Source code: com/memoire/re/RE.java

   
   
   package com.memoire.re;
   import com.memoire.re.*;
   
   /*
    *  gnu/regexp/RE.java
    *  Copyright (C) 1998 Wes Biggs
    *
   *  This library is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU Library General Public License as published
   *  by the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This library is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU Library General Public License for more details.
   *
   *  You should have received a copy of the GNU Library General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  
  import java.io.InputStream;
  import java.util.Vector;
  
  class IntPair {
    public int first, second;
  }
  
  class CharUnit {
    public char ch;
    public boolean bk;
  }
  
  /**
   * RE provides the user interface for compiling and matching regular
   * expressions.
   * <P>
   * A regular expression object (class RE) is compiled by constructing it
   * from a String, StringBuffer or character array, with optional 
   * compilation flags (below)
   * and an optional syntax specification (see RESyntax; if not specified,
   * <code>RESyntax.RE_SYNTAX_PERL5</code> is used).
   * <P>
   * Various methods attempt to match input text against a compiled
   * regular expression.  These methods are:
   * <LI><code>isMatch</code>: returns true if the input text in its entirety
   * matches the regular expression pattern.
   * <LI><code>getMatch</code>: returns the first match found in the input text,
   * or null if no match is found.
   * <LI><code>getAllMatches</code>: returns an array of all non-overlapping 
   * matches found in the input text.  If no matches are found, the array is
   * zero-length.
   * <LI><code>substitute</code>: substitute the first occurence of the pattern
   * in the input text with a replacement string (which may include
   * metacharacters $0-$9, see REMatch.substituteInto).
   * <LI><code>substituteAll</code>: same as above, but repeat for each match
   * before returning.
   * <LI><code>getMatchEnumeration</code>: returns an REMatchEnumeration object
   * that allows iteration over the matches (see REMatchEnumeration for some
   * reasons why you may want to do this instead of using <code>getAllMatches</code>.
   * <P>
   * These methods all have similar argument lists.  The input can be a
   * String, a character array, a StringBuffer or an InputStream of some sort.
   * Note that
   * when using an InputStream, the stream read position cannot be guaranteed
   * after attempting a match (this is not a bug, but a consequence of the way
   * regular expressions work).  Using an REMatchEnumeration can eliminate most
   * positioning problems.
   * <P>
   * The optional index argument specifies the offset from the beginning of the
   * text at which the search should start (see the descriptions of some of
   * the execution flags for how this can affect positional pattern operators).
   * For an InputStream, this means an offset from the current read position,
   * so subsequent calls with the same index argument on an InputStream will not
   * necessarily be accessing the same position on the stream, whereas repeated
   * searches at a given index in a fixed string will return consistent
   * results.
   * <P>
   * You can optionally affect the execution environment by using a
   * combination of execution flags (constants listed below).
   *
   * @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A>
   * @version 1.0.8, 21 March 1999
   */
  
  public class RE extends REToken {
    // This String will be returned by getVersion()
    private static final String s_version = "1.0.8";
  
    // These are, respectively, the first and last tokens in our linked list
    // If there is only one token, firstToken == lastToken
    private REToken firstToken, lastToken;
  
    // This is the number of subexpressions in this regular expression,
    // with a minimum value of zero.  Returned by getNumSubs()
   private int m_numSubs;
 
   /**
    * Compilation flag. Do  not  differentiate  case.   Subsequent
    * searches  using  this  RE will be case insensitive.
    */
   public static final int REG_ICASE = 2;
 
   /**
    * Compilation flag. The match-any-character operator (dot)
    * will match a newline character.  When set this overrides the syntax
    * bit RE_DOT_NEWLINE (see RESyntax for details).  This is equivalent to
    * the "/s" operator in Perl.
    */
   public static final int REG_DOT_NEWLINE = 4;
 
   /**
    * Compilation flag. Use multiline mode.  In this mode, the ^ and $
    * anchors will match based on newlines within the input. This is
    * equivalent to the "/m" operator in Perl.
    */
   public static final int REG_MULTILINE = 8;
 
   /**
    * Execution flag.
    * The match-beginning operator (^) will not match at the beginning
    * of the input string. Useful for matching on a substring when you
    * know the context of the input is such that position zero of the
    * input to the match test is not actually position zero of the text.
    * <P>
    * This example demonstrates the results of various ways of matching on
    * a substring.
    * <P>
    * <CODE>
    * String s = "food bar fool";<BR>
    * RE exp = new RE("^foo.");<BR>
    * REMatch m0 = exp.getMatch(s);<BR>
    * REMatch m1 = exp.getMatch(s.substring(8));<BR>
    * REMatch m2 = exp.getMatch(s.substring(8),0,RE.REG_NOTBOL); <BR>
    * REMatch m3 = exp.getMatch(s,8);                            <BR>
    * REMatch m4 = exp.getMatch(s,8,RE.REG_ANCHORINDEX);         <BR>
    * <P>
    * // Results:<BR>
    * //  m0 = "food"<BR>
    * //  m1 = "fool"<BR>
    * //  m2 = null<BR>
    * //  m3 = null<BR>
    * //  m4 = "fool"<BR>
    * </CODE>
    */
   public static final int REG_NOTBOL = 16;
 
   /**
    * Execution flag.
    * The match-end operator ($) does not match at the end
    * of the input string. Useful for matching on substrings.
    */
   public static final int REG_NOTEOL = 32;
 
   /**
    * Execution flag.
    * The match-beginning operator (^) matches not at position 0
    * in the input string, but at the position the search started at
    * (based on the index input given to the getMatch function).  See
    * the example under REG_NOTBOL.
    */
   public static final int REG_ANCHORINDEX = 64;
 
   /** Returns a string representing the version of the gnu.regexp package. */
   public static final String version() {
     return s_version;
   }
 
   /**
    * Constructs a regular expression pattern buffer without any compilation
    * flags set, and using the default syntax (RESyntax.RE_SYNTAX_PERL5).
    *
    * @param pattern A regular expression pattern, in the form of a String,
    *   StringBuffer or char[].
    * @exception REException The input pattern could not be parsed.
    * @exception IllegalArgumentException The pattern was not a String, 
    *   StringBuffer or char[].
    * @exception NullPointerException The pattern was null.
    */
   public RE(Object pattern) throws REException {
     this(pattern,0,RESyntax.RE_SYNTAX_PERL5,0,0);
   }
 
   /**
    * Constructs a regular expression pattern buffer using the specified
    * compilation flags and the default syntax (RESyntax.RE_SYNTAX_PERL5).
    *
    * @param pattern A regular expression pattern, in the form of a String,
    *   StringBuffer, or char[].
    * @param cflags The logical OR of any combination of the compilation flags listed above.
    * @exception REException The input pattern could not be parsed.
    * @exception IllegalArgumentException The pattern was not a String, 
    *   StringBuffer or char[].
    * @exception NullPointerException The pattern was null.
    */
   public RE(Object pattern, int cflags) throws REException {
     this(pattern,cflags,RESyntax.RE_SYNTAX_PERL5,0,0);
   }
 
   /**
    * Constructs a regular expression pattern buffer using the specified
    * compilation flags and regular expression syntax.
    *
    * @param pattern A regular expression pattern, in the form of a String,
    *   StringBuffer, or char[].
    * @param cflags The logical OR of any combination of the compilation flags listed above.
    * @param syntax The type of regular expression syntax to use.
    * @exception REException The input pattern could not be parsed.
    * @exception IllegalArgumentException The pattern was not a String, 
    *   StringBuffer or char[].
    * @exception NullPointerException The pattern was null.
    */
   public RE(Object pattern, int cflags, RESyntax syntax) throws REException {
     this(pattern,cflags,syntax,0,0);
   }
 
   // internal constructor used for alternation
   private RE(REToken f_first, REToken f_last,int f_subs, int f_subIndex) {
     super(f_subIndex); // ???
     firstToken = f_first;
     lastToken = f_last;
     m_numSubs = f_subs;
   }
 
   // Actual constructor implementation
   private RE(Object patternObj, int cflags, RESyntax syntax, int myIndex, int nextSub) throws REException {
     super(myIndex); // Subexpression index of this token.
     char[] pattern;
     if (patternObj instanceof String) {
       pattern = ((String) patternObj).toCharArray();
     } else if (patternObj instanceof char[]) {
       pattern = (char[]) patternObj;
     } else if (patternObj instanceof StringBuffer) {
       pattern = new char [((StringBuffer) patternObj).length()];
       ((StringBuffer) patternObj).getChars(0,pattern.length,pattern,0);
     } else throw new IllegalArgumentException("Invalid class for pattern");
 
     int pLength = pattern.length;
 
     m_numSubs = 0; // Number of subexpressions in this token.
     Vector branches = null;
 
     // linked list of tokens (sort of -- some closed loops can exist)
     firstToken = lastToken = null;
 
     // Precalculate these so we don't pay for the math every time we
     // need to access them.
     boolean insens = ((cflags & REG_ICASE) > 0);
 
     // Parse pattern into tokens.  Does anyone know if it's more efficient
     // to use char[] than a String.charAt()?  I'm assuming so.
 
     // index tracks the position in the char array
     int index = 0;
 
     // this will be the current parse character (pattern[index])
     CharUnit unit = new CharUnit();
 
     // This is used for {x,y} calculations
     IntPair minMax = new IntPair();
 
     // Buffer a token so we can create a TokenRepeated, etc.
     REToken currentToken = null;
     char ch;
 
     while (index < pLength) {
       // read the next character unit (including backslash escapes)
       index = getCharUnit(pattern,index,unit);
 
       // ALTERNATION OPERATOR
       //  \| or | (if RE_NO_BK_VBAR) or newline (if RE_NEWLINE_ALT)
       //  not available if RE_LIMITED_OPS is set
 
       // TODO: the '\n' literal here should be a test against REToken.newline,
       // which unfortunately may be more than a single character.
       if ( ( (unit.ch == '|' && (syntax.get(RESyntax.RE_NO_BK_VBAR) ^ unit.bk))
        || (syntax.get(RESyntax.RE_NEWLINE_ALT) && (unit.ch == '\n') && !unit.bk) )
      && !syntax.get(RESyntax.RE_LIMITED_OPS)) {
   // make everything up to here be a branch. create vector if nec.
   if (branches == null) branches = new Vector();
   addToken(currentToken);
   branches.addElement(new RE(firstToken,lastToken,m_numSubs,m_subIndex));
   firstToken = lastToken = currentToken = null;
       }
       
       // INTERVAL OPERATOR:
       //  {x} | {x,} | {x,y}  (RE_INTERVALS && RE_NO_BK_BRACES)
       //  \{x\} | \{x,\} | \{x,y\} (RE_INTERVALS && !RE_NO_BK_BRACES)
       //
       // OPEN QUESTION: 
       //  what is proper interpretation of '{' at start of string?
 
       else if ((unit.ch == '{') && syntax.get(RESyntax.RE_INTERVALS) && (syntax.get(RESyntax.RE_NO_BK_BRACES) ^ unit.bk)) {
   if (currentToken == null) throw new REException("{ without preceding token",REException.REG_EBRACE,index);
     
   index = getMinMax(pattern,index,minMax,syntax);
   if ((currentToken.getMinimumLength() == 0) && (minMax.second == Integer.MAX_VALUE))
     throw new REException("repeated argument may be empty",REException.REG_BADRPT,index);
   currentToken = setRepeated(currentToken,minMax.first,minMax.second,index);  
       }
       
       // LIST OPERATOR:
       //  [...] | [^...]
 
       else if ((unit.ch == '[') && !unit.bk) {
   Vector options = new Vector();
   boolean negative = false;
   char lastChar = 0;
   if (index == pLength) throw new REException("unmatched [",REException.REG_EBRACK,index);
   
   // Check for initial caret, negation
   if ((ch = pattern[index]) == '^') {
     negative = true;
     if (++index == pLength) throw new REException("no end of list",REException.REG_EBRACK,index);
     ch = pattern[index];
   }
 
   // Check for leading right bracket literal
   if (ch == ']') {
     lastChar = ch;
     if (++index == pLength) throw new REException("no end of list",REException.REG_EBRACK,index);
   }
 
   while ((ch = pattern[index++]) != ']') {
     if ((ch == '-') && (lastChar != 0)) {
       if (index == pLength) throw new REException("no end of list",REException.REG_EBRACK,index);
       if ((ch = pattern[index]) == ']') {
         options.addElement(new RETokenChar(m_subIndex,lastChar,insens));
         lastChar = '-';
       } else {
         options.addElement(new RETokenRange(m_subIndex,lastChar,ch,insens));
         lastChar = 0;
         index++;
       }
           } else if ((ch == '\\') && syntax.get(RESyntax.RE_BACKSLASH_ESCAPE_IN_LISTS)) {
             if (index == pLength) throw new REException("no end of list",REException.REG_EBRACK,index);
       int posixID = -1;
       boolean negate = false;
       if (syntax.get(RESyntax.RE_CHAR_CLASS_ESC_IN_LISTS)) {
         switch (pattern[index]) {
         case 'D':
     negate = true;
         case 'd':
     posixID = RETokenPOSIX.DIGIT;
     break;
         case 'S':
     negate = true;
         case 's':
     posixID = RETokenPOSIX.SPACE;
     break;
         case 'W':
     negate = true;
         case 'w':
     posixID = RETokenPOSIX.ALNUM;
     break;
         }
       }
       if (lastChar != 0) options.addElement(new RETokenChar(m_subIndex,lastChar,insens));
       
       if (posixID != -1) {
         options.addElement(new RETokenPOSIX(m_subIndex,posixID,insens,negate));
       } else {
         lastChar = pattern[index];
       }
       ++index;
     } else if ((ch == '[') && (syntax.get(RESyntax.RE_CHAR_CLASSES)) && (pattern[index] == ':')) {
       StringBuffer posixSet = new StringBuffer();
       index = getPosixSet(pattern,index+1,posixSet);
       int posixId = RETokenPOSIX.intValue(posixSet.toString());
       if (posixId != -1)
         options.addElement(new RETokenPOSIX(m_subIndex,posixId,insens,false));
     } else {
       if (lastChar != 0) options.addElement(new RETokenChar(m_subIndex,lastChar,insens));
       lastChar = ch;
     }
     if (index == pLength) throw new REException("no end of list",REException.REG_EBRACK,index);
   } // while in list
   // Out of list, index is one past ']'
       
   if (lastChar != 0) options.addElement(new RETokenChar(m_subIndex,lastChar,insens));
       
   // Create a new RETokenOneOf
   addToken(currentToken);
   options.trimToSize();
   currentToken = new RETokenOneOf(m_subIndex,options,negative);
       }
 
       // SUBEXPRESSIONS
       //  (...) | \(...\) depending on RE_NO_BK_PARENS
 
       else if ((unit.ch == '(') && (syntax.get(RESyntax.RE_NO_BK_PARENS) ^ unit.bk)) {
   boolean pure = false;
   boolean comment = false;
   if ((index+1 < pLength) && (pattern[index] == '?')) {
     switch (pattern[index+1]) {
     case ':':
       if (syntax.get(RESyntax.RE_PURE_GROUPING)) {
         pure = true;
         index += 2;
       }
       break;
     case '#':
       if (syntax.get(RESyntax.RE_COMMENTS)) {
         comment = true;
       }
       break;
     }
   }
 
   // find end of subexpression
   int endIndex = index;
   int nextIndex = index;
   int nested = 0;
 
   while ( ((nextIndex = getCharUnit(pattern,endIndex,unit)) > 0)
     && !(nested == 0 && (unit.ch == ')') && (syntax.get(RESyntax.RE_NO_BK_PARENS) ^ unit.bk)) )
     if ((endIndex = nextIndex) >= pLength)
       throw new REException("no end of subexpression",REException.REG_ESUBREG,index-1);
     else if (unit.ch == '(' && (syntax.get(RESyntax.RE_NO_BK_PARENS) ^ unit.bk))
       nested++;
     else if (unit.ch == ')' && (syntax.get(RESyntax.RE_NO_BK_PARENS) ^ unit.bk))
       nested--;
 
   // endIndex is now position at a ')','\)' 
   // nextIndex is end of string or position after ')' or '\)'
 
   if (comment) index = nextIndex;
   else { // not a comment
     // create RE subexpression as token.
     addToken(currentToken);
     if (!pure) {
       nextSub++;
       m_numSubs++;
     }
 
     int useIndex = pure ? 0 : nextSub;
 
     currentToken = new RE(String.valueOf(pattern,index,endIndex-index).toCharArray(),cflags,syntax,useIndex,nextSub);
     nextSub += ((RE) currentToken).getNumSubs();
     m_numSubs += ((RE) currentToken).getNumSubs();
     index = nextIndex;
   } // not a comment
       } // subexpression
     
       // UNMATCHED RIGHT PAREN
       // ) or \)?  need to implement throw exception if
       // !syntax.get(RESyntax.RE_UNMATCHED_RIGHT_PAREN_ORD)
       else if (!syntax.get(RESyntax.RE_UNMATCHED_RIGHT_PAREN_ORD) && ((unit.ch == ')') && (syntax.get(RESyntax.RE_NO_BK_PARENS) ^ unit.bk))) {
   throw new REException("unmatched right paren",REException.REG_EPAREN,index);
       }
 
       // START OF LINE OPERATOR
       //  ^
 
       else if ((unit.ch == '^') && !unit.bk) {
   addToken(currentToken);
   currentToken = null;
   addToken(new RETokenStart(m_subIndex,(cflags & REG_MULTILINE) > 0));
       }
 
       // END OF LINE OPERATOR
       //  $
 
       else if ((unit.ch == '$') && !unit.bk) {
   addToken(currentToken);
   currentToken = null;
   addToken(new RETokenEnd(m_subIndex,(cflags & REG_MULTILINE) > 0));
       }
 
       // MATCH-ANY-CHARACTER OPERATOR (except possibly newline and null)
       //  .
 
       else if ((unit.ch == '.') && !unit.bk) {
   addToken(currentToken);
   currentToken = new RETokenAny(m_subIndex,syntax.get(RESyntax.RE_DOT_NEWLINE) || ((cflags & REG_DOT_NEWLINE) > 0),syntax.get(RESyntax.RE_DOT_NOT_NULL));
       }
 
       // ZERO-OR-MORE REPEAT OPERATOR
       //  *
 
       else if ((unit.ch == '*') && !unit.bk) {
   if ((currentToken == null) || (currentToken.getMinimumLength() == 0))
     throw new REException("repeated argument may be empty",REException.REG_BADRPT,index);
   currentToken = setRepeated(currentToken,0,Integer.MAX_VALUE,index);
       }
 
       // ONE-OR-MORE REPEAT OPERATOR
       //  + | \+ depending on RE_BK_PLUS_QM
       //  not available if RE_LIMITED_OPS is set
 
       else if ((unit.ch == '+') && !syntax.get(RESyntax.RE_LIMITED_OPS) && (!syntax.get(RESyntax.RE_BK_PLUS_QM) ^ unit.bk)) {
   if ((currentToken == null) || (currentToken.getMinimumLength() == 0))
     throw new REException("repeated argument may be empty",REException.REG_BADRPT,index);
   currentToken = setRepeated(currentToken,1,Integer.MAX_VALUE,index);
       }
 
       // ZERO-OR-ONE REPEAT OPERATOR / STINGY MATCHING OPERATOR
       //  ? | \? depending on RE_BK_PLUS_QM
       //  not available if RE_LIMITED_OPS is set
       //  stingy matching if RE_STINGY_OPS is set and it follows a quantifier
 
       else if ((unit.ch == '?') && !syntax.get(RESyntax.RE_LIMITED_OPS) && (!syntax.get(RESyntax.RE_BK_PLUS_QM) ^ unit.bk)) {
   if (currentToken == null) throw new REException("? without preceding token",REException.REG_BADRPT,index);
 
   // Check for stingy matching on RETokenRepeated
   if ((currentToken instanceof RETokenRepeated) && (syntax.get(RESyntax.RE_STINGY_OPS)))
     ((RETokenRepeated) currentToken).makeStingy();
   else
     currentToken = setRepeated(currentToken,0,1,index);
       }
   
       // BACKREFERENCE OPERATOR
       //  \1 \2 \3 \4 ...
       // not available if RE_NO_BK_REFS is set
 
       else if (unit.bk && Character.isDigit(unit.ch) && !syntax.get(RESyntax.RE_NO_BK_REFS)) {
   addToken(currentToken);
   currentToken = new RETokenBackRef(m_subIndex,Character.digit(unit.ch,10),insens);
       }
 
       // START OF STRING OPERATOR
       //  \A if RE_STRING_ANCHORS is set
       
       else if (unit.bk && (unit.ch == 'A') && syntax.get(RESyntax.RE_STRING_ANCHORS)) {
   addToken(currentToken);
   currentToken = new RETokenStart(m_subIndex,false);
       }
       
       // DIGIT OPERATOR
       //  \d if RE_CHAR_CLASS_ESCAPES is set
       
       else if (unit.bk && (unit.ch == 'd') && syntax.get(RESyntax.RE_CHAR_CLASS_ESCAPES)) {
   addToken(currentToken);
   currentToken = new RETokenPOSIX(m_subIndex,RETokenPOSIX.DIGIT,insens,false);
       }
 
       // NON-DIGIT OPERATOR
       //  \D
 
   else if (unit.bk && (unit.ch == 'D') && syntax.get(RESyntax.RE_CHAR_CLASS_ESCAPES)) {
     addToken(currentToken);
     currentToken = new RETokenPOSIX(m_subIndex,RETokenPOSIX.DIGIT,insens,true);
   }
 
   // NEWLINE ESCAPE
         //  \n
 
   else if (unit.bk && (unit.ch == 'n')) {
     addToken(currentToken);
     currentToken = new RETokenChar(m_subIndex,'\n',false);
   }
 
   // RETURN ESCAPE
         //  \r
 
   else if (unit.bk && (unit.ch == 'r')) {
     addToken(currentToken);
     currentToken = new RETokenChar(m_subIndex,'\r',false);
   }
 
   // WHITESPACE OPERATOR
         //  \s if RE_CHAR_CLASS_ESCAPES is set
 
   else if (unit.bk && (unit.ch == 's') && syntax.get(RESyntax.RE_CHAR_CLASS_ESCAPES)) {
     addToken(currentToken);
     currentToken = new RETokenPOSIX(m_subIndex,RETokenPOSIX.SPACE,insens,false);
   }
 
   // NON-WHITESPACE OPERATOR
         //  \S
 
   else if (unit.bk && (unit.ch == 'S') && syntax.get(RESyntax.RE_CHAR_CLASS_ESCAPES)) {
     addToken(currentToken);
     currentToken = new RETokenPOSIX(m_subIndex,RETokenPOSIX.SPACE,insens,true);
   }
 
   // TAB ESCAPE
         //  \t
 
   else if (unit.bk && (unit.ch == 't')) {
     addToken(currentToken);
     currentToken = new RETokenChar(m_subIndex,'\t',false);
   }
 
   // ALPHANUMERIC OPERATOR
         //  \w
 
   else if (unit.bk && (unit.ch == 'w') && syntax.get(RESyntax.RE_CHAR_CLASS_ESCAPES)) {
     addToken(currentToken);
     currentToken = new RETokenPOSIX(m_subIndex,RETokenPOSIX.ALNUM,insens,false);
   }
 
   // NON-ALPHANUMERIC OPERATOR
         //  \W
 
   else if (unit.bk && (unit.ch == 'W') && syntax.get(RESyntax.RE_CHAR_CLASS_ESCAPES)) {
     addToken(currentToken);
     currentToken = new RETokenPOSIX(m_subIndex,RETokenPOSIX.ALNUM,insens,true);
   }
 
   // END OF STRING OPERATOR
         //  \Z
 
   else if (unit.bk && (unit.ch == 'Z') && syntax.get(RESyntax.RE_STRING_ANCHORS)) {
     addToken(currentToken);
     currentToken = new RETokenEnd(m_subIndex,false);
   }
 
   // NON-SPECIAL CHARACTER (or escape to make literal)
         //  c | \* for example
 
   else {  // not a special character
     addToken(currentToken);
     currentToken = new RETokenChar(m_subIndex,unit.ch,insens);
   } 
       } // end while
 
     // Add final buffered token if applicable
     addToken(currentToken);
       
     if (branches != null) {
       branches.addElement(new RE(firstToken,lastToken,m_numSubs,m_subIndex));
       branches.trimToSize(); // compact the Vector
       firstToken = lastToken = new RETokenOneOf(m_subIndex,branches,false);
     }
   }
 
   private static int getCharUnit(char[] input, int index, CharUnit unit) throws REException {
     unit.ch = input[index++];
     if (unit.bk = (unit.ch == '\\'))
       if (index < input.length)
   unit.ch = input[index++];
       else throw new REException("\\ at end of pattern.",REException.REG_ESCAPE,index);
     return index;
   }
 
   /**
    * Checks if the input in its entirety is an exact match of
    * this regular expression.
    *
    * @param input The input text.
    * @exception IllegalArgumentException The input text was not a String, char[], or InputStream.
    */
   public boolean isMatch(Object input) {
     return isMatch(input,0,0);
   }
   
   /**
    * Checks if the input string, starting from index, is an exact match of
    * this regular expression.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public boolean isMatch(Object input,int index) {
     return isMatch(input,index,0);
   }
   
 
   /**
    * Checks if the input, starting from index and using the specified
    * execution flags, is an exact match of this regular expression.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @param eflags The logical OR of any execution flags above.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public boolean isMatch(Object input,int index,int eflags) {
     return isMatchImpl(makeRECharIndexed(input,index),index,eflags);
   }
 
   private boolean isMatchImpl(RECharIndexed input, int index, int eflags) {
     if (firstToken == null)  // Trivial case
       return (input.charAt(0) == RECharIndexed.OUT_OF_BOUNDS);
     int[] i = firstToken.match(input,0,eflags,new REMatch(m_numSubs,index));
     return (i != null) && (input.charAt(i[0]) == RECharIndexed.OUT_OF_BOUNDS);
   }
     
   /**
    * Returns the maximum number of subexpressions in this regular expression.
    * If the expression contains branches, the value returned will be the
    * maximum subexpressions in any of the branches.
    */
   public int getNumSubs() {
     return m_numSubs;
   }
 
   // Overrides REToken.setUncle
   void setUncle(REToken f_uncle) {
     lastToken.setUncle(f_uncle);
   }
 
   // Overrides REToken.chain
   boolean chain(REToken f_next) {
     super.chain(f_next);
     if (lastToken != null) lastToken.setUncle(f_next);
     return true;
   }
     
   /**
    * Returns the minimum number of characters that could possibly
    * constitute a match of this regular expression.
    */
   public int getMinimumLength() {
     int min = 0;
     REToken t = firstToken;
     if (t == null) return 0;
     do {
       min += t.getMinimumLength();
     } while ((t = t.m_next) != null);
     return min;
   }
 
   /**
    * Returns an array of all matches found in the input.
    *
    * @param input The input text.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch[] getAllMatches(Object input) {
     return getAllMatches(input,0,0);
   }
 
   /**
    * Returns an array of all matches found in the input,
    * beginning at the specified index position.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch[] getAllMatches(Object input, int index) {
     return getAllMatches(input,index,0);
   }
 
   /**
    * Returns an array of all matches found in the input string,
    * beginning at the specified index position and using the specified
    * execution flags.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @param eflags The logical OR of any execution flags above.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch[] getAllMatches(Object input, int index, int eflags) {
     return getAllMatchesImpl(makeRECharIndexed(input,index),index,eflags);
   }
 
   // this has been changed since 1.03 to be non-overlapping matches
   private REMatch[] getAllMatchesImpl(RECharIndexed input, int index, int eflags) {
     Vector all = new Vector();
     REMatch m = null;
     while ((m = getMatchImpl(input,index,eflags,null)) != null) {
       all.addElement(m);
       index = m.getEndIndex();
       if (m.end[0] == 0) {   // handle pathological case of zero-length match
   index++;
   input.move(1);
       } else {
   input.move(m.end[0]);
       }
     }
     REMatch[] mset = new REMatch[all.size()];
     all.copyInto(mset);
     return mset;
   }
   
   /* Implements abstract method REToken.match() */
   int[] match(RECharIndexed input, int index, int eflags, REMatch mymatch) { 
     if (firstToken == null) return new int[] { index }; // Trivial case
     /*
     if ((mymatch.start[m_subIndex] == -1) 
          || (mymatch.start[m_subIndex] > index))
     */
     int oldstart = mymatch.start[m_subIndex];
     mymatch.start[m_subIndex] = index;
     int[] newIndex = firstToken.match(input,index,eflags,mymatch);
     if (newIndex == null) { 
   mymatch.start[m_subIndex] = oldstart;
     } else {
       // If this match succeeded, then whole rest of string is good,
       // and newIndex[0] is the end of the match AT THIS LEVEL
 
       // We need to make list of all possible nexts.
       int[] doables = new int[0];
       int[] thisResult;
       for (int i = 0; i < newIndex.length; i++) {
   thisResult = next(input,newIndex[i],eflags,mymatch);
   if (thisResult != null) {
     int[] temp = new int[doables.length + thisResult.length];
     System.arraycopy(doables,0,temp,0,doables.length);
     for (int j = 0; j < thisResult.length; j++) {
       temp[doables.length + j] = thisResult[j];
     }
     doables = temp;
   }
       }
       return (doables.length == 0) ? null : doables;
     }
     return null;
   }
   
   /**
    * Returns the first match found in the input.
    *
    * @param input The input text.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch getMatch(Object input) {
     return getMatch(input,0,0);
   }
   
   /**
    * Returns the first match found in the input, beginning
    * the search at the specified index.
    *
    * @param input The input text.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch getMatch(Object input, int index) {
     return getMatch(input,index,0);
   }
   
   /**
    * Returns the first match found in the input, beginning
    * the search at the specified index, and using the specified
    * execution flags.  If no match is found, returns null.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @param eflags The logical OR of any execution flags above.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch getMatch(Object input, int index, int eflags) {
     return getMatch(input,index,eflags,null);
   }
 
   /**
    * Returns the first match found in the input, beginning
    * the search at the specified index, and using the specified
    * execution flags.  If no match is found, returns null.  If a StringBuffer
    * is provided and is non-null, the contents of the input text from the index to the
    * beginning of the match (or to the end of the input, if there is no match)
    * are appended to the StringBuffer.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @param eflags The logical OR of any execution flags above.
    * @param buffer The StringBuffer to save pre-match text in.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatch getMatch(Object input, int index, int eflags, StringBuffer buffer) {
     return getMatchImpl(makeRECharIndexed(input,index),index,eflags,buffer);
   }
 
   REMatch getMatchImpl(RECharIndexed input, int index, int eflags, StringBuffer buffer) {
     // check if input is at a valid position
     if (!input.isValid()) return null;
     REMatch mymatch = new REMatch(m_numSubs,index);
     do {
       int[] result = match(input,0,eflags,mymatch);
       if (result != null) {
   mymatch.end[0] = result[0]; // may break leftmost longest
   mymatch.finish(input);
   return mymatch;
       }
       mymatch.clear(++index);
       if (buffer != null) buffer.append(input.charAt(0));
     } while (input.move(1));
 
     return null;
   }
 
   /**
    * Returns an REMatchEnumeration that can be used to iterate over the
    * matches found in the input text.
    *
    * @param input The input text.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatchEnumeration getMatchEnumeration(Object input) {
     return getMatchEnumeration(input,0,0);
   }
 
 
   /**
    * Returns an REMatchEnumeration that can be used to iterate over the
    * matches found in the input text.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatchEnumeration getMatchEnumeration(Object input, int index) {
     return getMatchEnumeration(input,index,0);
   }
 
   /**
    * Returns an REMatchEnumeration that can be used to iterate over the
    * matches found in the input text.
    *
    * @param input The input text.
    * @param index The offset index at which the search should be begin.
    * @param eflags The logical OR of any execution flags above.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public REMatchEnumeration getMatchEnumeration(Object input, int index, int eflags) {
     return new REMatchEnumeration(this,makeRECharIndexed(input,index),index,eflags);
   }
 
 
   /**
    * Substitutes the replacement text for the first match found in the input.
    *
    * @param input The input text.
    * @param replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public String substitute(Object input,String replace) {
     return substitute(input,replace,0,0);
   }
 
   /**
    * Substitutes the replacement text for the first match found in the input
    * beginning at the specified index position.
    *
    * @param input The input text.
    * @param replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
    * @param index The offset index at which the search should be begin.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public String substitute(Object input,String replace,int index) {
     return substitute(input,replace,index,0);
   }
 
   /**
    * Substitutes the replacement text for the first match found in the input
    * string, beginning at the specified index position and using the
    * specified execution flags.
    *
    * @param input The input text.
    * @param replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
    * @param index The offset index at which the search should be begin.
    * @param eflags The logical OR of any execution flags above.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public String substitute(Object input,String replace,int index,int eflags) {
     return substituteImpl(makeRECharIndexed(input,index),replace,index,eflags);
   }
 
   private String substituteImpl(RECharIndexed input,String replace,int index,int eflags) {
     StringBuffer buffer = new StringBuffer();
     REMatch m = getMatchImpl(input,index,eflags,buffer);
     if (m==null) return buffer.toString();
     buffer.append(m.substituteInto(replace));
     if (input.move(m.end[0])) {
       do {
   buffer.append(input.charAt(0));
       } while (input.move(1));
     }
     return buffer.toString();
   }
   
   /**
    * Substitutes the replacement text for each non-overlapping match found 
    * in the input text.
    *
    * @param input The input text.
    * @param replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public String substituteAll(Object input,String replace) {
     return substituteAll(input,replace,0,0);
   }
 
   /**
    * Substitutes the replacement text for each non-overlapping match found 
    * in the input text, starting at the specified index.
    *
    * @param input The input text.
    * @param replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
    * @param index The offset index at which the search should be begin.
    * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
    */
   public String substituteAll(Object input,String replace,int index) {
     return substituteAll(input,replace,index,0);
   }
  
   /**
    * Substitutes the replacement text for each non-overlapping match found 
    * in the input text, starting at the specified index and using the
    * specified execution flags.
   *
   * @param input The input text.
   * @param replace The replacement text, which may contain $x metacharacters (see REMatch.substituteInto).
   * @param index The offset index at which the search should be begin.
   * @param eflags The logical OR of any execution flags above.
   * @exception IllegalArgumentException The input text was not a String, char[], StringBuffer or InputStream.
   */
  public String substituteAll(Object input,String replace,int index,int eflags) {
    return substituteAllImpl(makeRECharIndexed(input,index),replace,index,eflags);
  }

  private String substituteAllImpl(RECharIndexed input,String replace,int index,int eflags) {
    StringBuffer buffer = new StringBuffer();
    REMatch m;
    while ((m = getMatchImpl(input,index,eflags,buffer)) != null) {
      buffer.append(m.substituteInto(replace));
      index = m.getEndIndex();
      if (m.end[0] == 0) {
  char ch = input.charAt(0);
  if (ch != RECharIndexed.OUT_OF_BOUNDS) 
    buffer.append(ch);
  input.move(1);
      } else {
  input.move(m.end[0]);
      }
    }
    return buffer.toString();
  }
  
  /* Helper function for constructor */
  private void addToken(REToken next) {
    if (next == null) return;
    if (firstToken == null)
      lastToken = firstToken = next;
    else
      // if chain returns false, it "rejected" the token due to
      // an optimization, and next was combined with lastToken
      if (lastToken.chain(next)) lastToken = next;
  }

  private static REToken setRepeated(REToken current, int min, int max, int index) throws REException {
    if (current == null) throw new REException("repeat preceding token",REException.REG_BADRPT,index);
    return new RETokenRepeated(current.m_subIndex,current,min,max);
  }

  private static int getPosixSet(char[] pattern,int index,StringBuffer buf) {
    // Precondition: pattern[index-1] == ':'
    // we will return pos of closing ']'.
    int i;
    for (i=index; i<(pattern.length-1); i++) {
      if ((pattern[i] == ':') && (pattern[i+1] == ']'))
  return i+2;
      buf.append(pattern[i]);
    }
    return index; // didn't match up
  }

  private int getMinMax(char[] input,int index,IntPair minMax,RESyntax syntax) throws REException {
    // Precondition: input[index-1] == '{', minMax != null

    if (index == input.length) throw new REException("no matching brace",REException.REG_EBRACE,index);
  
    int min,max=0;
    CharUnit unit = new CharUnit();
    StringBuffer buf = new StringBuffer();
    
    // Read string of digits
    while (((index = getCharUnit(input,index,unit)) != input.length)
     && Character.isDigit(unit.ch))
      buf.append(unit.ch);

    // Check for {} tomfoolery
    if (buf.length() == 0) throw new REException("bad brace construct",REException.REG_EBRACE,index);

    min = Integer.parseInt(buf.toString());
  
    if ((unit.ch == '}') && (syntax.get(RESyntax.RE_NO_BK_BRACES) ^ unit.bk))
      max = min;
    else if ((unit.ch == ',') && !unit.bk) {
      buf = new StringBuffer();
      // Read string of digits
      while (((index = getCharUnit(input,index,unit)) != input.length)
       && Character.isDigit(unit.ch))
  buf.append(unit.ch);

      if (!((unit.ch == '}') && (syntax.get(RESyntax.RE_NO_BK_BRACES) ^ unit.bk)))
  throw new REException("expected end of interval",REException.REG_EBRACE,index);

      // This is the case of {x,}
      if (buf.length() == 0) max = Integer.MAX_VALUE;
      else max = Integer.parseInt(buf.toString());
    } else throw new REException("invalid character in brace expression",REException.REG_EBRACE,index);

    // We know min and max now, and they are valid.

    minMax.first = min;
    minMax.second = max;

    // return the index following the '}'
    return index;
  }

   /**
    * Return a human readable form of the compiled regular expression,
    * useful for debugging.
    */
   public String toString() {
     StringBuffer sb = new StringBuffer();
     dump(sb);
     return sb.toString();
   }

  void dump(StringBuffer os) {
    os.append('(');
    if (m_subIndex == 0)
      os.append("?:");
    if (firstToken != null)
      firstToken.dumpAll(os);
    os.append(')');
  }

  // Cast input appropriately or throw exception
  private static RECharIndexed makeRECharIndexed(Object input, int index) {
    if (input instanceof String)
      return new RECharIndexedString((String) input,index);
    else if (input instanceof char[])
      return new RECharIndexedCharArray((char[]) input,index);
    else if (input instanceof StringBuffer)
      return new RECharIndexedStringBuffer((StringBuffer) input,index);
    else if (input instanceof InputStream)
      return new RECharIndexedInputStream((InputStream) input,index);
    else throw new IllegalArgumentException("Invalid class for input text");
  }
}