package org.apache.lucene.analysis;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * A filter that replaces accented characters in the ISO Latin 1 character set 
 * (ISO-8859-1) by their unaccented equivalent. The case will not be altered.
 * 

 * For instance, 'à' will be replaced by 'a'.
 * 

 */
public class ISOLatin1AccentFilter extends TokenFilter {
  public ISOLatin1AccentFilter(TokenStream input) {
    super(input);
  }

  private char[] output = new char[256];
  private int outputPos;

  public final Token next(Token result) throws java.io.IOException {
    result = input.next(result);
    if (result != null) {
      final char[] buffer = result.termBuffer();
      final int length = result.termLength();
      // If no characters actually require rewriting then we
      // just return token as-is:
      for(int i=0;i= '\u00c0' && c <= '\u0178') {
          removeAccents(buffer, length);
          result.setTermBuffer(output, 0, outputPos);
          break;
        }
      }
      return result;
    } else
      return null;
  }

  /**
   * To replace accented characters in a String by unaccented equivalents.
   */
  public final void removeAccents(char[] input, int length) {

    // Worst-case length required:
    final int maxSizeNeeded = 2*length;

    int size = output.length;
    while (size < maxSizeNeeded)
      size *= 2;

    if (size != output.length)
      output = new char[size];

    outputPos = 0;

    int pos = 0;

    for (int i=0; i