/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xpath.functions;

//import org.w3c.dom.Node;

import java.util.Vector;

import org.apache.xpath.XPathContext;
import org.apache.xpath.XPath;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.res.XPATHErrorResources;
import org.apache.xpath.objects.XString;

/**
 * <meta name="usage" content="advanced"/>
 * Execute the Translate() function.
 */
public class FuncTranslate extends Function3Args
{

  /**
   * Execute the function.  The function must return
   * a valid object.
   * @param xctxt The current execution context.
   * @return A valid XObject.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
  {

    String theFirstString = m_arg0.execute(xctxt).str();
    String theSecondString = m_arg1.execute(xctxt).str();
    String theThirdString = m_arg2.execute(xctxt).str();
    int theFirstStringLength = theFirstString.length();
    int theThirdStringLength = theThirdString.length();

    // A vector to contain the new characters.  We'll use it to construct
    // the result string.
    StringBuffer sbuffer = new StringBuffer();

    for (int i = 0; i < theFirstStringLength; i++)
    {
      char theCurrentChar = theFirstString.charAt(i);
      int theIndex = theSecondString.indexOf(theCurrentChar);

      if (theIndex < 0)
      {

        // Didn't find the character in the second string, so it
        // is not translated.
        sbuffer.append(theCurrentChar);
      }
      else if (theIndex < theThirdStringLength)
      {

        // OK, there's a corresponding character in the
        // third string, so do the translation...
        sbuffer.append(theThirdString.charAt(theIndex));
      }
      else
      {

        // There's no corresponding character in the
        // third string, since it's shorter than the
        // second string.  In this case, the character
        // is removed from the output string, so don't
        // do anything.
      }
    }

    return new XString(sbuffer.toString());
  }
}