1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . V A L _ E N U M --
11 -- Copyright (C) 1992-2000, Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
36 -- This package is used to compute the Value attribute for enumeration types
37 -- other than those in packages Standard and System. See unit Exp_Imgv for
38 -- details of the format of constructed image tables.
40 package System.Val_Enum is
41 pragma Pure (Val_Enum);
43 function Value_Enumeration_8
45 Indexes : System.Address;
49 -- Used to compute Enum'Value (Str) where Enum is some enumeration type
50 -- other than those defined in package Standard. Names is a string with
51 -- a lower bound of 1 containing the characters of all the enumeration
52 -- literals concatenated together in sequence. Indexes is the address
53 -- of an array of type array (0 .. N) of Natural_8, where N is the
54 -- number of enumeration literals in the type. The Indexes values are
55 -- the starting subscript of each enumeration literal, indexed by Pos
56 -- values, with an extra entry at the end containing Names'Length + 1.
57 -- The parameter Num is the value N - 1 (i.e. Enum'Pos (Enum'Last)).
58 -- The reason that Indexes is passed by address is that the actual type
59 -- is created on the fly by the expander.
61 -- Str is the argument of the attribute function, and may have leading
62 -- and trailing spaces, and letters can be upper or lower case or mixed.
63 -- If the image is found in Names, then the corresponding Pos value is
64 -- returned. If not, Constraint_Error is raised.
66 function Value_Enumeration_16
68 Indexes : System.Address;
72 -- Identical to Value_Enumeration_8 except that it handles types
73 -- using array (0 .. Num) of Natural_16 for the Indexes table.
75 function Value_Enumeration_32
77 Indexes : System.Address;
81 -- Identical to Value_Enumeration_8 except that it handles types
82 -- using array (0 .. Num) of Natural_32 for the Indexes table.