import java.io.ByteArrayOutputStream;


/**
 * Turns Strings of x-www-form-urlEncoded format into regular text.
 *
 * @version 1.0, 4/3/1996
 * @author Elliotte Rusty Harold
 */

public class URLDecoder {

  private URLDecoder() { }

  /**
  * Translates String from x-www-form-urlEncoded format into text.
  * @param s String to be translated
  * @return the translated String.
  */
  public static String decode(String s) {
  
    ByteArrayOutputStream out = new ByteArrayOutputStream(s.length());
  
    for (int i = 0; i < s.length(); i++) {
      int c = (int) s.charAt(i);
      if (c == '+') {
        out.write(' ');
      }
      else if (c == '%') {
        int c1 = Character.digit(s.charAt(++i), 16);
        int c2 = Character.digit(s.charAt(++i), 16);
        out.write((char) (c1 * 16 + c2));
      }
      else {
        out.write(c);
      }
    } // end for

    return out.toString();
   
  }
    
}