gcc/ada/s-htable.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                        S Y S T E M . H T A B L E                         --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                    Copyright (C) 1995-2011, AdaCore                      --
  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 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 pragma Compiler_Unit;
  33
  34 with Ada.Unchecked_Deallocation;
  35 with System.String_Hash;
  36
  37 package body System.HTable is
  38
  39    -------------------
  40    -- Static_HTable --
  41    -------------------
  42
  43    package body Static_HTable is
  44
  45       Table : array (Header_Num) of Elmt_Ptr;
  46
  47       Iterator_Index   : Header_Num;
  48       Iterator_Ptr     : Elmt_Ptr;
  49       Iterator_Started : Boolean := False;
  50
  51       function Get_Non_Null return Elmt_Ptr;
  52       --  Returns Null_Ptr if Iterator_Started is false or the Table is empty.
  53       --  Returns Iterator_Ptr if non null, or the next non null element in
  54       --  table if any.
  55
  56       ---------
  57       -- Get --
  58       ---------
  59
  60       function Get (K : Key) return Elmt_Ptr is
  61          Elmt : Elmt_Ptr;
  62
  63       begin
  64          Elmt := Table (Hash (K));
  65
  66          loop
  67             if Elmt = Null_Ptr then
  68                return Null_Ptr;
  69
  70             elsif Equal (Get_Key (Elmt), K) then
  71                return Elmt;
  72
  73             else
  74                Elmt := Next (Elmt);
  75             end if;
  76          end loop;
  77       end Get;
  78
  79       ---------------
  80       -- Get_First --
  81       ---------------
  82
  83       function Get_First return Elmt_Ptr is
  84       begin
  85          Iterator_Started := True;
  86          Iterator_Index := Table'First;
  87          Iterator_Ptr := Table (Iterator_Index);
  88          return Get_Non_Null;
  89       end Get_First;
  90
  91       --------------
  92       -- Get_Next --
  93       --------------
  94
  95       function Get_Next return Elmt_Ptr is
  96       begin
  97          if not Iterator_Started then
  98             return Null_Ptr;
  99          end if;
 100
 101          Iterator_Ptr := Next (Iterator_Ptr);
 102          return Get_Non_Null;
 103       end Get_Next;
 104
 105       ------------------
 106       -- Get_Non_Null --
 107       ------------------
 108
 109       function Get_Non_Null return Elmt_Ptr is
 110       begin
 111          while Iterator_Ptr = Null_Ptr loop
 112             if Iterator_Index = Table'Last then
 113                Iterator_Started := False;
 114                return Null_Ptr;
 115             end if;
 116
 117             Iterator_Index := Iterator_Index + 1;
 118             Iterator_Ptr   := Table (Iterator_Index);
 119          end loop;
 120
 121          return Iterator_Ptr;
 122       end Get_Non_Null;
 123
 124       -------------
 125       -- Present --
 126       -------------
 127
 128       function Present (K : Key) return Boolean is
 129       begin
 130          return Get (K) /= Null_Ptr;
 131       end Present;
 132
 133       ------------
 134       -- Remove --
 135       ------------
 136
 137       procedure Remove  (K : Key) is
 138          Index     : constant Header_Num := Hash (K);
 139          Elmt      : Elmt_Ptr;
 140          Next_Elmt : Elmt_Ptr;
 141
 142       begin
 143          Elmt := Table (Index);
 144
 145          if Elmt = Null_Ptr then
 146             return;
 147
 148          elsif Equal (Get_Key (Elmt), K) then
 149             Table (Index) := Next (Elmt);
 150
 151          else
 152             loop
 153                Next_Elmt :=  Next (Elmt);
 154
 155                if Next_Elmt = Null_Ptr then
 156                   return;
 157
 158                elsif Equal (Get_Key (Next_Elmt), K) then
 159                   Set_Next (Elmt, Next (Next_Elmt));
 160                   return;
 161
 162                else
 163                   Elmt := Next_Elmt;
 164                end if;
 165             end loop;
 166          end if;
 167       end Remove;
 168
 169       -----------
 170       -- Reset --
 171       -----------
 172
 173       procedure Reset is
 174       begin
 175          for J in Table'Range loop
 176             Table (J) := Null_Ptr;
 177          end loop;
 178       end Reset;
 179
 180       ---------
 181       -- Set --
 182       ---------
 183
 184       procedure Set (E : Elmt_Ptr) is
 185          Index : Header_Num;
 186
 187       begin
 188          Index := Hash (Get_Key (E));
 189          Set_Next (E, Table (Index));
 190          Table (Index) := E;
 191       end Set;
 192
 193       ------------------------
 194       -- Set_If_Not_Present --
 195       ------------------------
 196
 197       function Set_If_Not_Present (E : Elmt_Ptr) return Boolean is
 198          K     : constant Key := Get_Key (E);
 199          Index : constant Header_Num := Hash (K);
 200          Elmt  : Elmt_Ptr := Table (Index);
 201
 202       begin
 203          loop
 204             if Elmt = Null_Ptr then
 205                Set_Next (E, Table (Index));
 206                Table (Index) := E;
 207
 208                return True;
 209
 210             elsif Equal (Get_Key (Elmt), K) then
 211                return False;
 212
 213             else
 214                Elmt := Next (Elmt);
 215             end if;
 216          end loop;
 217       end Set_If_Not_Present;
 218
 219    end Static_HTable;
 220
 221    -------------------
 222    -- Simple_HTable --
 223    -------------------
 224
 225    package body Simple_HTable is
 226
 227       type Element_Wrapper;
 228       type Elmt_Ptr is access all Element_Wrapper;
 229       type Element_Wrapper is record
 230          K    : Key;
 231          E    : Element;
 232          Next : Elmt_Ptr;
 233       end record;
 234
 235       procedure Free is new
 236         Ada.Unchecked_Deallocation (Element_Wrapper, Elmt_Ptr);
 237
 238       procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
 239       function  Next     (E : Elmt_Ptr) return Elmt_Ptr;
 240       function  Get_Key  (E : Elmt_Ptr) return Key;
 241
 242       package Tab is new Static_HTable (
 243         Header_Num => Header_Num,
 244         Element    => Element_Wrapper,
 245         Elmt_Ptr   => Elmt_Ptr,
 246         Null_Ptr   => null,
 247         Set_Next   => Set_Next,
 248         Next       => Next,
 249         Key        => Key,
 250         Get_Key    => Get_Key,
 251         Hash       => Hash,
 252         Equal      => Equal);
 253
 254       ---------
 255       -- Get --
 256       ---------
 257
 258       function  Get (K : Key) return Element is
 259          Tmp : constant Elmt_Ptr := Tab.Get (K);
 260       begin
 261          if Tmp = null then
 262             return No_Element;
 263          else
 264             return Tmp.E;
 265          end if;
 266       end Get;
 267
 268       ---------------
 269       -- Get_First --
 270       ---------------
 271
 272       function Get_First return Element is
 273          Tmp : constant Elmt_Ptr := Tab.Get_First;
 274       begin
 275          if Tmp = null then
 276             return No_Element;
 277          else
 278             return Tmp.E;
 279          end if;
 280       end Get_First;
 281
 282       procedure Get_First (K : in out Key; E : out Element) is
 283          Tmp : constant Elmt_Ptr := Tab.Get_First;
 284       begin
 285          if Tmp = null then
 286             E := No_Element;
 287          else
 288             K := Tmp.K;
 289             E := Tmp.E;
 290          end if;
 291       end Get_First;
 292
 293       -------------
 294       -- Get_Key --
 295       -------------
 296
 297       function Get_Key (E : Elmt_Ptr) return Key is
 298       begin
 299          return E.K;
 300       end Get_Key;
 301
 302       --------------
 303       -- Get_Next --
 304       --------------
 305
 306       function Get_Next return Element is
 307          Tmp : constant Elmt_Ptr := Tab.Get_Next;
 308       begin
 309          if Tmp = null then
 310             return No_Element;
 311          else
 312             return Tmp.E;
 313          end if;
 314       end Get_Next;
 315
 316       procedure Get_Next (K : in out Key; E : out Element) is
 317          Tmp : constant Elmt_Ptr := Tab.Get_Next;
 318       begin
 319          if Tmp = null then
 320             E := No_Element;
 321          else
 322             K := Tmp.K;
 323             E := Tmp.E;
 324          end if;
 325       end Get_Next;
 326
 327       ----------
 328       -- Next --
 329       ----------
 330
 331       function Next (E : Elmt_Ptr) return Elmt_Ptr is
 332       begin
 333          return E.Next;
 334       end Next;
 335
 336       ------------
 337       -- Remove --
 338       ------------
 339
 340       procedure Remove  (K : Key) is
 341          Tmp : Elmt_Ptr;
 342
 343       begin
 344          Tmp := Tab.Get (K);
 345
 346          if Tmp /= null then
 347             Tab.Remove (K);
 348             Free (Tmp);
 349          end if;
 350       end Remove;
 351
 352       -----------
 353       -- Reset --
 354       -----------
 355
 356       procedure Reset is
 357          E1, E2 : Elmt_Ptr;
 358
 359       begin
 360          E1 := Tab.Get_First;
 361          while E1 /= null loop
 362             E2 := Tab.Get_Next;
 363             Free (E1);
 364             E1 := E2;
 365          end loop;
 366
 367          Tab.Reset;
 368       end Reset;
 369
 370       ---------
 371       -- Set --
 372       ---------
 373
 374       procedure Set (K : Key; E : Element) is
 375          Tmp : constant Elmt_Ptr := Tab.Get (K);
 376       begin
 377          if Tmp = null then
 378             Tab.Set (new Element_Wrapper'(K, E, null));
 379          else
 380             Tmp.E := E;
 381          end if;
 382       end Set;
 383
 384       --------------
 385       -- Set_Next --
 386       --------------
 387
 388       procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
 389       begin
 390          E.Next := Next;
 391       end Set_Next;
 392    end Simple_HTable;
 393
 394    ----------
 395    -- Hash --
 396    ----------
 397
 398    function Hash (Key : String) return Header_Num is
 399       type Uns is mod 2 ** 32;
 400
 401       function Hash_Fun is
 402          new System.String_Hash.Hash (Character, String, Uns);
 403
 404    begin
 405       return Header_Num'First +
 406         Header_Num'Base (Hash_Fun (Key) mod Header_Num'Range_Length);
 407    end Hash;
 408
 409 end System.HTable;