1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                      S Y S T E M . W I D _ E N U M                       --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2009, 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
32--  This package contains the routine used for Enumeration_Type'Width
33
34package System.Wid_Enum is
35   pragma Pure;
36
37   function Width_Enumeration_8
38     (Names   : String;
39      Indexes : System.Address;
40      Lo, Hi  : Natural)
41      return    Natural;
42   --  Used to compute Enum'Width where Enum is some enumeration subtype
43   --  other than those defined in package Standard. Names is a string with
44   --  a lower bound of 1 containing the characters of all the enumeration
45   --  literals concatenated together in sequence. Indexes is the address
46   --  of an array of type array (0 .. N) of Natural_8, where N is the
47   --  number of enumeration literals in the type. The Indexes values are
48   --  the starting subscript of each enumeration literal, indexed by Pos
49   --  values, with an extra entry at the end containing Names'Length + 1.
50   --  The reason that Indexes is passed by address is that the actual type
51   --  is created on the fly by the expander.
52   --
53   --  Lo and Hi are the Pos values of the lower and upper bounds of the
54   --  subtype. The result is the value of Width, i.e. the maximum value
55   --  of the length of any enumeration literal in the given range.
56
57   function Width_Enumeration_16
58     (Names   : String;
59      Indexes : System.Address;
60      Lo, Hi  : Natural)
61      return    Natural;
62   --  Identical to Width_Enumeration_8 except that it handles types
63   --  using array (0 .. Num) of Natural_16 for the Indexes table.
64
65   function Width_Enumeration_32
66     (Names   : String;
67      Indexes : System.Address;
68      Lo, Hi  : Natural)
69      return    Natural;
70   --  Identical to Width_Enumeration_8 except that it handles types
71   --  using array (0 .. Num) of Natural_32 for the Indexes table.
72
73end System.Wid_Enum;
74