/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001-2003 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 "Axis" 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.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.jboss.axis.encoding;

import org.jboss.axis.utils.JavaUtils;
import org.jboss.axis.utils.Messages;

import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;

/**
 * @author TAMURA Kent &lt;kent@trl.ibm.co.jp&gt;
 */
public class Base64
{
   private static final char[] S_BASE64CHAR = {
      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
      'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
      'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
      'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
      'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
      'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
      '8', '9', '+', '/'
   };
   private static final char S_BASE64PAD = '=';
   private static final byte[] S_DECODETABLE = new byte[128];

   static
   {
      for (int i = 0; i < S_DECODETABLE.length; i++)
         S_DECODETABLE[i] = Byte.MAX_VALUE;  // 127
      for (int i = 0; i < S_BASE64CHAR.length; i++) // 0 to 63
         S_DECODETABLE[S_BASE64CHAR[i]] = (byte)i;
   }

   private static int decode0(char[] ibuf, byte[] obuf, int wp)
   {
      int outlen = 3;
      if (ibuf[3] == S_BASE64PAD) outlen = 2;
      if (ibuf[2] == S_BASE64PAD) outlen = 1;
      int b0 = S_DECODETABLE[ibuf[0]];
      int b1 = S_DECODETABLE[ibuf[1]];
      int b2 = S_DECODETABLE[ibuf[2]];
      int b3 = S_DECODETABLE[ibuf[3]];
      switch (outlen)
      {
         case 1:
            obuf[wp] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
            return 1;
         case 2:
            obuf[wp++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
            obuf[wp] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
            return 2;
         case 3:
            obuf[wp++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
            obuf[wp++] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
            obuf[wp] = (byte)(b2 << 6 & 0xc0 | b3 & 0x3f);
            return 3;
         default:
            throw new RuntimeException(Messages.getMessage("internalError00"));
      }
   }

   /**
    *
    */
   public static byte[] decode(char[] data, int off, int len)
   {
      char[] ibuf = new char[4];
      int ibufcount = 0;
      byte[] obuf = new byte[len / 4 * 3 + 3];
      int obufcount = 0;
      for (int i = off; i < off + len; i++)
      {
         char ch = data[i];
         if (ch == S_BASE64PAD
                 || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE)
         {
            ibuf[ibufcount++] = ch;
            if (ibufcount == ibuf.length)
            {
               ibufcount = 0;
               obufcount += decode0(ibuf, obuf, obufcount);
            }
         }
      }
      if (obufcount == obuf.length)
         return obuf;
      byte[] ret = new byte[obufcount];
      System.arraycopy(obuf, 0, ret, 0, obufcount);
      return ret;
   }

   /**
    *
    */
   public static byte[] decode(String data)
   {
      char[] ibuf = new char[4];
      int ibufcount = 0;
      byte[] obuf = new byte[data.length() / 4 * 3 + 3];
      int obufcount = 0;
      for (int i = 0; i < data.length(); i++)
      {
         char ch = data.charAt(i);
         if (ch == S_BASE64PAD
                 || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE)
         {
            ibuf[ibufcount++] = ch;
            if (ibufcount == ibuf.length)
            {
               ibufcount = 0;
               obufcount += decode0(ibuf, obuf, obufcount);
            }
         }
      }
      if (obufcount == obuf.length)
         return obuf;
      byte[] ret = new byte[obufcount];
      System.arraycopy(obuf, 0, ret, 0, obufcount);
      return ret;
   }

   /**
    *
    */
   public static void decode(char[] data, int off, int len, OutputStream ostream) throws IOException
   {
      char[] ibuf = new char[4];
      int ibufcount = 0;
      byte[] obuf = new byte[3];
      for (int i = off; i < off + len; i++)
      {
         char ch = data[i];
         if (ch == S_BASE64PAD
                 || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE)
         {
            ibuf[ibufcount++] = ch;
            if (ibufcount == ibuf.length)
            {
               ibufcount = 0;
               int obufcount = decode0(ibuf, obuf, 0);
               ostream.write(obuf, 0, obufcount);
            }
         }
      }
   }

   /**
    *
    */
   public static void decode(String data, OutputStream ostream) throws IOException
   {
      char[] ibuf = new char[4];
      int ibufcount = 0;
      byte[] obuf = new byte[3];
      for (int i = 0; i < data.length(); i++)
      {
         char ch = data.charAt(i);
         if (ch == S_BASE64PAD
                 || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE)
         {
            ibuf[ibufcount++] = ch;
            if (ibufcount == ibuf.length)
            {
               ibufcount = 0;
               int obufcount = decode0(ibuf, obuf, 0);
               ostream.write(obuf, 0, obufcount);
            }
         }
      }
   }

   /**
    * Returns base64 representation of specified byte array.
    */
   public static String encode(byte[] data)
   {
      return encode(data, 0, data.length);
   }

   /**
    * Returns base64 representation of specified byte array.
    */
   public static String encode(byte[] data, int off, int len)
   {
      if (len <= 0) return "";
      char[] out = new char[len / 3 * 4 + 4];
      int rindex = off;
      int windex = 0;
      int rest = len - off;
      while (rest >= 3)
      {
         int i = ((data[rindex] & 0xff) << 16)
                 + ((data[rindex + 1] & 0xff) << 8)
                 + (data[rindex + 2] & 0xff);
         out[windex++] = S_BASE64CHAR[i >> 18];
         out[windex++] = S_BASE64CHAR[(i >> 12) & 0x3f];
         out[windex++] = S_BASE64CHAR[(i >> 6) & 0x3f];
         out[windex++] = S_BASE64CHAR[i & 0x3f];
         rindex += 3;
         rest -= 3;
      }
      if (rest == 1)
      {
         int i = data[rindex] & 0xff;
         out[windex++] = S_BASE64CHAR[i >> 2];
         out[windex++] = S_BASE64CHAR[(i << 4) & 0x3f];
         out[windex++] = S_BASE64PAD;
         out[windex++] = S_BASE64PAD;
      }
      else if (rest == 2)
      {
         int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff);
         out[windex++] = S_BASE64CHAR[i >> 10];
         out[windex++] = S_BASE64CHAR[(i >> 4) & 0x3f];
         out[windex++] = S_BASE64CHAR[(i << 2) & 0x3f];
         out[windex++] = S_BASE64PAD;
      }
      return new String(out, 0, windex);
   }

   /**
    * Outputs base64 representation of the specified byte array to a byte stream.
    */
   public static void encode(byte[] data, int off, int len, OutputStream ostream) throws IOException
   {
      if (len <= 0) return;
      byte[] out = new byte[4];
      int rindex = off;
      int rest = len - off;
      while (rest >= 3)
      {
         int i = ((data[rindex] & 0xff) << 16)
                 + ((data[rindex + 1] & 0xff) << 8)
                 + (data[rindex + 2] & 0xff);
         out[0] = (byte)S_BASE64CHAR[i >> 18];
         out[1] = (byte)S_BASE64CHAR[(i >> 12) & 0x3f];
         out[2] = (byte)S_BASE64CHAR[(i >> 6) & 0x3f];
         out[3] = (byte)S_BASE64CHAR[i & 0x3f];
         ostream.write(out, 0, 4);
         rindex += 3;
         rest -= 3;
      }
      if (rest == 1)
      {
         int i = data[rindex] & 0xff;
         out[0] = (byte)S_BASE64CHAR[i >> 2];
         out[1] = (byte)S_BASE64CHAR[(i << 4) & 0x3f];
         out[2] = (byte)S_BASE64PAD;
         out[3] = (byte)S_BASE64PAD;
         ostream.write(out, 0, 4);
      }
      else if (rest == 2)
      {
         int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff);
         out[0] = (byte)S_BASE64CHAR[i >> 10];
         out[1] = (byte)S_BASE64CHAR[(i >> 4) & 0x3f];
         out[2] = (byte)S_BASE64CHAR[(i << 2) & 0x3f];
         out[3] = (byte)S_BASE64PAD;
         ostream.write(out, 0, 4);
      }
   }

   /**
    * Outputs base64 representation of the specified byte array to a character stream.
    */
   public static void encode(byte[] data, int off, int len, Writer writer) throws IOException
   {
      if (len <= 0) return;
      char[] out = new char[4];
      int rindex = off;
      int rest = len - off;
      int output = 0;
      while (rest >= 3)
      {
         int i = ((data[rindex] & 0xff) << 16)
                 + ((data[rindex + 1] & 0xff) << 8)
                 + (data[rindex + 2] & 0xff);
         out[0] = S_BASE64CHAR[i >> 18];
         out[1] = S_BASE64CHAR[(i >> 12) & 0x3f];
         out[2] = S_BASE64CHAR[(i >> 6) & 0x3f];
         out[3] = S_BASE64CHAR[i & 0x3f];
         writer.write(out, 0, 4);
         rindex += 3;
         rest -= 3;
         output += 4;
         if (output % 76 == 0)
            writer.write(JavaUtils.LS);
      }
      if (rest == 1)
      {
         int i = data[rindex] & 0xff;
         out[0] = S_BASE64CHAR[i >> 2];
         out[1] = S_BASE64CHAR[(i << 4) & 0x3f];
         out[2] = S_BASE64PAD;
         out[3] = S_BASE64PAD;
         writer.write(out, 0, 4);
      }
      else if (rest == 2)
      {
         int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff);
         out[0] = S_BASE64CHAR[i >> 10];
         out[1] = S_BASE64CHAR[(i >> 4) & 0x3f];
         out[2] = S_BASE64CHAR[(i << 2) & 0x3f];
         out[3] = S_BASE64PAD;
         writer.write(out, 0, 4);
      }
   }
}