1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                       S Y S T E M . I M A G E _ N                        --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--             Copyright (C) 2021, 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-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32with Ada.Unchecked_Conversion;
33
34package body System.Image_N is
35
36   -----------------------
37   -- Image_Enumeration --
38   -----------------------
39
40   procedure Image_Enumeration
41     (Pos     : Natural;
42      S       : in out String;
43      P       : out Natural;
44      Names   : String;
45      Indexes : System.Address)
46   is
47      pragma Assert (S'First = 1);
48
49      subtype Names_Index is
50        Index_Type range Index_Type (Names'First)
51                          .. Index_Type (Names'Last) + 1;
52      subtype Index is Natural range Natural'First .. Names'Length;
53      type Index_Table is array (Index) of Names_Index;
54      type Index_Table_Ptr is access Index_Table;
55
56      function To_Index_Table_Ptr is
57        new Ada.Unchecked_Conversion (System.Address, Index_Table_Ptr);
58
59      IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
60
61      pragma Assert (Pos in IndexesT'Range);
62      pragma Assert (Pos + 1 in IndexesT'Range);
63
64      Start : constant Natural := Natural (IndexesT (Pos));
65      Next  : constant Natural := Natural (IndexesT (Pos + 1));
66
67      pragma Assert (Next - 1 >= Start);
68      pragma Assert (Start >= Names'First);
69      pragma Assert (Next - 1 <= Names'Last);
70
71      pragma Assert (Next - Start <= S'Last);
72      --  The caller should guarantee that S is large enough to contain the
73      --  enumeration image.
74   begin
75      S (1 .. Next - Start) := Names (Start .. Next - 1);
76      P := Next - Start;
77   end Image_Enumeration;
78
79end System.Image_N;
80