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+------------------------------------------------------------------------------
+-- --
+-- GNAT LIBRARY COMPONENTS --
+-- --
+-- A D A . C O N T A I N E R S . B O U N D E D _ V E C T O R S --
+-- --
+-- B o d y --
+-- --
+-- Copyright (C) 2004-2012, Free Software Foundation, Inc. --
+-- --
+-- GNAT is free software; you can redistribute it and/or modify it under --
+-- terms of the GNU General Public License as published by the Free Soft- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
+-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
+-- --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
+-- --
+-- This unit was originally developed by Matthew J Heaney. --
+------------------------------------------------------------------------------
+
+with Ada.Containers.Generic_Array_Sort;
+with Ada.Finalization; use Ada.Finalization;
+
+with System; use type System.Address;
+
+package body Ada.Containers.Bounded_Vectors is
+
+ type Iterator is new Limited_Controlled and
+ Vector_Iterator_Interfaces.Reversible_Iterator with
+ record
+ Container : Vector_Access;
+ Index : Index_Type'Base;
+ end record;
+
+ overriding procedure Finalize (Object : in out Iterator);
+
+ overriding function First (Object : Iterator) return Cursor;
+ overriding function Last (Object : Iterator) return Cursor;
+
+ overriding function Next
+ (Object : Iterator;
+ Position : Cursor) return Cursor;
+
+ overriding function Previous
+ (Object : Iterator;
+ Position : Cursor) return Cursor;
+
+ -----------------------
+ -- Local Subprograms --
+ -----------------------
+
+ function To_Array_Index (Index : Index_Type'Base) return Count_Type'Base;
+
+ ---------
+ -- "&" --
+ ---------
+
+ function "&" (Left, Right : Vector) return Vector is
+ LN : constant Count_Type := Length (Left);
+ RN : constant Count_Type := Length (Right);
+ N : Count_Type'Base; -- length of result
+ J : Count_Type'Base; -- for computing intermediate index values
+ Last : Index_Type'Base; -- Last index of result
+
+ begin
+ -- We decide that the capacity of the result is the sum of the lengths
+ -- of the vector parameters. We could decide to make it larger, but we
+ -- have no basis for knowing how much larger, so we just allocate the
+ -- minimum amount of storage.
+
+ -- Here we handle the easy cases first, when one of the vector
+ -- parameters is empty. (We say "easy" because there's nothing to
+ -- compute, that can potentially overflow.)
+
+ if LN = 0 then
+ if RN = 0 then
+ return Empty_Vector;
+ end if;
+
+ return Vector'(Capacity => RN,
+ Elements => Right.Elements (1 .. RN),
+ Last => Right.Last,
+ others => <>);
+ end if;
+
+ if RN = 0 then
+ return Vector'(Capacity => LN,
+ Elements => Left.Elements (1 .. LN),
+ Last => Left.Last,
+ others => <>);
+ end if;
+
+ -- Neither of the vector parameters is empty, so must compute the length
+ -- of the result vector and its last index. (This is the harder case,
+ -- because our computations must avoid overflow.)
+
+ -- There are two constraints we need to satisfy. The first constraint is
+ -- that a container cannot have more than Count_Type'Last elements, so
+ -- we must check the sum of the combined lengths. Note that we cannot
+ -- simply add the lengths, because of the possibility of overflow.
+
+ if LN > Count_Type'Last - RN then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ -- It is now safe compute the length of the new vector, without fear of
+ -- overflow.
+
+ N := LN + RN;
+
+ -- The second constraint is that the new Last index value cannot
+ -- exceed Index_Type'Last. We use the wider of Index_Type'Base and
+ -- Count_Type'Base as the type for intermediate values.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ -- We perform a two-part test. First we determine whether the
+ -- computed Last value lies in the base range of the type, and then
+ -- determine whether it lies in the range of the index (sub)type.
+
+ -- Last must satisfy this relation:
+ -- First + Length - 1 <= Last
+ -- We regroup terms:
+ -- First - 1 <= Last - Length
+ -- Which can rewrite as:
+ -- No_Index <= Last - Length
+
+ if Index_Type'Base'Last - Index_Type'Base (N) < No_Index then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ -- We now know that the computed value of Last is within the base
+ -- range of the type, so it is safe to compute its value:
+
+ Last := No_Index + Index_Type'Base (N);
+
+ -- Finally we test whether the value is within the range of the
+ -- generic actual index subtype:
+
+ if Last > Index_Type'Last then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ elsif Index_Type'First <= 0 then
+ -- Here we can compute Last directly, in the normal way. We know that
+ -- No_Index is less than 0, so there is no danger of overflow when
+ -- adding the (positive) value of length.
+
+ J := Count_Type'Base (No_Index) + N; -- Last
+
+ if J > Count_Type'Base (Index_Type'Last) then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ -- We know that the computed value (having type Count_Type) of Last
+ -- is within the range of the generic actual index subtype, so it is
+ -- safe to convert to Index_Type:
+
+ Last := Index_Type'Base (J);
+
+ else
+ -- Here Index_Type'First (and Index_Type'Last) is positive, so we
+ -- must test the length indirectly (by working backwards from the
+ -- largest possible value of Last), in order to prevent overflow.
+
+ J := Count_Type'Base (Index_Type'Last) - N; -- No_Index
+
+ if J < Count_Type'Base (No_Index) then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ -- We have determined that the result length would not create a Last
+ -- index value outside of the range of Index_Type, so we can now
+ -- safely compute its value.
+
+ Last := Index_Type'Base (Count_Type'Base (No_Index) + N);
+ end if;
+
+ declare
+ LE : Elements_Array renames Left.Elements (1 .. LN);
+ RE : Elements_Array renames Right.Elements (1 .. RN);
+
+ begin
+ return Vector'(Capacity => N,
+ Elements => LE & RE,
+ Last => Last,
+ others => <>);
+ end;
+ end "&";
+
+ function "&" (Left : Vector; Right : Element_Type) return Vector is
+ LN : constant Count_Type := Length (Left);
+
+ begin
+ -- We decide that the capacity of the result is the sum of the lengths
+ -- of the parameters. We could decide to make it larger, but we have no
+ -- basis for knowing how much larger, so we just allocate the minimum
+ -- amount of storage.
+
+ -- We must compute the length of the result vector and its last index,
+ -- but in such a way that overflow is avoided. We must satisfy two
+ -- constraints: the new length cannot exceed Count_Type'Last, and the
+ -- new Last index cannot exceed Index_Type'Last.
+
+ if LN = Count_Type'Last then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ if Left.Last >= Index_Type'Last then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ return Vector'(Capacity => LN + 1,
+ Elements => Left.Elements (1 .. LN) & Right,
+ Last => Left.Last + 1,
+ others => <>);
+ end "&";
+
+ function "&" (Left : Element_Type; Right : Vector) return Vector is
+ RN : constant Count_Type := Length (Right);
+
+ begin
+ -- We decide that the capacity of the result is the sum of the lengths
+ -- of the parameters. We could decide to make it larger, but we have no
+ -- basis for knowing how much larger, so we just allocate the minimum
+ -- amount of storage.
+
+ -- We compute the length of the result vector and its last index, but in
+ -- such a way that overflow is avoided. We must satisfy two constraints:
+ -- the new length cannot exceed Count_Type'Last, and the new Last index
+ -- cannot exceed Index_Type'Last.
+
+ if RN = Count_Type'Last then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ if Right.Last >= Index_Type'Last then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ return Vector'(Capacity => 1 + RN,
+ Elements => Left & Right.Elements (1 .. RN),
+ Last => Right.Last + 1,
+ others => <>);
+ end "&";
+
+ function "&" (Left, Right : Element_Type) return Vector is
+ begin
+ -- We decide that the capacity of the result is the sum of the lengths
+ -- of the parameters. We could decide to make it larger, but we have no
+ -- basis for knowing how much larger, so we just allocate the minimum
+ -- amount of storage.
+
+ -- We must compute the length of the result vector and its last index,
+ -- but in such a way that overflow is avoided. We must satisfy two
+ -- constraints: the new length cannot exceed Count_Type'Last (here, we
+ -- know that that condition is satisfied), and the new Last index cannot
+ -- exceed Index_Type'Last.
+
+ if Index_Type'First >= Index_Type'Last then
+ raise Constraint_Error with "new length is out of range";
+ end if;
+
+ return Vector'(Capacity => 2,
+ Elements => (Left, Right),
+ Last => Index_Type'First + 1,
+ others => <>);
+ end "&";
+
+ ---------
+ -- "=" --
+ ---------
+
+ overriding function "=" (Left, Right : Vector) return Boolean is
+ begin
+ if Left'Address = Right'Address then
+ return True;
+ end if;
+
+ if Left.Last /= Right.Last then
+ return False;
+ end if;
+
+ for J in Count_Type range 1 .. Left.Length loop
+ if Left.Elements (J) /= Right.Elements (J) then
+ return False;
+ end if;
+ end loop;
+
+ return True;
+ end "=";
+
+ ------------
+ -- Assign --
+ ------------
+
+ procedure Assign (Target : in out Vector; Source : Vector) is
+ begin
+ if Target'Address = Source'Address then
+ return;
+ end if;
+
+ if Target.Capacity < Source.Length then
+ raise Capacity_Error -- ???
+ with "Target capacity is less than Source length";
+ end if;
+
+ Target.Clear;
+
+ Target.Elements (1 .. Source.Length) :=
+ Source.Elements (1 .. Source.Length);
+
+ Target.Last := Source.Last;
+ end Assign;
+
+ ------------
+ -- Append --
+ ------------
+
+ procedure Append (Container : in out Vector; New_Item : Vector) is
+ begin
+ if New_Item.Is_Empty then
+ return;
+ end if;
+
+ if Container.Last >= Index_Type'Last then
+ raise Constraint_Error with "vector is already at its maximum length";
+ end if;
+
+ Container.Insert (Container.Last + 1, 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;
+
+ if Container.Last >= Index_Type'Last then
+ raise Constraint_Error with "vector is already at its maximum length";
+ end if;
+
+ Container.Insert (Container.Last + 1, New_Item, Count);
+ end Append;
+
+ --------------
+ -- Capacity --
+ --------------
+
+ function Capacity (Container : Vector) return Count_Type is
+ begin
+ return Container.Elements'Length;
+ end Capacity;
+
+ -----------
+ -- Clear --
+ -----------
+
+ procedure Clear (Container : in out Vector) is
+ begin
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ Container.Last := No_Index;
+ end Clear;
+
+ ------------------------
+ -- Constant_Reference --
+ ------------------------
+
+ function Constant_Reference
+ (Container : aliased Vector;
+ Position : Cursor) return Constant_Reference_Type
+ is
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ end if;
+
+ if Position.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ if Position.Index > Position.Container.Last then
+ raise Constraint_Error with "Position cursor is out of range";
+ end if;
+
+ declare
+ A : Elements_Array renames Container.Elements;
+ I : constant Count_Type := To_Array_Index (Position.Index);
+ begin
+ return (Element => A (I)'Access);
+ end;
+ end Constant_Reference;
+
+ function Constant_Reference
+ (Container : aliased Vector;
+ Index : Index_Type) return Constant_Reference_Type
+ is
+ begin
+ if Index > Container.Last then
+ raise Constraint_Error with "Index is out of range";
+ end if;
+
+ declare
+ A : Elements_Array renames Container.Elements;
+ I : constant Count_Type := To_Array_Index (Index);
+ begin
+ return (Element => A (I)'Access);
+ end;
+ end Constant_Reference;
+
+ --------------
+ -- Contains --
+ --------------
+
+ function Contains
+ (Container : Vector;
+ Item : Element_Type) return Boolean
+ is
+ begin
+ return Find_Index (Container, Item) /= No_Index;
+ end Contains;
+
+ ----------
+ -- Copy --
+ ----------
+
+ function Copy
+ (Source : Vector;
+ Capacity : Count_Type := 0) return Vector
+ is
+ C : Count_Type;
+
+ begin
+ if Capacity = 0 then
+ C := Source.Length;
+
+ elsif Capacity >= Source.Length then
+ C := Capacity;
+
+ else
+ raise Capacity_Error
+ with "Requested capacity is less than Source length";
+ end if;
+
+ return Target : Vector (C) do
+ Target.Elements (1 .. Source.Length) :=
+ Source.Elements (1 .. Source.Length);
+
+ Target.Last := Source.Last;
+ end return;
+ end Copy;
+
+ ------------
+ -- Delete --
+ ------------
+
+ procedure Delete
+ (Container : in out Vector;
+ Index : Extended_Index;
+ Count : Count_Type := 1)
+ is
+ Old_Last : constant Index_Type'Base := Container.Last;
+ Old_Len : constant Count_Type := Container.Length;
+ New_Last : Index_Type'Base;
+ Count2 : Count_Type'Base; -- count of items from Index to Old_Last
+ Off : Count_Type'Base; -- Index expressed as offset from IT'First
+
+ begin
+ -- Delete removes items from the vector, the number of which is the
+ -- minimum of the specified Count and the items (if any) that exist from
+ -- Index to Container.Last. There are no constraints on the specified
+ -- value of Count (it can be larger than what's available at this
+ -- position in the vector, for example), but there are constraints on
+ -- the allowed values of the Index.
+
+ -- As a precondition on the generic actual Index_Type, the base type
+ -- must include Index_Type'Pred (Index_Type'First); this is the value
+ -- that Container.Last assumes when the vector is empty. However, we do
+ -- not allow that as the value for Index when specifying which items
+ -- should be deleted, so we must manually check. (That the user is
+ -- allowed to specify the value at all here is a consequence of the
+ -- declaration of the Extended_Index subtype, which includes the values
+ -- in the base range that immediately precede and immediately follow the
+ -- values in the Index_Type.)
+
+ if Index < Index_Type'First then
+ raise Constraint_Error with "Index is out of range (too small)";
+ end if;
+
+ -- We do allow a value greater than Container.Last to be specified as
+ -- the Index, but only if it's immediately greater. This allows the
+ -- corner case of deleting no items from the back end of the vector to
+ -- be treated as a no-op. (It is assumed that specifying an index value
+ -- greater than Last + 1 indicates some deeper flaw in the caller's
+ -- algorithm, so that case is treated as a proper error.)
+
+ if Index > Old_Last then
+ if Index > Old_Last + 1 then
+ raise Constraint_Error with "Index is out of range (too large)";
+ end if;
+
+ return;
+ end if;
+
+ -- Here and elsewhere we treat deleting 0 items from the container as a
+ -- no-op, even when the container is busy, so we simply return.
+
+ if Count = 0 then
+ return;
+ end if;
+
+ -- The tampering bits exist to prevent an item from being deleted (or
+ -- otherwise harmfully manipulated) while it is being visited. Query,
+ -- Update, and Iterate increment the busy count on entry, and decrement
+ -- the count on exit. Delete checks the count to determine whether it is
+ -- being called while the associated callback procedure is executing.
+
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ -- We first calculate what's available for deletion starting at
+ -- Index. Here and elsewhere we use the wider of Index_Type'Base and
+ -- Count_Type'Base as the type for intermediate values. (See function
+ -- Length for more information.)
+
+ if Count_Type'Base'Last >= Index_Type'Pos (Index_Type'Base'Last) then
+ Count2 := Count_Type'Base (Old_Last) - Count_Type'Base (Index) + 1;
+
+ else
+ Count2 := Count_Type'Base (Old_Last - Index + 1);
+ end if;
+
+ -- If more elements are requested (Count) for deletion than are
+ -- available (Count2) for deletion beginning at Index, then everything
+ -- from Index is deleted. There are no elements to slide down, and so
+ -- all we need to do is set the value of Container.Last.
+
+ if Count >= Count2 then
+ Container.Last := Index - 1;
+ return;
+ end if;
+
+ -- There are some elements aren't being deleted (the requested count was
+ -- less than the available count), so we must slide them down to
+ -- Index. We first calculate the index values of the respective array
+ -- slices, using the wider of Index_Type'Base and Count_Type'Base as the
+ -- type for intermediate calculations.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ Off := Count_Type'Base (Index - Index_Type'First);
+ New_Last := Old_Last - Index_Type'Base (Count);
+
+ else
+ Off := Count_Type'Base (Index) - Count_Type'Base (Index_Type'First);
+ New_Last := Index_Type'Base (Count_Type'Base (Old_Last) - Count);
+ end if;
+
+ -- The array index values for each slice have already been determined,
+ -- so we just slide down to Index the elements that weren't deleted.
+
+ declare
+ EA : Elements_Array renames Container.Elements;
+ Idx : constant Count_Type := EA'First + Off;
+
+ begin
+ EA (Idx .. Old_Len - Count) := EA (Idx + Count .. Old_Len);
+ Container.Last := New_Last;
+ end;
+ end Delete;
+
+ procedure Delete
+ (Container : in out Vector;
+ Position : in out Cursor;
+ Count : Count_Type := 1)
+ is
+ pragma Warnings (Off, Position);
+
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ end if;
+
+ if Position.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ if Position.Index > Container.Last then
+ raise Program_Error with "Position index is out of range";
+ end if;
+
+ Delete (Container, Position.Index, Count);
+ Position := No_Element;
+ end Delete;
+
+ ------------------
+ -- Delete_First --
+ ------------------
+
+ procedure Delete_First
+ (Container : in out Vector;
+ Count : 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;
+
+ -----------------
+ -- Delete_Last --
+ -----------------
+
+ procedure Delete_Last
+ (Container : in out Vector;
+ Count : Count_Type := 1)
+ is
+ begin
+ -- It is not permitted to delete items while the container is busy (for
+ -- example, we're in the middle of a passive iteration). However, we
+ -- always treat deleting 0 items as a no-op, even when we're busy, so we
+ -- simply return without checking.
+
+ if Count = 0 then
+ return;
+ end if;
+
+ -- The tampering bits exist to prevent an item from being deleted (or
+ -- otherwise harmfully manipulated) while it is being visited. Query,
+ -- Update, and Iterate increment the busy count on entry, and decrement
+ -- the count on exit. Delete_Last checks the count to determine whether
+ -- it is being called while the associated callback procedure is
+ -- executing.
+
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ -- There is no restriction on how large Count can be when deleting
+ -- items. If it is equal or greater than the current length, then this
+ -- is equivalent to clearing the vector. (In particular, there's no need
+ -- for us to actually calculate the new value for Last.)
+
+ -- If the requested count is less than the current length, then we must
+ -- calculate the new value for Last. For the type we use the widest of
+ -- Index_Type'Base and Count_Type'Base for the intermediate values of
+ -- our calculation. (See the comments in Length for more information.)
+
+ if Count >= Container.Length then
+ Container.Last := No_Index;
+
+ elsif Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ Container.Last := Container.Last - Index_Type'Base (Count);
+
+ else
+ Container.Last :=
+ Index_Type'Base (Count_Type'Base (Container.Last) - Count);
+ end if;
+ end Delete_Last;
+
+ -------------
+ -- Element --
+ -------------
+
+ function Element
+ (Container : Vector;
+ Index : Index_Type) return Element_Type
+ is
+ begin
+ if Index > Container.Last then
+ raise Constraint_Error with "Index is out of range";
+ else
+ return Container.Elements (To_Array_Index (Index));
+ end if;
+ end Element;
+
+ function Element (Position : Cursor) return Element_Type is
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ else
+ return Position.Container.Element (Position.Index);
+ end if;
+ end Element;
+
+ --------------
+ -- Finalize --
+ --------------
+
+ procedure Finalize (Object : in out Iterator) is
+ B : Natural renames Object.Container.Busy;
+ begin
+ B := B - 1;
+ end Finalize;
+
+ ----------
+ -- Find --
+ ----------
+
+ function Find
+ (Container : Vector;
+ Item : Element_Type;
+ Position : Cursor := No_Element) return Cursor
+ is
+ begin
+ if Position.Container /= null then
+ if Position.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ if Position.Index > Container.Last then
+ raise Program_Error with "Position index is out of range";
+ end if;
+ end if;
+
+ for J in Position.Index .. Container.Last loop
+ if Container.Elements (To_Array_Index (J)) = Item then
+ return (Container'Unrestricted_Access, J);
+ end if;
+ end loop;
+
+ return No_Element;
+ end Find;
+
+ ----------------
+ -- Find_Index --
+ ----------------
+
+ 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 (To_Array_Index (Indx)) = Item then
+ return Indx;
+ end if;
+ end loop;
+
+ return No_Index;
+ end Find_Index;
+
+ -----------
+ -- First --
+ -----------
+
+ function First (Container : Vector) return Cursor is
+ begin
+ if Is_Empty (Container) then
+ return No_Element;
+ else
+ return (Container'Unrestricted_Access, Index_Type'First);
+ end if;
+ end First;
+
+ function First (Object : Iterator) return Cursor is
+ begin
+ -- The value of the iterator object's Index component influences the
+ -- behavior of the First (and Last) selector function.
+
+ -- When the Index component is No_Index, this means the iterator
+ -- object was constructed without a start expression, in which case the
+ -- (forward) iteration starts from the (logical) beginning of the entire
+ -- sequence of items (corresponding to Container.First, for a forward
+ -- iterator).
+
+ -- Otherwise, this is iteration over a partial sequence of items.
+ -- When the Index component isn't No_Index, the iterator object was
+ -- constructed with a start expression, that specifies the position
+ -- from which the (forward) partial iteration begins.
+
+ if Object.Index = No_Index then
+ return First (Object.Container.all);
+ else
+ return Cursor'(Object.Container, Object.Index);
+ end if;
+ end First;
+
+ -------------------
+ -- First_Element --
+ -------------------
+
+ function First_Element (Container : Vector) return Element_Type is
+ begin
+ if Container.Last = No_Index then
+ raise Constraint_Error with "Container is empty";
+ else
+ return Container.Elements (To_Array_Index (Index_Type'First));
+ end if;
+ 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
+
+ ---------------
+ -- Is_Sorted --
+ ---------------
+
+ function Is_Sorted (Container : Vector) return Boolean is
+ begin
+ if Container.Last <= Index_Type'First then
+ return True;
+ end if;
+
+ declare
+ EA : Elements_Array renames Container.Elements;
+ begin
+ for J in 1 .. Container.Length - 1 loop
+ if EA (J + 1) < EA (J) then
+ return False;
+ end if;
+ end loop;
+ end;
+
+ return True;
+ end Is_Sorted;
+
+ -----------
+ -- Merge --
+ -----------
+
+ procedure Merge (Target, Source : in out Vector) is
+ I, J : Count_Type;
+
+ begin
+
+ -- The semantics of Merge changed slightly per AI05-0021. It was
+ -- originally the case that if Target and Source denoted the same
+ -- container object, then the GNAT implementation of Merge did
+ -- nothing. However, it was argued that RM05 did not precisely
+ -- specify the semantics for this corner case. The decision of the
+ -- ARG was that if Target and Source denote the same non-empty
+ -- container object, then Program_Error is raised.
+
+ if Source.Is_Empty then
+ return;
+ end if;
+
+ if Target'Address = Source'Address then
+ raise Program_Error with
+ "Target and Source denote same non-empty container";
+ end if;
+
+ if Target.Is_Empty then
+ Move (Target => Target, Source => Source);
+ return;
+ end if;
+
+ if Source.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ I := Target.Length;
+ Target.Set_Length (I + Source.Length);
+
+ declare
+ TA : Elements_Array renames Target.Elements;
+ SA : Elements_Array renames Source.Elements;
+
+ begin
+ J := Target.Length;
+ while not Source.Is_Empty loop
+ pragma Assert (Source.Length <= 1
+ or else not (SA (Source.Length) <
+ SA (Source.Length - 1)));
+
+ if I = 0 then
+ TA (1 .. J) := SA (1 .. Source.Length);
+ Source.Last := No_Index;
+ return;
+ end if;
+
+ pragma Assert (I <= 1
+ or else not (TA (I) < TA (I - 1)));
+
+ if SA (Source.Length) < TA (I) then
+ TA (J) := TA (I);
+ I := I - 1;
+
+ else
+ TA (J) := SA (Source.Length);
+ Source.Last := Source.Last - 1;
+ end if;
+
+ J := J - 1;
+ end loop;
+ end;
+ end Merge;
+
+ ----------
+ -- Sort --
+ ----------
+
+ procedure Sort (Container : in out Vector) is
+ procedure Sort is
+ new Generic_Array_Sort
+ (Index_Type => Count_Type,
+ Element_Type => Element_Type,
+ Array_Type => Elements_Array,
+ "<" => "<");
+
+ begin
+ if Container.Last <= Index_Type'First then
+ return;
+ end if;
+
+ -- The exception behavior for the vector container must match that
+ -- for the list container, so we check for cursor tampering here
+ -- (which will catch more things) instead of for element tampering
+ -- (which will catch fewer things). It's true that the elements of
+ -- this vector container could be safely moved around while (say) an
+ -- iteration is taking place (iteration only increments the busy
+ -- counter), and so technically all we would need here is a test for
+ -- element tampering (indicated by the lock counter), that's simply
+ -- an artifact of our array-based implementation. Logically Sort
+ -- requires a check for cursor tampering.
+
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ Sort (Container.Elements (1 .. Container.Length));
+ end Sort;
+
+ end Generic_Sorting;
+
+ -----------------
+ -- Has_Element --
+ -----------------
+
+ function Has_Element (Position : Cursor) return Boolean is
+ begin
+ if Position.Container = null then
+ return False;
+ end if;
+
+ return Position.Index <= Position.Container.Last;
+ end Has_Element;
+
+ ------------
+ -- Insert --
+ ------------
+
+ procedure Insert
+ (Container : in out Vector;
+ Before : Extended_Index;
+ New_Item : Element_Type;
+ Count : Count_Type := 1)
+ is
+ EA : Elements_Array renames Container.Elements;
+ Old_Length : constant Count_Type := Container.Length;
+
+ Max_Length : Count_Type'Base; -- determined from range of Index_Type
+ New_Length : Count_Type'Base; -- sum of current length and Count
+
+ Index : Index_Type'Base; -- scratch for intermediate values
+ J : Count_Type'Base; -- scratch
+
+ begin
+ -- As a precondition on the generic actual Index_Type, the base type
+ -- must include Index_Type'Pred (Index_Type'First); this is the value
+ -- that Container.Last assumes when the vector is empty. However, we do
+ -- not allow that as the value for Index when specifying where the new
+ -- items should be inserted, so we must manually check. (That the user
+ -- is allowed to specify the value at all here is a consequence of the
+ -- declaration of the Extended_Index subtype, which includes the values
+ -- in the base range that immediately precede and immediately follow the
+ -- values in the Index_Type.)
+
+ if Before < Index_Type'First then
+ raise Constraint_Error with
+ "Before index is out of range (too small)";
+ end if;
+
+ -- We do allow a value greater than Container.Last to be specified as
+ -- the Index, but only if it's immediately greater. This allows for the
+ -- case of appending items to the back end of the vector. (It is assumed
+ -- that specifying an index value greater than Last + 1 indicates some
+ -- deeper flaw in the caller's algorithm, so that case is treated as a
+ -- proper error.)
+
+ if Before > Container.Last
+ and then Before > Container.Last + 1
+ then
+ raise Constraint_Error with
+ "Before index is out of range (too large)";
+ end if;
+
+ -- We treat inserting 0 items into the container as a no-op, even when
+ -- the container is busy, so we simply return.
+
+ if Count = 0 then
+ return;
+ end if;
+
+ -- There are two constraints we need to satisfy. The first constraint is
+ -- that a container cannot have more than Count_Type'Last elements, so
+ -- we must check the sum of the current length and the insertion
+ -- count. Note that we cannot simply add these values, because of the
+ -- possibility of overflow.
+
+ if Old_Length > Count_Type'Last - Count then
+ raise Constraint_Error with "Count is out of range";
+ end if;
+
+ -- It is now safe compute the length of the new vector, without fear of
+ -- overflow.
+
+ New_Length := Old_Length + Count;
+
+ -- The second constraint is that the new Last index value cannot exceed
+ -- Index_Type'Last. In each branch below, we calculate the maximum
+ -- length (computed from the range of values in Index_Type), and then
+ -- compare the new length to the maximum length. If the new length is
+ -- acceptable, then we compute the new last index from that.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ -- We have to handle the case when there might be more values in the
+ -- range of Index_Type than in the range of Count_Type.
+
+ if Index_Type'First <= 0 then
+ -- We know that No_Index (the same as Index_Type'First - 1) is
+ -- less than 0, so it is safe to compute the following sum without
+ -- fear of overflow.
+
+ Index := No_Index + Index_Type'Base (Count_Type'Last);
+
+ if Index <= Index_Type'Last then
+ -- We have determined that range of Index_Type has at least as
+ -- many values as in Count_Type, so Count_Type'Last is the
+ -- maximum number of items that are allowed.
+
+ Max_Length := Count_Type'Last;
+
+ else
+ -- The range of Index_Type has fewer values than in Count_Type,
+ -- so the maximum number of items is computed from the range of
+ -- the Index_Type.
+
+ Max_Length := Count_Type'Base (Index_Type'Last - No_Index);
+ end if;
+
+ else
+ -- No_Index is equal or greater than 0, so we can safely compute
+ -- the difference without fear of overflow (which we would have to
+ -- worry about if No_Index were less than 0, but that case is
+ -- handled above).
+
+ Max_Length := Count_Type'Base (Index_Type'Last - No_Index);
+ end if;
+
+ elsif Index_Type'First <= 0 then
+ -- We know that No_Index (the same as Index_Type'First - 1) is less
+ -- than 0, so it is safe to compute the following sum without fear of
+ -- overflow.
+
+ J := Count_Type'Base (No_Index) + Count_Type'Last;
+
+ if J <= Count_Type'Base (Index_Type'Last) then
+ -- We have determined that range of Index_Type has at least as
+ -- many values as in Count_Type, so Count_Type'Last is the maximum
+ -- number of items that are allowed.
+
+ Max_Length := Count_Type'Last;
+
+ else
+ -- The range of Index_Type has fewer values than Count_Type does,
+ -- so the maximum number of items is computed from the range of
+ -- the Index_Type.
+
+ Max_Length :=
+ Count_Type'Base (Index_Type'Last) - Count_Type'Base (No_Index);
+ end if;
+
+ else
+ -- No_Index is equal or greater than 0, so we can safely compute the
+ -- difference without fear of overflow (which we would have to worry
+ -- about if No_Index were less than 0, but that case is handled
+ -- above).
+
+ Max_Length :=
+ Count_Type'Base (Index_Type'Last) - Count_Type'Base (No_Index);
+ end if;
+
+ -- We have just computed the maximum length (number of items). We must
+ -- now compare the requested length to the maximum length, as we do not
+ -- allow a vector expand beyond the maximum (because that would create
+ -- an internal array with a last index value greater than
+ -- Index_Type'Last, with no way to index those elements).
+
+ if New_Length > Max_Length then
+ raise Constraint_Error with "Count is out of range";
+ end if;
+
+ -- The tampering bits exist to prevent an item from being harmfully
+ -- manipulated while it is being visited. Query, Update, and Iterate
+ -- increment the busy count on entry, and decrement the count on
+ -- exit. Insert checks the count to determine whether it is being called
+ -- while the associated callback procedure is executing.
+
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ if New_Length > Container.Capacity then
+ raise Capacity_Error with "New length is larger than capacity";
+ end if;
+
+ J := To_Array_Index (Before);
+
+ if Before > Container.Last then
+ -- The new items are being appended to the vector, so no
+ -- sliding of existing elements is required.
+
+ EA (J .. New_Length) := (others => New_Item);
+
+ else
+ -- The new items are being inserted before some existing
+ -- elements, so we must slide the existing elements up to their
+ -- new home.
+
+ EA (J + Count .. New_Length) := EA (J .. Old_Length);
+ EA (J .. J + Count - 1) := (others => New_Item);
+ end if;
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ Container.Last := No_Index + Index_Type'Base (New_Length);
+
+ else
+ Container.Last :=
+ Index_Type'Base (Count_Type'Base (No_Index) + New_Length);
+ end if;
+ end Insert;
+
+ procedure Insert
+ (Container : in out Vector;
+ Before : Extended_Index;
+ New_Item : Vector)
+ is
+ N : constant Count_Type := Length (New_Item);
+ B : Count_Type; -- index Before converted to Count_Type
+
+ begin
+ -- Use Insert_Space to create the "hole" (the destination slice) into
+ -- which we copy the source items.
+
+ Insert_Space (Container, Before, Count => N);
+
+ if N = 0 then
+ -- There's nothing else to do here (vetting of parameters was
+ -- performed already in Insert_Space), so we simply return.
+
+ return;
+ end if;
+
+ B := To_Array_Index (Before);
+
+ if Container'Address /= New_Item'Address then
+ -- This is the simple case. New_Item denotes an object different
+ -- from Container, so there's nothing special we need to do to copy
+ -- the source items to their destination, because all of the source
+ -- items are contiguous.
+
+ Container.Elements (B .. B + N - 1) := New_Item.Elements (1 .. N);
+ return;
+ end if;
+
+ -- We refer to array index value Before + N - 1 as J. This is the last
+ -- index value of the destination slice.
+
+ -- New_Item denotes the same object as Container, so an insertion has
+ -- potentially split the source items. The destination is always the
+ -- range [Before, J], but the source is [Index_Type'First, Before) and
+ -- (J, Container.Last]. We perform the copy in two steps, using each of
+ -- the two slices of the source items.
+
+ declare
+ subtype Src_Index_Subtype is Count_Type'Base range 1 .. B - 1;
+
+ Src : Elements_Array renames Container.Elements (Src_Index_Subtype);
+
+ begin
+ -- We first copy the source items that precede the space we
+ -- inserted. (If Before equals Index_Type'First, then this first
+ -- source slice will be empty, which is harmless.)
+
+ Container.Elements (B .. B + Src'Length - 1) := Src;
+ end;
+
+ declare
+ subtype Src_Index_Subtype is Count_Type'Base range
+ B + N .. Container.Length;
+
+ Src : Elements_Array renames Container.Elements (Src_Index_Subtype);
+
+ begin
+ -- We next copy the source items that follow the space we inserted.
+
+ Container.Elements (B + N - Src'Length .. B + N - 1) := Src;
+ end;
+ end Insert;
+
+ 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 /= Container'Unchecked_Access
+ then
+ raise Program_Error with "Before cursor denotes wrong container";
+ end if;
+
+ if Is_Empty (New_Item) then
+ return;
+ end if;
+
+ if Before.Container = null
+ or else Before.Index > Container.Last
+ then
+ if Container.Last = Index_Type'Last then
+ raise Constraint_Error with
+ "vector is already at its maximum length";
+ end if;
+
+ Index := Container.Last + 1;
+
+ else
+ Index := Before.Index;
+ end if;
+
+ Insert (Container, Index, New_Item);
+ end Insert;
+
+ procedure Insert
+ (Container : in out Vector;
+ Before : Cursor;
+ New_Item : Vector;
+ Position : out Cursor)
+ is
+ Index : Index_Type'Base;
+
+ begin
+ if Before.Container /= null
+ and then Before.Container /= Container'Unchecked_Access
+ then
+ raise Program_Error with "Before cursor denotes wrong container";
+ end if;
+
+ if Is_Empty (New_Item) then
+ if Before.Container = null
+ or else Before.Index > Container.Last
+ then
+ Position := No_Element;
+ else
+ Position := (Container'Unchecked_Access, Before.Index);
+ end if;
+
+ return;
+ end if;
+
+ if Before.Container = null
+ or else Before.Index > Container.Last
+ then
+ if Container.Last = Index_Type'Last then
+ raise Constraint_Error with
+ "vector is already at its maximum length";
+ end if;
+
+ Index := Container.Last + 1;
+
+ else
+ Index := Before.Index;
+ end if;
+
+ Insert (Container, Index, New_Item);
+
+ 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;
+
+ begin
+ if Before.Container /= null
+ and then Before.Container /= Container'Unchecked_Access
+ then
+ raise Program_Error with "Before cursor denotes wrong container";
+ end if;
+
+ if Count = 0 then
+ return;
+ end if;
+
+ if Before.Container = null
+ or else Before.Index > Container.Last
+ then
+ if Container.Last = Index_Type'Last then
+ raise Constraint_Error with
+ "vector is already at its maximum length";
+ end if;
+
+ Index := Container.Last + 1;
+
+ else
+ Index := Before.Index;
+ end if;
+
+ Insert (Container, Index, New_Item, Count);
+ end Insert;
+
+ 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 Before.Container /= null
+ and then Before.Container /= Container'Unchecked_Access
+ then
+ raise Program_Error with "Before cursor denotes wrong container";
+ end if;
+
+ 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;
+
+ return;
+ end if;
+
+ if Before.Container = null
+ or else Before.Index > Container.Last
+ then
+ if Container.Last = Index_Type'Last then
+ raise Constraint_Error with
+ "vector is already at its maximum length";
+ end if;
+
+ Index := Container.Last + 1;
+
+ else
+ Index := Before.Index;
+ end if;
+
+ Insert (Container, Index, New_Item, Count);
+
+ Position := Cursor'(Container'Unchecked_Access, Index);
+ end Insert;
+
+ procedure Insert
+ (Container : in out Vector;
+ Before : Extended_Index;
+ Count : Count_Type := 1)
+ is
+ New_Item : Element_Type; -- Default-initialized value
+ pragma Warnings (Off, New_Item);
+
+ begin
+ Insert (Container, Before, New_Item, Count);
+ end Insert;
+
+ procedure Insert
+ (Container : in out Vector;
+ Before : Cursor;
+ Position : out Cursor;
+ Count : Count_Type := 1)
+ is
+ New_Item : Element_Type; -- Default-initialized value
+ pragma Warnings (Off, New_Item);
+
+ begin
+ Insert (Container, Before, New_Item, Position, Count);
+ end Insert;
+
+ ------------------
+ -- Insert_Space --
+ ------------------
+
+ procedure Insert_Space
+ (Container : in out Vector;
+ Before : Extended_Index;
+ Count : Count_Type := 1)
+ is
+ EA : Elements_Array renames Container.Elements;
+ Old_Length : constant Count_Type := Container.Length;
+
+ Max_Length : Count_Type'Base; -- determined from range of Index_Type
+ New_Length : Count_Type'Base; -- sum of current length and Count
+
+ Index : Index_Type'Base; -- scratch for intermediate values
+ J : Count_Type'Base; -- scratch
+
+ begin
+ -- As a precondition on the generic actual Index_Type, the base type
+ -- must include Index_Type'Pred (Index_Type'First); this is the value
+ -- that Container.Last assumes when the vector is empty. However, we do
+ -- not allow that as the value for Index when specifying where the new
+ -- items should be inserted, so we must manually check. (That the user
+ -- is allowed to specify the value at all here is a consequence of the
+ -- declaration of the Extended_Index subtype, which includes the values
+ -- in the base range that immediately precede and immediately follow the
+ -- values in the Index_Type.)
+
+ if Before < Index_Type'First then
+ raise Constraint_Error with
+ "Before index is out of range (too small)";
+ end if;
+
+ -- We do allow a value greater than Container.Last to be specified as
+ -- the Index, but only if it's immediately greater. This allows for the
+ -- case of appending items to the back end of the vector. (It is assumed
+ -- that specifying an index value greater than Last + 1 indicates some
+ -- deeper flaw in the caller's algorithm, so that case is treated as a
+ -- proper error.)
+
+ if Before > Container.Last
+ and then Before > Container.Last + 1
+ then
+ raise Constraint_Error with
+ "Before index is out of range (too large)";
+ end if;
+
+ -- We treat inserting 0 items into the container as a no-op, even when
+ -- the container is busy, so we simply return.
+
+ if Count = 0 then
+ return;
+ end if;
+
+ -- There are two constraints we need to satisfy. The first constraint is
+ -- that a container cannot have more than Count_Type'Last elements, so
+ -- we must check the sum of the current length and the insertion count.
+ -- Note that we cannot simply add these values, because of the
+ -- possibility of overflow.
+
+ if Old_Length > Count_Type'Last - Count then
+ raise Constraint_Error with "Count is out of range";
+ end if;
+
+ -- It is now safe compute the length of the new vector, without fear of
+ -- overflow.
+
+ New_Length := Old_Length + Count;
+
+ -- The second constraint is that the new Last index value cannot exceed
+ -- Index_Type'Last. In each branch below, we calculate the maximum
+ -- length (computed from the range of values in Index_Type), and then
+ -- compare the new length to the maximum length. If the new length is
+ -- acceptable, then we compute the new last index from that.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ -- We have to handle the case when there might be more values in the
+ -- range of Index_Type than in the range of Count_Type.
+
+ if Index_Type'First <= 0 then
+ -- We know that No_Index (the same as Index_Type'First - 1) is
+ -- less than 0, so it is safe to compute the following sum without
+ -- fear of overflow.
+
+ Index := No_Index + Index_Type'Base (Count_Type'Last);
+
+ if Index <= Index_Type'Last then
+ -- We have determined that range of Index_Type has at least as
+ -- many values as in Count_Type, so Count_Type'Last is the
+ -- maximum number of items that are allowed.
+
+ Max_Length := Count_Type'Last;
+
+ else
+ -- The range of Index_Type has fewer values than in Count_Type,
+ -- so the maximum number of items is computed from the range of
+ -- the Index_Type.
+
+ Max_Length := Count_Type'Base (Index_Type'Last - No_Index);
+ end if;
+
+ else
+ -- No_Index is equal or greater than 0, so we can safely compute
+ -- the difference without fear of overflow (which we would have to
+ -- worry about if No_Index were less than 0, but that case is
+ -- handled above).
+
+ Max_Length := Count_Type'Base (Index_Type'Last - No_Index);
+ end if;
+
+ elsif Index_Type'First <= 0 then
+ -- We know that No_Index (the same as Index_Type'First - 1) is less
+ -- than 0, so it is safe to compute the following sum without fear of
+ -- overflow.
+
+ J := Count_Type'Base (No_Index) + Count_Type'Last;
+
+ if J <= Count_Type'Base (Index_Type'Last) then
+ -- We have determined that range of Index_Type has at least as
+ -- many values as in Count_Type, so Count_Type'Last is the maximum
+ -- number of items that are allowed.
+
+ Max_Length := Count_Type'Last;
+
+ else
+ -- The range of Index_Type has fewer values than Count_Type does,
+ -- so the maximum number of items is computed from the range of
+ -- the Index_Type.
+
+ Max_Length :=
+ Count_Type'Base (Index_Type'Last) - Count_Type'Base (No_Index);
+ end if;
+
+ else
+ -- No_Index is equal or greater than 0, so we can safely compute the
+ -- difference without fear of overflow (which we would have to worry
+ -- about if No_Index were less than 0, but that case is handled
+ -- above).
+
+ Max_Length :=
+ Count_Type'Base (Index_Type'Last) - Count_Type'Base (No_Index);
+ end if;
+
+ -- We have just computed the maximum length (number of items). We must
+ -- now compare the requested length to the maximum length, as we do not
+ -- allow a vector expand beyond the maximum (because that would create
+ -- an internal array with a last index value greater than
+ -- Index_Type'Last, with no way to index those elements).
+
+ if New_Length > Max_Length then
+ raise Constraint_Error with "Count is out of range";
+ end if;
+
+ -- The tampering bits exist to prevent an item from being harmfully
+ -- manipulated while it is being visited. Query, Update, and Iterate
+ -- increment the busy count on entry, and decrement the count on
+ -- exit. Insert checks the count to determine whether it is being called
+ -- while the associated callback procedure is executing.
+
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ -- An internal array has already been allocated, so we need to check
+ -- whether there is enough unused storage for the new items.
+
+ if New_Length > Container.Capacity then
+ raise Capacity_Error with "New length is larger than capacity";
+ end if;
+
+ -- In this case, we're inserting space into a vector that has already
+ -- allocated an internal array, and the existing array has enough
+ -- unused storage for the new items.
+
+ if Before <= Container.Last then
+ -- The space is being inserted before some existing elements,
+ -- so we must slide the existing elements up to their new home.
+
+ J := To_Array_Index (Before);
+ EA (J + Count .. New_Length) := EA (J .. Old_Length);
+ end if;
+
+ -- New_Last is the last index value of the items in the container after
+ -- insertion. Use the wider of Index_Type'Base and Count_Type'Base to
+ -- compute its value from the New_Length.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ Container.Last := No_Index + Index_Type'Base (New_Length);
+
+ else
+ Container.Last :=
+ Index_Type'Base (Count_Type'Base (No_Index) + New_Length);
+ end if;
+ end Insert_Space;
+
+ procedure Insert_Space
+ (Container : in out Vector;
+ Before : Cursor;
+ Position : out Cursor;
+ Count : Count_Type := 1)
+ is
+ Index : Index_Type'Base;
+
+ begin
+ if Before.Container /= null
+ and then Before.Container /= Container'Unchecked_Access
+ then
+ raise Program_Error with "Before cursor denotes wrong container";
+ end if;
+
+ 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;
+
+ return;
+ end if;
+
+ if Before.Container = null
+ or else Before.Index > Container.Last
+ then
+ if Container.Last = Index_Type'Last then
+ raise Constraint_Error with
+ "vector is already at its maximum length";
+ end if;
+
+ Index := Container.Last + 1;
+
+ else
+ Index := Before.Index;
+ end if;
+
+ Insert_Space (Container, Index, Count => Count);
+
+ Position := Cursor'(Container'Unchecked_Access, Index);
+ end Insert_Space;
+
+ --------------
+ -- Is_Empty --
+ --------------
+
+ function Is_Empty (Container : Vector) return Boolean is
+ begin
+ return Container.Last < Index_Type'First;
+ end Is_Empty;
+
+ -------------
+ -- Iterate --
+ -------------
+
+ procedure Iterate
+ (Container : Vector;
+ Process : not null access procedure (Position : Cursor))
+ is
+ B : Natural renames Container'Unrestricted_Access.all.Busy;
+
+ begin
+ B := B + 1;
+
+ begin
+ for Indx in Index_Type'First .. Container.Last loop
+ Process (Cursor'(Container'Unrestricted_Access, Indx));
+ end loop;
+ exception
+ when others =>
+ B := B - 1;
+ raise;
+ end;
+
+ B := B - 1;
+ end Iterate;
+
+ function Iterate
+ (Container : Vector)
+ return Vector_Iterator_Interfaces.Reversible_Iterator'Class
+ is
+ V : constant Vector_Access := Container'Unrestricted_Access;
+ B : Natural renames V.Busy;
+
+ begin
+ -- The value of its Index component influences the behavior of the First
+ -- and Last selector functions of the iterator object. When the Index
+ -- component is No_Index (as is the case here), this means the iterator
+ -- object was constructed without a start expression. This is a complete
+ -- iterator, meaning that the iteration starts from the (logical)
+ -- beginning of the sequence of items.
+
+ -- Note: For a forward iterator, Container.First is the beginning, and
+ -- for a reverse iterator, Container.Last is the beginning.
+
+ return It : constant Iterator :=
+ (Limited_Controlled with
+ Container => V,
+ Index => No_Index)
+ do
+ B := B + 1;
+ end return;
+ end Iterate;
+
+ function Iterate
+ (Container : Vector;
+ Start : Cursor)
+ return Vector_Iterator_Interfaces.Reversible_Iterator'Class
+ is
+ V : constant Vector_Access := Container'Unrestricted_Access;
+ B : Natural renames V.Busy;
+
+ begin
+ -- It was formerly the case that when Start = No_Element, the partial
+ -- iterator was defined to behave the same as for a complete iterator,
+ -- and iterate over the entire sequence of items. However, those
+ -- semantics were unintuitive and arguably error-prone (it is too easy
+ -- to accidentally create an endless loop), and so they were changed,
+ -- per the ARG meeting in Denver on 2011/11. However, there was no
+ -- consensus about what positive meaning this corner case should have,
+ -- and so it was decided to simply raise an exception. This does imply,
+ -- however, that it is not possible to use a partial iterator to specify
+ -- an empty sequence of items.
+
+ if Start.Container = null then
+ raise Constraint_Error with
+ "Start position for iterator equals No_Element";
+ end if;
+
+ if Start.Container /= V then
+ raise Program_Error with
+ "Start cursor of Iterate designates wrong vector";
+ end if;
+
+ if Start.Index > V.Last then
+ raise Constraint_Error with
+ "Start position for iterator equals No_Element";
+ end if;
+
+ -- The value of its Index component influences the behavior of the First
+ -- and Last selector functions of the iterator object. When the Index
+ -- component is not No_Index (as is the case here), it means that this
+ -- is a partial iteration, over a subset of the complete sequence of
+ -- items. The iterator object was constructed with a start expression,
+ -- indicating the position from which the iteration begins. Note that
+ -- the start position has the same value irrespective of whether this is
+ -- a forward or reverse iteration.
+
+ return It : constant Iterator :=
+ (Limited_Controlled with
+ Container => V,
+ Index => Start.Index)
+ do
+ B := B + 1;
+ end return;
+ end Iterate;
+
+ ----------
+ -- Last --
+ ----------
+
+ function Last (Container : Vector) return Cursor is
+ begin
+ if Is_Empty (Container) then
+ return No_Element;
+ else
+ return (Container'Unrestricted_Access, Container.Last);
+ end if;
+ end Last;
+
+ function Last (Object : Iterator) return Cursor is
+ begin
+ -- The value of the iterator object's Index component influences the
+ -- behavior of the Last (and First) selector function.
+
+ -- When the Index component is No_Index, this means the iterator object
+ -- was constructed without a start expression, in which case the
+ -- (reverse) iteration starts from the (logical) beginning of the entire
+ -- sequence (corresponding to Container.Last, for a reverse iterator).
+
+ -- Otherwise, this is iteration over a partial sequence of items. When
+ -- the Index component is not No_Index, the iterator object was
+ -- constructed with a start expression, that specifies the position from
+ -- which the (reverse) partial iteration begins.
+
+ if Object.Index = No_Index then
+ return Last (Object.Container.all);
+ else
+ return Cursor'(Object.Container, Object.Index);
+ end if;
+ end Last;
+
+ ------------------
+ -- Last_Element --
+ ------------------
+
+ function Last_Element (Container : Vector) return Element_Type is
+ begin
+ if Container.Last = No_Index then
+ raise Constraint_Error with "Container is empty";
+ else
+ return Container.Elements (Container.Length);
+ end if;
+ end Last_Element;
+
+ ----------------
+ -- Last_Index --
+ ----------------
+
+ function Last_Index (Container : Vector) return Extended_Index is
+ begin
+ return Container.Last;
+ end Last_Index;
+
+ ------------
+ -- Length --
+ ------------
+
+ function Length (Container : Vector) return Count_Type is
+ L : constant Index_Type'Base := Container.Last;
+ F : constant Index_Type := Index_Type'First;
+
+ begin
+ -- The base range of the index type (Index_Type'Base) might not include
+ -- all values for length (Count_Type). Contrariwise, the index type
+ -- might include values outside the range of length. Hence we use
+ -- whatever type is wider for intermediate values when calculating
+ -- length. Note that no matter what the index type is, the maximum
+ -- length to which a vector is allowed to grow is always the minimum
+ -- of Count_Type'Last and (IT'Last - IT'First + 1).
+
+ -- For example, an Index_Type with range -127 .. 127 is only guaranteed
+ -- to have a base range of -128 .. 127, but the corresponding vector
+ -- would have lengths in the range 0 .. 255. In this case we would need
+ -- to use Count_Type'Base for intermediate values.
+
+ -- Another case would be the index range -2**63 + 1 .. -2**63 + 10. The
+ -- vector would have a maximum length of 10, but the index values lie
+ -- outside the range of Count_Type (which is only 32 bits). In this
+ -- case we would need to use Index_Type'Base for intermediate values.
+
+ if Count_Type'Base'Last >= Index_Type'Pos (Index_Type'Base'Last) then
+ return Count_Type'Base (L) - Count_Type'Base (F) + 1;
+ else
+ return Count_Type (L - F + 1);
+ end if;
+ end Length;
+
+ ----------
+ -- Move --
+ ----------
+
+ procedure Move
+ (Target : in out Vector;
+ Source : in out Vector)
+ is
+ begin
+ if Target'Address = Source'Address then
+ return;
+ end if;
+
+ if Target.Capacity < Source.Length then
+ raise Capacity_Error -- ???
+ with "Target capacity is less than Source length";
+ end if;
+
+ if Target.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (Target is busy)";
+ end if;
+
+ if Source.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (Source is busy)";
+ end if;
+
+ -- Clear Target now, in case element assignment fails
+
+ Target.Last := No_Index;
+
+ Target.Elements (1 .. Source.Length) :=
+ Source.Elements (1 .. Source.Length);
+
+ Target.Last := Source.Last;
+ 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 < Position.Container.Last then
+ return (Position.Container, Position.Index + 1);
+ end if;
+
+ return No_Element;
+ end Next;
+
+ function Next (Object : Iterator; Position : Cursor) return Cursor is
+ begin
+ if Position.Container = null then
+ return No_Element;
+ end if;
+
+ if Position.Container /= Object.Container then
+ raise Program_Error with
+ "Position cursor of Next designates wrong vector";
+ end if;
+
+ return Next (Position);
+ end Next;
+
+ procedure Next (Position : in out Cursor) is
+ begin
+ if Position.Container = null then
+ return;
+ end if;
+
+ if Position.Index < Position.Container.Last then
+ Position.Index := Position.Index + 1;
+ else
+ Position := No_Element;
+ end if;
+ end Next;
+
+ -------------
+ -- Prepend --
+ -------------
+
+ 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;
+
+ if Position.Index > Index_Type'First then
+ Position.Index := Position.Index - 1;
+ else
+ Position := No_Element;
+ end if;
+ end Previous;
+
+ function Previous (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, Position.Index - 1);
+ end if;
+
+ return No_Element;
+ end Previous;
+
+ function Previous (Object : Iterator; Position : Cursor) return Cursor is
+ begin
+ if Position.Container = null then
+ return No_Element;
+ end if;
+
+ if Position.Container /= Object.Container then
+ raise Program_Error with
+ "Position cursor of Previous designates wrong vector";
+ end if;
+
+ return Previous (Position);
+ end Previous;
+
+ -------------------
+ -- Query_Element --
+ -------------------
+
+ procedure Query_Element
+ (Container : Vector;
+ Index : Index_Type;
+ Process : not null access procedure (Element : Element_Type))
+ is
+ V : Vector renames Container'Unrestricted_Access.all;
+ B : Natural renames V.Busy;
+ L : Natural renames V.Lock;
+
+ begin
+ if Index > Container.Last then
+ raise Constraint_Error with "Index is out of range";
+ end if;
+
+ B := B + 1;
+ L := L + 1;
+
+ begin
+ Process (V.Elements (To_Array_Index (Index)));
+ exception
+ when others =>
+ L := L - 1;
+ B := B - 1;
+ raise;
+ end;
+
+ L := L - 1;
+ B := B - 1;
+ end Query_Element;
+
+ procedure Query_Element
+ (Position : Cursor;
+ Process : not null access procedure (Element : Element_Type))
+ is
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ end if;
+
+ Query_Element (Position.Container.all, Position.Index, Process);
+ end Query_Element;
+
+ ----------
+ -- Read --
+ ----------
+
+ procedure Read
+ (Stream : not null access Root_Stream_Type'Class;
+ Container : out Vector)
+ is
+ Length : Count_Type'Base;
+ Last : Index_Type'Base := No_Index;
+
+ begin
+ Clear (Container);
+
+ Count_Type'Base'Read (Stream, Length);
+
+ Reserve_Capacity (Container, Capacity => Length);
+
+ for Idx in Count_Type range 1 .. Length loop
+ Last := Last + 1;
+ Element_Type'Read (Stream, Container.Elements (Idx));
+ Container.Last := Last;
+ end loop;
+ end Read;
+
+ procedure Read
+ (Stream : not null access Root_Stream_Type'Class;
+ Position : out Cursor)
+ is
+ begin
+ raise Program_Error with "attempt to stream vector cursor";
+ end Read;
+
+ procedure Read
+ (Stream : not null access Root_Stream_Type'Class;
+ Item : out Reference_Type)
+ is
+ begin
+ raise Program_Error with "attempt to stream reference";
+ end Read;
+
+ procedure Read
+ (Stream : not null access Root_Stream_Type'Class;
+ Item : out Constant_Reference_Type)
+ is
+ begin
+ raise Program_Error with "attempt to stream reference";
+ end Read;
+
+ ---------------
+ -- Reference --
+ ---------------
+
+ function Reference
+ (Container : aliased in out Vector;
+ Position : Cursor) return Reference_Type
+ is
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ end if;
+
+ if Position.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ if Position.Index > Position.Container.Last then
+ raise Constraint_Error with "Position cursor is out of range";
+ end if;
+
+ declare
+ A : Elements_Array renames Container.Elements;
+ I : constant Count_Type := To_Array_Index (Position.Index);
+ begin
+ return (Element => A (I)'Access);
+ end;
+ end Reference;
+
+ function Reference
+ (Container : aliased in out Vector;
+ Index : Index_Type) return Reference_Type
+ is
+ begin
+ if Index > Container.Last then
+ raise Constraint_Error with "Index is out of range";
+ end if;
+
+ declare
+ A : Elements_Array renames Container.Elements;
+ I : constant Count_Type := To_Array_Index (Index);
+ begin
+ return (Element => A (I)'Access);
+ end;
+ end Reference;
+
+ ---------------------
+ -- Replace_Element --
+ ---------------------
+
+ procedure Replace_Element
+ (Container : in out Vector;
+ Index : Index_Type;
+ New_Item : Element_Type)
+ is
+ begin
+ if Index > Container.Last then
+ raise Constraint_Error with "Index is out of range";
+ end if;
+
+ if Container.Lock > 0 then
+ raise Program_Error with
+ "attempt to tamper with elements (vector is locked)";
+ end if;
+
+ Container.Elements (To_Array_Index (Index)) := New_Item;
+ end Replace_Element;
+
+ procedure Replace_Element
+ (Container : in out Vector;
+ Position : Cursor;
+ New_Item : Element_Type)
+ is
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ end if;
+
+ if Position.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ if Position.Index > Container.Last then
+ raise Constraint_Error with "Position cursor is out of range";
+ end if;
+
+ if Container.Lock > 0 then
+ raise Program_Error with
+ "attempt to tamper with elements (vector is locked)";
+ end if;
+
+ Container.Elements (To_Array_Index (Position.Index)) := New_Item;
+ end Replace_Element;
+
+ ----------------------
+ -- Reserve_Capacity --
+ ----------------------
+
+ procedure Reserve_Capacity
+ (Container : in out Vector;
+ Capacity : Count_Type)
+ is
+ begin
+ if Capacity > Container.Capacity then
+ raise Constraint_Error with "Capacity is out of range";
+ end if;
+ end Reserve_Capacity;
+
+ ----------------------
+ -- Reverse_Elements --
+ ----------------------
+
+ procedure Reverse_Elements (Container : in out Vector) is
+ E : Elements_Array renames Container.Elements;
+ Idx : Count_Type;
+ Jdx : Count_Type;
+
+ begin
+ if Container.Length <= 1 then
+ return;
+ end if;
+
+ -- The exception behavior for the vector container must match that for
+ -- the list container, so we check for cursor tampering here (which will
+ -- catch more things) instead of for element tampering (which will catch
+ -- fewer things). It's true that the elements of this vector container
+ -- could be safely moved around while (say) an iteration is taking place
+ -- (iteration only increments the busy counter), and so technically
+ -- all we would need here is a test for element tampering (indicated
+ -- by the lock counter), that's simply an artifact of our array-based
+ -- implementation. Logically Reverse_Elements requires a check for
+ -- cursor tampering.
+
+ if Container.Busy > 0 then
+ raise Program_Error with
+ "attempt to tamper with cursors (vector is busy)";
+ end if;
+
+ Idx := 1;
+ Jdx := Container.Length;
+ while Idx < Jdx loop
+ declare
+ EI : constant Element_Type := E (Idx);
+
+ begin
+ E (Idx) := E (Jdx);
+ E (Jdx) := EI;
+ end;
+
+ Idx := Idx + 1;
+ Jdx := Jdx - 1;
+ end loop;
+ end Reverse_Elements;
+
+ ------------------
+ -- Reverse_Find --
+ ------------------
+
+ function Reverse_Find
+ (Container : Vector;
+ Item : Element_Type;
+ Position : Cursor := No_Element) return Cursor
+ is
+ Last : Index_Type'Base;
+
+ begin
+ if Position.Container /= null
+ and then Position.Container /= Container'Unrestricted_Access
+ then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ Last :=
+ (if Position.Container = null or else Position.Index > Container.Last
+ then Container.Last
+ else Position.Index);
+
+ for Indx in reverse Index_Type'First .. Last loop
+ if Container.Elements (To_Array_Index (Indx)) = Item then
+ return (Container'Unrestricted_Access, Indx);
+ end if;
+ end loop;
+
+ return No_Element;
+ end Reverse_Find;
+
+ ------------------------
+ -- Reverse_Find_Index --
+ ------------------------
+
+ function Reverse_Find_Index
+ (Container : Vector;
+ Item : Element_Type;
+ Index : Index_Type := Index_Type'Last) return Extended_Index
+ is
+ Last : constant Index_Type'Base :=
+ Index_Type'Min (Container.Last, Index);
+
+ begin
+ for Indx in reverse Index_Type'First .. Last loop
+ if Container.Elements (To_Array_Index (Indx)) = Item then
+ return Indx;
+ end if;
+ end loop;
+
+ return No_Index;
+ end Reverse_Find_Index;
+
+ ---------------------
+ -- Reverse_Iterate --
+ ---------------------
+
+ procedure Reverse_Iterate
+ (Container : Vector;
+ Process : not null access procedure (Position : Cursor))
+ is
+ V : Vector renames Container'Unrestricted_Access.all;
+ B : Natural renames V.Busy;
+
+ begin
+ B := B + 1;
+
+ begin
+ for Indx in reverse Index_Type'First .. Container.Last loop
+ Process (Cursor'(Container'Unrestricted_Access, Indx));
+ end loop;
+ exception
+ when others =>
+ B := B - 1;
+ raise;
+ end;
+
+ B := B - 1;
+ end Reverse_Iterate;
+
+ ----------------
+ -- Set_Length --
+ ----------------
+
+ procedure Set_Length (Container : in out Vector; Length : Count_Type) is
+ Count : constant Count_Type'Base := Container.Length - Length;
+
+ begin
+ -- Set_Length allows the user to set the length explicitly, instead of
+ -- implicitly as a side-effect of deletion or insertion. If the
+ -- requested length is less then the current length, this is equivalent
+ -- to deleting items from the back end of the vector. If the requested
+ -- length is greater than the current length, then this is equivalent to
+ -- inserting "space" (nonce items) at the end.
+
+ if Count >= 0 then
+ Container.Delete_Last (Count);
+
+ elsif Container.Last >= Index_Type'Last then
+ raise Constraint_Error with "vector is already at its maximum length";
+
+ else
+ Container.Insert_Space (Container.Last + 1, -Count);
+ end if;
+ end Set_Length;
+
+ ----------
+ -- Swap --
+ ----------
+
+ procedure Swap (Container : in out Vector; I, J : Index_Type) is
+ E : Elements_Array renames Container.Elements;
+
+ begin
+ if I > Container.Last then
+ raise Constraint_Error with "I index is out of range";
+ end if;
+
+ if J > Container.Last then
+ raise Constraint_Error with "J index is out of range";
+ end if;
+
+ if I = J then
+ return;
+ end if;
+
+ if Container.Lock > 0 then
+ raise Program_Error with
+ "attempt to tamper with elements (vector is locked)";
+ end if;
+
+ declare
+ EI_Copy : constant Element_Type := E (To_Array_Index (I));
+ begin
+ E (To_Array_Index (I)) := E (To_Array_Index (J));
+ E (To_Array_Index (J)) := EI_Copy;
+ end;
+ end Swap;
+
+ procedure Swap (Container : in out Vector; I, J : Cursor) is
+ begin
+ if I.Container = null then
+ raise Constraint_Error with "I cursor has no element";
+ end if;
+
+ if J.Container = null then
+ raise Constraint_Error with "J cursor has no element";
+ end if;
+
+ if I.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "I cursor denotes wrong container";
+ end if;
+
+ if J.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "J cursor denotes wrong container";
+ end if;
+
+ Swap (Container, I.Index, J.Index);
+ end Swap;
+
+ --------------------
+ -- To_Array_Index --
+ --------------------
+
+ function To_Array_Index (Index : Index_Type'Base) return Count_Type'Base is
+ Offset : Count_Type'Base;
+
+ begin
+ -- We know that
+ -- Index >= Index_Type'First
+ -- hence we also know that
+ -- Index - Index_Type'First >= 0
+
+ -- The issue is that even though 0 is guaranteed to be a value
+ -- in the type Index_Type'Base, there's no guarantee that the
+ -- difference is a value in that type. To prevent overflow we
+ -- use the wider of Count_Type'Base and Index_Type'Base to
+ -- perform intermediate calculations.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ Offset := Count_Type'Base (Index - Index_Type'First);
+
+ else
+ Offset := Count_Type'Base (Index) -
+ Count_Type'Base (Index_Type'First);
+ end if;
+
+ -- The array index subtype for all container element arrays
+ -- always starts with 1.
+
+ return 1 + Offset;
+ end To_Array_Index;
+
+ ---------------
+ -- To_Cursor --
+ ---------------
+
+ function To_Cursor
+ (Container : Vector;
+ Index : Extended_Index) return Cursor
+ is
+ begin
+ if Index not in Index_Type'First .. Container.Last then
+ return No_Element;
+ end if;
+
+ return Cursor'(Container'Unrestricted_Access, Index);
+ end To_Cursor;
+
+ --------------
+ -- To_Index --
+ --------------
+
+ function To_Index (Position : Cursor) return Extended_Index is
+ begin
+ if Position.Container = null then
+ return No_Index;
+ end if;
+
+ if Position.Index <= Position.Container.Last then
+ return Position.Index;
+ end if;
+
+ return No_Index;
+ end To_Index;
+
+ ---------------
+ -- To_Vector --
+ ---------------
+
+ function To_Vector (Length : Count_Type) return Vector is
+ Index : Count_Type'Base;
+ Last : Index_Type'Base;
+
+ begin
+ if Length = 0 then
+ return Empty_Vector;
+ end if;
+
+ -- We create a vector object with a capacity that matches the specified
+ -- Length, but we do not allow the vector capacity (the length of the
+ -- internal array) to exceed the number of values in Index_Type'Range
+ -- (otherwise, there would be no way to refer to those components via an
+ -- index). We must therefore check whether the specified Length would
+ -- create a Last index value greater than Index_Type'Last.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+ -- We perform a two-part test. First we determine whether the
+ -- computed Last value lies in the base range of the type, and then
+ -- determine whether it lies in the range of the index (sub)type.
+
+ -- Last must satisfy this relation:
+ -- First + Length - 1 <= Last
+ -- We regroup terms:
+ -- First - 1 <= Last - Length
+ -- Which can rewrite as:
+ -- No_Index <= Last - Length
+
+ if Index_Type'Base'Last - Index_Type'Base (Length) < No_Index then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ -- We now know that the computed value of Last is within the base
+ -- range of the type, so it is safe to compute its value:
+
+ Last := No_Index + Index_Type'Base (Length);
+
+ -- Finally we test whether the value is within the range of the
+ -- generic actual index subtype:
+
+ if Last > Index_Type'Last then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ elsif Index_Type'First <= 0 then
+
+ -- Here we can compute Last directly, in the normal way. We know that
+ -- No_Index is less than 0, so there is no danger of overflow when
+ -- adding the (positive) value of Length.
+
+ Index := Count_Type'Base (No_Index) + Length; -- Last
+
+ if Index > Count_Type'Base (Index_Type'Last) then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ -- We know that the computed value (having type Count_Type) of Last
+ -- is within the range of the generic actual index subtype, so it is
+ -- safe to convert to Index_Type:
+
+ Last := Index_Type'Base (Index);
+
+ else
+ -- Here Index_Type'First (and Index_Type'Last) is positive, so we
+ -- must test the length indirectly (by working backwards from the
+ -- largest possible value of Last), in order to prevent overflow.
+
+ Index := Count_Type'Base (Index_Type'Last) - Length; -- No_Index
+
+ if Index < Count_Type'Base (No_Index) then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ -- We have determined that the value of Length would not create a
+ -- Last index value outside of the range of Index_Type, so we can now
+ -- safely compute its value.
+
+ Last := Index_Type'Base (Count_Type'Base (No_Index) + Length);
+ end if;
+
+ return V : Vector (Capacity => Length) do
+ V.Last := Last;
+ end return;
+ end To_Vector;
+
+ function To_Vector
+ (New_Item : Element_Type;
+ Length : Count_Type) return Vector
+ is
+ Index : Count_Type'Base;
+ Last : Index_Type'Base;
+
+ begin
+ if Length = 0 then
+ return Empty_Vector;
+ end if;
+
+ -- We create a vector object with a capacity that matches the specified
+ -- Length, but we do not allow the vector capacity (the length of the
+ -- internal array) to exceed the number of values in Index_Type'Range
+ -- (otherwise, there would be no way to refer to those components via an
+ -- index). We must therefore check whether the specified Length would
+ -- create a Last index value greater than Index_Type'Last.
+
+ if Index_Type'Base'Last >= Count_Type'Pos (Count_Type'Last) then
+
+ -- We perform a two-part test. First we determine whether the
+ -- computed Last value lies in the base range of the type, and then
+ -- determine whether it lies in the range of the index (sub)type.
+
+ -- Last must satisfy this relation:
+ -- First + Length - 1 <= Last
+ -- We regroup terms:
+ -- First - 1 <= Last - Length
+ -- Which can rewrite as:
+ -- No_Index <= Last - Length
+
+ if Index_Type'Base'Last - Index_Type'Base (Length) < No_Index then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ -- We now know that the computed value of Last is within the base
+ -- range of the type, so it is safe to compute its value:
+
+ Last := No_Index + Index_Type'Base (Length);
+
+ -- Finally we test whether the value is within the range of the
+ -- generic actual index subtype:
+
+ if Last > Index_Type'Last then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ elsif Index_Type'First <= 0 then
+
+ -- Here we can compute Last directly, in the normal way. We know that
+ -- No_Index is less than 0, so there is no danger of overflow when
+ -- adding the (positive) value of Length.
+
+ Index := Count_Type'Base (No_Index) + Length; -- same value as V.Last
+
+ if Index > Count_Type'Base (Index_Type'Last) then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ -- We know that the computed value (having type Count_Type) of Last
+ -- is within the range of the generic actual index subtype, so it is
+ -- safe to convert to Index_Type:
+
+ Last := Index_Type'Base (Index);
+
+ else
+ -- Here Index_Type'First (and Index_Type'Last) is positive, so we
+ -- must test the length indirectly (by working backwards from the
+ -- largest possible value of Last), in order to prevent overflow.
+
+ Index := Count_Type'Base (Index_Type'Last) - Length; -- No_Index
+
+ if Index < Count_Type'Base (No_Index) then
+ raise Constraint_Error with "Length is out of range";
+ end if;
+
+ -- We have determined that the value of Length would not create a
+ -- Last index value outside of the range of Index_Type, so we can now
+ -- safely compute its value.
+
+ Last := Index_Type'Base (Count_Type'Base (No_Index) + Length);
+ end if;
+
+ return V : Vector (Capacity => Length) do
+ V.Elements := (others => New_Item);
+ V.Last := Last;
+ end return;
+ end To_Vector;
+
+ --------------------
+ -- Update_Element --
+ --------------------
+
+ procedure Update_Element
+ (Container : in out Vector;
+ Index : Index_Type;
+ Process : not null access procedure (Element : in out Element_Type))
+ is
+ B : Natural renames Container.Busy;
+ L : Natural renames Container.Lock;
+
+ begin
+ if Index > Container.Last then
+ raise Constraint_Error with "Index is out of range";
+ end if;
+
+ B := B + 1;
+ L := L + 1;
+
+ begin
+ Process (Container.Elements (To_Array_Index (Index)));
+ exception
+ when others =>
+ L := L - 1;
+ B := B - 1;
+ raise;
+ end;
+
+ L := L - 1;
+ B := B - 1;
+ end Update_Element;
+
+ procedure Update_Element
+ (Container : in out Vector;
+ Position : Cursor;
+ Process : not null access procedure (Element : in out Element_Type))
+ is
+ begin
+ if Position.Container = null then
+ raise Constraint_Error with "Position cursor has no element";
+ end if;
+
+ if Position.Container /= Container'Unrestricted_Access then
+ raise Program_Error with "Position cursor denotes wrong container";
+ end if;
+
+ Update_Element (Container, Position.Index, Process);
+ end Update_Element;
+
+ -----------
+ -- Write --
+ -----------
+
+ procedure Write
+ (Stream : not null access Root_Stream_Type'Class;
+ Container : Vector)
+ is
+ N : Count_Type;
+
+ begin
+ N := Container.Length;
+ Count_Type'Base'Write (Stream, N);
+
+ for J in 1 .. N loop
+ Element_Type'Write (Stream, Container.Elements (J));
+ end loop;
+ end Write;
+
+ procedure Write
+ (Stream : not null access Root_Stream_Type'Class;
+ Position : Cursor)
+ is
+ begin
+ raise Program_Error with "attempt to stream vector cursor";
+ end Write;
+
+ procedure Write
+ (Stream : not null access Root_Stream_Type'Class;
+ Item : Reference_Type)
+ is
+ begin
+ raise Program_Error with "attempt to stream reference";
+ end Write;
+
+ procedure Write
+ (Stream : not null access Root_Stream_Type'Class;
+ Item : Constant_Reference_Type)
+ is
+ begin
+ raise Program_Error with "attempt to stream reference";
+ end Write;
+
+end Ada.Containers.Bounded_Vectors;