gcc/ada/libgnat/s-valuen.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                       S Y S T E M . V A L U E _ N                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --             Copyright (C) 2021-2023, 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
  36 generic
  37
  38    type Index_Type is range <>;
  39
  40 package System.Value_N is
  41    pragma Preelaborate;
  42
  43    type Hash_Function_Ptr is access function (S : String) return Natural;
  44
  45    function Value_Enumeration
  46      (Names   : String;
  47       Indexes : System.Address;
  48       Hash    : Hash_Function_Ptr;
  49       Num     : Natural;
  50       Str     : String)
  51       return    Natural with Inline;
  52    --  Used to compute Enum'Value (Str) where Enum is some enumeration type
  53    --  other than those defined in package Standard. Names is a string with
  54    --  a lower bound of 1 containing the characters of all the enumeration
  55    --  literals concatenated together in sequence. Indexes is the address
  56    --  of an array of type array (0 .. N) of Index_Type, where N is the
  57    --  number of enumeration literals in the type. The Indexes values are
  58    --  the starting subscript of each enumeration literal, indexed by Pos
  59    --  values, with an extra entry at the end containing Names'Length + 1.
  60    --  The parameter Hash is a (perfect) hash function for Names and Indexes.
  61    --  The parameter Num is the value N - 1 (i.e. Enum'Pos (Enum'Last)).
  62    --  The reason that Indexes is passed by address is that the actual type
  63    --  is created on the fly by the expander.
  64    --
  65    --  Str is the argument of the attribute function, and may have leading
  66    --  and trailing spaces, and letters can be upper or lower case or mixed.
  67    --  If the image is found in Names, then the corresponding Pos value is
  68    --  returned. If not, Constraint_Error is raised.
  69
  70    function Valid_Value_Enumeration
  71      (Names   : String;
  72       Indexes : System.Address;
  73       Hash    : Hash_Function_Ptr;
  74       Num     : Natural;
  75       Str     : String)
  76       return    Boolean with Inline;
  77    --  Returns True if Str is a valid Image of some enumeration literal, False
  78    --  otherwise. That is, returns False if and only if Value_Enumeration would
  79    --  raise Constraint_Error. The parameters have the same meaning as for
  80    --  Value_Enumeration.
  81
  82 end System.Value_N;