|
|
-- the Node component is non-null, the iterator object was constructed
|
|
-- with a start expression, that specifies the position from which the
|
|
-- (reverse) partial iteration begins.
|
|
|
|
if Object.Node = null then
|
|
return Indefinite_Doubly_Linked_Lists.Last (Object.Container.all);
|
|
else
|
|
return Cursor'(Object.Container, Object.Node);
|
|
end if;
|
|
end Last;
|
|
|
|
------------------
|
|
-- Last_Element --
|
|
------------------
|
|
|
|
function Last_Element (Container : List) return Element_Type is
|
|
begin
|
|
if Checks and then Container.Last = null then
|
|
raise Constraint_Error with "list is empty";
|
|
end if;
|
|
|
|
return Container.Last.Element.all;
|
|
end Last_Element;
|
|
|
|
------------
|
|
-- Length --
|
|
------------
|
|
|
|
function Length (Container : List) return Count_Type is
|
|
begin
|
|
return Container.Length;
|
|
end Length;
|
|
|
|
----------
|
|
-- Move --
|
|
----------
|
|
|
|
procedure Move (Target : in out List; Source : in out List) is
|
|
begin
|
|
if Target'Address = Source'Address then
|
|
return;
|
|
end if;
|
|
|
|
TC_Check (Source.TC);
|
|
|
|
Clear (Target);
|
|
|
|
Target.First := Source.First;
|
|
Source.First := null;
|
|
|
|
Target.Last := Source.Last;
|
|
Source.Last := null;
|
|
|
|
Target.Length := Source.Length;
|
|
Source.Length := 0;
|
|
end Move;
|
|
|
|
----------
|
|
-- Next --
|
|
----------
|
|
|
|
procedure Next (Position : in out Cursor) is
|
|
begin
|
|
Position := Next (Position);
|
|
end Next;
|
|
|
|
function Next (Position : Cursor) return Cursor is
|
|
begin
|
|
if Position.Node = null then
|
|
return No_Element;
|
|
|
|
else
|
|
pragma Assert (Vet (Position), "bad cursor in Next");
|
|
|
|
declare
|
|
Next_Node : constant Node_Access := Position.Node.Next;
|
|
begin
|
|
if Next_Node = null then
|
|
return No_Element;
|
|
else
|
|
return Cursor'(Position.Container, Next_Node);
|
|
end if;
|
|
end;
|
|
end if;
|
|
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 list";
|
|
end if;
|
|
|
|
return Next (Position);
|
|
end Next;
|
|
|
|
-------------
|
|
-- Prepend --
|
|
-------------
|
|
|
|
procedure Prepend
|
|
(Container : in out List;
|
|
New_Item : Element_Type;
|
|
Count : Count_Type := 1)
|
|
is
|
|
begin
|
|
Insert (Container, First (Container), New_Item, Count);
|
|
end Prepend;
|
|
|
|
--------------
|
|
-- Previous --
|
|
--------------
|
|
|
|
procedure Previous (Position : in out Cursor) is
|
|
begin
|
|
Position := Previous (Position);
|
|
end Previous;
|
|
|
|
function Previous (Position : Cursor) return Cursor is
|
|
begin
|
|
if Position.Node = null then
|
|
return No_Element;
|
|
|
|
else
|
|
pragma Assert (Vet (Position), "bad cursor in Previous");
|
|
|
|
declare
|
|
Prev_Node : constant Node_Access := Position.Node.Prev;
|
|
begin
|
|
if Prev_Node = null then
|
|
return No_Element;
|
|
else
|
|
return Cursor'(Position.Container, Prev_Node);
|
|
end if;
|
|
end;
|
|
end if;
|
|
end Previous;
|
|
|
|
function Previous (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 Previous designates wrong list";
|
|
end if;
|
|
|
|
return Previous (Position);
|
|
end Previous;
|
|
|
|
----------------------
|
|
-- Pseudo_Reference --
|
|
----------------------
|
|
|
|
function Pseudo_Reference
|
|
(Container : aliased List'Class) return Reference_Control_Type
|
|
is
|
|
TC : constant Tamper_Counts_Access := Container.TC'Unrestricted_Access;
|
|
begin
|
|
return R : constant Reference_Control_Type := (Controlled with TC) do
|
|
Lock (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 has no element";
|
|
end if;
|
|
|
|
if Checks and then Position.Node.Element = null then
|
|
raise Program_Error with
|
|
"Position cursor has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Position), "bad cursor in Query_Element");
|
|
|
|
declare
|
|
Lock : With_Lock (Position.Container.TC'Unrestricted_Access);
|
|
begin
|
|
Process (Position.Node.Element.all);
|
|
end;
|
|
end Query_Element;
|
|
|
|
----------
|
|
-- Read --
|
|
----------
|
|
|
|
procedure Read
|
|
(Stream : not null access Root_Stream_Type'Class;
|
|
Item : out List)
|
|
is
|
|
N : Count_Type'Base;
|
|
Dst : Node_Access;
|
|
|
|
begin
|
|
Clear (Item);
|
|
|
|
Count_Type'Base'Read (Stream, N);
|
|
|
|
if N = 0 then
|
|
return;
|
|
end if;
|
|
|
|
declare
|
|
Element : Element_Access :=
|
|
new Element_Type'(Element_Type'Input (Stream));
|
|
begin
|
|
Dst := new Node_Type'(Element, null, null);
|
|
exception
|
|
when others =>
|
|
Free (Element);
|
|
raise;
|
|
end;
|
|
|
|
Item.First := Dst;
|
|
Item.Last := Dst;
|
|
Item.Length := 1;
|
|
|
|
while Item.Length < N loop
|
|
declare
|
|
Element : Element_Access :=
|
|
new Element_Type'(Element_Type'Input (Stream));
|
|
begin
|
|
Dst := new Node_Type'(Element, Next => null, Prev => Item.Last);
|
|
exception
|
|
when others =>
|
|
Free (Element);
|
|
raise;
|
|
end;
|
|
|
|
Item.Last.Next := Dst;
|
|
Item.Last := Dst;
|
|
Item.Length := Item.Length + 1;
|
|
end loop;
|
|
end Read;
|
|
|
|
procedure Read
|
|
(Stream : not null access Root_Stream_Type'Class;
|
|
Item : out Cursor)
|
|
is
|
|
begin
|
|
raise Program_Error with "attempt to stream list cursor";
|
|
end 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;
|
|
|
|
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;
|
|
|
|
---------------
|
|
-- Reference --
|
|
---------------
|
|
|
|
function Reference
|
|
(Container : aliased in out List;
|
|
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;
|
|
|
|
if Checks and then Position.Node.Element = null then
|
|
raise Program_Error with "Node has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Position), "bad cursor in function Reference");
|
|
|
|
declare
|
|
TC : constant Tamper_Counts_Access :=
|
|
Container.TC'Unrestricted_Access;
|
|
begin
|
|
return R : constant Reference_Type :=
|
|
(Element => Position.Node.Element,
|
|
Control => (Controlled with TC))
|
|
do
|
|
Lock (TC.all);
|
|
end return;
|
|
end;
|
|
end Reference;
|
|
|
|
---------------------
|
|
-- Replace_Element --
|
|
---------------------
|
|
|
|
procedure Replace_Element
|
|
(Container : in out List;
|
|
Position : Cursor;
|
|
New_Item : Element_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'Unchecked_Access then
|
|
raise Program_Error with
|
|
"Position cursor designates wrong container";
|
|
end if;
|
|
|
|
TE_Check (Container.TC);
|
|
|
|
if Checks and then Position.Node.Element = null then
|
|
raise Program_Error with
|
|
"Position cursor has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Position), "bad cursor in Replace_Element");
|
|
|
|
declare
|
|
-- The element allocator may need an accessibility check in the
|
|
-- case the actual type is class-wide or has access discriminants
|
|
-- (see RM 4.8(10.1) and AI12-0035).
|
|
|
|
pragma Unsuppress (Accessibility_Check);
|
|
|
|
X : Element_Access := Position.Node.Element;
|
|
|
|
begin
|
|
Position.Node.Element := new Element_Type'(New_Item);
|
|
Free (X);
|
|
end;
|
|
end Replace_Element;
|
|
|
|
----------------------
|
|
-- Reverse_Elements --
|
|
----------------------
|
|
|
|
procedure Reverse_Elements (Container : in out List) is
|
|
I : Node_Access := Container.First;
|
|
J : Node_Access := Container.Last;
|
|
|
|
procedure Swap (L, R : Node_Access);
|
|
|
|
----------
|
|
-- Swap --
|
|
----------
|
|
|
|
procedure Swap (L, R : Node_Access) is
|
|
LN : constant Node_Access := L.Next;
|
|
LP : constant Node_Access := L.Prev;
|
|
|
|
RN : constant Node_Access := R.Next;
|
|
RP : constant Node_Access := R.Prev;
|
|
|
|
begin
|
|
if LP /= null then
|
|
LP.Next := R;
|
|
end if;
|
|
|
|
if RN /= null then
|
|
RN.Prev := L;
|
|
end if;
|
|
|
|
L.Next := RN;
|
|
R.Prev := LP;
|
|
|
|
if LN = R then
|
|
pragma Assert (RP = L);
|
|
|
|
L.Prev := R;
|
|
R.Next := L;
|
|
|
|
else
|
|
L.Prev := RP;
|
|
RP.Next := L;
|
|
|
|
R.Next := LN;
|
|
LN.Prev := R;
|
|
end if;
|
|
end Swap;
|
|
|
|
-- Start of processing for Reverse_Elements
|
|
|
|
begin
|
|
if Container.Length <= 1 then
|
|
return;
|
|
end if;
|
|
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
|
|
TC_Check (Container.TC);
|
|
|
|
Container.First := J;
|
|
Container.Last := I;
|
|
loop
|
|
Swap (L => I, R => J);
|
|
|
|
J := J.Next;
|
|
exit when I = J;
|
|
|
|
I := I.Prev;
|
|
exit when I = J;
|
|
|
|
Swap (L => J, R => I);
|
|
|
|
I := I.Next;
|
|
exit when I = J;
|
|
|
|
J := J.Prev;
|
|
exit when I = J;
|
|
end loop;
|
|
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
end Reverse_Elements;
|
|
|
|
------------------
|
|
-- Reverse_Find --
|
|
------------------
|
|
|
|
function Reverse_Find
|
|
(Container : List;
|
|
Item : Element_Type;
|
|
Position : Cursor := No_Element) return Cursor
|
|
is
|
|
Node : Node_Access := Position.Node;
|
|
|
|
begin
|
|
if Node = null then
|
|
Node := Container.Last;
|
|
|
|
else
|
|
if Checks and then Node.Element = null then
|
|
raise Program_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 Reverse_Find");
|
|
end if;
|
|
|
|
-- Per AI05-0022, the container implementation is required to detect
|
|
-- element tampering by a generic actual subprogram.
|
|
|
|
declare
|
|
Lock : With_Lock (Container.TC'Unrestricted_Access);
|
|
begin
|
|
while Node /= null loop
|
|
if Node.Element.all = Item then
|
|
return Cursor'(Container'Unrestricted_Access, Node);
|
|
end if;
|
|
|
|
Node := Node.Prev;
|
|
end loop;
|
|
|
|
return No_Element;
|
|
end;
|
|
end Reverse_Find;
|
|
|
|
---------------------
|
|
-- Reverse_Iterate --
|
|
---------------------
|
|
|
|
procedure Reverse_Iterate
|
|
(Container : List;
|
|
Process : not null access procedure (Position : Cursor))
|
|
is
|
|
Busy : With_Busy (Container.TC'Unrestricted_Access);
|
|
Node : Node_Access := Container.Last;
|
|
|
|
begin
|
|
while Node /= null loop
|
|
Process (Cursor'(Container'Unrestricted_Access, Node));
|
|
Node := Node.Prev;
|
|
end loop;
|
|
end Reverse_Iterate;
|
|
|
|
------------
|
|
-- Splice --
|
|
------------
|
|
|
|
procedure Splice
|
|
(Target : in out List;
|
|
Before : Cursor;
|
|
Source : in out List)
|
|
is
|
|
begin
|
|
if Before.Container /= null then
|
|
if Checks and then Before.Container /= Target'Unrestricted_Access then
|
|
raise Program_Error with
|
|
"Before cursor designates wrong container";
|
|
end if;
|
|
|
|
if Checks and then
|
|
(Before.Node = null or else Before.Node.Element = null)
|
|
then
|
|
raise Program_Error with
|
|
"Before cursor has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Before), "bad cursor in Splice");
|
|
end if;
|
|
|
|
if Target'Address = Source'Address or else Source.Length = 0 then
|
|
return;
|
|
end if;
|
|
|
|
if Checks and then Target.Length > Count_Type'Last - Source.Length then
|
|
raise Constraint_Error with "new length exceeds maximum";
|
|
end if;
|
|
|
|
TC_Check (Target.TC);
|
|
TC_Check (Source.TC);
|
|
|
|
Splice_Internal (Target, Before.Node, Source);
|
|
end Splice;
|
|
|
|
procedure Splice
|
|
(Container : in out List;
|
|
Before : Cursor;
|
|
Position : Cursor)
|
|
is
|
|
begin
|
|
if Before.Container /= null then
|
|
if Checks and then Before.Container /= Container'Unchecked_Access then
|
|
raise Program_Error with
|
|
"Before cursor designates wrong container";
|
|
end if;
|
|
|
|
if Checks and then
|
|
(Before.Node = null or else Before.Node.Element = null)
|
|
then
|
|
raise Program_Error with
|
|
"Before cursor has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Before), "bad Before cursor in Splice");
|
|
end if;
|
|
|
|
if Checks and then Position.Node = null then
|
|
raise Constraint_Error with "Position cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then Position.Node.Element = null then
|
|
raise Program_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 Position cursor in Splice");
|
|
|
|
if Position.Node = Before.Node
|
|
or else Position.Node.Next = Before.Node
|
|
then
|
|
return;
|
|
end if;
|
|
|
|
pragma Assert (Container.Length >= 2);
|
|
|
|
TC_Check (Container.TC);
|
|
|
|
if Before.Node = null then
|
|
pragma Assert (Position.Node /= Container.Last);
|
|
|
|
if Position.Node = Container.First then
|
|
Container.First := Position.Node.Next;
|
|
Container.First.Prev := null;
|
|
else
|
|
Position.Node.Prev.Next := Position.Node.Next;
|
|
Position.Node.Next.Prev := Position.Node.Prev;
|
|
end if;
|
|
|
|
Container.Last.Next := Position.Node;
|
|
Position.Node.Prev := Container.Last;
|
|
|
|
Container.Last := Position.Node;
|
|
Container.Last.Next := null;
|
|
|
|
return;
|
|
end if;
|
|
|
|
if Before.Node = Container.First then
|
|
pragma Assert (Position.Node /= Container.First);
|
|
|
|
if Position.Node = Container.Last then
|
|
Container.Last := Position.Node.Prev;
|
|
Container.Last.Next := null;
|
|
else
|
|
Position.Node.Prev.Next := Position.Node.Next;
|
|
Position.Node.Next.Prev := Position.Node.Prev;
|
|
end if;
|
|
|
|
Container.First.Prev := Position.Node;
|
|
Position.Node.Next := Container.First;
|
|
|
|
Container.First := Position.Node;
|
|
Container.First.Prev := null;
|
|
|
|
return;
|
|
end if;
|
|
|
|
if Position.Node = Container.First then
|
|
Container.First := Position.Node.Next;
|
|
Container.First.Prev := null;
|
|
|
|
elsif Position.Node = Container.Last then
|
|
Container.Last := Position.Node.Prev;
|
|
Container.Last.Next := null;
|
|
|
|
else
|
|
Position.Node.Prev.Next := Position.Node.Next;
|
|
Position.Node.Next.Prev := Position.Node.Prev;
|
|
end if;
|
|
|
|
Before.Node.Prev.Next := Position.Node;
|
|
Position.Node.Prev := Before.Node.Prev;
|
|
|
|
Before.Node.Prev := Position.Node;
|
|
Position.Node.Next := Before.Node;
|
|
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
end Splice;
|
|
|
|
procedure Splice
|
|
(Target : in out List;
|
|
Before : Cursor;
|
|
Source : in out List;
|
|
Position : in out Cursor)
|
|
is
|
|
begin
|
|
if Target'Address = Source'Address then
|
|
Splice (Target, Before, Position);
|
|
return;
|
|
end if;
|
|
|
|
if Before.Container /= null then
|
|
if Checks and then Before.Container /= Target'Unrestricted_Access then
|
|
raise Program_Error with
|
|
"Before cursor designates wrong container";
|
|
end if;
|
|
|
|
if Checks and then
|
|
(Before.Node = null or else Before.Node.Element = null)
|
|
then
|
|
raise Program_Error with
|
|
"Before cursor has no element";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Before), "bad Before cursor in Splice");
|
|
end if;
|
|
|
|
if Checks and then Position.Node = null then
|
|
raise Constraint_Error with "Position cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then Position.Node.Element = null then
|
|
raise Program_Error with
|
|
"Position cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then Position.Container /= Source'Unrestricted_Access then
|
|
raise Program_Error with
|
|
"Position cursor designates wrong container";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Position), "bad Position cursor in Splice");
|
|
|
|
if Checks and then Target.Length = Count_Type'Last then
|
|
raise Constraint_Error with "Target is full";
|
|
end if;
|
|
|
|
TC_Check (Target.TC);
|
|
TC_Check (Source.TC);
|
|
|
|
Splice_Internal (Target, Before.Node, Source, Position.Node);
|
|
Position.Container := Target'Unchecked_Access;
|
|
end Splice;
|
|
|
|
---------------------
|
|
-- Splice_Internal --
|
|
---------------------
|
|
|
|
procedure Splice_Internal
|
|
(Target : in out List;
|
|
Before : Node_Access;
|
|
Source : in out List)
|
|
is
|
|
begin
|
|
-- This implements the corresponding Splice operation, after the
|
|
-- parameters have been vetted, and corner-cases disposed of.
|
|
|
|
pragma Assert (Target'Address /= Source'Address);
|
|
pragma Assert (Source.Length > 0);
|
|
pragma Assert (Source.First /= null);
|
|
pragma Assert (Source.First.Prev = null);
|
|
pragma Assert (Source.Last /= null);
|
|
pragma Assert (Source.Last.Next = null);
|
|
pragma Assert (Target.Length <= Count_Type'Last - Source.Length);
|
|
|
|
if Target.Length = 0 then
|
|
pragma Assert (Before = null);
|
|
pragma Assert (Target.First = null);
|
|
pragma Assert (Target.Last = null);
|
|
|
|
Target.First := Source.First;
|
|
Target.Last := Source.Last;
|
|
|
|
elsif Before = null then
|
|
pragma Assert (Target.Last.Next = null);
|
|
|
|
Target.Last.Next := Source.First;
|
|
Source.First.Prev := Target.Last;
|
|
|
|
Target.Last := Source.Last;
|
|
|
|
elsif Before = Target.First then
|
|
pragma Assert (Target.First.Prev = null);
|
|
|
|
Source.Last.Next := Target.First;
|
|
Target.First.Prev := Source.Last;
|
|
|
|
Target.First := Source.First;
|
|
|
|
else
|
|
pragma Assert (Target.Length >= 2);
|
|
Before.Prev.Next := Source.First;
|
|
Source.First.Prev := Before.Prev;
|
|
|
|
Before.Prev := Source.Last;
|
|
Source.Last.Next := Before;
|
|
end if;
|
|
|
|
Source.First := null;
|
|
Source.Last := null;
|
|
|
|
Target.Length := Target.Length + Source.Length;
|
|
Source.Length := 0;
|
|
end Splice_Internal;
|
|
|
|
procedure Splice_Internal
|
|
(Target : in out List;
|
|
Before : Node_Access; -- node of Target
|
|
Source : in out List;
|
|
Position : Node_Access) -- node of Source
|
|
is
|
|
begin
|
|
-- This implements the corresponding Splice operation, after the
|
|
-- parameters have been vetted.
|
|
|
|
pragma Assert (Target'Address /= Source'Address);
|
|
pragma Assert (Target.Length < Count_Type'Last);
|
|
pragma Assert (Source.Length > 0);
|
|
pragma Assert (Source.First /= null);
|
|
pragma Assert (Source.First.Prev = null);
|
|
pragma Assert (Source.Last /= null);
|
|
pragma Assert (Source.Last.Next = null);
|
|
pragma Assert (Position /= null);
|
|
|
|
if Position = Source.First then
|
|
Source.First := Position.Next;
|
|
|
|
if Position = Source.Last then
|
|
pragma Assert (Source.First = null);
|
|
pragma Assert (Source.Length = 1);
|
|
Source.Last := null;
|
|
|
|
else
|
|
Source.First.Prev := null;
|
|
end if;
|
|
|
|
elsif Position = Source.Last then
|
|
pragma Assert (Source.Length >= 2);
|
|
Source.Last := Position.Prev;
|
|
Source.Last.Next := null;
|
|
|
|
else
|
|
pragma Assert (Source.Length >= 3);
|
|
Position.Prev.Next := Position.Next;
|
|
Position.Next.Prev := Position.Prev;
|
|
end if;
|
|
|
|
if Target.Length = 0 then
|
|
pragma Assert (Before = null);
|
|
pragma Assert (Target.First = null);
|
|
pragma Assert (Target.Last = null);
|
|
|
|
Target.First := Position;
|
|
Target.Last := Position;
|
|
|
|
Target.First.Prev := null;
|
|
Target.Last.Next := null;
|
|
|
|
elsif Before = null then
|
|
pragma Assert (Target.Last.Next = null);
|
|
Target.Last.Next := Position;
|
|
Position.Prev := Target.Last;
|
|
|
|
Target.Last := Position;
|
|
Target.Last.Next := null;
|
|
|
|
elsif Before = Target.First then
|
|
pragma Assert (Target.First.Prev = null);
|
|
Target.First.Prev := Position;
|
|
Position.Next := Target.First;
|
|
|
|
Target.First := Position;
|
|
Target.First.Prev := null;
|
|
|
|
else
|
|
pragma Assert (Target.Length >= 2);
|
|
Before.Prev.Next := Position;
|
|
Position.Prev := Before.Prev;
|
|
|
|
Before.Prev := Position;
|
|
Position.Next := Before;
|
|
end if;
|
|
|
|
Target.Length := Target.Length + 1;
|
|
Source.Length := Source.Length - 1;
|
|
end Splice_Internal;
|
|
|
|
----------
|
|
-- Swap --
|
|
----------
|
|
|
|
procedure Swap
|
|
(Container : in out List;
|
|
I, J : Cursor)
|
|
is
|
|
begin
|
|
if Checks and then I.Node = null then
|
|
raise Constraint_Error with "I cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then J.Node = null then
|
|
raise Constraint_Error with "J cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then I.Container /= Container'Unchecked_Access then
|
|
raise Program_Error with "I cursor designates wrong container";
|
|
end if;
|
|
|
|
if Checks and then J.Container /= Container'Unchecked_Access then
|
|
raise Program_Error with "J cursor designates wrong container";
|
|
end if;
|
|
|
|
if I.Node = J.Node then
|
|
return;
|
|
end if;
|
|
|
|
TE_Check (Container.TC);
|
|
|
|
pragma Assert (Vet (I), "bad I cursor in Swap");
|
|
pragma Assert (Vet (J), "bad J cursor in Swap");
|
|
|
|
declare
|
|
EI_Copy : constant Element_Access := I.Node.Element;
|
|
|
|
begin
|
|
I.Node.Element := J.Node.Element;
|
|
J.Node.Element := EI_Copy;
|
|
end;
|
|
end Swap;
|
|
|
|
----------------
|
|
-- Swap_Links --
|
|
----------------
|
|
|
|
procedure Swap_Links
|
|
(Container : in out List;
|
|
I, J : Cursor)
|
|
is
|
|
begin
|
|
if Checks and then I.Node = null then
|
|
raise Constraint_Error with "I cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then J.Node = null then
|
|
raise Constraint_Error with "J cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then I.Container /= Container'Unrestricted_Access then
|
|
raise Program_Error with "I cursor designates wrong container";
|
|
end if;
|
|
|
|
if Checks and then J.Container /= Container'Unrestricted_Access then
|
|
raise Program_Error with "J cursor designates wrong container";
|
|
end if;
|
|
|
|
if I.Node = J.Node then
|
|
return;
|
|
end if;
|
|
|
|
TC_Check (Container.TC);
|
|
|
|
pragma Assert (Vet (I), "bad I cursor in Swap_Links");
|
|
pragma Assert (Vet (J), "bad J cursor in Swap_Links");
|
|
|
|
declare
|
|
I_Next : constant Cursor := Next (I);
|
|
|
|
begin
|
|
if I_Next = J then
|
|
Splice (Container, Before => I, Position => J);
|
|
|
|
else
|
|
declare
|
|
J_Next : constant Cursor := Next (J);
|
|
|
|
begin
|
|
if J_Next = I then
|
|
Splice (Container, Before => J, Position => I);
|
|
|
|
else
|
|
pragma Assert (Container.Length >= 3);
|
|
|
|
Splice (Container, Before => I_Next, Position => J);
|
|
Splice (Container, Before => J_Next, Position => I);
|
|
end if;
|
|
end;
|
|
end if;
|
|
end;
|
|
|
|
pragma Assert (Container.First.Prev = null);
|
|
pragma Assert (Container.Last.Next = null);
|
|
end Swap_Links;
|
|
|
|
--------------------
|
|
-- Update_Element --
|
|
--------------------
|
|
|
|
procedure Update_Element
|
|
(Container : in out List;
|
|
Position : Cursor;
|
|
Process : not null access procedure (Element : in out Element_Type))
|
|
is
|
|
begin
|
|
if Checks and then Position.Node = null then
|
|
raise Constraint_Error with "Position cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then Position.Node.Element = null then
|
|
raise Program_Error with
|
|
"Position cursor has no element";
|
|
end if;
|
|
|
|
if Checks and then Position.Container /= Container'Unchecked_Access then
|
|
raise Program_Error with
|
|
"Position cursor designates wrong container";
|
|
end if;
|
|
|
|
pragma Assert (Vet (Position), "bad cursor in Update_Element");
|
|
|
|
declare
|
|
Lock : With_Lock (Container.TC'Unchecked_Access);
|
|
begin
|
|
Process (Position.Node.Element.all);
|
|
end;
|
|
end Update_Element;
|
|
|
|
---------
|
|
-- 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;
|
|
|
|
-- An invariant of a node is that its Previous and Next components can
|
|
-- be null, or designate a different node. Also, its element access
|
|
-- value must be non-null. Operation Free sets the node access value
|
|
-- components of the node to designate the node itself, and the element
|
|
-- access value to null, before actually deallocating the node, thus
|
|
-- deliberately violating the node invariant. This gives us a simple way
|
|
-- to detect a dangling reference to a node.
|
|
|
|
if Position.Node.Next = Position.Node then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Prev = Position.Node then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Element = null then
|
|
return False;
|
|
end if;
|
|
|
|
-- In practice the tests above will detect most instances of a dangling
|
|
-- reference. If we get here, it means that the invariants of the
|
|
-- designated node are satisfied (they at least appear to be satisfied),
|
|
-- so we perform some more tests, to determine whether invariants of the
|
|
-- designated list are satisfied too.
|
|
|
|
declare
|
|
L : List renames Position.Container.all;
|
|
|
|
begin
|
|
if L.Length = 0 then
|
|
return False;
|
|
end if;
|
|
|
|
if L.First = null then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last = null then
|
|
return False;
|
|
end if;
|
|
|
|
if L.First.Prev /= null then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last.Next /= null then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Prev = null and then Position.Node /= L.First then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Next = null and then Position.Node /= L.Last then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Length = 1 then
|
|
return L.First = L.Last;
|
|
end if;
|
|
|
|
if L.First = L.Last then
|
|
return False;
|
|
end if;
|
|
|
|
if L.First.Next = null then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last.Prev = null then
|
|
return False;
|
|
end if;
|
|
|
|
if L.First.Next.Prev /= L.First then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last.Prev.Next /= L.Last then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Length = 2 then
|
|
if L.First.Next /= L.Last then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last.Prev /= L.First then
|
|
return False;
|
|
end if;
|
|
|
|
return True;
|
|
end if;
|
|
|
|
if L.First.Next = L.Last then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last.Prev = L.First then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node = L.First then
|
|
return True;
|
|
end if;
|
|
|
|
if Position.Node = L.Last then
|
|
return True;
|
|
end if;
|
|
|
|
if Position.Node.Next = null then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Prev = null then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Next.Prev /= Position.Node then
|
|
return False;
|
|
end if;
|
|
|
|
if Position.Node.Prev.Next /= Position.Node then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Length = 3 then
|
|
if L.First.Next /= Position.Node then
|
|
return False;
|
|
end if;
|
|
|
|
if L.Last.Prev /= Position.Node then
|
|
return False;
|
|
end if;
|
|
end if;
|
|
|
|
return True;
|
|
end;
|
|
end Vet;
|
|
|
|
-----------
|
|
-- Write --
|
|
-----------
|
|
|
|
procedure Write
|
|
(Stream : not null access Root_Stream_Type'Class;
|
|
Item : List)
|
|
is
|
|
Node : Node_Access := Item.First;
|
|
|
|
begin
|
|
Count_Type'Base'Write (Stream, Item.Length);
|
|
|
|
while Node /= null loop
|
|
Element_Type'Output (Stream, Node.Element.all);
|
|
Node := Node.Next;
|
|
end loop;
|
|
end Write;
|
|
|
|
procedure Write
|
|
(Stream : not null access Root_Stream_Type'Class;
|
|
Item : Cursor)
|
|
is
|
|
begin
|
|
raise Program_Error with "attempt to stream list cursor";
|
|
end 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;
|
|
|
|
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;
|
|
|
|
end Ada.Containers.Indefinite_Doubly_Linked_Lists;
|