gcc/ada/libgnat/s-widenu.ads

   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) 1992-2017, 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
  34 package 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
  73 end System.Wid_Enum;