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) 1992-2004 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
 284       begin
 285          for J in Source'Range loop
 286             Mapped_Source (J) := Mapping.all (Source (J));
 287          end loop;
 288       end;
 289
 290       --  Forwards case
 291
 292       if Going = Forward then
 293          for J in 1 .. Source'Length - Pattern'Length + 1 loop
 294             Cur_Index := Source'First + J - 1;
 295
 296             if Pattern = Mapped_Source
 297                            (Cur_Index .. Cur_Index + Pattern'Length - 1)
 298             then
 299                return Cur_Index;
 300             end if;
 301          end loop;
 302
 303       --  Backwards case
 304
 305       else
 306          for J in reverse 1 .. Source'Length - Pattern'Length + 1 loop
 307             Cur_Index := Source'First + J - 1;
 308
 309             if Pattern = Mapped_Source
 310                            (Cur_Index .. Cur_Index + Pattern'Length - 1)
 311             then
 312                return Cur_Index;
 313             end if;
 314          end loop;
 315       end if;
 316
 317       return 0;
 318    end Index;
 319
 320    function Index
 321      (Source : String;
 322       Set    : Maps.Character_Set;
 323       Test   : Membership := Inside;
 324       Going  : Direction  := Forward) return Natural
 325    is
 326    begin
 327       --  Forwards case
 328
 329       if Going = Forward then
 330          for J in Source'Range loop
 331             if Belongs (Source (J), Set, Test) then
 332                return J;
 333             end if;
 334          end loop;
 335
 336       --  Backwards case
 337
 338       else
 339          for J in reverse Source'Range loop
 340             if Belongs (Source (J), Set, Test) then
 341                return J;
 342             end if;
 343          end loop;
 344       end if;
 345
 346       --  Fall through if no match
 347
 348       return 0;
 349    end Index;
 350
 351    ---------------------
 352    -- Index_Non_Blank --
 353    ---------------------
 354
 355    function Index_Non_Blank
 356      (Source : String;
 357       Going  : Direction := Forward) return Natural
 358    is
 359    begin
 360       if Going = Forward then
 361          for J in Source'Range loop
 362             if Source (J) /= ' ' then
 363                return J;
 364             end if;
 365          end loop;
 366
 367       else -- Going = Backward
 368          for J in reverse Source'Range loop
 369             if Source (J) /= ' ' then
 370                return J;
 371             end if;
 372          end loop;
 373       end if;
 374
 375       --  Fall through if no match
 376
 377       return 0;
 378
 379    end Index_Non_Blank;
 380
 381 end Ada.Strings.Search;