2005-06-14 Matthew Heaney <heaney@adacore.com>

	* a-swunha.ads, a-swunha.adb: Removed. Replaced by a-swuwha.ad[sb]
	* a-swuwha.ads, a-swuwha.adb: New files

	* a-szunha.ads, a-szunha.adb: Removed, replaced by a-szuzha.ad[sb]
	* a-szuzha.ads, a-szuzha.adb: New files.

	* a-rbtgso.adb, a-crbtgo.ads, a-crbtgo.adb, a-crbtgk.ads,
	a-crbtgk.adb, a-crbltr.ads, a-coorse.ads, a-coorse.adb, a-convec.ads,
	a-convec.adb, a-coinve.ads, a-coinve.adb, a-cohata.ads, a-cohama.ads,
	a-cohama.adb, a-ciorse.ads, a-ciorse.adb, a-cihama.ads, a-cihama.adb,
	a-cidlli.ads, a-cidlli.adb, a-chtgop.ads, a-chtgop.adb, a-cdlili.ads,
	a-cdlili.adb, a-coormu.adb, a-ciormu.adb, a-cihase.adb, a-cohase.adb,
	a-cohase.ads, a-ciorma.ads, a-coorma.ads, a-ciormu.ads, a-coormu.ads,
	a-swunha.adb, a-stunha.adb, a-ciorma.adb, a-coorma.adb, a-shcain.ads,
	a-shcain.adb, a-chtgke.ads, a-chtgke.adb, a-stwiha.ads, a-stwiha.adb,
	a-strhas.adb, a-stzhas.adb: synchronized to the latest version of the
	Ada 2005 RM.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@101069 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 1600 insertions, 1427 deletions

diff --git a/gcc/ada/a-coinve.adb b/gcc/ada/a-coinve.adb
index c997430f6f0..39ef4e5f190 100644
--- a/gcc/ada/a-coinve.adb
+++ b/gcc/ada/a-coinve.adb
@@ -2,11 +2,11 @@
 --                                                                          --
 --                         GNAT LIBRARY COMPONENTS                          --
 --                                                                          --
---                    ADA.CONTAINERS.INDEFINITE_VECTORS                     --
+--    A D A . C O N T A I N E R S . I N D E F I N I T E _ V E C T O R S     --
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---             Copyright (C) 2004 Free Software Foundation, Inc.            --
+--          Copyright (C) 2004-2005 Free Software Foundation, Inc.          --
 --                                                                          --
 -- This specification is derived from the Ada Reference Manual for use with --
 -- GNAT. The copyright notice above, and the license provisions that follow --
@@ -39,209 +39,272 @@ with System;  use type System.Address;
 
 package body Ada.Containers.Indefinite_Vectors is
 
-
    type Int is range System.Min_Int .. System.Max_Int;
 
    procedure Free is
-      new Ada.Unchecked_Deallocation (Elements_Type, Elements_Access);
+     new Ada.Unchecked_Deallocation (Elements_Type, Elements_Access);
 
    procedure Free is
-      new Ada.Unchecked_Deallocation (Element_Type, Element_Access);
-
-
-   procedure Adjust (Container : in out Vector) is
-   begin
-
-      if Container.Elements = null then
-         return;
-      end if;
+     new Ada.Unchecked_Deallocation (Element_Type, Element_Access);
 
-      if Container.Elements'Length = 0
-        or else Container.Last < Index_Type'First
-      then
-         Container.Elements := null;
-         return;
-      end if;
+   ---------
+   -- "&" --
+   ---------
 
-      declare
-         E : Elements_Type renames Container.Elements.all;
-         L : constant Index_Type := Container.Last;
-      begin
-
-         Container.Elements := null;
-         Container.Last := Index_Type'Pred (Index_Type'First);
-
-         Container.Elements := new Elements_Type (Index_Type'First .. L);
-
-         for I in Container.Elements'Range loop
-
-            if E (I) /= null then
-               Container.Elements (I) := new Element_Type'(E (I).all);
-            end if;
+   function "&" (Left, Right : Vector) return Vector is
+      LN : constant Count_Type := Length (Left);
+      RN : constant Count_Type := Length (Right);
 
-            Container.Last := I;
+   begin
+      if LN = 0 then
+         if RN = 0 then
+            return Empty_Vector;
+         end if;
 
-         end loop;
+         declare
+            RE : Elements_Type renames
+                   Right.Elements (Index_Type'First .. Right.Last);
 
-      end;
+            Elements : Elements_Access :=
+                         new Elements_Type (RE'Range);
 
-   end Adjust;
+         begin
+            for I in Elements'Range loop
+               begin
+                  if RE (I) /= null then
+                     Elements (I) := new Element_Type'(RE (I).all);
+                  end if;
+               exception
+                  when others =>
+                     for J in Index_Type'First .. Index_Type'Pred (I) loop
+                        Free (Elements (J));
+                     end loop;
 
+                     Free (Elements);
+                     raise;
+               end;
+            end loop;
 
-   procedure Finalize (Container : in out Vector) is
+            return (Controlled with Elements, Right.Last, 0, 0);
+         end;
 
-      E : Elements_Access := Container.Elements;
-      L : constant Index_Type'Base := Container.Last;
+      end if;
 
-   begin
+      if RN = 0 then
+         declare
+            LE : Elements_Type renames
+                   Left.Elements (Index_Type'First .. Left.Last);
 
-      Container.Elements := null;
-      Container.Last := Index_Type'Pred (Index_Type'First);
+            Elements : Elements_Access :=
+                         new Elements_Type (LE'Range);
 
-      for I in Index_Type'First .. L loop
-         Free (E (I));
-      end loop;
+         begin
+            for I in Elements'Range loop
+               begin
+                  if LE (I) /= null then
+                     Elements (I) := new Element_Type'(LE (I).all);
+                  end if;
+               exception
+                  when others =>
+                     for J in Index_Type'First .. Index_Type'Pred (I) loop
+                        Free (Elements (J));
+                     end loop;
 
-      Free (E);
+                     Free (Elements);
+                     raise;
+               end;
+            end loop;
 
-   end Finalize;
+            return (Controlled with Elements, Left.Last, 0, 0);
+         end;
+      end if;
 
+      declare
+         Last_As_Int : constant Int'Base :=
+                         Int (Index_Type'First) + Int (LN) + Int (RN) - 1;
 
-   procedure Write
-     (Stream    : access Root_Stream_Type'Class;
-      Container : in     Vector) is
+         Last : constant Index_Type := Index_Type (Last_As_Int);
 
-      N : constant Count_Type := Length (Container);
+         LE : Elements_Type renames
+                Left.Elements (Index_Type'First .. Left.Last);
 
-   begin
+         RE : Elements_Type renames
+                Right.Elements (Index_Type'First .. Right.Last);
 
-      Count_Type'Base'Write (Stream, N);
+         Elements : Elements_Access :=
+                      new Elements_Type (Index_Type'First .. Last);
 
-      if N = 0 then
-         return;
-      end if;
+         I : Index_Type'Base := Index_Type'Pred (Index_Type'First);
 
-      declare
-         E : Elements_Type renames Container.Elements.all;
       begin
-         for I in Index_Type'First .. Container.Last loop
-
-            --  There's another way to do this.  Instead a separate
-            --  Boolean for each element, you could write a Boolean
-            --  followed by a count of how many nulls or non-nulls
-            --  follow in the array.  Alternately you could use a
-            --  signed integer, and use the sign as the indicator
-            --  or null-ness.
+         for LI in LE'Range loop
+            I := Index_Type'Succ (I);
 
-            if E (I) = null then
-               Boolean'Write (Stream, False);
-            else
-               Boolean'Write (Stream, True);
-               Element_Type'Output (Stream, E (I).all);
-            end if;
+            begin
+               if LE (LI) /= null then
+                  Elements (I) := new Element_Type'(LE (LI).all);
+               end if;
+            exception
+               when others =>
+                  for J in Index_Type'First .. Index_Type'Pred (I) loop
+                     Free (Elements (J));
+                  end loop;
 
+                  Free (Elements);
+                  raise;
+            end;
          end loop;
-      end;
 
-   end Write;
+         for RI in RE'Range loop
+            I := Index_Type'Succ (I);
 
+            begin
+               if RE (RI) /= null then
+                  Elements (I) := new Element_Type'(RE (RI).all);
+               end if;
+            exception
+               when others =>
+                  for J in Index_Type'First .. Index_Type'Pred (I) loop
+                     Free (Elements (J));
+                  end loop;
 
-   procedure Read
-     (Stream    : access Root_Stream_Type'Class;
-      Container :    out Vector) is
+                  Free (Elements);
+                  raise;
+            end;
+         end loop;
 
-      Length : Count_Type'Base;
-      Last   : Index_Type'Base := Index_Type'Pred (Index_Type'First);
+         return (Controlled with Elements, Last, 0, 0);
+      end;
+   end "&";
 
-      B : Boolean;
+   function "&" (Left : Vector; Right : Element_Type) return Vector is
+      LN : constant Count_Type := Length (Left);
 
    begin
+      if LN = 0 then
+         declare
+            subtype Elements_Subtype is
+              Elements_Type (Index_Type'First .. Index_Type'First);
 
-      Clear (Container);
-
-      Count_Type'Base'Read (Stream, Length);
-
-      if Length > Capacity (Container) then
-         Reserve_Capacity (Container, Capacity => Length);
-      end if;
-
-      for I in Count_Type range 1 .. Length loop
-
-         Last := Index_Type'Succ (Last);
-
-         Boolean'Read (Stream, B);
-
-         if B then
-            Container.Elements (Last) :=
-              new Element_Type'(Element_Type'Input (Stream));
-         end if;
-
-         Container.Last := Last;
-
-      end loop;
-
-   end Read;
-
+            Elements : Elements_Access := new Elements_Subtype;
 
-   function To_Vector (Length : Count_Type) return Vector is
-   begin
+         begin
+            begin
+               Elements (Elements'First) := new Element_Type'(Right);
+            exception
+               when others =>
+                  Free (Elements);
+                  raise;
+            end;
 
-      if Length = 0 then
-         return Empty_Vector;
+            return (Controlled with Elements, Index_Type'First, 0, 0);
+         end;
       end if;
 
       declare
-
-         First : constant Int := Int (Index_Type'First);
-
          Last_As_Int : constant Int'Base :=
-           First + Int (Length) - 1;
+                         Int (Index_Type'First) + Int (LN);
 
-         Last : constant Index_Type :=
-           Index_Type (Last_As_Int);
+         Last : constant Index_Type := Index_Type (Last_As_Int);
 
-         Elements : constant Elements_Access :=
-           new Elements_Type (Index_Type'First .. Last);
+         LE : Elements_Type renames
+                Left.Elements (Index_Type'First .. Left.Last);
 
-      begin
+         Elements : Elements_Access :=
+                      new Elements_Type (Index_Type'First .. Last);
 
-         return (Controlled with Elements, Last);
+      begin
+         for I in LE'Range loop
+            begin
+               if LE (I) /= null then
+                  Elements (I) := new Element_Type'(LE (I).all);
+               end if;
+            exception
+               when others =>
+                  for J in Index_Type'First .. Index_Type'Pred (I) loop
+                     Free (Elements (J));
+                  end loop;
 
-      end;
+                  Free (Elements);
+                  raise;
+            end;
+         end loop;
 
-   end To_Vector;
+         begin
+            Elements (Elements'Last) := new Element_Type'(Right);
+         exception
+            when others =>
+               declare
+                  subtype J_Subtype is Index_Type'Base range
+                    Index_Type'First .. Index_Type'Pred (Elements'Last);
+               begin
+                  for J in J_Subtype loop
+                     Free (Elements (J));
+                  end loop;
+               end;
 
+               Free (Elements);
+               raise;
+         end;
 
+         return (Controlled with Elements, Last, 0, 0);
+      end;
+   end "&";
 
-   function To_Vector
-     (New_Item : Element_Type;
-      Length   : Count_Type) return Vector is
+   function "&" (Left : Element_Type; Right : Vector) return Vector is
+      RN : constant Count_Type := Length (Right);
 
    begin
+      if RN = 0 then
+         declare
+            subtype Elements_Subtype is
+              Elements_Type (Index_Type'First .. Index_Type'First);
 
-      if Length = 0 then
-         return Empty_Vector;
-      end if;
+            Elements : Elements_Access := new Elements_Subtype;
 
-      declare
+         begin
+            begin
+               Elements (Elements'First) := new Element_Type'(Left);
+            exception
+               when others =>
+                  Free (Elements);
+                  raise;
+            end;
 
-         First : constant Int := Int (Index_Type'First);
+            return (Controlled with Elements, Index_Type'First, 0, 0);
+         end;
+      end if;
 
+      declare
          Last_As_Int : constant Int'Base :=
-           First + Int (Length) - 1;
+                         Int (Index_Type'First) + Int (RN);
+
+         Last : constant Index_Type := Index_Type (Last_As_Int);
 
-         Last : constant Index_Type :=
-           Index_Type (Last_As_Int);
+         RE : Elements_Type renames
+                Right.Elements (Index_Type'First .. Right.Last);
 
          Elements : Elements_Access :=
-           new Elements_Type (Index_Type'First .. Last);
+                      new Elements_Type (Index_Type'First .. Last);
+
+         I : Index_Type'Base := Index_Type'First;
 
       begin
+         begin
+            Elements (I) := new Element_Type'(Left);
+         exception
+            when others =>
+               Free (Elements);
+               raise;
+         end;
 
-         for I in Elements'Range loop
+         for RI in RE'Range loop
+            I := Index_Type'Succ (I);
 
             begin
-               Elements (I) := new Element_Type'(New_Item);
+               if RE (RI) /= null then
+                  Elements (I) := new Element_Type'(RE (RI).all);
+               end if;
             exception
                when others =>
                   for J in Index_Type'First .. Index_Type'Pred (I) loop
@@ -251,19 +314,45 @@ package body Ada.Containers.Indefinite_Vectors is
                   Free (Elements);
                   raise;
             end;
-
          end loop;
 
-         return (Controlled with Elements, Last);
+         return (Controlled with Elements, Last, 0, 0);
+      end;
+   end "&";
+
+   function "&" (Left, Right : Element_Type) return Vector is
+      subtype IT is Index_Type'Base range
+        Index_Type'First .. Index_Type'Succ (Index_Type'First);
 
+      Elements : Elements_Access := new Elements_Type (IT);
+
+   begin
+      begin
+         Elements (Elements'First) := new Element_Type'(Left);
+      exception
+         when others =>
+            Free (Elements);
+            raise;
       end;
 
-   end To_Vector;
+      begin
+         Elements (Elements'Last) := new Element_Type'(Right);
+      exception
+         when others =>
+            Free (Elements (Elements'First));
+            Free (Elements);
+            raise;
+      end;
 
+      return (Controlled with Elements, Elements'Last, 0, 0);
+   end "&";
+
+   ---------
+   -- "=" --
+   ---------
 
    function "=" (Left, Right : Vector) return Boolean is
    begin
-
       if Left'Address = Right'Address then
          return True;
       end if;
@@ -272,8 +361,7 @@ package body Ada.Containers.Indefinite_Vectors is
          return False;
       end if;
 
-      for I in Index_Type'First .. Left.Last loop
-
+      for J in Index_Type'First .. Left.Last loop
          --  NOTE:
          --  I think it's a bounded error to read or otherwise manipulate
          --  an "empty" element, which here means that it has the value
@@ -285,396 +373,719 @@ package body Ada.Containers.Indefinite_Vectors is
          --  you have a contrary argument then let me know.
          --  END NOTE.
 
-         if Left.Elements (I) = null then
-
-            if Right.Elements (I) /= null then
+         if Left.Elements (J) = null then
+            if Right.Elements (J) /= null then
                return False;
             end if;
 
-         elsif Right.Elements (I) = null then
-
+         elsif Right.Elements (J) = null then
             return False;
 
-         elsif Left.Elements (I).all /= Right.Elements (I).all then
-
+         elsif Left.Elements (J).all /= Right.Elements (J).all then
             return False;
 
          end if;
-
       end loop;
 
       return True;
-
    end "=";
 
+   ------------
+   -- Adjust --
+   ------------
 
-   function Length (Container : Vector) return Count_Type is
-
-      L : constant Int := Int (Container.Last);
-      F : constant Int := Int (Index_Type'First);
-
-      N : constant Int'Base := L - F + 1;
+   procedure Adjust (Container : in out Vector) is
    begin
-      return Count_Type (N);
-   end Length;
+      if Container.Elements = null then
+         return;
+      end if;
 
+      if Container.Elements'Length = 0
+        or else Container.Last < Index_Type'First
+      then
+         Container.Elements := null;
+         return;
+      end if;
 
-   function Is_Empty (Container : Vector) return Boolean is
-   begin
-      return Container.Last < Index_Type'First;
-   end Is_Empty;
+      declare
+         E : Elements_Type renames Container.Elements.all;
+         L : constant Index_Type := Container.Last;
+      begin
+         Container.Elements := null;
+         Container.Last := No_Index;
+         Container.Busy := 0;
+         Container.Lock := 0;
 
+         Container.Elements := new Elements_Type (Index_Type'First .. L);
 
-   procedure Set_Length
-     (Container : in out Vector;
-      Length    : in     Count_Type) is
+         for I in Container.Elements'Range loop
+            if E (I) /= null then
+               Container.Elements (I) := new Element_Type'(E (I).all);
+            end if;
 
-      N : constant Count_Type := Indefinite_Vectors.Length (Container);
+            Container.Last := I;
+         end loop;
+      end;
+   end Adjust;
 
-   begin
+   ------------
+   -- Append --
+   ------------
 
-      if Length = N then
+   procedure Append (Container : in out Vector; New_Item : Vector) is
+   begin
+      if Is_Empty (New_Item) then
          return;
       end if;
 
-      if Length = 0 then
-         Clear (Container);
+      Insert
+        (Container,
+         Index_Type'Succ (Container.Last),
+         New_Item);
+   end Append;
+
+   procedure Append
+     (Container : in out Vector;
+      New_Item  : Element_Type;
+      Count     : Count_Type := 1)
+   is
+   begin
+      if Count = 0 then
          return;
       end if;
 
-      declare
-         Last_As_Int : constant Int'Base :=
-           Int (Index_Type'First) + Int (Length) - 1;
+      Insert
+        (Container,
+         Index_Type'Succ (Container.Last),
+         New_Item,
+         Count);
+   end Append;
 
-         Last : constant Index_Type :=
-           Index_Type (Last_As_Int);
-      begin
+   ------------
+   -- Assign --
+   ------------
 
-         if Length > N then
+   procedure Assign
+     (Target : in out Vector;
+      Source : Vector)
+   is
+      N : constant Count_Type := Length (Source);
 
-            if Length > Capacity (Container) then
-               Reserve_Capacity (Container, Capacity => Length);
-            end if;
+   begin
+      if Target'Address = Source'Address then
+         return;
+      end if;
 
-            Container.Last := Last;
+      Clear (Target);
 
-            return;
+      if N = 0 then
+         return;
+      end if;
 
-         end if;
+      if N > Capacity (Target) then
+         Reserve_Capacity (Target, Capacity => N);
+      end if;
 
-         for I in reverse Index_Type'Succ (Last) .. Container.Last loop
+      for J in Index_Type'First .. Source.Last loop
+         declare
+            EA : constant Element_Access := Source.Elements (J);
+         begin
+            if EA /= null then
+               Target.Elements (J) := new Element_Type'(EA.all);
+            end if;
+         end;
 
-            declare
-               X : Element_Access := Container.Elements (I);
-            begin
-               Container.Elements (I) := null;
-               Container.Last := Index_Type'Pred (Container.Last);
-               Free (X);
-            end;
+         Target.Last := J;
+      end loop;
+   end Assign;
 
-         end loop;
+   --------------
+   -- Capacity --
+   --------------
 
-      end;
+   function Capacity (Container : Vector) return Count_Type is
+   begin
+      if Container.Elements = null then
+         return 0;
+      end if;
 
-   end Set_Length;
+      return Container.Elements'Length;
+   end Capacity;
 
+   -----------
+   -- Clear --
+   -----------
 
    procedure Clear (Container : in out Vector) is
    begin
+      if Container.Busy > 0 then
+         raise Program_Error;
+      end if;
 
-      for I in reverse Index_Type'First .. Container.Last loop
-
+      for J in reverse Index_Type'First .. Container.Last loop
          declare
-            X : Element_Access := Container.Elements (I);
+            X : Element_Access := Container.Elements (J);
          begin
-            Container.Elements (I) := null;
-            Container.Last := Index_Type'Pred (I);
+            Container.Elements (J) := null;
+            Container.Last := Index_Type'Pred (J);
             Free (X);
          end;
-
       end loop;
-
    end Clear;
 
+   --------------
+   -- Contains --
+   --------------
+
+   function Contains
+     (Container : Vector;
+      Item      : Element_Type) return Boolean is
+   begin
+      return Find_Index (Container, Item) /= No_Index;
+   end Contains;
+
+   ------------
+   -- Delete --
+   ------------
 
-   procedure Append (Container : in out Vector;
-                     New_Item  : in     Element_Type;
-                     Count     : in     Count_Type := 1) is
+   procedure Delete
+     (Container : in out Vector;
+      Index     : Extended_Index;
+      Count     : Count_Type := 1)
+   is
    begin
+      if Index < Index_Type'First then
+         raise Constraint_Error;
+      end if;
+
+      if Index > Container.Last then
+         if Index > Container.Last + 1 then
+            raise Constraint_Error;
+         end if;
+
+         return;
+      end if;
+
       if Count = 0 then
          return;
       end if;
 
-      Insert
-        (Container,
-         Index_Type'Succ (Container.Last),
-         New_Item,
-         Count);
-   end Append;
+      if Container.Busy > 0 then
+         raise Program_Error;
+      end if;
 
+      declare
+         I_As_Int : constant Int := Int (Index);
 
-   procedure Insert
-     (Container : in out Vector;
-      Before    : in     Extended_Index;
-      New_Item  : in     Element_Type;
-      Count     : in     Count_Type := 1) is
+         Old_Last_As_Int : constant Int := Int (Container.Last);
 
-      Old_Last_As_Int : constant Int := Int (Container.Last);
+         Count1 : constant Int'Base := Int (Count);
+         Count2 : constant Int'Base := Old_Last_As_Int - I_As_Int + 1;
 
-      N : constant Int := Int (Count);
+         N : constant Int'Base := Int'Min (Count1, Count2);
 
-      New_Last_As_Int : constant Int'Base := Old_Last_As_Int + N;
+         J_As_Int : constant Int'Base := I_As_Int + N;
+         J        : constant Index_Type'Base := Index_Type'Base (J_As_Int);
 
-      New_Last : constant Extended_Index := Extended_Index (New_Last_As_Int);
+         E : Elements_Type renames Container.Elements.all;
 
-      Index : Index_Type;
+         New_Last_As_Int : constant Int'Base := Old_Last_As_Int - N;
 
-      Dst_Last : Index_Type;
-      Dst      : Elements_Access;
+         New_Last : constant Extended_Index :=
+                      Extended_Index (New_Last_As_Int);
+
+      begin
+         for K in Index .. Index_Type'Pred (J) loop
+            declare
+               X : Element_Access := E (K);
+            begin
+               E (K) := null;
+               Free (X);
+            end;
+         end loop;
+
+         E (Index .. New_Last) := E (J .. Container.Last);
+         Container.Last := New_Last;
+      end;
+   end Delete;
 
+   procedure Delete
+     (Container : in out Vector;
+      Position  : in out Cursor;
+      Count     : Count_Type := 1)
+   is
    begin
+      if Position.Container = null then
+         raise Constraint_Error;
+      end if;
 
-      if Count = 0 then
-         return;
+      if Position.Container /=
+           Vector_Access'(Container'Unchecked_Access)
+        or else Position.Index > Container.Last
+      then
+         raise Program_Error;
       end if;
 
-      declare
-         subtype Before_Subtype is Index_Type'Base range
-           Index_Type'First .. Index_Type'Succ (Container.Last);
+      Delete (Container, Position.Index, Count);
 
-         Old_First : constant Before_Subtype := Before;
+      if Position.Index <= Container.Last then
+         Position := (Container'Unchecked_Access, Position.Index);
+      else
+         Position := No_Element;
+      end if;
+   end Delete;
 
-         Old_First_As_Int : constant Int := Int (Old_First);
+   ------------------
+   -- Delete_First --
+   ------------------
 
-         New_First_As_Int : constant Int'Base := Old_First_As_Int + N;
-      begin
-         Index := Index_Type (New_First_As_Int);
-      end;
+   procedure Delete_First
+     (Container : in out Vector;
+      Count     : Count_Type := 1)
+   is
+   begin
+      if Count = 0 then
+         return;
+      end if;
 
-      if Container.Elements = null then
+      if Count >= Length (Container) then
+         Clear (Container);
+         return;
+      end if;
 
-         declare
-            subtype Elements_Subtype is
-              Elements_Type (Index_Type'First .. New_Last);
-         begin
-            Container.Elements := new Elements_Subtype;
-            Container.Last := Index_Type'Pred (Index_Type'First);
+      Delete (Container, Index_Type'First, Count);
+   end Delete_First;
 
-            for I in Container.Elements'Range loop
-               Container.Elements (I) := new Element_Type'(New_Item);
-               Container.Last := I;
-            end loop;
-         end;
+   -----------------
+   -- Delete_Last --
+   -----------------
+
+   procedure Delete_Last
+     (Container : in out Vector;
+      Count     : Count_Type := 1)
+   is
+      Index : Int'Base;
 
+   begin
+      if Count = 0 then
          return;
+      end if;
 
+      if Count >= Length (Container) then
+         Clear (Container);
+         return;
       end if;
 
-      if New_Last <= Container.Elements'Last then
+      Index := Int'Base (Container.Last) - Int'Base (Count) + 1;
 
-         declare
-            E : Elements_Type renames Container.Elements.all;
-         begin
-            E (Index .. New_Last) := E (Before .. Container.Last);
-            Container.Last := New_Last;
+      Delete (Container, Index_Type'Base (Index), Count);
+   end Delete_Last;
 
-            --  NOTE:
-            --  Now we do the allocation.  If it fails, we can propagate the
-            --  exception and invariants are more or less satisfied.  The
-            --  issue is that we have some slots still null, and the client
-            --  has no way of detecting whether the slot is null (unless we
-            --  give him a way).
-            --
-            --  Another way is to allocate a subarray on the stack, do the
-            --  allocation into that array, and if that success then do
-            --  the insertion proper.  The issue there is that you have to
-            --  allocate the subarray on the stack, and that may fail if the
-            --  subarray is long.
-            --
-            --  Or we could try to roll-back the changes: deallocate the
-            --  elements we have successfully deallocated, and then copy
-            --  the elements ptrs back to their original posns.
-            --  END NOTE.
+   -------------
+   -- Element --
+   -------------
 
-            --  NOTE: I have written the loop manually here.  I could
-            --  have done it this way too:
-            --    E (Before .. Index_Type'Pred (Index)) :=
-            --      (others => new Element_Type'New_Item);
-            --  END NOTE.
+   function Element
+     (Container : Vector;
+      Index     : Index_Type) return Element_Type
+   is
+      subtype T is Index_Type'Base range
+        Index_Type'First .. Container.Last;
+   begin
+      return Container.Elements (T'(Index)).all;
+   end Element;
 
-            for I in Before .. Index_Type'Pred (Index) loop
+   function Element (Position : Cursor) return Element_Type is
+   begin
+      return Element (Position.Container.all, Position.Index);
+   end Element;
 
-               begin
-                  E (I) := new Element_Type'(New_Item);
-               exception
-                  when others =>
-                     E (I .. Index_Type'Pred (Index)) := (others => null);
-                     raise;
-               end;
+   --------------
+   -- Finalize --
+   --------------
 
-            end loop;
-         end;
+   procedure Finalize (Container : in out Vector) is
+   begin
+      Clear (Container);
 
-         return;
+      declare
+         X : Elements_Access := Container.Elements;
+      begin
+         Container.Elements := null;
+         Free (X);
+      end;
+   end Finalize;
 
+   ----------
+   -- Find --
+   ----------
+
+   function Find
+     (Container : Vector;
+      Item      : Element_Type;
+      Position  : Cursor := No_Element) return Cursor is
+
+   begin
+      if Position.Container /= null
+        and then (Position.Container /=
+                    Vector_Access'(Container'Unchecked_Access)
+                  or else Position.Index > Container.Last)
+      then
+         raise Program_Error;
       end if;
 
-      declare
+      for J in Position.Index .. Container.Last loop
+         if Container.Elements (J) /= null
+           and then Container.Elements (J).all = Item
+         then
+            return (Container'Unchecked_Access, J);
+         end if;
+      end loop;
 
-         First : constant Int := Int (Index_Type'First);
+      return No_Element;
+   end Find;
 
-         New_Size : constant Int'Base :=
-           New_Last_As_Int - First + 1;
+   ----------------
+   -- Find_Index --
+   ----------------
 
-         Max_Size : constant Int'Base :=
-           Int (Index_Type'Last) - First + 1;
+   function Find_Index
+     (Container : Vector;
+      Item      : Element_Type;
+      Index     : Index_Type := Index_Type'First) return Extended_Index is
+   begin
+      for Indx in Index .. Container.Last loop
+         if Container.Elements (Indx) /= null
+           and then Container.Elements (Indx).all = Item
+         then
+            return Indx;
+         end if;
+      end loop;
 
-         Size, Dst_Last_As_Int : Int'Base;
+      return No_Index;
+   end Find_Index;
 
-      begin
+   -----------
+   -- First --
+   -----------
 
-         if New_Size >= Max_Size / 2 then
+   function First (Container : Vector) return Cursor is
+   begin
+      if Is_Empty (Container) then
+         return No_Element;
+      end if;
 
-            Dst_Last := Index_Type'Last;
+      return (Container'Unchecked_Access, Index_Type'First);
+   end First;
+
+   -------------------
+   -- First_Element --
+   -------------------
 
+   function First_Element (Container : Vector) return Element_Type is
+   begin
+      return Element (Container, Index_Type'First);
+   end First_Element;
+
+   -----------------
+   -- First_Index --
+   -----------------
+
+   function First_Index (Container : Vector) return Index_Type is
+      pragma Unreferenced (Container);
+   begin
+      return Index_Type'First;
+   end First_Index;
+
+   ---------------------
+   -- Generic_Sorting --
+   ---------------------
+
+   package body Generic_Sorting is
+
+      -----------------------
+      -- Local Subprograms --
+      -----------------------
+
+      function Is_Less (L, R : Element_Access) return Boolean;
+      pragma Inline (Is_Less);
+
+      -------------
+      -- Is_Less --
+      -------------
+
+      function Is_Less (L, R : Element_Access) return Boolean is
+      begin
+         if L = null then
+            return R /= null;
+         elsif R = null then
+            return False;
          else
+            return L.all < R.all;
+         end if;
+      end Is_Less;
 
-            Size := Container.Elements'Length;
+      ---------------
+      -- Is_Sorted --
+      ---------------
 
-            if Size = 0 then
-               Size := 1;
-            end if;
+      function Is_Sorted (Container : Vector) return Boolean is
+      begin
+         if Container.Last <= Index_Type'First then
+            return True;
+         end if;
 
-            while Size < New_Size loop
-               Size := 2 * Size;
+         declare
+            E : Elements_Type renames Container.Elements.all;
+         begin
+            for I in Index_Type'First .. Container.Last - 1 loop
+               if Is_Less (E (I + 1), E (I)) then
+                  return False;
+               end if;
             end loop;
+         end;
 
-            Dst_Last_As_Int := First + Size - 1;
-            Dst_Last := Index_Type (Dst_Last_As_Int);
+         return True;
+      end Is_Sorted;
 
+      -----------
+      -- Merge --
+      -----------
+
+      procedure Merge (Target, Source : in out Vector) is
+         I : Index_Type'Base := Target.Last;
+         J : Index_Type'Base;
+
+      begin
+         if Target.Last < Index_Type'First then
+            Move (Target => Target, Source => Source);
+            return;
          end if;
 
-      end;
+         if Target'Address = Source'Address then
+            return;
+         end if;
 
-      Dst := new Elements_Type (Index_Type'First .. Dst_Last);
+         if Source.Last < Index_Type'First then
+            return;
+         end if;
 
-      declare
-         Src : Elements_Type renames Container.Elements.all;
-      begin
-         Dst (Index_Type'First .. Index_Type'Pred (Before)) :=
-           Src (Index_Type'First .. Index_Type'Pred (Before));
+         if Source.Busy > 0 then
+            raise Program_Error;
+         end if;
 
-         Dst (Index .. New_Last) := Src (Before .. Container.Last);
-      end;
+         Target.Set_Length (Length (Target) + Length (Source));
+
+         J := Target.Last;
+         while Source.Last >= Index_Type'First loop
+            if I < Index_Type'First then
+               declare
+                  Src : Elements_Type renames
+                    Source.Elements (Index_Type'First .. Source.Last);
+
+               begin
+                  Target.Elements (Index_Type'First .. J) := Src;
+                  Src := (others => null);
+               end;
+
+               Source.Last := No_Index;
+               return;
+            end if;
+
+            declare
+               Src : Element_Access renames Source.Elements (Source.Last);
+               Tgt : Element_Access renames Target.Elements (I);
+
+            begin
+               if Is_Less (Src, Tgt) then
+                  Target.Elements (J) := Tgt;
+                  Tgt := null;
+                  I := I - 1;
+
+               else
+                  Target.Elements (J) := Src;
+                  Src := null;
+                  Source.Last := Source.Last - 1;
+               end if;
+            end;
+
+            J := J - 1;
+         end loop;
+      end Merge;
+
+      ----------
+      -- Sort --
+      ----------
+
+      procedure Sort (Container : in out Vector)
+      is
+         procedure Sort is
+            new Generic_Array_Sort
+             (Index_Type   => Index_Type,
+              Element_Type => Element_Access,
+              Array_Type   => Elements_Type,
+              "<"          => Is_Less);
+
+      --  Start of processing for Sort
 
-      declare
-         X : Elements_Access := Container.Elements;
       begin
-         Container.Elements := Dst;
-         Container.Last := New_Last;
+         if Container.Last <= Index_Type'First then
+            return;
+         end if;
 
-         Free (X);
-      end;
+         if Container.Lock > 0 then
+            raise Program_Error;
+         end if;
 
-      --  NOTE:
-      --  Now do the allocation.  If the allocation fails,
-      --  then the worst thing is that we have a few null slots.
-      --  Our invariants are otherwise satisfied.
-      --  END NOTE.
+         Sort (Container.Elements (Index_Type'First .. Container.Last));
+      end Sort;
 
-      for I in Before .. Index_Type'Pred (Index) loop
-         Dst (I) := new Element_Type'(New_Item);
-      end loop;
+   end Generic_Sorting;
 
-   end Insert;
+   -----------------
+   -- Has_Element --
+   -----------------
 
+   function Has_Element (Position : Cursor) return Boolean is
+   begin
+      if Position.Container = null then
+         return False;
+      end if;
 
-   procedure Insert_Space
-     (Container : in out Vector;
-      Before    : in     Extended_Index;
-      Count     : in     Count_Type := 1) is
+      return Position.Index <= Position.Container.Last;
+   end Has_Element;
 
-      Old_Last_As_Int : constant Int := Int (Container.Last);
+   ------------
+   -- Insert --
+   ------------
 
+   procedure Insert
+     (Container : in out Vector;
+      Before    : Extended_Index;
+      New_Item  : Element_Type;
+      Count     : Count_Type := 1)
+   is
       N : constant Int := Int (Count);
 
-      New_Last_As_Int : constant Int'Base := Old_Last_As_Int + N;
-
-      New_Last : constant Extended_Index := Extended_Index (New_Last_As_Int);
+      New_Last_As_Int : Int'Base;
+      New_Last        : Index_Type;
 
-      Index : Index_Type;
+      Index : Extended_Index;  -- TODO: see note in a-convec.adb.
 
       Dst_Last : Index_Type;
       Dst      : Elements_Access;
 
    begin
+      if Before < Index_Type'First then
+         raise Constraint_Error;
+      end if;
+
+      if Before > Container.Last
+        and then Before > Container.Last + 1
+      then
+         raise Constraint_Error;
+      end if;
 
       if Count = 0 then
          return;
       end if;
 
       declare
-         subtype Before_Subtype is Index_Type'Base range
-           Index_Type'First .. Index_Type'Succ (Container.Last);
+         Old_Last_As_Int : constant Int := Int (Container.Last);
 
-         Old_First : constant Before_Subtype := Before;
+      begin
+         New_Last_As_Int := Old_Last_As_Int + N;
+         New_Last := Index_Type (New_Last_As_Int);
+      end;
 
-         Old_First_As_Int : constant Int := Int (Old_First);
+      if Container.Busy > 0 then
+         raise Program_Error;
+      end if;
+
+      declare
+         Old_First_As_Int : constant Int := Int (Before);
 
          New_First_As_Int : constant Int'Base := Old_First_As_Int + N;
+
       begin
-         Index := Index_Type (New_First_As_Int);
+         Index := Extended_Index (New_First_As_Int);  --  TODO
       end;
 
       if Container.Elements = null then
-
          declare
             subtype Elements_Subtype is
               Elements_Type (Index_Type'First .. New_Last);
          begin
             Container.Elements := new Elements_Subtype;
-            Container.Last := New_Last;
+            Container.Last := Index_Type'Pred (Index_Type'First);
+
+            for J in Container.Elements'Range loop
+               Container.Elements (J) := new Element_Type'(New_Item);
+               Container.Last := J;
+            end loop;
          end;
 
          return;
-
       end if;
 
       if New_Last <= Container.Elements'Last then
-
          declare
             E : Elements_Type renames Container.Elements.all;
          begin
             E (Index .. New_Last) := E (Before .. Container.Last);
-            E (Before .. Index_Type'Pred (Index)) := (others => null);
-
             Container.Last := New_Last;
+
+            --  NOTE:
+            --  Now we do the allocation.  If it fails, we can propagate the
+            --  exception and invariants are more or less satisfied.  The
+            --  issue is that we have some slots still null, and the client
+            --  has no way of detecting whether the slot is null (unless we
+            --  give him a way).
+            --
+            --  Another way is to allocate a subarray on the stack, do the
+            --  allocation into that array, and if that success then do
+            --  the insertion proper.  The issue there is that you have to
+            --  allocate the subarray on the stack, and that may fail if the
+            --  subarray is long.
+            --
+            --  Or we could try to roll-back the changes: deallocate the
+            --  elements we have successfully deallocated, and then copy
+            --  the elements ptrs back to their original posns.
+            --  END NOTE.
+
+            --  NOTE: I have written the loop manually here.  I could
+            --  have done it this way too:
+            --    E (Before .. Index_Type'Pred (Index)) :=
+            --      (others => new Element_Type'New_Item);
+            --  END NOTE.
+
+            for J in Before .. Index_Type'Pred (Index) loop
+               begin
+                  E (J) := new Element_Type'(New_Item);
+               exception
+                  when others =>
+                     E (J .. Index_Type'Pred (Index)) := (others => null);
+                     raise;
+               end;
+            end loop;
          end;
 
          return;
-
       end if;
 
       declare
-
          First : constant Int := Int (Index_Type'First);
 
-         New_Size : constant Int'Base :=
-           Int (New_Last_As_Int) - First + 1;
-
-         Max_Size : constant Int'Base :=
-           Int (Index_Type'Last) - First + 1;
+         New_Size : constant Int'Base := New_Last_As_Int - First + 1;
+         Max_Size : constant Int'Base := Int (Index_Type'Last) - First + 1;
 
          Size, Dst_Last_As_Int : Int'Base;
 
       begin
-
          if New_Size >= Max_Size / 2 then
-
             Dst_Last := Index_Type'Last;
 
          else
-
             Size := Container.Elements'Length;
 
             if Size = 0 then
@@ -687,15 +1098,14 @@ package body Ada.Containers.Indefinite_Vectors is
 
             Dst_Last_As_Int := First + Size - 1;
             Dst_Last := Index_Type (Dst_Last_As_Int);
-
          end if;
-
       end;
 
       Dst := new Elements_Type (Index_Type'First .. Dst_Last);
 
       declare
          Src : Elements_Type renames Container.Elements.all;
+
       begin
          Dst (Index_Type'First .. Index_Type'Pred (Before)) :=
            Src (Index_Type'First .. Index_Type'Pred (Before));
@@ -712,900 +1122,564 @@ package body Ada.Containers.Indefinite_Vectors is
          Free (X);
       end;
 
-   end Insert_Space;
-
-
-   procedure Delete_First (Container : in out Vector;
-                           Count     : in     Count_Type := 1) is
-   begin
-
-      if Count = 0 then
-         return;
-      end if;
-
-      if Count >= Length (Container) then
-         Clear (Container);
-         return;
-      end if;
-
-      Delete (Container, Index_Type'First, Count);
-
-   end Delete_First;
-
+      --  NOTE:
+      --  Now do the allocation.  If the allocation fails,
+      --  then the worst thing is that we have a few null slots.
+      --  Our invariants are otherwise satisfied.
+      --  END NOTE.
 
-   procedure Delete_Last (Container : in out Vector;
-                          Count     : in     Count_Type := 1) is
+      for J in Before .. Index_Type'Pred (Index) loop
+         Dst (J) := new Element_Type'(New_Item);
+      end loop;
+   end Insert;
 
-      Index : Int'Base;
+   procedure Insert
+     (Container : in out Vector;
+      Before    : Extended_Index;
+      New_Item  : Vector)
+   is
+      N : constant Count_Type := Length (New_Item);
 
    begin
-
-      if Count = 0 then
-         return;
+      if Before < Index_Type'First then
+         raise Constraint_Error;
       end if;
 
-      if Count >= Length (Container) then
-         Clear (Container);
-         return;
+      if Before > Container.Last
+        and then Before > Container.Last + 1
+      then
+         raise Constraint_Error;
       end if;
 
-      Index := Int'Base (Container.Last) - Int'Base (Count) + 1;
-
-      Delete (Container, Index_Type'Base (Index), Count);
-
-   end Delete_Last;
-
-
-   procedure Delete
-     (Container : in out Vector;
-      Index     : in     Extended_Index;  --  TODO: verify in Atlanta
-      Count     : in     Count_Type := 1) is
-
-   begin
-
-      if Count = 0 then
+      if N = 0 then
          return;
       end if;
 
-      declare
-
-         subtype I_Subtype is Index_Type'Base range
-           Index_Type'First .. Container.Last;
-
-         I : constant I_Subtype := Index;
-         I_As_Int : constant Int := Int (I);
-
-         Old_Last_As_Int : constant Int := Int (Container.Last);
-
-         Count1 : constant Int'Base := Int (Count);
-         Count2 : constant Int'Base := Old_Last_As_Int - I_As_Int + 1;
-
-         N : constant Int'Base := Int'Min (Count1, Count2);
+      Insert_Space (Container, Before, Count => N);
 
-         J_As_Int : constant Int'Base := I_As_Int + N;
-         J : constant Index_Type'Base := Index_Type'Base (J_As_Int);
+      if Container'Address = New_Item'Address then
+         declare
+            Dst_Last_As_Int : constant Int'Base :=
+                                Int'Base (Before) + Int'Base (N) - 1;
 
-         E : Elements_Type renames Container.Elements.all;
+            Dst_Last : constant Index_Type := Index_Type (Dst_Last_As_Int);
 
-         New_Last_As_Int : constant Int'Base := Old_Last_As_Int - N;
+            Dst_Index : Index_Type'Base := Index_Type'Pred (Before);
 
-         New_Last : constant Extended_Index :=
-           Extended_Index (New_Last_As_Int);
+            Dst : Elements_Type renames
+                    Container.Elements (Before .. Dst_Last);
 
-      begin
+         begin
+            declare
+               subtype Src_Index_Subtype is Index_Type'Base range
+                 Index_Type'First .. Index_Type'Pred (Before);
 
-         for K in I .. Index_Type'Pred (J) loop
+               Src : Elements_Type renames
+                       Container.Elements (Src_Index_Subtype);
 
             begin
-               Free (E (K));
-            exception
-               when others =>
-                  E (K) := null;
-                  raise;
-            end;
-
-         end loop;
-
-         E (I .. New_Last) := E (J .. Container.Last);
-         Container.Last := New_Last;
-
-      end;
-
-   end Delete;
-
-
-   function Capacity (Container : Vector) return Count_Type is
-   begin
-      if Container.Elements = null then
-         return 0;
-      end if;
-
-      return Container.Elements'Length;
-   end Capacity;
-
-
-   procedure Reserve_Capacity (Container : in out Vector;
-                               Capacity  : in     Count_Type) is
-
-      N : constant Count_Type := Length (Container);
-
-   begin
-
-      if Capacity = 0 then
-
-         if N = 0 then
+               for Src_Index in Src'Range loop
+                  Dst_Index := Index_Type'Succ (Dst_Index);
 
-            declare
-               X : Elements_Access := Container.Elements;
-            begin
-               Container.Elements := null;
-               Free (X);
+                  if Src (Src_Index) /= null then
+                     Dst (Dst_Index) := new Element_Type'(Src (Src_Index).all);
+                  end if;
+               end loop;
             end;
 
-         elsif N < Container.Elements'Length then
-
             declare
-               subtype Array_Index_Subtype is Index_Type'Base range
-                 Index_Type'First .. Container.Last;
+               subtype Src_Index_Subtype is Index_Type'Base range
+                 Index_Type'Succ (Dst_Last) .. Container.Last;
 
                Src : Elements_Type renames
-                 Container.Elements (Array_Index_Subtype);
+                       Container.Elements (Src_Index_Subtype);
 
-               subtype Array_Subtype is
-                 Elements_Type (Array_Index_Subtype);
-
-               X : Elements_Access := Container.Elements;
             begin
-               Container.Elements := new Array_Subtype'(Src);
-               Free (X);
-            end;
-
-         end if;
+               for Src_Index in Src'Range loop
+                  Dst_Index := Index_Type'Succ (Dst_Index);
 
-         return;
+                  if Src (Src_Index) /= null then
+                     Dst (Dst_Index) := new Element_Type'(Src (Src_Index).all);
+                  end if;
+               end loop;
+            end;
+         end;
 
-      end if;
+      else
+         declare
+            Dst_Last_As_Int : constant Int'Base :=
+                                Int'Base (Before) + Int'Base (N) - 1;
 
-      if Container.Elements = null then
+            Dst_Last : constant Index_Type := Index_Type (Dst_Last_As_Int);
 
-         declare
-            Last_As_Int : constant Int'Base :=
-              Int (Index_Type'First) + Int (Capacity) - 1;
+            Dst_Index : Index_Type'Base := Index_Type'Pred (Before);
 
-            Last : constant Index_Type :=
-              Index_Type (Last_As_Int);
+            Src : Elements_Type renames
+                    New_Item.Elements (Index_Type'First .. New_Item.Last);
 
-            subtype Array_Subtype is
-              Elements_Type (Index_Type'First .. Last);
+            Dst : Elements_Type renames
+                    Container.Elements (Before .. Dst_Last);
          begin
-            Container.Elements := new Array_Subtype;
-         end;
+            for Src_Index in Src'Range loop
+               Dst_Index := Index_Type'Succ (Dst_Index);
 
-         return;
+               if Src (Src_Index) /= null then
+                  Dst (Dst_Index) := new Element_Type'(Src (Src_Index).all);
+               end if;
+            end loop;
+         end;
 
       end if;
+   end Insert;
 
-      if Capacity <= N then
-
-         if N < Container.Elements'Length then
-
-            declare
-               subtype Array_Index_Subtype is Index_Type'Base range
-                 Index_Type'First .. Container.Last;
-
-               Src : Elements_Type renames
-                 Container.Elements (Array_Index_Subtype);
-
-               subtype Array_Subtype is
-                 Elements_Type (Array_Index_Subtype);
-
-               X : Elements_Access := Container.Elements;
-            begin
-               Container.Elements := new Array_Subtype'(Src);
-               Free (X);
-            end;
-
-         end if;
-
-         return;
+   procedure Insert
+     (Container : in out Vector;
+      Before    : Cursor;
+      New_Item  : Vector)
+   is
+      Index : Index_Type'Base;
 
+   begin
+      if Before.Container /= null
+        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
+      then
+         raise Program_Error;
       end if;
 
-      if Capacity = Container.Elements'Length then
+      if Is_Empty (New_Item) then
          return;
       end if;
 
-      declare
-         Last_As_Int : constant Int'Base :=
-           Int (Index_Type'First) + Int (Capacity) - 1;
-
-         Last : constant Index_Type :=
-           Index_Type (Last_As_Int);
-
-         subtype Array_Subtype is
-           Elements_Type (Index_Type'First .. Last);
-
-         X : Elements_Access := Container.Elements;
-      begin
-         Container.Elements := new Array_Subtype;
-
-         declare
-            Src : Elements_Type renames
-              X (Index_Type'First .. Container.Last);
-
-            Tgt : Elements_Type renames
-              Container.Elements (Index_Type'First .. Container.Last);
-         begin
-            Tgt := Src;
-         end;
-
-         Free (X);
-      end;
-
-   end Reserve_Capacity;
-
-
-   function First_Index (Container : Vector) return Index_Type is
-      pragma Warnings (Off, Container);
-   begin
-      return Index_Type'First;
-   end First_Index;
-
-
-   function First_Element (Container : Vector) return Element_Type is
-   begin
-      return Element (Container, Index_Type'First);
-   end First_Element;
-
-
-   function Last_Index (Container : Vector) return Extended_Index is
-   begin
-      return Container.Last;
-   end Last_Index;
-
-
-   function Last_Element (Container : Vector) return Element_Type is
-   begin
-      return Element (Container, Container.Last);
-   end Last_Element;
-
-
-   function Element (Container : Vector;
-                     Index     : Index_Type)
-      return Element_Type is
-
-      subtype T is Index_Type'Base range
-        Index_Type'First .. Container.Last;
-   begin
-      return Container.Elements (T'(Index)).all;
-   end Element;
-
+      if Before.Container = null
+        or else Before.Index > Container.Last
+      then
+         Index := Index_Type'Succ (Container.Last);
+      else
+         Index := Before.Index;
+      end if;
 
-   procedure Replace_Element (Container : in Vector;
-                              Index     : in Index_Type;
-                              By        : in Element_Type) is
+      Insert (Container, Index, New_Item);
+   end Insert;
 
-      subtype T is Index_Type'Base range
-        Index_Type'First .. Container.Last;
+   procedure Insert
+     (Container : in out Vector;
+      Before    : Cursor;
+      New_Item  : Vector;
+      Position  : out Cursor)
+   is
+      Index : Index_Type'Base;
 
-      X : Element_Access := Container.Elements (T'(Index));
    begin
-      Container.Elements (T'(Index)) := new Element_Type'(By);
-      Free (X);
-   end Replace_Element;
-
-
-   procedure Generic_Sort (Container : in Vector) is
-
-      function Is_Less (L, R : Element_Access) return Boolean;
-      pragma Inline (Is_Less);
+      if Before.Container /= null
+        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
+      then
+         raise Program_Error;
+      end if;
 
-      function Is_Less (L, R : Element_Access) return Boolean is
-      begin
-         if L = null then
-            return R /= null;
-         elsif R = null then
-            return False;
+      if Is_Empty (New_Item) then
+         if Before.Container = null
+           or else Before.Index > Container.Last
+         then
+            Position := No_Element;
          else
-            return L.all < R.all;
+            Position := (Container'Unchecked_Access, Before.Index);
          end if;
-      end Is_Less;
-
-      procedure Sort is
-         new Generic_Array_Sort
-          (Index_Type,
-           Element_Access,
-           Elements_Type,
-           "<" => Is_Less);
 
-   begin
-
-      if Container.Elements = null then
          return;
       end if;
 
-      Sort (Container.Elements (Index_Type'First .. Container.Last));
-
-   end Generic_Sort;
-
-
-   function Find_Index
-     (Container : Vector;
-      Item      : Element_Type;
-      Index     : Index_Type := Index_Type'First)
-     return Extended_Index is
-
-   begin
-
-      for I in Index .. Container.Last loop
-         if Container.Elements (I) /= null
-           and then Container.Elements (I).all = Item
-         then
-            return I;
-         end if;
-      end loop;
-
-      return No_Index;
-
-   end Find_Index;
-
-
-   function Reverse_Find_Index
-     (Container : Vector;
-      Item      : Element_Type;
-      Index     : Index_Type := Index_Type'Last)
-     return Extended_Index is
-
-      Last : Index_Type'Base;
-
-   begin
-
-      if Index > Container.Last then
-         Last := Container.Last;
+      if Before.Container = null
+        or else Before.Index > Container.Last
+      then
+         Index := Index_Type'Succ (Container.Last);
       else
-         Last := Index;
+         Index := Before.Index;
       end if;
 
-      for I in reverse Index_Type'First .. Last loop
-         if Container.Elements (I) /= null
-           and then Container.Elements (I).all = Item
-         then
-            return I;
-         end if;
-      end loop;
-
-      return No_Index;
+      Insert (Container, Index, New_Item);
 
-   end Reverse_Find_Index;
+      Position := Cursor'(Container'Unchecked_Access, Index);
+   end Insert;
 
+   procedure Insert
+     (Container : in out Vector;
+      Before    : Cursor;
+      New_Item  : Element_Type;
+      Count     : Count_Type := 1)
+   is
+      Index : Index_Type'Base;
 
-   function Contains (Container : Vector;
-                      Item      : Element_Type) return Boolean is
    begin
-      return Find_Index (Container, Item) /= No_Index;
-   end Contains;
+      if Before.Container /= null
+        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
+      then
+         raise Program_Error;
+      end if;
 
+      if Count = 0 then
+         return;
+      end if;
 
+      if Before.Container = null
+        or else Before.Index > Container.Last
+      then
+         Index := Index_Type'Succ (Container.Last);
+      else
+         Index := Before.Index;
+      end if;
 
-   procedure Assign
-     (Target : in out Vector;
-      Source : in     Vector) is
+      Insert (Container, Index, New_Item, Count);
+   end Insert;
 
-      N : constant Count_Type := Length (Source);
+   procedure Insert
+     (Container : in out Vector;
+      Before    : Cursor;
+      New_Item  : Element_Type;
+      Position  : out Cursor;
+      Count     : Count_Type := 1)
+   is
+      Index : Index_Type'Base;
 
    begin
-
-      if Target'Address = Source'Address then
-         return;
+      if Before.Container /= null
+        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
+      then
+         raise Program_Error;
       end if;
 
-      Clear (Target);
+      if Count = 0 then
+         if Before.Container = null
+           or else Before.Index > Container.Last
+         then
+            Position := No_Element;
+         else
+            Position := (Container'Unchecked_Access, Before.Index);
+         end if;
 
-      if N = 0 then
          return;
       end if;
 
-      if N > Capacity (Target) then
-         Reserve_Capacity (Target, Capacity => N);
+      if Before.Container = null
+        or else Before.Index > Container.Last
+      then
+         Index := Index_Type'Succ (Container.Last);
+      else
+         Index := Before.Index;
       end if;
 
-      for I in Index_Type'First .. Source.Last loop
-
-         declare
-            EA : constant Element_Access := Source.Elements (I);
-         begin
-            if EA /= null then
-               Target.Elements (I) := new Element_Type'(EA.all);
-            end if;
-         end;
+      Insert (Container, Index, New_Item, Count);
 
-         Target.Last := I;
+      Position := (Container'Unchecked_Access, Index);
+   end Insert;
 
-      end loop;
+   ------------------
+   -- Insert_Space --
+   ------------------
 
-   end Assign;
+   procedure Insert_Space
+     (Container : in out Vector;
+      Before    : Extended_Index;
+      Count     : Count_Type := 1)
+   is
+      N : constant Int := Int (Count);
 
+      New_Last_As_Int : Int'Base;
+      New_Last        : Index_Type;
 
-   procedure Move
-     (Target : in out Vector;
-      Source : in out Vector) is
+      Index : Extended_Index;  --  TODO: see a-convec.adb.
 
-      X : Elements_Access := Target.Elements;
+      Dst_Last : Index_Type;
+      Dst      : Elements_Access;
 
    begin
-
-      if Target'Address = Source'Address then
-         return;
+      if Before < Index_Type'First then
+         raise Constraint_Error;
       end if;
 
-      if Target.Last >= Index_Type'First then
+      if Before > Container.Last
+        and then Before > Container.Last + 1
+      then
          raise Constraint_Error;
       end if;
 
-      Target.Elements := null;
-      Free (X);  --  shouldn't fail
-
-      Target.Elements := Source.Elements;
-      Target.Last := Source.Last;
-
-      Source.Elements := null;
-      Source.Last := Index_Type'Pred (Index_Type'First);
-
-   end Move;
-
-
-   procedure Query_Element
-     (Container : in Vector;
-      Index     : in Index_Type;
-      Process   : not null access procedure (Element : in Element_Type)) is
-
-      subtype T is Index_Type'Base range
-        Index_Type'First .. Container.Last;
-   begin
-      Process (Container.Elements (T'(Index)).all);
-   end Query_Element;
-
-
-   procedure Update_Element
-     (Container : in Vector;
-      Index     : in Index_Type;
-      Process   : not null access procedure (Element : in out Element_Type)) is
-
-      subtype T is Index_Type'Base range
-        Index_Type'First .. Container.Last;
-   begin
-      Process (Container.Elements (T'(Index)).all);
-   end Update_Element;
-
-
-   procedure Prepend (Container : in out Vector;
-                      New_Item  : in     Element_Type;
-                      Count     : in     Count_Type := 1) is
-   begin
-      Insert (Container,
-              Index_Type'First,
-              New_Item,
-              Count);
-   end Prepend;
-
-
-   procedure Swap
-     (Container : in Vector;
-      I, J      : in Index_Type) is
-
-      subtype T is Index_Type'Base range
-        Index_Type'First .. Container.Last;
-
-      EI : constant Element_Access := Container.Elements (T'(I));
-
-   begin
-
-      Container.Elements (T'(I)) := Container.Elements (T'(J));
-      Container.Elements (T'(J)) := EI;
-
-   end Swap;
+      if Count = 0 then
+         return;
+      end if;
 
+      declare
+         Old_Last_As_Int : constant Int := Int (Container.Last);
 
-   function "&" (Left, Right : Vector) return Vector is
+      begin
+         New_Last_As_Int := Old_Last_As_Int + N;
+         New_Last := Index_Type (New_Last_As_Int);
+      end;
 
-      LN : constant Count_Type := Length (Left);
-      RN : constant Count_Type := Length (Right);
+      if Container.Busy > 0 then
+         raise Program_Error;
+      end if;
 
-   begin
+      declare
+         Old_First_As_Int : constant Int := Int (Before);
 
-      if LN = 0 then
+         New_First_As_Int : constant Int'Base := Old_First_As_Int + N;
 
-         if RN = 0 then
-            return Empty_Vector;
-         end if;
+      begin
+         Index := Extended_Index (New_First_As_Int);  --  TODO
+      end;
 
+      if Container.Elements = null then
          declare
-            RE : Elements_Type renames
-              Right.Elements (Index_Type'First .. Right.Last);
-
-            Elements : Elements_Access :=
-              new Elements_Type (RE'Range);
+            subtype Elements_Subtype is
+              Elements_Type (Index_Type'First .. New_Last);
          begin
-            for I in Elements'Range loop
-               begin
-                  if RE (I) /= null then
-                     Elements (I) := new Element_Type'(RE (I).all);
-                  end if;
-               exception
-                  when others =>
-                     for J in Index_Type'First .. Index_Type'Pred (I) loop
-                        Free (Elements (J));
-                     end loop;
-
-                     Free (Elements);
-                     raise;
-               end;
-            end loop;
-
-            return (Controlled with Elements, Right.Last);
+            Container.Elements := new Elements_Subtype;
+            Container.Last := New_Last;
          end;
 
+         return;
       end if;
 
-      if RN = 0 then
-
+      if New_Last <= Container.Elements'Last then
          declare
-            LE : Elements_Type renames
-              Left.Elements (Index_Type'First .. Left.Last);
-
-            Elements : Elements_Access :=
-              new Elements_Type (LE'Range);
+            E : Elements_Type renames Container.Elements.all;
          begin
-            for I in Elements'Range loop
-               begin
-                  if LE (I) /= null then
-                     Elements (I) := new Element_Type'(LE (I).all);
-                  end if;
-               exception
-                  when others =>
-                     for J in Index_Type'First .. Index_Type'Pred (I) loop
-                        Free (Elements (J));
-                     end loop;
-
-                     Free (Elements);
-                     raise;
-               end;
-            end loop;
+            E (Index .. New_Last) := E (Before .. Container.Last);
+            E (Before .. Index_Type'Pred (Index)) := (others => null);
 
-            return (Controlled with Elements, Left.Last);
+            Container.Last := New_Last;
          end;
 
+         return;
       end if;
 
       declare
+         First : constant Int := Int (Index_Type'First);
 
-         Last_As_Int : constant Int'Base :=
-            Int (Index_Type'First) + Int (LN) + Int (RN) - 1;
-
-         Last : constant Index_Type := Index_Type (Last_As_Int);
-
-         LE : Elements_Type renames
-           Left.Elements (Index_Type'First .. Left.Last);
-
-         RE : Elements_Type renames
-           Right.Elements (Index_Type'First .. Right.Last);
+         New_Size : constant Int'Base :=
+                      Int (New_Last_As_Int) - First + 1;
 
-         Elements : Elements_Access :=
-           new Elements_Type (Index_Type'First .. Last);
+         Max_Size : constant Int'Base :=
+                      Int (Index_Type'Last) - First + 1;
 
-         I : Index_Type'Base := Index_Type'Pred (Index_Type'First);
+         Size, Dst_Last_As_Int : Int'Base;
 
       begin
+         if New_Size >= Max_Size / 2 then
+            Dst_Last := Index_Type'Last;
 
-         for LI in LE'Range loop
-
-            I := Index_Type'Succ (I);
-
-            begin
-               if LE (LI) /= null then
-                  Elements (I) := new Element_Type'(LE (LI).all);
-               end if;
-            exception
-               when others =>
-                  for J in Index_Type'First .. Index_Type'Pred (I) loop
-                     Free (Elements (J));
-                  end loop;
-
-                  Free (Elements);
-                  raise;
-            end;
-
-         end loop;
-
-         for RI in RE'Range loop
-
-            I := Index_Type'Succ (I);
-
-            begin
-               if RE (RI) /= null then
-                  Elements (I) := new Element_Type'(RE (RI).all);
-               end if;
-            exception
-               when others =>
-                  for J in Index_Type'First .. Index_Type'Pred (I) loop
-                     Free (Elements (J));
-                  end loop;
+         else
+            Size := Container.Elements'Length;
 
-                  Free (Elements);
-                  raise;
-            end;
+            if Size = 0 then
+               Size := 1;
+            end if;
 
-         end loop;
+            while Size < New_Size loop
+               Size := 2 * Size;
+            end loop;
 
-         return (Controlled with Elements, Last);
+            Dst_Last_As_Int := First + Size - 1;
+            Dst_Last := Index_Type (Dst_Last_As_Int);
+         end if;
       end;
 
-   end "&";
-
-
-   function "&" (Left  : Vector;
-                 Right : Element_Type) return Vector is
-
-      LN : constant Count_Type := Length (Left);
-
-   begin
-
-      if LN = 0 then
-
-         declare
-            Elements : Elements_Access :=
-              new Elements_Type (Index_Type'First .. Index_Type'First);
-         begin
-
-            begin
-               Elements (Elements'First) := new Element_Type'(Right);
-            exception
-               when others =>
-                  Free (Elements);
-                  raise;
-            end;
-
-            return (Controlled with Elements, Index_Type'First);
-
-         end;
-
-      end if;
+      Dst := new Elements_Type (Index_Type'First .. Dst_Last);
 
       declare
-
-         Last_As_Int : constant Int'Base :=
-            Int (Index_Type'First) + Int (LN);
-
-         Last : constant Index_Type := Index_Type (Last_As_Int);
-
-         LE : Elements_Type renames
-           Left.Elements (Index_Type'First .. Left.Last);
-
-         Elements : Elements_Access :=
-           new Elements_Type (Index_Type'First .. Last);
+         Src : Elements_Type renames Container.Elements.all;
 
       begin
+         Dst (Index_Type'First .. Index_Type'Pred (Before)) :=
+           Src (Index_Type'First .. Index_Type'Pred (Before));
 
-         for I in LE'Range loop
-
-            begin
-               if LE (I) /= null then
-                  Elements (I) := new Element_Type'(LE (I).all);
-               end if;
-            exception
-               when others =>
-                  for J in Index_Type'First .. Index_Type'Pred (I) loop
-                     Free (Elements (J));
-                  end loop;
-
-                  Free (Elements);
-                  raise;
-            end;
-
-         end loop;
-
-         begin
-            Elements (Elements'Last) := new Element_Type'(Right);
-         exception
-            when others =>
-
-               declare
-                  subtype J_Subtype is Index_Type'Base range
-                    Index_Type'First .. Index_Type'Pred (Elements'Last);
-               begin
-                  for J in J_Subtype loop
-                     Free (Elements (J));
-                  end loop;
-               end;
-
-               Free (Elements);
-               raise;
-         end;
-
-         return (Controlled with Elements, Last);
+         Dst (Index .. New_Last) := Src (Before .. Container.Last);
       end;
 
-   end "&";
-
-
-
-   function "&" (Left  : Element_Type;
-                 Right : Vector) return Vector is
-
-      RN : constant Count_Type := Length (Right);
-
-   begin
-
-      if RN = 0 then
-
-         declare
-            Elements : Elements_Access :=
-              new Elements_Type (Index_Type'First .. Index_Type'First);
-         begin
-
-            begin
-               Elements (Elements'First) := new Element_Type'(Left);
-            exception
-               when others =>
-                  Free (Elements);
-                  raise;
-            end;
-
-            return (Controlled with Elements, Index_Type'First);
-
-         end;
-
-      end if;
-
       declare
-
-         Last_As_Int : constant Int'Base :=
-            Int (Index_Type'First) + Int (RN);
-
-         Last : constant Index_Type := Index_Type (Last_As_Int);
-
-         RE : Elements_Type renames
-           Right.Elements (Index_Type'First .. Right.Last);
-
-         Elements : Elements_Access :=
-           new Elements_Type (Index_Type'First .. Last);
-
-         I : Index_Type'Base := Index_Type'First;
-
+         X : Elements_Access := Container.Elements;
       begin
+         Container.Elements := Dst;
+         Container.Last := New_Last;
 
-         begin
-            Elements (I) := new Element_Type'(Left);
-         exception
-            when others =>
-               Free (Elements);
-               raise;
-         end;
+         Free (X);
+      end;
+   end Insert_Space;
 
-         for RI in RE'Range loop
+   procedure Insert_Space
+     (Container : in out Vector;
+      Before    : Cursor;
+      Position  : out Cursor;
+      Count     : Count_Type := 1)
+   is
+      Index : Index_Type'Base;
 
-            I := Index_Type'Succ (I);
+   begin
+      if Before.Container /= null
+        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
+      then
+         raise Program_Error;
+      end if;
 
-            begin
-               if RE (RI) /= null then
-                  Elements (I) := new Element_Type'(RE (RI).all);
-               end if;
-            exception
-               when others =>
-                  for J in Index_Type'First .. Index_Type'Pred (I) loop
-                     Free (Elements (J));
-                  end loop;
+      if Count = 0 then
+         if Before.Container = null
+           or else Before.Index > Container.Last
+         then
+            Position := No_Element;
+         else
+            Position := (Container'Unchecked_Access, Before.Index);
+         end if;
 
-                  Free (Elements);
-                  raise;
-            end;
+         return;
+      end if;
 
-         end loop;
+      if Before.Container = null
+        or else Before.Index > Container.Last
+      then
+         Index := Index_Type'Succ (Container.Last);
+      else
+         Index := Before.Index;
+      end if;
 
-         return (Controlled with Elements, Last);
-      end;
+      Insert_Space (Container, Index, Count);
 
-   end "&";
+      Position := Cursor'(Container'Unchecked_Access, Index);
+   end Insert_Space;
 
+   --------------
+   -- Is_Empty --
+   --------------
 
-   function "&" (Left, Right  : Element_Type) return Vector is
+   function Is_Empty (Container : Vector) return Boolean is
+   begin
+      return Container.Last < Index_Type'First;
+   end Is_Empty;
 
-      subtype IT is Index_Type'Base range
-        Index_Type'First .. Index_Type'Succ (Index_Type'First);
+   -------------
+   -- Iterate --
+   -------------
 
-      Elements : Elements_Access := new Elements_Type (IT);
+   procedure Iterate
+     (Container : Vector;
+      Process   : not null access procedure (Position : in Cursor))
+   is
+      V : Vector renames Container'Unrestricted_Access.all;
+      B : Natural renames V.Busy;
 
    begin
+      B := B + 1;
 
       begin
-         Elements (Elements'First) := new Element_Type'(Left);
-      exception
-         when others =>
-            Free (Elements);
-            raise;
-      end;
-
-      begin
-         Elements (Elements'Last) := new Element_Type'(Right);
+         for Indx in Index_Type'First .. Container.Last loop
+            Process (Cursor'(Container'Unchecked_Access, Indx));
+         end loop;
       exception
          when others =>
-            Free (Elements (Elements'First));
-            Free (Elements);
+            B := B - 1;
             raise;
       end;
 
-      return (Controlled with Elements, Elements'Last);
-
-   end "&";
+      B := B - 1;
+   end Iterate;
 
+   ----------
+   -- Last --
+   ----------
 
-   function To_Cursor (Container : Vector;
-                       Index     : Extended_Index)
-      return Cursor is
+   function Last (Container : Vector) return Cursor is
    begin
-      if Index not in Index_Type'First .. Container.Last then
+      if Is_Empty (Container) then
          return No_Element;
       end if;
 
-      return Cursor'(Container'Unchecked_Access, Index);
-   end To_Cursor;
+      return (Container'Unchecked_Access, Container.Last);
+   end Last;
 
+   ------------------
+   -- Last_Element --
+   ------------------
 
-   function To_Index (Position : Cursor) return Extended_Index is
+   function Last_Element (Container : Vector) return Element_Type is
    begin
-      if Position.Container = null then
-         return No_Index;
-      end if;
+      return Element (Container, Container.Last);
+   end Last_Element;
 
-      if Position.Index <= Position.Container.Last then
-         return Position.Index;
-      end if;
+   ----------------
+   -- Last_Index --
+   ----------------
 
-      return No_Index;
-   end To_Index;
+   function Last_Index (Container : Vector) return Extended_Index is
+   begin
+      return Container.Last;
+   end Last_Index;
 
+   ------------
+   -- Length --
+   ------------
 
-   function Element (Position : Cursor) return Element_Type is
+   function Length (Container : Vector) return Count_Type is
+      L : constant Int := Int (Container.Last);
+      F : constant Int := Int (Index_Type'First);
+      N : constant Int'Base := L - F + 1;
    begin
-      return Element (Position.Container.all, Position.Index);
-   end Element;
+      return Count_Type (N);
+   end Length;
 
+   ----------
+   -- Move --
+   ----------
 
-   function Next (Position : Cursor) return Cursor is
+   procedure Move
+     (Target : in out Vector;
+      Source : in out Vector)
+   is
    begin
-
-      if Position.Container = null then
-         return No_Element;
+      if Target'Address = Source'Address then
+         return;
       end if;
 
-      if Position.Index < Position.Container.Last then
-         return (Position.Container, Index_Type'Succ (Position.Index));
+      if Source.Busy > 0 then
+         raise Program_Error;
       end if;
 
-      return No_Element;
+      Clear (Target);
 
-   end Next;
+      declare
+         X : Elements_Access := Target.Elements;
+      begin
+         Target.Elements := null;
+         Free (X);
+      end;
 
+      Target.Elements := Source.Elements;
+      Target.Last := Source.Last;
 
-   function Previous (Position : Cursor) return Cursor is
-   begin
+      Source.Elements := null;
+      Source.Last := No_Index;
+   end Move;
 
+   ----------
+   -- Next --
+   ----------
+
+   function Next (Position : Cursor) return Cursor is
+   begin
       if Position.Container = null then
          return No_Element;
       end if;
 
-      if Position.Index > Index_Type'First then
-         return (Position.Container, Index_Type'Pred (Position.Index));
+      if Position.Index < Position.Container.Last then
+         return (Position.Container, Index_Type'Succ (Position.Index));
       end if;
 
       return No_Element;
+   end Next;
 
-   end Previous;
-
+   ----------
+   -- Next --
+   ----------
 
    procedure Next (Position : in out Cursor) is
    begin
-
       if Position.Container = null then
          return;
       end if;
@@ -1615,13 +1689,35 @@ package body Ada.Containers.Indefinite_Vectors is
       else
          Position := No_Element;
       end if;
-
    end Next;
 
+   -------------
+   -- Prepend --
+   -------------
 
-   procedure Previous (Position : in out Cursor) is
+   procedure Prepend (Container : in out Vector; New_Item : Vector) is
    begin
+      Insert (Container, Index_Type'First, New_Item);
+   end Prepend;
 
+   procedure Prepend
+     (Container : in out Vector;
+      New_Item  : Element_Type;
+      Count     : Count_Type := 1)
+   is
+   begin
+      Insert (Container,
+              Index_Type'First,
+              New_Item,
+              Count);
+   end Prepend;
+
+   --------------
+   -- Previous --
+   --------------
+
+   procedure Previous (Position : in out Cursor) is
+   begin
       if Position.Container = null then
          return;
       end if;
@@ -1631,541 +1727,618 @@ package body Ada.Containers.Indefinite_Vectors is
       else
          Position := No_Element;
       end if;
-
    end Previous;
 
-
-   function Has_Element (Position : Cursor) return Boolean is
+   function Previous (Position : Cursor) return Cursor is
    begin
-
       if Position.Container = null then
-         return False;
+         return No_Element;
       end if;
 
-      return Position.Index <= Position.Container.Last;
-
-   end Has_Element;
+      if Position.Index > Index_Type'First then
+         return (Position.Container, Index_Type'Pred (Position.Index));
+      end if;
 
+      return No_Element;
+   end Previous;
 
-   procedure Iterate
-     (Container : in Vector;
-      Process   : not null access procedure (Position : in Cursor)) is
-   begin
+   -------------------
+   -- Query_Element --
+   -------------------
 
-      for I in Index_Type'First .. Container.Last loop
-         Process (Cursor'(Container'Unchecked_Access, I));
-      end loop;
+   procedure Query_Element
+     (Container : Vector;
+      Index     : Index_Type;
+      Process   : not null access procedure (Element : in Element_Type))
+   is
+      subtype T is Index_Type'Base range
+        Index_Type'First .. Container.Last;
 
-   end Iterate;
+      E : Element_Type renames Container.Elements (T'(Index)).all;
 
+      V : Vector renames Container'Unrestricted_Access.all;
+      B : Natural renames V.Busy;
+      L : Natural renames V.Lock;
 
-   procedure Reverse_Iterate
-     (Container : in Vector;
-      Process   : not null access procedure (Position : in Cursor)) is
    begin
+      B := B + 1;
+      L := L + 1;
 
-      for I in reverse Index_Type'First .. Container.Last loop
-         Process (Cursor'(Container'Unchecked_Access, I));
-      end loop;
-
-   end Reverse_Iterate;
+      begin
+         Process (E);
+      exception
+         when others =>
+            L := L - 1;
+            B := B - 1;
+            raise;
+      end;
 
+      L := L - 1;
+      B := B - 1;
+   end Query_Element;
 
    procedure Query_Element
-     (Position : in Cursor;
-      Process  : not null access procedure (Element : in Element_Type)) is
-
-      C : Vector renames Position.Container.all;
-      E : Elements_Type renames C.Elements.all;
-
-      subtype T is Index_Type'Base range
-        Index_Type'First .. C.Last;
+     (Position : Cursor;
+      Process  : not null access procedure (Element : in Element_Type))
+   is
    begin
-      Process (E (T'(Position.Index)).all);
+      Query_Element (Position.Container.all, Position.Index, Process);
    end Query_Element;
 
+   ----------
+   -- Read --
+   ----------
 
-   procedure Update_Element
-     (Position : in Cursor;
-      Process  : not null access procedure (Element : in out Element_Type)) is
+   procedure Read
+     (Stream    : access Root_Stream_Type'Class;
+      Container : out Vector)
+   is
+      Length : Count_Type'Base;
+      Last   : Index_Type'Base := Index_Type'Pred (Index_Type'First);
 
-      C : Vector renames Position.Container.all;
-      E : Elements_Type renames C.Elements.all;
+      B : Boolean;
 
-      subtype T is Index_Type'Base range
-        Index_Type'First .. C.Last;
    begin
-      Process (E (T'(Position.Index)).all);
-   end Update_Element;
+      Clear (Container);
 
+      Count_Type'Base'Read (Stream, Length);
 
-   procedure Replace_Element (Position : in Cursor;
-                              By       : in Element_Type) is
+      if Length > Capacity (Container) then
+         Reserve_Capacity (Container, Capacity => Length);
+      end if;
 
-      C : Vector renames Position.Container.all;
-      E : Elements_Type renames C.Elements.all;
+      for J in Count_Type range 1 .. Length loop
+         Last := Index_Type'Succ (Last);
 
-      subtype T is Index_Type'Base range
-        Index_Type'First .. C.Last;
+         Boolean'Read (Stream, B);
 
-      X : Element_Access := E (T'(Position.Index));
-   begin
-      E (T'(Position.Index)) := new Element_Type'(By);
-      Free (X);
-   end Replace_Element;
+         if B then
+            Container.Elements (Last) :=
+              new Element_Type'(Element_Type'Input (Stream));
+         end if;
 
+         Container.Last := Last;
+      end loop;
+   end Read;
 
-   procedure Insert (Container : in out Vector;
-                     Before    : in     Extended_Index;
-                     New_Item  : in     Vector) is
+   ---------------------
+   -- Replace_Element --
+   ---------------------
 
-      N : constant Count_Type := Length (New_Item);
+   procedure Replace_Element
+     (Container : Vector;
+      Index     : Index_Type;
+      By        : Element_Type)
+   is
+      subtype T is Index_Type'Base range
+        Index_Type'First .. Container.Last;
 
-   begin
+      X : Element_Access := Container.Elements (T'(Index));
 
-      if N = 0 then
-         return;
+   begin
+      if Container.Lock > 0 then
+         raise Program_Error;
       end if;
 
-      Insert_Space (Container, Before, Count => N);
-
-      if Container'Address = New_Item'Address then
-
-         declare
-            Dst_Last_As_Int : constant Int'Base :=
-              Int'Base (Before) + Int'Base (N) - 1;
+      Container.Elements (T'(Index)) := new Element_Type'(By);
+      Free (X);
+   end Replace_Element;
 
-            Dst_Last : constant Index_Type := Index_Type (Dst_Last_As_Int);
+   procedure Replace_Element (Position : Cursor; By : Element_Type) is
+   begin
+      Replace_Element (Position.Container.all, Position.Index, By);
+   end Replace_Element;
 
-            Dst_Index : Index_Type'Base := Index_Type'Pred (Before);
+   ----------------------
+   -- Reserve_Capacity --
+   ----------------------
 
-            Dst : Elements_Type renames
-              Container.Elements (Before .. Dst_Last);
-         begin
+   procedure Reserve_Capacity
+     (Container : in out Vector;
+      Capacity  : Count_Type)
+   is
+      N : constant Count_Type := Length (Container);
 
+   begin
+      if Capacity = 0 then
+         if N = 0 then
             declare
-               subtype Src_Index_Subtype is Index_Type'Base range
-                 Index_Type'First .. Index_Type'Pred (Before);
-
-               Src : Elements_Type renames
-                 Container.Elements (Src_Index_Subtype);
+               X : Elements_Access := Container.Elements;
             begin
-               for Src_Index in Src'Range loop
-                  Dst_Index := Index_Type'Succ (Dst_Index);
-
-                  if Src (Src_Index) /= null then
-                     Dst (Dst_Index) := new Element_Type'(Src (Src_Index).all);
-                  end if;
-               end loop;
+               Container.Elements := null;
+               Free (X);
             end;
 
+         elsif N < Container.Elements'Length then
+            if Container.Busy > 0 then
+               raise Program_Error;
+            end if;
+
             declare
-               subtype Src_Index_Subtype is Index_Type'Base range
-                 Index_Type'Succ (Dst_Last) .. Container.Last;
+               subtype Array_Index_Subtype is Index_Type'Base range
+                 Index_Type'First .. Container.Last;
 
                Src : Elements_Type renames
-                 Container.Elements (Src_Index_Subtype);
-            begin
-               for Src_Index in Src'Range loop
-                  Dst_Index := Index_Type'Succ (Dst_Index);
+                       Container.Elements (Array_Index_Subtype);
 
-                  if Src (Src_Index) /= null then
-                     Dst (Dst_Index) := new Element_Type'(Src (Src_Index).all);
-                  end if;
-               end loop;
+               subtype Array_Subtype is
+                 Elements_Type (Array_Index_Subtype);
+
+               X : Elements_Access := Container.Elements;
+            begin
+               Container.Elements := new Array_Subtype'(Src);
+               Free (X);
             end;
 
-         end;
+         end if;
 
-      else
+         return;
+      end if;
 
+      if Container.Elements = null then
          declare
-            Dst_Last_As_Int : constant Int'Base :=
-              Int'Base (Before) + Int'Base (N) - 1;
-
-            Dst_Last : constant Index_Type := Index_Type (Dst_Last_As_Int);
+            Last_As_Int : constant Int'Base :=
+                            Int (Index_Type'First) + Int (Capacity) - 1;
 
-            Dst_Index : Index_Type'Base := Index_Type'Pred (Before);
+            Last : constant Index_Type :=
+                     Index_Type (Last_As_Int);
 
-            Src : Elements_Type renames
-              New_Item.Elements (Index_Type'First .. New_Item.Last);
+            subtype Array_Subtype is
+              Elements_Type (Index_Type'First .. Last);
 
-            Dst : Elements_Type renames
-              Container.Elements (Before .. Dst_Last);
          begin
-            for Src_Index in Src'Range loop
-               Dst_Index := Index_Type'Succ (Dst_Index);
-
-               if Src (Src_Index) /= null then
-                  Dst (Dst_Index) := new Element_Type'(Src (Src_Index).all);
-               end if;
-            end loop;
+            Container.Elements := new Array_Subtype;
          end;
 
+         return;
       end if;
 
-   end Insert;
+      if Capacity <= N then
+         if N < Container.Elements'Length then
+            if Container.Busy > 0 then
+               raise Program_Error;
+            end if;
 
+            declare
+               subtype Array_Index_Subtype is Index_Type'Base range
+                 Index_Type'First .. Container.Last;
 
-   procedure Insert (Container : in out Vector;
-                     Before    : in     Cursor;
-                     New_Item  : in     Vector) is
+               Src : Elements_Type renames
+                       Container.Elements (Array_Index_Subtype);
 
-      Index : Index_Type'Base;
+               subtype Array_Subtype is
+                 Elements_Type (Array_Index_Subtype);
 
-   begin
+               X : Elements_Access := Container.Elements;
 
-      if Before.Container /= null
-        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
-      then
-         raise Program_Error;
-      end if;
+            begin
+               Container.Elements := new Array_Subtype'(Src);
+               Free (X);
+            end;
+
+         end if;
 
-      if Is_Empty (New_Item) then
          return;
       end if;
 
-      if Before.Container = null
-        or else Before.Index > Container.Last
-      then
-         Index := Index_Type'Succ (Container.Last);
-      else
-         Index := Before.Index;
+      if Capacity = Container.Elements'Length then
+         return;
       end if;
 
-      Insert (Container, Index, New_Item);
-
-   end Insert;
-
-
-
-   procedure Insert (Container : in out Vector;
-                     Before    : in     Cursor;
-                     New_Item  : in     Vector;
-                     Position  :    out Cursor) is
-
-      Index : Index_Type'Base;
-
-   begin
-
-      if Before.Container /= null
-        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
-      then
+      if Container.Busy > 0 then
          raise Program_Error;
       end if;
 
-      if Is_Empty (New_Item) then
+      declare
+         Last_As_Int : constant Int'Base :=
+                         Int (Index_Type'First) + Int (Capacity) - 1;
 
-         if Before.Container = null
-           or else Before.Index > Container.Last
-         then
-            Position := No_Element;
-         else
-            Position := (Container'Unchecked_Access, Before.Index);
-         end if;
+         Last        : constant Index_Type := Index_Type (Last_As_Int);
 
-         return;
+         subtype Array_Subtype is
+           Elements_Type (Index_Type'First .. Last);
 
-      end if;
+         X : Elements_Access := Container.Elements;
 
-      if Before.Container = null
-        or else Before.Index > Container.Last
-      then
-         Index := Index_Type'Succ (Container.Last);
-      else
-         Index := Before.Index;
-      end if;
+      begin
+         Container.Elements := new Array_Subtype;
 
-      Insert (Container, Index, New_Item);
+         declare
+            Src : Elements_Type renames
+                    X (Index_Type'First .. Container.Last);
 
-      Position := (Container'Unchecked_Access, Index);
+            Tgt : Elements_Type renames
+                    Container.Elements (Index_Type'First .. Container.Last);
 
-   end Insert;
+         begin
+            Tgt := Src;
+         end;
 
+         Free (X);
+      end;
+   end Reserve_Capacity;
 
-   procedure Insert (Container : in out Vector;
-                     Before    : in     Cursor;
-                     New_Item  : in     Element_Type;
-                     Count     : in     Count_Type := 1) is
+   ------------------
+   -- Reverse_Find --
+   ------------------
 
-      Index : Index_Type'Base;
+   function Reverse_Find
+     (Container : Vector;
+      Item      : Element_Type;
+      Position  : Cursor := No_Element) return Cursor
+   is
+      Last : Index_Type'Base;
 
    begin
-
-      if Before.Container /= null
-        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
+      if Position.Container /= null
+        and then Position.Container /=
+                   Vector_Access'(Container'Unchecked_Access)
       then
          raise Program_Error;
       end if;
 
-      if Count = 0 then
-         return;
-      end if;
-
-      if Before.Container = null
-        or else Before.Index > Container.Last
+      if Position.Container = null
+        or else Position.Index > Container.Last
       then
-         Index := Index_Type'Succ (Container.Last);
+         Last := Container.Last;
       else
-         Index := Before.Index;
+         Last := Position.Index;
       end if;
 
-      Insert (Container, Index, New_Item, Count);
-
-   end Insert;
+      for Indx in reverse Index_Type'First .. Last loop
+         if Container.Elements (Indx) /= null
+           and then Container.Elements (Indx).all = Item
+         then
+            return (Container'Unchecked_Access, Indx);
+         end if;
+      end loop;
 
+      return No_Element;
+   end Reverse_Find;
 
-   procedure Insert (Container : in out Vector;
-                     Before    : in     Cursor;
-                     New_Item  : in     Element_Type;
-                     Position  :    out Cursor;
-                     Count     : in     Count_Type := 1) is
+   ------------------------
+   -- Reverse_Find_Index --
+   ------------------------
 
-      Index : Index_Type'Base;
+   function Reverse_Find_Index
+     (Container : Vector;
+      Item      : Element_Type;
+      Index     : Index_Type := Index_Type'Last) return Extended_Index
+   is
+      Last : Index_Type'Base;
 
    begin
-
-      if Before.Container /= null
-        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
-      then
-         raise Program_Error;
+      if Index > Container.Last then
+         Last := Container.Last;
+      else
+         Last := Index;
       end if;
 
-      if Count = 0 then
-
-         if Before.Container = null
-           or else Before.Index > Container.Last
+      for Indx in reverse Index_Type'First .. Last loop
+         if Container.Elements (Indx) /= null
+           and then Container.Elements (Indx).all = Item
          then
-            Position := No_Element;
-         else
-            Position := (Container'Unchecked_Access, Before.Index);
+            return Indx;
          end if;
+      end loop;
 
-         return;
-
-      end if;
-
-      if Before.Container = null
-        or else Before.Index > Container.Last
-      then
-         Index := Index_Type'Succ (Container.Last);
-      else
-         Index := Before.Index;
-      end if;
+      return No_Index;
+   end Reverse_Find_Index;
 
-      Insert (Container, Index, New_Item, Count);
+   ---------------------
+   -- Reverse_Iterate --
+   ---------------------
 
-      Position := (Container'Unchecked_Access, Index);
+   procedure Reverse_Iterate
+     (Container : Vector;
+      Process   : not null access procedure (Position : in Cursor))
+   is
+      V : Vector renames Container'Unrestricted_Access.all;
+      B : Natural renames V.Busy;
 
-   end Insert;
+   begin
+      B := B + 1;
 
+      begin
+         for Indx in reverse Index_Type'First .. Container.Last loop
+            Process (Cursor'(Container'Unchecked_Access, Indx));
+         end loop;
+      exception
+         when others =>
+            B := B - 1;
+            raise;
+      end;
 
+      B := B - 1;
+   end Reverse_Iterate;
 
-   procedure Prepend (Container : in out Vector;
-                      New_Item  : in     Vector) is
-   begin
-      Insert (Container, Index_Type'First, New_Item);
-   end Prepend;
+   ----------------
+   -- Set_Length --
+   ----------------
 
+   procedure Set_Length
+     (Container : in out Vector;
+      Length    : Count_Type)
+   is
+      N : constant Count_Type := Indefinite_Vectors.Length (Container);
 
-   procedure Append (Container : in out Vector;
-                     New_Item  : in     Vector) is
    begin
-      if Is_Empty (New_Item) then
+      if Length = N then
          return;
       end if;
 
-      Insert
-        (Container,
-         Index_Type'Succ (Container.Last),
-         New_Item);
-   end Append;
-
-
-
-   procedure Insert_Space (Container : in out Vector;
-                           Before    : in     Cursor;
-                           Position  :    out Cursor;
-                           Count     : in     Count_Type := 1) is
-
-      Index : Index_Type'Base;
-
-   begin
+      if Length = 0 then
+         Clear (Container);
+         return;
+      end if;
 
-      if Before.Container /= null
-        and then Before.Container /= Vector_Access'(Container'Unchecked_Access)
-      then
+      if Container.Busy > 0 then
          raise Program_Error;
       end if;
 
-      if Count = 0 then
+      declare
+         Last_As_Int : constant Int'Base :=
+                         Int (Index_Type'First) + Int (Length) - 1;
 
-         if Before.Container = null
-           or else Before.Index > Container.Last
-         then
-            Position := No_Element;
-         else
-            Position := (Container'Unchecked_Access, Before.Index);
-         end if;
+         Last        : constant Index_Type :=
+                         Index_Type (Last_As_Int);
 
-         return;
+      begin
+         if Length > N then
+            if Length > Capacity (Container) then
+               Reserve_Capacity (Container, Capacity => Length);
+            end if;
 
-      end if;
+            Container.Last := Last;
+            return;
+         end if;
 
-      if Before.Container = null
-        or else Before.Index > Container.Last
-      then
-         Index := Index_Type'Succ (Container.Last);
-      else
-         Index := Before.Index;
-      end if;
+         for Indx in reverse Index_Type'Succ (Last) .. Container.Last loop
+            declare
+               X : Element_Access := Container.Elements (Indx);
 
-      Insert_Space (Container, Index, Count);
+            begin
+               Container.Elements (Indx) := null;
+               Container.Last := Index_Type'Pred (Container.Last);
+               Free (X);
+            end;
+         end loop;
+      end;
+   end Set_Length;
 
-      Position := (Container'Unchecked_Access, Index);
+   ----------
+   -- Swap --
+   ----------
 
-   end Insert_Space;
+   procedure Swap
+     (Container : Vector;
+      I, J      : Index_Type)
+   is
+      subtype T is Index_Type'Base range
+        Index_Type'First .. Container.Last;
 
+      EI : Element_Type renames Container.Elements (T'(I)).all;
+      EJ : Element_Type renames Container.Elements (T'(J)).all;
 
-   procedure Delete (Container : in out Vector;
-                     Position  : in out Cursor;
-                     Count     : in     Count_Type := 1) is
    begin
-
-      if Position.Container /= null
-        and then Position.Container /=
-                   Vector_Access'(Container'Unchecked_Access)
-      then
+      if Container.Lock > 0 then
          raise Program_Error;
       end if;
 
-      if Position.Container = null
-        or else Position.Index > Container.Last
+      declare
+         EI_Copy : constant Element_Type := EI;
+      begin
+         EI := EJ;
+         EJ := EI_Copy;
+      end;
+   end Swap;
+
+   procedure Swap (I, J : Cursor)
+   is
+   begin
+      if I.Container = null
+        or else J.Container = null
       then
-         Position := No_Element;
-         return;
+         raise Constraint_Error;
       end if;
 
-      Delete (Container, Position.Index, Count);
-
-      if Position.Index <= Container.Last then
-         Position := (Container'Unchecked_Access, Position.Index);
-      else
-         Position := No_Element;
+      if I.Container /= J.Container then
+         raise Program_Error;
       end if;
 
-   end Delete;
+      Swap (I.Container.all, I.Index, J.Index);
+   end Swap;
 
+   ---------------
+   -- To_Cursor --
+   ---------------
 
-   function First (Container : Vector) return Cursor is
+   function To_Cursor
+     (Container : Vector;
+      Index     : Extended_Index) return Cursor
+   is
    begin
-      if Is_Empty (Container) then
+      if Index not in Index_Type'First .. Container.Last then
          return No_Element;
       end if;
 
-      return (Container'Unchecked_Access, Index_Type'First);
-   end First;
+      return Cursor'(Container'Unchecked_Access, Index);
+   end To_Cursor;
 
+   --------------
+   -- To_Index --
+   --------------
 
-   function Last (Container : Vector) return Cursor is
+   function To_Index (Position : Cursor) return Extended_Index is
    begin
-      if Is_Empty (Container) then
-         return No_Element;
+      if Position.Container = null then
+         return No_Index;
       end if;
 
-      return (Container'Unchecked_Access, Container.Last);
-   end Last;
+      if Position.Index <= Position.Container.Last then
+         return Position.Index;
+      end if;
 
+      return No_Index;
+   end To_Index;
 
-   procedure Swap (I, J : in Cursor) is
+   ---------------
+   -- To_Vector --
+   ---------------
 
-      --  NOTE: I've liberalized the behavior here, to
-      --  allow I and J to designate different containers.
-      --  TODO: I think this is suppose to raise P_E.
+   function To_Vector (Length : Count_Type) return Vector is
+   begin
+      if Length = 0 then
+         return Empty_Vector;
+      end if;
 
-      subtype TI is Index_Type'Base range
-        Index_Type'First .. I.Container.Last;
+      declare
+         First       : constant Int := Int (Index_Type'First);
+         Last_As_Int : constant Int'Base := First + Int (Length) - 1;
+         Last        : constant Index_Type := Index_Type (Last_As_Int);
+         Elements    : constant Elements_Access :=
+                         new Elements_Type (Index_Type'First .. Last);
+      begin
+         return (Controlled with Elements, Last, 0, 0);
+      end;
+   end To_Vector;
 
-      EI : Element_Access renames
-        I.Container.Elements (TI'(I.Index));
+   function To_Vector
+     (New_Item : Element_Type;
+      Length   : Count_Type) return Vector
+   is
+   begin
+      if Length = 0 then
+         return Empty_Vector;
+      end if;
 
-      EI_Copy : constant Element_Access := EI;
+      declare
+         First       : constant Int := Int (Index_Type'First);
+         Last_As_Int : constant Int'Base := First + Int (Length) - 1;
+         Last        : constant Index_Type := Index_Type (Last_As_Int);
+         Elements    : Elements_Access :=
+                         new Elements_Type (Index_Type'First .. Last);
+      begin
+         for Indx in Elements'Range loop
+            begin
+               Elements (Indx) := new Element_Type'(New_Item);
+            exception
+               when others =>
+                  for J in Index_Type'First .. Index_Type'Pred (Indx) loop
+                     Free (Elements (J));
+                  end loop;
 
-      subtype TJ is Index_Type'Base range
-        Index_Type'First .. J.Container.Last;
+                  Free (Elements);
+                  raise;
+            end;
 
-      EJ : Element_Access renames
-        J.Container.Elements (TJ'(J.Index));
+         end loop;
 
-   begin
+         return (Controlled with Elements, Last, 0, 0);
+      end;
+   end To_Vector;
 
-      EI := EJ;
-      EJ := EI_Copy;
+   --------------------
+   -- Update_Element --
+   --------------------
 
-   end Swap;
+   procedure Update_Element
+     (Container : Vector;
+      Index     : Index_Type;
+      Process   : not null access procedure (Element : in out Element_Type))
+   is
+      subtype T is Index_Type'Base range
+        Index_Type'First .. Container.Last;
 
+      E : Element_Type renames Container.Elements (T'(Index)).all;
 
-   function Find (Container : Vector;
-                  Item      : Element_Type;
-                  Position  : Cursor := No_Element) return Cursor is
+      V : Vector renames Container'Unrestricted_Access.all;
+      B : Natural renames V.Busy;
+      L : Natural renames V.Lock;
 
    begin
+      B := B + 1;
+      L := L + 1;
 
-      if Position.Container /= null
-        and then Position.Container /=
-                   Vector_Access'(Container'Unchecked_Access)
-      then
-         raise Program_Error;
-      end if;
-
-      for I in Position.Index .. Container.Last loop
-         if Container.Elements (I) /= null
-           and then Container.Elements (I).all = Item
-         then
-            return (Container'Unchecked_Access, I);
-         end if;
-      end loop;
-
-      return No_Element;
+      begin
+         Process (E);
+      exception
+         when others =>
+            L := L - 1;
+            B := B - 1;
+            raise;
+      end;
 
-   end Find;
+      L := L - 1;
+      B := B - 1;
+   end Update_Element;
 
+   procedure Update_Element
+     (Position : Cursor;
+      Process  : not null access procedure (Element : in out Element_Type))
+   is
+   begin
+      Update_Element (Position.Container.all, Position.Index, Process);
+   end Update_Element;
 
-   function Reverse_Find (Container : Vector;
-                          Item      : Element_Type;
-                          Position  : Cursor := No_Element) return Cursor is
+   -----------
+   -- Write --
+   -----------
 
-      Last : Index_Type'Base;
+   procedure Write
+     (Stream    : access Root_Stream_Type'Class;
+      Container : Vector)
+   is
+      N : constant Count_Type := Length (Container);
 
    begin
+      Count_Type'Base'Write (Stream, N);
 
-      if Position.Container /= null
-        and then Position.Container /=
-                   Vector_Access'(Container'Unchecked_Access)
-      then
-         raise Program_Error;
-      end if;
-
-      if Position.Container = null
-        or else Position.Index > Container.Last
-      then
-         Last := Container.Last;
-      else
-         Last := Position.Index;
+      if N = 0 then
+         return;
       end if;
 
-      for I in reverse Index_Type'First .. Last loop
-         if Container.Elements (I) /= null
-           and then Container.Elements (I).all = Item
-         then
-            return (Container'Unchecked_Access, I);
-         end if;
-      end loop;
+      declare
+         E : Elements_Type renames Container.Elements.all;
 
-      return No_Element;
+      begin
+         for Indx in Index_Type'First .. Container.Last loop
 
-   end Reverse_Find;
+            --  There's another way to do this.  Instead a separate
+            --  Boolean for each element, you could write a Boolean
+            --  followed by a count of how many nulls or non-nulls
+            --  follow in the array.  Alternately you could use a
+            --  signed integer, and use the sign as the indicator
+            --  of null-ness.
 
+            if E (Indx) = null then
+               Boolean'Write (Stream, False);
+            else
+               Boolean'Write (Stream, True);
+               Element_Type'Output (Stream, E (Indx).all);
+            end if;
+         end loop;
+      end;
+   end Write;
 
 end Ada.Containers.Indefinite_Vectors;
-