gcc/ada/s-widenu.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME 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) 1992-2000 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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package contains the routine used for Enumeration_Type'Width
  35
  36 package System.Wid_Enum is
  37 pragma Pure (Wid_Enum);
  38
  39    function Width_Enumeration_8
  40      (Names   : String;
  41       Indexes : System.Address;
  42       Lo, Hi  : Natural)
  43       return    Natural;
  44    --  Used to compute Enum'Width where Enum is some enumeration subtype
  45    --  other than those defined in package Standard. Names is a string with
  46    --  a lower bound of 1 containing the characters of all the enumeration
  47    --  literals concatenated together in sequence. Indexes is the address
  48    --  of an array of type array (0 .. N) of Natural_8, where N is the
  49    --  number of enumeration literals in the type. The Indexes values are
  50    --  the starting subscript of each enumeration literal, indexed by Pos
  51    --  values, with an extra entry at the end containing Names'Length + 1.
  52    --  The reason that Indexes is passed by address is that the actual type
  53    --  is created on the fly by the expander.
  54    --
  55    --  Lo and Hi are the Pos values of the lower and upper bounds of the
  56    --  subtype. The result is the value of Width, i.e. the maximum value
  57    --  of the length of any enumeration literal in the given range.
  58
  59    function Width_Enumeration_16
  60      (Names   : String;
  61       Indexes : System.Address;
  62       Lo, Hi  : Natural)
  63       return    Natural;
  64    --  Identical to Width_Enumeration_8 except that it handles types
  65    --  using array (0 .. Num) of Natural_16 for the Indexes table.
  66
  67    function Width_Enumeration_32
  68      (Names   : String;
  69       Indexes : System.Address;
  70       Lo, Hi  : Natural)
  71       return    Natural;
  72    --  Identical to Width_Enumeration_8 except that it handles types
  73    --  using array (0 .. Num) of Natural_32 for the Indexes table.
  74
  75 end System.Wid_Enum;