gcc/ada/s-wwdwch.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                     S Y S T E M . W W D _ W C H A R                      --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
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  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 --
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  27 -- covered by the  GNU Public License.                                      --
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  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 with Interfaces; use Interfaces;
  35
  36 with System.WWd_Char;
  37
  38 package body System.Wwd_WChar is
  39
  40    ------------------------------------
  41    -- Wide_Wide_Width_Wide_Character --
  42    ------------------------------------
  43
  44    --  This is the case where we are talking about the Wide_Wide_Image of
  45    --  a Wide_Character, which is always the same character sequence as the
  46    --  Wide_Image of the same Wide_Character.
  47
  48    function Wide_Wide_Width_Wide_Character
  49      (Lo, Hi : Wide_Character) return Natural
  50    is
  51    begin
  52       return Wide_Width_Wide_Character (Lo, Hi);
  53    end Wide_Wide_Width_Wide_Character;
  54
  55    ------------------------------------
  56    -- Wide_Wide_Width_Wide_Wide_Char --
  57    ------------------------------------
  58
  59    function Wide_Wide_Width_Wide_Wide_Char
  60      (Lo, Hi : Wide_Wide_Character) return Natural
  61    is
  62       W  : Natural := 0;
  63       LV : constant Unsigned_32 := Wide_Wide_Character'Pos (Lo);
  64       HV : constant Unsigned_32 := Wide_Wide_Character'Pos (Hi);
  65
  66    begin
  67       --  Return zero if empty range
  68
  69       if LV > HV then
  70          return 0;
  71       end if;
  72
  73       --  If any characters in normal character range, then use normal
  74       --  Wide_Wide_Width attribute on this range to find out a starting point.
  75       --  Otherwise start with zero.
  76
  77       if LV <= 255 then
  78          W :=
  79            System.WWd_Char.Wide_Wide_Width_Character
  80              (Lo => Character'Val (LV),
  81               Hi => Character'Val (Unsigned_32'Min (255, HV)));
  82       else
  83          W := 0;
  84       end if;
  85
  86       --  Increase to at least 4 if FFFE or FFFF present. These correspond
  87       --  to the special language defined names FFFE/FFFF for these values.
  88
  89       if 16#FFFF# in LV .. HV or else 16#FFFE# in LV .. HV then
  90          W := Natural'Max (W, 4);
  91       end if;
  92
  93       --  Increase to at least 3 if any wide characters, corresponding to
  94       --  the normal ' character ' sequence. We know that the character fits.
  95
  96       if HV > 255 then
  97          W := Natural'Max (W, 3);
  98       end if;
  99
 100       return W;
 101    end Wide_Wide_Width_Wide_Wide_Char;
 102
 103    -------------------------------
 104    -- Wide_Width_Wide_Character --
 105    -------------------------------
 106
 107    function Wide_Width_Wide_Character
 108      (Lo, Hi : Wide_Character) return Natural
 109    is
 110       W  : Natural := 0;
 111       LV : constant Unsigned_32 := Wide_Character'Pos (Lo);
 112       HV : constant Unsigned_32 := Wide_Character'Pos (Hi);
 113
 114    begin
 115       --  Return zero if empty range
 116
 117       if LV > HV then
 118          return 0;
 119       end if;
 120
 121       --  If any characters in normal character range, then use normal
 122       --  Wide_Wide_Width attribute on this range to find out a starting point.
 123       --  Otherwise start with zero.
 124
 125       if LV <= 255 then
 126          W :=
 127            System.WWd_Char.Wide_Width_Character
 128              (Lo => Character'Val (LV),
 129               Hi => Character'Val (Unsigned_32'Min (255, HV)));
 130       else
 131          W := 0;
 132       end if;
 133
 134       --  Increase to at least 4 if FFFE or FFFF present. These correspond
 135       --  to the special language defined names FFFE/FFFF for these values.
 136
 137       if 16#FFFF# in LV .. HV or else 16#FFFE# in LV .. HV then
 138          W := Natural'Max (W, 4);
 139       end if;
 140
 141       --  Increase to at least 3 if any wide characters, corresponding to
 142       --  the normal 'character' sequence. We know that the character fits.
 143
 144       if HV > 255 then
 145          W := Natural'Max (W, 3);
 146       end if;
 147
 148       return W;
 149    end Wide_Width_Wide_Character;
 150
 151    ------------------------------------
 152    -- Wide_Width_Wide_Wide_Character --
 153    ------------------------------------
 154
 155    --  This is a nasty case, because we get into the business of representing
 156    --  out of range wide wide characters as wide strings. Let's let image do
 157    --  the work here. Too bad if this takes lots of time. It's silly anyway!
 158
 159    function Wide_Width_Wide_Wide_Character
 160      (Lo, Hi : Wide_Wide_Character) return Natural
 161    is
 162       W : Natural;
 163
 164    begin
 165       W := 0;
 166       for J in Lo .. Hi loop
 167          declare
 168             S : constant Wide_String := Wide_Wide_Character'Wide_Image (J);
 169          begin
 170             W := Natural'Max (W, S'Length);
 171          end;
 172       end loop;
 173
 174       return W;
 175    end Wide_Width_Wide_Wide_Character;
 176
 177 end System.Wwd_WChar;