gcc/ada/a-coinho.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT LIBRARY COMPONENTS                          --
   4 --                                                                          --
   5 --     A D A . C O N T A I N E R S . I N D E F I N I T E _ H O L D E R S    --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --             Copyright (C) 2012, 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
  28 with Ada.Unchecked_Deallocation;
  29
  30 package body Ada.Containers.Indefinite_Holders is
  31
  32    procedure Free is
  33      new Ada.Unchecked_Deallocation (Element_Type, Element_Access);
  34
  35    ---------
  36    -- "=" --
  37    ---------
  38
  39    function "=" (Left, Right : Holder) return Boolean is
  40    begin
  41       if Left.Element = null and Right.Element = null then
  42          return True;
  43
  44       elsif Left.Element /= null and Right.Element /= null then
  45          return Left.Element.all = Right.Element.all;
  46
  47       else
  48          return False;
  49       end if;
  50    end "=";
  51
  52    ------------
  53    -- Adjust --
  54    ------------
  55
  56    overriding procedure Adjust (Container : in out Holder) is
  57    begin
  58       if Container.Element /= null then
  59          Container.Element := new Element_Type'(Container.Element.all);
  60       end if;
  61
  62       Container.Busy := 0;
  63    end Adjust;
  64
  65    ------------
  66    -- Assign --
  67    ------------
  68
  69    procedure Assign (Target : in out Holder; Source : Holder) is
  70    begin
  71       if Target.Busy /= 0 then
  72          raise Program_Error with "attempt to tamper with elements";
  73       end if;
  74
  75       if Target.Element /= Source.Element then
  76          Free (Target.Element);
  77
  78          if Source.Element /= null then
  79             Target.Element := new Element_Type'(Source.Element.all);
  80          end if;
  81       end if;
  82    end Assign;
  83
  84    -----------
  85    -- Clear --
  86    -----------
  87
  88    procedure Clear (Container : in out Holder) is
  89    begin
  90       if Container.Busy /= 0 then
  91          raise Program_Error with "attempt to tamper with elements";
  92       end if;
  93
  94       Free (Container.Element);
  95    end Clear;
  96
  97    ----------
  98    -- Copy --
  99    ----------
 100
 101    function Copy (Source : Holder) return Holder is
 102    begin
 103       if Source.Element = null then
 104          return (AF.Controlled with null, 0);
 105       else
 106          return (AF.Controlled with new Element_Type'(Source.Element.all), 0);
 107       end if;
 108    end Copy;
 109
 110    -------------
 111    -- Element --
 112    -------------
 113
 114    function Element (Container : Holder) return Element_Type is
 115    begin
 116       if Container.Element = null then
 117          raise Constraint_Error with "container is empty";
 118       else
 119          return Container.Element.all;
 120       end if;
 121    end Element;
 122
 123    --------------
 124    -- Finalize --
 125    --------------
 126
 127    overriding procedure Finalize (Container : in out Holder) is
 128    begin
 129       if Container.Busy /= 0 then
 130          raise Program_Error with "attempt to tamper with elements";
 131       end if;
 132
 133       Free (Container.Element);
 134    end Finalize;
 135
 136    --------------
 137    -- Is_Empty --
 138    --------------
 139
 140    function Is_Empty (Container : Holder) return Boolean is
 141    begin
 142       return Container.Element = null;
 143    end Is_Empty;
 144
 145    ----------
 146    -- Move --
 147    ----------
 148
 149    procedure Move (Target : in out Holder; Source : in out Holder) is
 150    begin
 151       if Target.Busy /= 0 then
 152          raise Program_Error with "attempt to tamper with elements";
 153       end if;
 154
 155       if Source.Busy /= 0 then
 156          raise Program_Error with "attempt to tamper with elements";
 157       end if;
 158
 159       if Target.Element /= Source.Element then
 160          Free (Target.Element);
 161          Target.Element := Source.Element;
 162          Source.Element := null;
 163       end if;
 164    end Move;
 165
 166    -------------------
 167    -- Query_Element --
 168    -------------------
 169
 170    procedure Query_Element
 171      (Container : Holder;
 172       Process   : not null access procedure (Element : Element_Type))
 173    is
 174       B : Natural renames Container'Unrestricted_Access.Busy;
 175
 176    begin
 177       if Container.Element = null then
 178          raise Constraint_Error with "container is empty";
 179       end if;
 180
 181       B := B + 1;
 182
 183       begin
 184          Process (Container.Element.all);
 185       exception
 186          when others =>
 187             B := B - 1;
 188             raise;
 189       end;
 190
 191       B := B - 1;
 192    end Query_Element;
 193
 194    ----------
 195    -- Read --
 196    ----------
 197
 198    procedure Read
 199      (Stream    : not null access Ada.Streams.Root_Stream_Type'Class;
 200       Container : out Holder)
 201    is
 202    begin
 203       Clear (Container);
 204
 205       if not Boolean'Input (Stream) then
 206          Container.Element := new Element_Type'(Element_Type'Input (Stream));
 207       end if;
 208    end Read;
 209
 210    ---------------------
 211    -- Replace_Element --
 212    ---------------------
 213
 214    procedure Replace_Element
 215      (Container : in out Holder;
 216       New_Item  : Element_Type)
 217    is
 218    begin
 219       if Container.Busy /= 0 then
 220          raise Program_Error with "attempt to tamper with elements";
 221       end if;
 222
 223       declare
 224          X : Element_Access := Container.Element;
 225
 226          --  Element allocator may need an accessibility check in case actual
 227          --  type is class-wide or has access discriminants (RM 4.8(10.1) and
 228          --  AI12-0035).
 229
 230          pragma Unsuppress (Accessibility_Check);
 231
 232       begin
 233          Container.Element := new Element_Type'(New_Item);
 234          Free (X);
 235       end;
 236    end Replace_Element;
 237
 238    ---------------
 239    -- To_Holder --
 240    ---------------
 241
 242    function To_Holder (New_Item : Element_Type) return Holder is
 243       --  The element allocator may need an accessibility check in the case the
 244       --  actual type is class-wide or has access discriminants (RM 4.8(10.1)
 245       --  and AI12-0035).
 246
 247       pragma Unsuppress (Accessibility_Check);
 248
 249    begin
 250       return (AF.Controlled with new Element_Type'(New_Item), 0);
 251    end To_Holder;
 252
 253    --------------------
 254    -- Update_Element --
 255    --------------------
 256
 257    procedure Update_Element
 258      (Container : Holder;
 259       Process   : not null access procedure (Element : in out Element_Type))
 260    is
 261       B : Natural renames Container'Unrestricted_Access.Busy;
 262
 263    begin
 264       if Container.Element = null then
 265          raise Constraint_Error with "container is empty";
 266       end if;
 267
 268       B := B + 1;
 269
 270       begin
 271          Process (Container.Element.all);
 272       exception
 273          when others =>
 274             B := B - 1;
 275             raise;
 276       end;
 277
 278       B := B - 1;
 279    end Update_Element;
 280
 281    -----------
 282    -- Write --
 283    -----------
 284
 285    procedure Write
 286      (Stream    : not null access Ada.Streams.Root_Stream_Type'Class;
 287       Container : Holder)
 288    is
 289    begin
 290       Boolean'Output (Stream, Container.Element = null);
 291
 292       if Container.Element /= null then
 293          Element_Type'Output (Stream, Container.Element.all);
 294       end if;
 295    end Write;
 296
 297 end Ada.Containers.Indefinite_Holders;