1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                      S Y S T E M . V A L _ 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 is used to compute the Value attribute for enumeration types
33--  other than those in packages Standard and System. See unit Exp_Imgv for
34--  details of the format of constructed image tables.
35
36package System.Val_Enum is
37   pragma Pure;
38
39   function Value_Enumeration_8
40     (Names   : String;
41      Indexes : System.Address;
42      Num     : Natural;
43      Str     : String)
44      return    Natural;
45   --  Used to compute Enum'Value (Str) where Enum is some enumeration type
46   --  other than those defined in package Standard. Names is a string with
47   --  a lower bound of 1 containing the characters of all the enumeration
48   --  literals concatenated together in sequence. Indexes is the address
49   --  of an array of type array (0 .. N) of Natural_8, where N is the
50   --  number of enumeration literals in the type. The Indexes values are
51   --  the starting subscript of each enumeration literal, indexed by Pos
52   --  values, with an extra entry at the end containing Names'Length + 1.
53   --  The parameter Num is the value N - 1 (i.e. Enum'Pos (Enum'Last)).
54   --  The reason that Indexes is passed by address is that the actual type
55   --  is created on the fly by the expander.
56   --
57   --  Str is the argument of the attribute function, and may have leading
58   --  and trailing spaces, and letters can be upper or lower case or mixed.
59   --  If the image is found in Names, then the corresponding Pos value is
60   --  returned. If not, Constraint_Error is raised.
61
62   function Value_Enumeration_16
63     (Names   : String;
64      Indexes : System.Address;
65      Num     : Natural;
66      Str     : String)
67      return    Natural;
68   --  Identical to Value_Enumeration_8 except that it handles types
69   --  using array (0 .. Num) of Natural_16 for the Indexes table.
70
71   function Value_Enumeration_32
72     (Names   : String;
73      Indexes : System.Address;
74      Num     : Natural;
75      Str     : String)
76      return    Natural;
77   --  Identical to Value_Enumeration_8 except that it handles types
78   --  using array (0 .. Num) of Natural_32 for the Indexes table.
79
80end System.Val_Enum;
81