/base64coder-2010-12-19/src/main/java/biz/source_code/base64Coder/Base64Coder.java

// Copyright 2003-2010 Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland

// www.source-code.biz, www.inventec.ch/chdh

//

// This module is multi-licensed and may be used under the terms

// of any of the following licenses:

//

//  EPL, Eclipse Public License, V1.0 or later, http://www.eclipse.org/legal

//  LGPL, GNU Lesser General Public License, V2.1 or later, http://www.gnu.org/licenses/lgpl.html

//  GPL, GNU General Public License, V2 or later, http://www.gnu.org/licenses/gpl.html

//  AL, Apache License, V2.0 or later, http://www.apache.org/licenses

//  BSD, BSD License, http://www.opensource.org/licenses/bsd-license.php

//

// Please contact the author if you need another license.

// This module is provided "as is", without warranties of any kind.



package biz.source_code.base64Coder;



/**

* A Base64 encoder/decoder.

*

* <p>

* This class is used to encode and decode data in Base64 format as described in RFC 1521.

*

* <p>

* Project home page: <a href="http://www.source-code.biz/base64coder/java/">www.source-code.biz/base64coder/java</a><br>

* Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland<br>

* Multi-licensed: EPL / LGPL / GPL / AL / BSD.

*/

public class Base64Coder {



// The line separator string of the operating system.

private static final String systemLineSeparator = System.getProperty("line.separator");



// Mapping table from 6-bit nibbles to Base64 characters.

private static final char[] map1 = new char[64];

   static {

      int i=0;

      for (char c='A'; c<='Z'; c++) map1[i++] = c;

      for (char c='a'; c<='z'; c++) map1[i++] = c;

      for (char c='0'; c<='9'; c++) map1[i++] = c;

      map1[i++] = '+'; map1[i++] = '/'; }



// Mapping table from Base64 characters to 6-bit nibbles.

private static final byte[] map2 = new byte[128];

   static {

      for (int i=0; i<map2.length; i++) map2[i] = -1;

      for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; }



/**

* Encodes a string into Base64 format.

* No blanks or line breaks are inserted.

* @param s  A String to be encoded.

* @return   A String containing the Base64 encoded data.

*/

public static String encodeString (String s) {

   return new String(encode(s.getBytes())); }



/**

* Encodes a byte array into Base 64 format and breaks the output into lines of 76 characters.

* This method is compatible with <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.

* @param in  An array containing the data bytes to be encoded.

* @return    A String containing the Base64 encoded data, broken into lines.

*/

public static String encodeLines (byte[] in) {

   return encodeLines(in, 0, in.length, 76, systemLineSeparator); }



/**

* Encodes a byte array into Base 64 format and breaks the output into lines.

* @param in            An array containing the data bytes to be encoded.

* @param iOff          Offset of the first byte in <code>in</code> to be processed.

* @param iLen          Number of bytes to be processed in <code>in</code>, starting at <code>iOff</code>.

* @param lineLen       Line length for the output data. Should be a multiple of 4.

* @param lineSeparator The line separator to be used to separate the output lines.

* @return              A String containing the Base64 encoded data, broken into lines.

*/

public static String encodeLines (byte[] in, int iOff, int iLen, int lineLen, String lineSeparator) {

   int blockLen = (lineLen*3) / 4;

   if (blockLen <= 0) throw new IllegalArgumentException();

   int lines = (iLen+blockLen-1) / blockLen;

   int bufLen = ((iLen+2)/3)*4 + lines*lineSeparator.length();

   StringBuilder buf = new StringBuilder(bufLen);

   int ip = 0;

   while (ip < iLen) {

      int l = Math.min(iLen-ip, blockLen);

      buf.append (encode(in, iOff+ip, l));

      buf.append (lineSeparator);

      ip += l; }

   return buf.toString(); }



/**

* Encodes a byte array into Base64 format.

* No blanks or line breaks are inserted in the output.

* @param in  An array containing the data bytes to be encoded.

* @return    A character array containing the Base64 encoded data.

*/

public static char[] encode (byte[] in) {

   return encode(in, 0, in.length); }



/**

* Encodes a byte array into Base64 format.

* No blanks or line breaks are inserted in the output.

* @param in    An array containing the data bytes to be encoded.

* @param iLen  Number of bytes to process in <code>in</code>.

* @return      A character array containing the Base64 encoded data.

*/

public static char[] encode (byte[] in, int iLen) {

   return encode(in, 0, iLen); }



/**

* Encodes a byte array into Base64 format.

* No blanks or line breaks are inserted in the output.

* @param in    An array containing the data bytes to be encoded.

* @param iOff  Offset of the first byte in <code>in</code> to be processed.

* @param iLen  Number of bytes to process in <code>in</code>, starting at <code>iOff</code>.

* @return      A character array containing the Base64 encoded data.

*/

public static char[] encode (byte[] in, int iOff, int iLen) {

   int oDataLen = (iLen*4+2)/3;       // output length without padding

   int oLen = ((iLen+2)/3)*4;         // output length including padding

   char[] out = new char[oLen];

   int ip = iOff;

   int iEnd = iOff + iLen;

   int op = 0;

   while (ip < iEnd) {

      int i0 = in[ip++] & 0xff;

      int i1 = ip < iEnd ? in[ip++] & 0xff : 0;

      int i2 = ip < iEnd ? in[ip++] & 0xff : 0;

      int o0 = i0 >>> 2;

      int o1 = ((i0 &   3) << 4) | (i1 >>> 4);

      int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);

      int o3 = i2 & 0x3F;

      out[op++] = map1[o0];

      out[op++] = map1[o1];

      out[op] = op < oDataLen ? map1[o2] : '='; op++;

      out[op] = op < oDataLen ? map1[o3] : '='; op++; }

   return out; }



/**

* Decodes a string from Base64 format.

* No blanks or line breaks are allowed within the Base64 encoded input data.

* @param s  A Base64 String to be decoded.

* @return   A String containing the decoded data.

* @throws   IllegalArgumentException If the input is not valid Base64 encoded data.

*/

public static String decodeString (String s) {

   return new String(decode(s)); }



/**

* Decodes a byte array from Base64 format and ignores line separators, tabs and blanks.

* CR, LF, Tab and Space characters are ignored in the input data.

* This method is compatible with <code>sun.misc.BASE64Decoder.decodeBuffer(String)</code>.

* @param s  A Base64 String to be decoded.

* @return   An array containing the decoded data bytes.

* @throws   IllegalArgumentException If the input is not valid Base64 encoded data.

*/

public static byte[] decodeLines (String s) {

   char[] buf = new char[s.length()];

   int p = 0;

   for (int ip = 0; ip < s.length(); ip++) {

      char c = s.charAt(ip);

      if (c != ' ' && c != '\r' && c != '\n' && c != '\t')

         buf[p++] = c; }

   return decode(buf, 0, p); }



/**

* Decodes a byte array from Base64 format.

* No blanks or line breaks are allowed within the Base64 encoded input data.

* @param s  A Base64 String to be decoded.

* @return   An array containing the decoded data bytes.

* @throws   IllegalArgumentException If the input is not valid Base64 encoded data.

*/

public static byte[] decode (String s) {

   return decode(s.toCharArray()); }



/**

* Decodes a byte array from Base64 format.

* No blanks or line breaks are allowed within the Base64 encoded input data.

* @param in  A character array containing the Base64 encoded data.

* @return    An array containing the decoded data bytes.

* @throws    IllegalArgumentException If the input is not valid Base64 encoded data.

*/

public static byte[] decode (char[] in) {

   return decode(in, 0, in.length); }



/**

* Decodes a byte array from Base64 format.

* No blanks or line breaks are allowed within the Base64 encoded input data.

* @param in    A character array containing the Base64 encoded data.

* @param iOff  Offset of the first character in <code>in</code> to be processed.

* @param iLen  Number of characters to process in <code>in</code>, starting at <code>iOff</code>.

* @return      An array containing the decoded data bytes.

* @throws      IllegalArgumentException If the input is not valid Base64 encoded data.

*/

public static byte[] decode (char[] in, int iOff, int iLen) {

   if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");

   while (iLen > 0 && in[iOff+iLen-1] == '=') iLen--;

   int oLen = (iLen*3) / 4;

   byte[] out = new byte[oLen];

   int ip = iOff;

   int iEnd = iOff + iLen;

   int op = 0;

   while (ip < iEnd) {

      int i0 = in[ip++];

      int i1 = in[ip++];

      int i2 = ip < iEnd ? in[ip++] : 'A';

      int i3 = ip < iEnd ? in[ip++] : 'A';

      if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)

         throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");

      int b0 = map2[i0];

      int b1 = map2[i1];

      int b2 = map2[i2];

      int b3 = map2[i3];

      if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)

         throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");

      int o0 = ( b0       <<2) | (b1>>>4);

      int o1 = ((b1 & 0xf)<<4) | (b2>>>2);

      int o2 = ((b2 &   3)<<6) |  b3;

      out[op++] = (byte)o0;

      if (op<oLen) out[op++] = (byte)o1;

      if (op<oLen) out[op++] = (byte)o2; }

   return out; }



// Dummy constructor.

private Base64Coder() {}



} // end class Base64Coder