libjava/gnu/regexp/RESyntax.java

   1 /* gnu/regexp/RESyntax.java
   2    Copyright (C) 1998-2002, 2004 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.regexp;
  40 import java.io.Serializable;
  41 import java.util.BitSet;
  42
  43 /**
  44  * An RESyntax specifies the way a regular expression will be compiled.
  45  * This class provides a number of predefined useful constants for
  46  * emulating popular regular expression syntaxes.  Additionally the
  47  * user may construct his or her own syntax, using any combination of the
  48  * syntax bit constants.  The syntax is an optional argument to any of the
  49  * matching methods on class RE.
  50  *
  51  * @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A>
  52  */
  53
  54 public final class RESyntax implements Serializable {
  55     static final String DEFAULT_LINE_SEPARATOR = System.getProperty("line.separator");
  56
  57     private static final String SYNTAX_IS_FINAL = RE.getLocalizedMessage("syntax.final");
  58
  59     private BitSet bits;
  60
  61     // true for the constant defined syntaxes
  62     private boolean isFinal = false;
  63
  64     private String lineSeparator = DEFAULT_LINE_SEPARATOR;
  65
  66   // Values for constants are bit indexes
  67
  68   /**
  69    * Syntax bit. Backslash is an escape character in lists.
  70    */
  71   public static final int RE_BACKSLASH_ESCAPE_IN_LISTS =  0;
  72
  73   /**
  74    * Syntax bit. Use \? instead of ? and \+ instead of +.
  75    */
  76   public static final int RE_BK_PLUS_QM                =  1;
  77
  78   /**
  79    * Syntax bit. POSIX character classes ([:...:]) in lists are allowed.
  80    */
  81   public static final int RE_CHAR_CLASSES              =  2;
  82
  83   /**
  84    * Syntax bit. ^ and $ are special everywhere.
  85    * <B>Not implemented.</B>
  86    */
  87   public static final int RE_CONTEXT_INDEP_ANCHORS     =  3;
  88
  89   /**
  90    * Syntax bit. Repetition operators are only special in valid positions.
  91    * <B>Not implemented.</B>
  92    */
  93   public static final int RE_CONTEXT_INDEP_OPS         =  4;
  94
  95   /**
  96    * Syntax bit. Repetition and alternation operators are invalid
  97    * at start and end of pattern and other places.
  98    * <B>Not implemented</B>.
  99    */
 100   public static final int RE_CONTEXT_INVALID_OPS       =  5;
 101
 102   /**
 103    * Syntax bit. Match-any-character operator (.) matches a newline.
 104    */
 105   public static final int RE_DOT_NEWLINE               =  6;
 106
 107   /**
 108    * Syntax bit. Match-any-character operator (.) does not match a null.
 109    */
 110   public static final int RE_DOT_NOT_NULL              =  7;
 111
 112   /**
 113    * Syntax bit. Intervals ({x}, {x,}, {x,y}) are allowed.
 114    */
 115   public static final int RE_INTERVALS                 =  8;
 116
 117   /**
 118    * Syntax bit. No alternation (|), match one-or-more (+), or
 119    * match zero-or-one (?) operators.
 120    */
 121   public static final int RE_LIMITED_OPS               =  9;
 122
 123   /**
 124    * Syntax bit. Newline is an alternation operator.
 125    */
 126   public static final int RE_NEWLINE_ALT               = 10; // impl.
 127
 128   /**
 129    * Syntax bit. Intervals use { } instead of \{ \}
 130    */
 131   public static final int RE_NO_BK_BRACES              = 11;
 132
 133   /**
 134    * Syntax bit. Grouping uses ( ) instead of \( \).
 135    */
 136   public static final int RE_NO_BK_PARENS              = 12;
 137
 138   /**
 139    * Syntax bit. Backreferences not allowed.
 140    */
 141   public static final int RE_NO_BK_REFS                = 13;
 142
 143   /**
 144    * Syntax bit. Alternation uses | instead of \|
 145    */
 146   public static final int RE_NO_BK_VBAR                = 14;
 147
 148   /**
 149    * Syntax bit. <B>Not implemented</B>.
 150    */
 151   public static final int RE_NO_EMPTY_RANGES           = 15;
 152
 153   /**
 154    * Syntax bit. An unmatched right parenthesis (')' or '\)', depending
 155    * on RE_NO_BK_PARENS) will throw an exception when compiling.
 156    */
 157   public static final int RE_UNMATCHED_RIGHT_PAREN_ORD = 16;
 158
 159   /**
 160    * Syntax bit. <B>Not implemented.</B>
 161    */
 162   public static final int RE_HAT_LISTS_NOT_NEWLINE     = 17;
 163
 164   /**
 165    * Syntax bit.  Stingy matching is allowed (+?, *?, ??, {x,y}?).
 166    */
 167   public static final int RE_STINGY_OPS                = 18;
 168
 169   /**
 170    * Syntax bit. Allow character class escapes (\d, \D, \s, \S, \w, \W).
 171    */
 172   public static final int RE_CHAR_CLASS_ESCAPES        = 19;
 173
 174   /**
 175    * Syntax bit. Allow use of (?:xxx) grouping (subexpression is not saved).
 176    */
 177   public static final int RE_PURE_GROUPING             = 20;
 178
 179   /**
 180    * Syntax bit. Allow use of (?=xxx) and (?!xxx) apply the subexpression
 181    * to the text following the current position without consuming that text.
 182    */
 183   public static final int RE_LOOKAHEAD                 = 21;
 184
 185   /**
 186    * Syntax bit. Allow beginning- and end-of-string anchors (\A, \Z).
 187    */
 188   public static final int RE_STRING_ANCHORS            = 22;
 189
 190   /**
 191    * Syntax bit. Allow embedded comments, (?#comment), as in Perl5.
 192    */
 193   public static final int RE_COMMENTS                  = 23;
 194
 195   /**
 196    * Syntax bit. Allow character class escapes within lists, as in Perl5.
 197    */
 198   public static final int RE_CHAR_CLASS_ESC_IN_LISTS   = 24;
 199
 200   /**
 201    * Syntax bit.  Possessive matching is allowed (++, *+, ?+, {x,y}+).
 202    */
 203   public static final int RE_POSSESSIVE_OPS            = 25;
 204
 205   private static final int BIT_TOTAL                   = 26;
 206
 207   /**
 208    * Predefined syntax.
 209    * Emulates regular expression support in the awk utility.
 210    */
 211   public static final RESyntax RE_SYNTAX_AWK;
 212
 213   /**
 214    * Predefined syntax.
 215    * Emulates regular expression support in the ed utility.
 216    */
 217   public static final RESyntax RE_SYNTAX_ED;
 218
 219   /**
 220    * Predefined syntax.
 221    * Emulates regular expression support in the egrep utility.
 222    */
 223   public static final RESyntax RE_SYNTAX_EGREP;
 224
 225   /**
 226    * Predefined syntax.
 227    * Emulates regular expression support in the GNU Emacs editor.
 228    */
 229   public static final RESyntax RE_SYNTAX_EMACS;
 230
 231   /**
 232    * Predefined syntax.
 233    * Emulates regular expression support in the grep utility.
 234    */
 235   public static final RESyntax RE_SYNTAX_GREP;
 236
 237   /**
 238    * Predefined syntax.
 239    * Emulates regular expression support in the POSIX awk specification.
 240    */
 241   public static final RESyntax RE_SYNTAX_POSIX_AWK;
 242
 243   /**
 244    * Predefined syntax.
 245    * Emulates POSIX basic regular expression support.
 246    */
 247   public static final RESyntax RE_SYNTAX_POSIX_BASIC;
 248
 249   /**
 250    * Predefined syntax.
 251    * Emulates regular expression support in the POSIX egrep specification.
 252    */
 253   public static final RESyntax RE_SYNTAX_POSIX_EGREP;
 254
 255   /**
 256    * Predefined syntax.
 257    * Emulates POSIX extended regular expression support.
 258    */
 259   public static final RESyntax RE_SYNTAX_POSIX_EXTENDED;
 260
 261   /**
 262    * Predefined syntax.
 263    * Emulates POSIX basic minimal regular expressions.
 264    */
 265   public static final RESyntax RE_SYNTAX_POSIX_MINIMAL_BASIC;
 266
 267   /**
 268    * Predefined syntax.
 269    * Emulates POSIX extended minimal regular expressions.
 270    */
 271   public static final RESyntax RE_SYNTAX_POSIX_MINIMAL_EXTENDED;
 272
 273   /**
 274    * Predefined syntax.
 275    * Emulates regular expression support in the sed utility.
 276    */
 277   public static final RESyntax RE_SYNTAX_SED;
 278
 279   /**
 280    * Predefined syntax.
 281    * Emulates regular expression support in Larry Wall's perl, version 4,
 282    */
 283   public static final RESyntax RE_SYNTAX_PERL4;
 284
 285   /**
 286    * Predefined syntax.
 287    * Emulates regular expression support in Larry Wall's perl, version 4,
 288    * using single line mode (/s modifier).
 289    */
 290   public static final RESyntax RE_SYNTAX_PERL4_S; // single line mode (/s)
 291
 292   /**
 293    * Predefined syntax.
 294    * Emulates regular expression support in Larry Wall's perl, version 5.
 295    */
 296   public static final RESyntax RE_SYNTAX_PERL5;
 297
 298   /**
 299    * Predefined syntax.
 300    * Emulates regular expression support in Larry Wall's perl, version 5,
 301    * using single line mode (/s modifier).
 302    */
 303   public static final RESyntax RE_SYNTAX_PERL5_S;
 304
 305     /**
 306      * Predefined syntax.
 307      * Emulates regular expression support in Java 1.4's java.util.regex
 308      * package.
 309      */
 310     public static final RESyntax RE_SYNTAX_JAVA_1_4;
 311
 312   static {
 313       // Define syntaxes
 314
 315       RE_SYNTAX_EMACS = new RESyntax().makeFinal();
 316
 317       RESyntax RE_SYNTAX_POSIX_COMMON = new RESyntax()
 318           .set(RE_CHAR_CLASSES)
 319           .set(RE_DOT_NEWLINE)
 320           .set(RE_DOT_NOT_NULL)
 321           .set(RE_INTERVALS)
 322           .set(RE_NO_EMPTY_RANGES)
 323           .makeFinal();
 324
 325       RE_SYNTAX_POSIX_BASIC = new RESyntax(RE_SYNTAX_POSIX_COMMON)
 326           .set(RE_BK_PLUS_QM)
 327           .makeFinal();
 328
 329       RE_SYNTAX_POSIX_EXTENDED = new RESyntax(RE_SYNTAX_POSIX_COMMON)
 330           .set(RE_CONTEXT_INDEP_ANCHORS)
 331           .set(RE_CONTEXT_INDEP_OPS)
 332           .set(RE_NO_BK_BRACES)
 333           .set(RE_NO_BK_PARENS)
 334           .set(RE_NO_BK_VBAR)
 335           .set(RE_UNMATCHED_RIGHT_PAREN_ORD)
 336           .makeFinal();
 337
 338       RE_SYNTAX_AWK = new RESyntax()
 339           .set(RE_BACKSLASH_ESCAPE_IN_LISTS)
 340           .set(RE_DOT_NOT_NULL)
 341           .set(RE_NO_BK_PARENS)
 342           .set(RE_NO_BK_REFS)
 343           .set(RE_NO_BK_VBAR)
 344           .set(RE_NO_EMPTY_RANGES)
 345           .set(RE_UNMATCHED_RIGHT_PAREN_ORD)
 346           .makeFinal();
 347
 348       RE_SYNTAX_POSIX_AWK = new RESyntax(RE_SYNTAX_POSIX_EXTENDED)
 349           .set(RE_BACKSLASH_ESCAPE_IN_LISTS)
 350           .makeFinal();
 351
 352       RE_SYNTAX_GREP = new RESyntax()
 353           .set(RE_BK_PLUS_QM)
 354           .set(RE_CHAR_CLASSES)
 355           .set(RE_HAT_LISTS_NOT_NEWLINE)
 356           .set(RE_INTERVALS)
 357           .set(RE_NEWLINE_ALT)
 358           .makeFinal();
 359
 360       RE_SYNTAX_EGREP = new RESyntax()
 361           .set(RE_CHAR_CLASSES)
 362           .set(RE_CONTEXT_INDEP_ANCHORS)
 363           .set(RE_CONTEXT_INDEP_OPS)
 364           .set(RE_HAT_LISTS_NOT_NEWLINE)
 365           .set(RE_NEWLINE_ALT)
 366           .set(RE_NO_BK_PARENS)
 367           .set(RE_NO_BK_VBAR)
 368           .makeFinal();
 369
 370       RE_SYNTAX_POSIX_EGREP = new RESyntax(RE_SYNTAX_EGREP)
 371           .set(RE_INTERVALS)
 372           .set(RE_NO_BK_BRACES)
 373           .makeFinal();
 374
 375       /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
 376
 377       RE_SYNTAX_ED = new RESyntax(RE_SYNTAX_POSIX_BASIC)
 378           .makeFinal();
 379
 380       RE_SYNTAX_SED = new RESyntax(RE_SYNTAX_POSIX_BASIC)
 381           .makeFinal();
 382
 383       RE_SYNTAX_POSIX_MINIMAL_BASIC = new RESyntax(RE_SYNTAX_POSIX_COMMON)
 384           .set(RE_LIMITED_OPS)
 385           .makeFinal();
 386
 387       /* Differs from RE_SYNTAX_POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
 388          replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added. */
 389
 390       RE_SYNTAX_POSIX_MINIMAL_EXTENDED = new RESyntax(RE_SYNTAX_POSIX_COMMON)
 391           .set(RE_CONTEXT_INDEP_ANCHORS)
 392           .set(RE_CONTEXT_INVALID_OPS)
 393           .set(RE_NO_BK_BRACES)
 394           .set(RE_NO_BK_PARENS)
 395           .set(RE_NO_BK_REFS)
 396           .set(RE_NO_BK_VBAR)
 397           .set(RE_UNMATCHED_RIGHT_PAREN_ORD)
 398           .makeFinal();
 399
 400       /* There is no official Perl spec, but here's a "best guess" */
 401
 402       RE_SYNTAX_PERL4 = new RESyntax()
 403           .set(RE_BACKSLASH_ESCAPE_IN_LISTS)
 404           .set(RE_CONTEXT_INDEP_ANCHORS)
 405           .set(RE_CONTEXT_INDEP_OPS)          // except for '{', apparently
 406           .set(RE_INTERVALS)
 407           .set(RE_NO_BK_BRACES)
 408           .set(RE_NO_BK_PARENS)
 409           .set(RE_NO_BK_VBAR)
 410           .set(RE_NO_EMPTY_RANGES)
 411           .set(RE_CHAR_CLASS_ESCAPES)    // \d,\D,\w,\W,\s,\S
 412           .makeFinal();
 413
 414       RE_SYNTAX_PERL4_S = new RESyntax(RE_SYNTAX_PERL4)
 415           .set(RE_DOT_NEWLINE)
 416           .makeFinal();
 417
 418       RE_SYNTAX_PERL5 = new RESyntax(RE_SYNTAX_PERL4)
 419           .set(RE_PURE_GROUPING)          // (?:)
 420           .set(RE_STINGY_OPS)             // *?,??,+?,{}?
 421           .set(RE_LOOKAHEAD)              // (?=)(?!)
 422           .set(RE_STRING_ANCHORS)         // \A,\Z
 423           .set(RE_CHAR_CLASS_ESC_IN_LISTS)// \d,\D,\w,\W,\s,\S within []
 424           .set(RE_COMMENTS)              // (?#)
 425           .makeFinal();
 426
 427       RE_SYNTAX_PERL5_S = new RESyntax(RE_SYNTAX_PERL5)
 428           .set(RE_DOT_NEWLINE)
 429           .makeFinal();
 430
 431       RE_SYNTAX_JAVA_1_4 = new RESyntax(RE_SYNTAX_PERL5)
 432           // XXX
 433           .set(RE_POSSESSIVE_OPS)         // *+,?+,++,{}+
 434           .makeFinal();
 435   }
 436
 437   /**
 438    * Construct a new syntax object with all bits turned off.
 439    * This is equivalent to RE_SYNTAX_EMACS.
 440    */
 441   public RESyntax() {
 442     bits = new BitSet(BIT_TOTAL);
 443   }
 444
 445     /**
 446      * Called internally when constructing predefined syntaxes
 447      * so their interpretation cannot vary.  Conceivably useful
 448      * for your syntaxes as well.  Causes IllegalAccessError to
 449      * be thrown if any attempt to modify the syntax is made.
 450      *
 451      * @return this object for convenient chaining
 452      */
 453     public RESyntax makeFinal() {
 454         isFinal = true;
 455         return this;
 456     }
 457
 458   /**
 459    * Construct a new syntax object with all bits set the same
 460    * as the other syntax.
 461    */
 462   public RESyntax(RESyntax other) {
 463     bits = (BitSet) other.bits.clone();
 464   }
 465
 466   /**
 467    * Check if a given bit is set in this syntax.
 468    */
 469   public boolean get(int index) {
 470     return bits.get(index);
 471   }
 472
 473   /**
 474    * Set a given bit in this syntax.
 475    *
 476    * @param index the constant (RESyntax.RE_xxx) bit to set.
 477    * @return a reference to this object for easy chaining.
 478    */
 479   public RESyntax set(int index) {
 480       if (isFinal) throw new IllegalAccessError(SYNTAX_IS_FINAL);
 481     bits.set(index);
 482     return this;
 483   }
 484
 485   /**
 486    * Clear a given bit in this syntax.
 487    *
 488    * @param index the constant (RESyntax.RE_xxx) bit to clear.
 489    * @return a reference to this object for easy chaining.
 490    */
 491   public RESyntax clear(int index) {
 492       if (isFinal) throw new IllegalAccessError(SYNTAX_IS_FINAL);
 493       bits.clear(index);
 494       return this;
 495   }
 496
 497     /**
 498      * Changes the line separator string for regular expressions
 499      * created using this RESyntax.  The default separator is the
 500      * value returned by the system property "line.separator", which
 501      * should be correct when reading platform-specific files from a
 502      * filesystem.  However, many programs may collect input from
 503      * sources where the line separator is differently specified (for
 504      * example, in the applet environment, the text box widget
 505      * interprets line breaks as single-character newlines,
 506      * regardless of the host platform.
 507      *
 508      * Note that setting the line separator to a character or
 509      * characters that have specific meaning within the current syntax
 510      * can cause unexpected chronosynclastic infundibula.
 511      *
 512      * @return this object for convenient chaining
 513      */
 514     public RESyntax setLineSeparator(String aSeparator) {
 515         if (isFinal) throw new IllegalAccessError(SYNTAX_IS_FINAL);
 516         lineSeparator = aSeparator;
 517         return this;
 518     }
 519
 520     /**
 521      * Returns the currently active line separator string.  The default
 522      * is the platform-dependent system property "line.separator".
 523      */
 524     public String getLineSeparator() {
 525         return lineSeparator;
 526     }
 527 }