1--  Copyright 1994 Grady Booch
2--  Copyright 2003-2014 Simon Wright <simon@pushface.org>
3
4--  This package is free software; you can redistribute it and/or
5--  modify it under terms of the GNU General Public License as
6--  published by the Free Software Foundation; either version 2, or
7--  (at your option) any later version. This package is distributed in
8--  the hope that it will be useful, but WITHOUT ANY WARRANTY; without
9--  even the implied warranty of MERCHANTABILITY or FITNESS FOR A
10--  PARTICULAR PURPOSE. See the GNU General Public License for more
11--  details. You should have received a copy of the GNU General Public
12--  License distributed with this package; see file COPYING.  If not,
13--  write to the Free Software Foundation, 59 Temple Place - Suite
14--  330, Boston, MA 02111-1307, USA.
15
16--  As a special exception, if other files instantiate generics from
17--  this unit, or you link this unit with other files to produce an
18--  executable, this unit does not by itself cause the resulting
19--  executable to be covered by the GNU General Public License.  This
20--  exception does not however invalidate any other reasons why the
21--  executable file might be covered by the GNU Public License.
22
23with BC.Support.Unmanaged;
24
25generic
26package BC.Containers.Stacks.Unmanaged is
27
28   pragma Preelaborate;
29
30   type Stack is new Abstract_Stack with private;
31   --  This Stack exhibits unlimited growth and collapsing, limited
32   --  only by available memory.  Assignment is "deep".
33
34   function Null_Container return Stack;
35
36   function "=" (Left, Right : in Stack) return Boolean;
37   --  Return True if and only if both stacks have the same depth and
38   --  the same items in the same order; return False otherwise.
39
40   procedure Clear (S : in out Stack);
41   --  Empty the Stack of all items.
42
43   procedure Push (S : in out Stack; Elem : Item);
44   --  Add a copy of the item to the top of the Stack.
45
46   procedure Pop (S : in out Stack);
47   --  Remove the item from the top of the Stack.
48
49   function Depth (S : in Stack) return Natural;
50   --  Returns the number of items in the Stack.
51
52   function Is_Empty (S : in Stack) return Boolean;
53   --  Returns True if and only if no items are in the stack.
54
55   function Top (S : in Stack) return Item;
56   --  Return a copy of the item at the top of the Stack.
57
58   function New_Iterator (For_The_Stack : Stack) return Iterator'Class;
59   --  Return a reset Iterator bound to the specific Stack.
60
61private
62
63   function Item_At (S : Stack; Index : Positive) return Item_Ptr;
64
65   procedure Add (S : in out Stack; Elem : Item);
66   procedure Remove (S : in out Stack; From : Positive);
67
68   package Stack_Nodes
69   is new BC.Support.Unmanaged (Item => Item,
70                                Item_Ptr => Item_Ptr);
71
72   type Stack is new Abstract_Stack with record
73      Rep : Stack_Nodes.Unm_Node;
74   end record;
75
76end BC.Containers.Stacks.Unmanaged;
77