gcc/ada/s-widenu.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                      S Y S T E M . W I D _ E N U M                       --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                            $Revision: 1.9 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2000 Free Software Foundation, Inc.          --
  12 --                                                                          --
  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.                                                      --
  23 --                                                                          --
  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.                                      --
  30 --                                                                          --
  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). --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 with Unchecked_Conversion;
  37
  38 package body System.Wid_Enum is
  39
  40    -------------------------
  41    -- Width_Enumeration_8 --
  42    -------------------------
  43
  44    function Width_Enumeration_8
  45      (Names   : String;
  46       Indexes : System.Address;
  47       Lo, Hi  : Natural)
  48       return    Natural
  49    is
  50       W : Natural;
  51
  52       type Natural_8 is range 0 .. 2 ** 7 - 1;
  53       type Index_Table is array (Natural) of Natural_8;
  54       type Index_Table_Ptr is access Index_Table;
  55
  56       function To_Index_Table_Ptr is
  57         new Unchecked_Conversion (System.Address, Index_Table_Ptr);
  58
  59       IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
  60
  61    begin
  62       W := 0;
  63
  64       for J in Lo .. Hi loop
  65          W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
  66       end loop;
  67
  68       return W;
  69    end Width_Enumeration_8;
  70
  71    --------------------------
  72    -- Width_Enumeration_16 --
  73    --------------------------
  74
  75    function Width_Enumeration_16
  76      (Names   : String;
  77       Indexes : System.Address;
  78       Lo, Hi  : Natural)
  79       return    Natural
  80    is
  81       W : Natural;
  82
  83       type Natural_16 is range 0 .. 2 ** 15 - 1;
  84       type Index_Table is array (Natural) of Natural_16;
  85       type Index_Table_Ptr is access Index_Table;
  86
  87       function To_Index_Table_Ptr is
  88         new Unchecked_Conversion (System.Address, Index_Table_Ptr);
  89
  90       IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
  91
  92    begin
  93       W := 0;
  94
  95       for J in Lo .. Hi loop
  96          W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
  97       end loop;
  98
  99       return W;
 100    end Width_Enumeration_16;
 101
 102    --------------------------
 103    -- Width_Enumeration_32 --
 104    --------------------------
 105
 106    function Width_Enumeration_32
 107      (Names   : String;
 108       Indexes : System.Address;
 109       Lo, Hi  : Natural)
 110       return    Natural
 111    is
 112       W : Natural;
 113
 114       type Natural_32 is range 0 .. 2 ** 31 - 1;
 115       type Index_Table is array (Natural) of Natural_32;
 116       type Index_Table_Ptr is access Index_Table;
 117
 118       function To_Index_Table_Ptr is
 119         new Unchecked_Conversion (System.Address, Index_Table_Ptr);
 120
 121       IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
 122
 123    begin
 124       W := 0;
 125
 126       for J in Lo .. Hi loop
 127          W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
 128       end loop;
 129
 130       return W;
 131    end Width_Enumeration_32;
 132
 133 end System.Wid_Enum;