gcc/ada/a-strsea.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                   A D A . S T R I N G S . S E A R C H                    --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005 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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  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 --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  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 --  Note: This code is derived from the ADAR.CSH public domain Ada 83
  35 --  versions of the Appendix C string handling packages (code extracted
  36 --  from Ada.Strings.Fixed). A significant change is that we optimize the
  37 --  case of identity mappings for Count and Index, and also Index_Non_Blank
  38 --  is specialized (rather than using the general Index routine).
  39
  40
  41 with Ada.Strings.Maps; use Ada.Strings.Maps;
  42
  43 package body Ada.Strings.Search is
  44
  45    -----------------------
  46    -- Local Subprograms --
  47    -----------------------
  48
  49    function Belongs
  50      (Element : Character;
  51       Set     : Maps.Character_Set;
  52       Test    : Membership) return Boolean;
  53    pragma Inline (Belongs);
  54    --  Determines if the given element is in (Test = Inside) or not in
  55    --  (Test = Outside) the given character set.
  56
  57    -------------
  58    -- Belongs --
  59    -------------
  60
  61    function Belongs
  62      (Element : Character;
  63       Set     : Maps.Character_Set;
  64       Test    : Membership) return Boolean
  65    is
  66    begin
  67       if Test = Inside then
  68          return Is_In (Element, Set);
  69       else
  70          return not Is_In (Element, Set);
  71       end if;
  72    end Belongs;
  73
  74    -----------
  75    -- Count --
  76    -----------
  77
  78    function Count
  79      (Source  : String;
  80       Pattern : String;
  81       Mapping : Maps.Character_Mapping := Maps.Identity) return Natural
  82    is
  83       N : Natural;
  84       J : Natural;
  85
  86       Mapped_Source : String (Source'Range);
  87
  88    begin
  89       for J in Source'Range loop
  90          Mapped_Source (J) := Value (Mapping, Source (J));
  91       end loop;
  92
  93       if Pattern = "" then
  94          raise Pattern_Error;
  95       end if;
  96
  97       N := 0;
  98       J := Source'First;
  99
 100       while J <= Source'Last - (Pattern'Length - 1) loop
 101          if Mapped_Source (J .. J + (Pattern'Length - 1)) = Pattern then
 102             N := N + 1;
 103             J := J + Pattern'Length;
 104          else
 105             J := J + 1;
 106          end if;
 107       end loop;
 108
 109       return N;
 110    end Count;
 111
 112    function Count
 113      (Source  : String;
 114       Pattern : String;
 115       Mapping : Maps.Character_Mapping_Function) return Natural
 116    is
 117       Mapped_Source : String (Source'Range);
 118       N             : Natural;
 119       J             : Natural;
 120
 121    begin
 122       if Pattern = "" then
 123          raise Pattern_Error;
 124       end if;
 125
 126       --  We make sure Access_Check is unsuppressed so that the Mapping.all
 127       --  call will generate a friendly Constraint_Error if the value for
 128       --  Mapping is uninitialized (and hence null).
 129
 130       declare
 131          pragma Unsuppress (Access_Check);
 132
 133       begin
 134          for J in Source'Range loop
 135             Mapped_Source (J) := Mapping.all (Source (J));
 136          end loop;
 137       end;
 138
 139       N := 0;
 140       J := Source'First;
 141
 142       while J <= Source'Last - (Pattern'Length - 1) loop
 143          if Mapped_Source (J .. J + (Pattern'Length - 1)) = Pattern then
 144             N := N + 1;
 145             J := J + Pattern'Length;
 146          else
 147             J := J + 1;
 148          end if;
 149       end loop;
 150
 151       return N;
 152    end Count;
 153
 154    function Count
 155      (Source : String;
 156       Set    : Maps.Character_Set) return Natural
 157    is
 158       N : Natural := 0;
 159
 160    begin
 161       for J in Source'Range loop
 162          if Is_In (Source (J), Set) then
 163             N := N + 1;
 164          end if;
 165       end loop;
 166
 167       return N;
 168    end Count;
 169
 170    ----------------
 171    -- Find_Token --
 172    ----------------
 173
 174    procedure Find_Token
 175      (Source : String;
 176       Set    : Maps.Character_Set;
 177       Test   : Membership;
 178       First  : out Positive;
 179       Last   : out Natural)
 180    is
 181    begin
 182       for J in Source'Range loop
 183          if Belongs (Source (J), Set, Test) then
 184             First := J;
 185
 186             for K in J + 1 .. Source'Last loop
 187                if not Belongs (Source (K), Set, Test) then
 188                   Last := K - 1;
 189                   return;
 190                end if;
 191             end loop;
 192
 193             --  Here if J indexes 1st char of token, and all chars
 194             --  after J are in the token
 195
 196             Last := Source'Last;
 197             return;
 198          end if;
 199       end loop;
 200
 201       --  Here if no token found
 202
 203       First := Source'First;
 204       Last  := 0;
 205    end Find_Token;
 206
 207    -----------
 208    -- Index --
 209    -----------
 210
 211    function Index
 212      (Source  : String;
 213       Pattern : String;
 214       Going   : Direction := Forward;
 215       Mapping : Maps.Character_Mapping := Maps.Identity) return Natural
 216    is
 217       Cur_Index     : Natural;
 218       Mapped_Source : String (Source'Range);
 219
 220
 221    begin
 222       if Pattern = "" then
 223          raise Pattern_Error;
 224       end if;
 225
 226       for J in Source'Range loop
 227          Mapped_Source (J) := Value (Mapping, Source (J));
 228       end loop;
 229
 230       --  Forwards case
 231
 232       if Going = Forward then
 233          for J in 1 .. Source'Length - Pattern'Length + 1 loop
 234             Cur_Index := Source'First + J - 1;
 235
 236             if Pattern = Mapped_Source
 237                            (Cur_Index .. Cur_Index + Pattern'Length - 1)
 238             then
 239                return Cur_Index;
 240             end if;
 241          end loop;
 242
 243       --  Backwards case
 244
 245       else
 246          for J in reverse 1 .. Source'Length - Pattern'Length + 1 loop
 247             Cur_Index := Source'First + J - 1;
 248
 249             if Pattern = Mapped_Source
 250                            (Cur_Index .. Cur_Index + Pattern'Length - 1)
 251             then
 252                return Cur_Index;
 253             end if;
 254          end loop;
 255       end if;
 256
 257       --  Fall through if no match found. Note that the loops are skipped
 258       --  completely in the case of the pattern being longer than the source.
 259
 260       return 0;
 261    end Index;
 262
 263    function Index
 264      (Source  : String;
 265       Pattern : String;
 266       Going   : Direction := Forward;
 267       Mapping : Maps.Character_Mapping_Function) return Natural
 268    is
 269       Mapped_Source : String (Source'Range);
 270       Cur_Index     : Natural;
 271
 272    begin
 273       if Pattern = "" then
 274          raise Pattern_Error;
 275       end if;
 276
 277       --  We make sure Access_Check is unsuppressed so that the Mapping.all
 278       --  call will generate a friendly Constraint_Error if the value for
 279       --  Mapping is uninitialized (and hence null).
 280
 281       declare
 282          pragma Unsuppress (Access_Check);
 283       begin
 284          for J in Source'Range loop
 285             Mapped_Source (J) := Mapping.all (Source (J));
 286          end loop;
 287       end;
 288
 289       --  Forwards case
 290
 291       if Going = Forward then
 292          for J in 1 .. Source'Length - Pattern'Length + 1 loop
 293             Cur_Index := Source'First + J - 1;
 294
 295             if Pattern = Mapped_Source
 296                            (Cur_Index .. Cur_Index + Pattern'Length - 1)
 297             then
 298                return Cur_Index;
 299             end if;
 300          end loop;
 301
 302       --  Backwards case
 303
 304       else
 305          for J in reverse 1 .. Source'Length - Pattern'Length + 1 loop
 306             Cur_Index := Source'First + J - 1;
 307
 308             if Pattern = Mapped_Source
 309                            (Cur_Index .. Cur_Index + Pattern'Length - 1)
 310             then
 311                return Cur_Index;
 312             end if;
 313          end loop;
 314       end if;
 315
 316       return 0;
 317    end Index;
 318
 319    function Index
 320      (Source : String;
 321       Set    : Maps.Character_Set;
 322       Test   : Membership := Inside;
 323       Going  : Direction  := Forward) return Natural
 324    is
 325    begin
 326       --  Forwards case
 327
 328       if Going = Forward then
 329          for J in Source'Range loop
 330             if Belongs (Source (J), Set, Test) then
 331                return J;
 332             end if;
 333          end loop;
 334
 335       --  Backwards case
 336
 337       else
 338          for J in reverse Source'Range loop
 339             if Belongs (Source (J), Set, Test) then
 340                return J;
 341             end if;
 342          end loop;
 343       end if;
 344
 345       --  Fall through if no match
 346
 347       return 0;
 348    end Index;
 349
 350    function Index
 351      (Source  : String;
 352       Pattern : String;
 353       From    : Positive;
 354       Going   : Direction := Forward;
 355       Mapping : Maps.Character_Mapping := Maps.Identity) return Natural
 356    is
 357    begin
 358       if Going = Forward then
 359          if From < Source'First then
 360             raise Index_Error;
 361          end if;
 362
 363          return
 364            Index (Source (From .. Source'Last), Pattern, Forward, Mapping);
 365
 366       else
 367          if From > Source'Last then
 368             raise Index_Error;
 369          end if;
 370
 371          return
 372            Index (Source (Source'First .. From), Pattern, Backward, Mapping);
 373       end if;
 374    end Index;
 375
 376    function Index
 377      (Source  : String;
 378       Pattern : String;
 379       From    : Positive;
 380       Going   : Direction := Forward;
 381       Mapping : Maps.Character_Mapping_Function) return Natural
 382    is
 383    begin
 384       if Going = Forward then
 385          if From < Source'First then
 386             raise Index_Error;
 387          end if;
 388
 389          return Index
 390            (Source (From .. Source'Last), Pattern, Forward, Mapping);
 391
 392       else
 393          if From > Source'Last then
 394             raise Index_Error;
 395          end if;
 396
 397          return Index
 398            (Source (Source'First .. From), Pattern, Backward, Mapping);
 399       end if;
 400    end Index;
 401
 402    function Index
 403      (Source  : String;
 404       Set     : Maps.Character_Set;
 405       From    : Positive;
 406       Test    : Membership := Inside;
 407       Going   : Direction := Forward) return Natural
 408    is
 409    begin
 410       if Going = Forward then
 411          if From < Source'First then
 412             raise Index_Error;
 413          end if;
 414
 415          return
 416            Index (Source (From .. Source'Last), Set, Test, Forward);
 417
 418       else
 419          if From > Source'Last then
 420             raise Index_Error;
 421          end if;
 422
 423          return
 424            Index (Source (Source'First .. From), Set, Test, Backward);
 425       end if;
 426    end Index;
 427
 428    ---------------------
 429    -- Index_Non_Blank --
 430    ---------------------
 431
 432    function Index_Non_Blank
 433      (Source : String;
 434       Going  : Direction := Forward) return Natural
 435    is
 436    begin
 437       if Going = Forward then
 438          for J in Source'Range loop
 439             if Source (J) /= ' ' then
 440                return J;
 441             end if;
 442          end loop;
 443
 444       else -- Going = Backward
 445          for J in reverse Source'Range loop
 446             if Source (J) /= ' ' then
 447                return J;
 448             end if;
 449          end loop;
 450       end if;
 451
 452       --  Fall through if no match
 453
 454       return 0;
 455    end Index_Non_Blank;
 456
 457    function Index_Non_Blank
 458      (Source : String;
 459       From   : Positive;
 460       Going  : Direction := Forward) return Natural
 461    is
 462    begin
 463       if Going = Forward then
 464          if From < Source'First then
 465             raise Index_Error;
 466          end if;
 467
 468          return
 469            Index_Non_Blank (Source (From .. Source'Last), Forward);
 470
 471       else
 472          if From > Source'Last then
 473             raise Index_Error;
 474          end if;
 475
 476          return
 477            Index_Non_Blank (Source (Source'First .. From), Backward);
 478       end if;
 479    end Index_Non_Blank;
 480
 481 end Ada.Strings.Search;