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 --                                                                          --
  10 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 with Unchecked_Conversion;
  36
  37 package body System.Wid_Enum is
  38
  39    -------------------------
  40    -- Width_Enumeration_8 --
  41    -------------------------
  42
  43    function Width_Enumeration_8
  44      (Names   : String;
  45       Indexes : System.Address;
  46       Lo, Hi  : Natural)
  47       return    Natural
  48    is
  49       pragma Warnings (Off, Names);
  50
  51       W : Natural;
  52
  53       type Natural_8 is range 0 .. 2 ** 7 - 1;
  54       type Index_Table is array (Natural) of Natural_8;
  55       type Index_Table_Ptr is access Index_Table;
  56
  57       function To_Index_Table_Ptr is
  58         new Unchecked_Conversion (System.Address, Index_Table_Ptr);
  59
  60       IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
  61
  62    begin
  63       W := 0;
  64
  65       for J in Lo .. Hi loop
  66          W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
  67       end loop;
  68
  69       return W;
  70    end Width_Enumeration_8;
  71
  72    --------------------------
  73    -- Width_Enumeration_16 --
  74    --------------------------
  75
  76    function Width_Enumeration_16
  77      (Names   : String;
  78       Indexes : System.Address;
  79       Lo, Hi  : Natural)
  80       return    Natural
  81    is
  82       pragma Warnings (Off, Names);
  83
  84       W : Natural;
  85
  86       type Natural_16 is range 0 .. 2 ** 15 - 1;
  87       type Index_Table is array (Natural) of Natural_16;
  88       type Index_Table_Ptr is access Index_Table;
  89
  90       function To_Index_Table_Ptr is
  91         new Unchecked_Conversion (System.Address, Index_Table_Ptr);
  92
  93       IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
  94
  95    begin
  96       W := 0;
  97
  98       for J in Lo .. Hi loop
  99          W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
 100       end loop;
 101
 102       return W;
 103    end Width_Enumeration_16;
 104
 105    --------------------------
 106    -- Width_Enumeration_32 --
 107    --------------------------
 108
 109    function Width_Enumeration_32
 110      (Names   : String;
 111       Indexes : System.Address;
 112       Lo, Hi  : Natural)
 113       return    Natural
 114    is
 115       pragma Warnings (Off, Names);
 116
 117       W : Natural;
 118
 119       type Natural_32 is range 0 .. 2 ** 31 - 1;
 120       type Index_Table is array (Natural) of Natural_32;
 121       type Index_Table_Ptr is access Index_Table;
 122
 123       function To_Index_Table_Ptr is
 124         new Unchecked_Conversion (System.Address, Index_Table_Ptr);
 125
 126       IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);
 127
 128    begin
 129       W := 0;
 130
 131       for J in Lo .. Hi loop
 132          W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
 133       end loop;
 134
 135       return W;
 136    end Width_Enumeration_32;
 137
 138 end System.Wid_Enum;