1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--       A D A . C O N T A I N E R S . B O U N D E D _ H O L D E R S        --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--            Copyright (C) 2015-2018, Free Software Foundation, Inc.       --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26------------------------------------------------------------------------------
27
28with Unchecked_Conversion;
29
30package body Ada.Containers.Bounded_Holders is
31
32   function Size_In_Storage_Elements (Element : Element_Type) return Natural;
33   --  This returns the size of Element in storage units. It raises an
34   --  exception if the size is not a multiple of Storage_Unit, or if the size
35   --  is too big.
36
37   ------------------------------
38   -- Size_In_Storage_Elements --
39   ------------------------------
40
41   function Size_In_Storage_Elements (Element : Element_Type) return Natural is
42      Max_Size : Natural renames Max_Size_In_Storage_Elements;
43
44   begin
45      return S : constant Natural := Element'Size / System.Storage_Unit do
46         pragma Assert
47           (Element'Size mod System.Storage_Unit = 0,
48            "Size must be a multiple of Storage_Unit");
49
50         pragma Assert
51           (S <= Max_Size, "Size is too big:" & S'Img & " >" & Max_Size'Img);
52      end return;
53   end Size_In_Storage_Elements;
54
55   function Cast is new
56     Unchecked_Conversion (System.Address, Element_Access);
57
58   ---------
59   -- "=" --
60   ---------
61
62   function "=" (Left, Right : Holder) return Boolean is
63   begin
64      return Get (Left) = Get (Right);
65   end "=";
66
67   -------------
68   -- Element --
69   -------------
70
71   function Get (Container : Holder) return Element_Type is
72   begin
73      return Cast (Container'Address).all;
74   end Get;
75
76   ---------
77   -- Set --
78   ---------
79
80   procedure Set (Container : in out Holder; New_Item  : Element_Type) is
81      Storage : Storage_Array
82        (1 .. Size_In_Storage_Elements (New_Item)) with
83          Address => New_Item'Address;
84   begin
85      Container.Data (Storage'Range) := Storage;
86   end Set;
87
88   ---------------
89   -- To_Holder --
90   ---------------
91
92   function To_Holder (New_Item : Element_Type) return Holder is
93   begin
94      return Result : Holder do
95         Set (Result, New_Item);
96      end return;
97   end To_Holder;
98
99end Ada.Containers.Bounded_Holders;
100