content: /*
   * Copyright 1999,2004 The Apache Software Foundation.
   * 
   * Licensed 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.
   */
  
  package net.sf.webdav.fromcatalina;
  
  /**
   * Encode an MD5 digest into a String.
   * <p>
   * The 128 bit MD5 hash is converted into a 32 character long String. Each
   * character of the String is the hexadecimal representation of 4 bits of the
   * digest.
   * 
   * @author Remy Maucherat
   * @version $Revision: 1.2 $ $Date: 2008-08-05 07:38:45 $
   */
  
  public final class MD5Encoder {
  
      // ----------------------------------------------------- Instance Variables
  
      private static final char[] HEXADECIMAL = { '0', '1', '2', '3', '4', '5',
              '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
  
      // --------------------------------------------------------- Public Methods
  
      /**
       * Encodes the 128 bit (16 bytes) MD5 into a 32 character String.
       * 
       * @param binaryData
       *      Array containing the digest
       * @return Encoded MD5, or null if encoding failed
       */
      public String encode(byte[] binaryData) {
  
          if (binaryData.length != 16)
              return null;
  
          char[] buffer = new char[32];
  
          for (int i = 0; i < 16; i++) {
              int low = (int) (binaryData[i] & 0x0f);
              int high = (int) ((binaryData[i] & 0xf0) >> 4);
              buffer[i * 2] = HEXADECIMAL[high];
              buffer[i * 2 + 1] = HEXADECIMAL[low];
          }
  
          return new String(buffer);
  
      }
  
  }
  