/* gnu/regexp/RETokenLookAhead.java
   Copyright (C) 2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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any later version.

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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
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package gnu.java.util.regex;

/**
 * @since gnu.regexp 1.1.3
 * @author Shashank Bapat
 */
final class RETokenLookAhead extends REToken
{
  REToken re;
  boolean negative;

  RETokenLookAhead(REToken re, boolean negative) throws REException {
    super(0);
    this.re = re;
    this.negative = negative;
  }

  int getMaximumLength() {
    return 0;
  }

  REMatch matchThis(CharIndexed input, REMatch mymatch)
  {
    REMatch trymatch = (REMatch)mymatch.clone();
    if (re.match(input, trymatch)) {
      if (negative) return null;
      trymatch.index = mymatch.index;
      return trymatch;
    }
    else {
      if (negative) return mymatch;
      return null;
    }
  }

    void dump(StringBuffer os) {
	os.append("(?");
	os.append(negative ? '!' : '=');
	re.dumpAll(os);
	os.append(')');
    }
}