/* *  gnu/regexp/REFilterReader.java *  Copyright (C) 2001 Lee Sau Dan *  Based on gnu.regexp.REFilterInputStream by Wes Biggs * *  This library is free software; you can redistribute it and/or modify *  it under the terms of the GNU Lesser General Public License as published *  by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. * *  You should have received a copy of the GNU Lesser General Public License *  along with this program; if not, write to the Free Software *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */package gnu.regexp;import java.io.FilterReader;import java.io.Reader;/** * Replaces instances of a given RE with replacement text.  * * @author <A HREF="http://www.csis.hku.hk/~sdlee/">Lee Sau Dan</A> * @since gnu.regexp 1.1.0 */public class REFilterReader extends FilterReader {  private RE expr;  private String replace;  private String buffer;  private int bufpos;  private int offset;  private CharIndexedReader stream;  /**   * Creates an REFilterReader.  When reading from this stream,   * occurrences of patterns matching the supplied regular expression   * will be replaced with the supplied replacement text (the   * metacharacters $0 through $9 may be used to refer to the full   * match or subexpression matches.   *   * @param stream The Reader to be filtered.   * @param expr The regular expression to search for.   * @param replace The text pattern to replace matches with.     */  public REFilterReader(Reader stream, RE expr, String replace) {    super(stream);    this.stream = new CharIndexedReader(stream,0);    this.expr = expr;    this.replace = replace;  }  /**   * Reads the next character from the stream per the general contract of   * Reader.read().  Returns -1 on error or end of stream.   */  public int read() {    // If we have buffered replace data, use it.    if ((buffer != null) && (bufpos < buffer.length())) {      return (int) buffer.charAt(bufpos++);    }    // check if input is at a valid position    if (!stream.isValid()) return -1;    REMatch mymatch = new REMatch(expr.getNumSubs(),offset,0);    if (expr.match(stream,mymatch)) {      mymatch.end[0] = mymatch.index;      mymatch.finish(stream);      stream.move(mymatch.toString().length());      offset += mymatch.toString().length();      buffer = mymatch.substituteInto(replace);      bufpos = 1;      if (buffer.length() > 0) {	  return buffer.charAt(0);      }    }    char ch = stream.charAt(0);    if (ch == CharIndexed.OUT_OF_BOUNDS) return -1;    stream.move(1);    offset++;    return ch;  }  /**    * Returns false.  REFilterReader does not support mark() and   * reset() methods.    */  public boolean markSupported() {    return false;  }  /** Reads from the stream into the provided array. */  public int read(char[] b, int off, int len) {    int i;    int ok = 0;    while (len-- > 0) {      i = read();      if (i == -1) return (ok == 0) ? -1 : ok;      b[off++] = (char) i;      ok++;    }    return ok;  }  /** Reads from the stream into the provided array. */  public int read(char[] b) {    return read(b,0,b.length);  }}