/**
* This file is distributed under the GPL
* Copyright 2003: Christian d'Heureuse, Inventec Informatik AG, Switzerland.
* Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br>
* $Id: Base64.java 1590 2008-08-27 18:24:10Z scotta $
*/
package net.bnubot.util.crypto;
import net.bnubot.util.ByteArray;
/**
* A Base64 Encoder/Decoder.
*
* <p>
* This class is used to encode and decode data in Base64 format as described in
* RFC 1521.
*
* <p>
* Version history:<br>
* 2003-07-22 Christian d'Heureuse (chdh): Module created.<br>
* 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br>
* 2006-11-21 chdh:<br>
* Method encode(String) renamed to encodeString(String).<br>
* Method decode(String) renamed to decodeString(String).<br>
* New method encode(byte[],int) added.<br>
* New method decode(String) added.<br>
*
* @author scotta
* @author Christian d'Heureuse
*/
public class Base64 {
// Mapping table from 6-bit nibbles to Base64 characters.
private static byte[] map1 = new byte[64];
static {
int i = 0;
for (byte c = 'A'; c <= 'Z'; c++)
map1[i++] = c;
for (byte c = 'a'; c <= 'z'; c++)
map1[i++] = c;
for (byte c = '0'; c <= '9'; c++)
map1[i++] = c;
map1[i++] = '+';
map1[i++] = '/';
}
// Mapping table from Base64 characters to 6-bit nibbles.
private static 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 byte array into Base64 format. No blanks or line breaks are
* inserted.
*
* @param in an array containing the data bytes to be encoded.
* @return A character array with the Base64 encoded data.
*/
public static ByteArray encode(ByteArray in) {
return new ByteArray(encode(in.getBytes(), in.length()));
}
/**
* Encodes a byte array into Base64 format. No blanks or line breaks are
* inserted.
*
* @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 with the Base64 encoded data.
*/
public static byte[] encode(byte[] in, int iLen) {
int oDataLen = (iLen * 4 + 2) / 3; // output length without padding
int oLen = ((iLen + 2) / 3) * 4; // output length including padding
byte[] out = new byte[oLen];
int ip = 0;
int op = 0;
while (ip < iLen) {
int i0 = in[ip++] & 0xff;
int i1 = ip < iLen ? in[ip++] & 0xff : 0;
int i2 = ip < iLen ? 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] = (byte)(op < oDataLen ? map1[o2] : '=');
op++;
out[op] = (byte)(op < oDataLen ? map1[o3] : '=');
op++;
}
return out;
}
/**
* Decodes a string from Base64 format.
*
* @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 ByteArray decode(ByteArray s) {
return new ByteArray(decode(s.getBytes()));
}
/**
* Decodes a byte array from Base64 format. No blanks or line breaks are
* allowed within the Base64 encoded 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(byte[] in) {
int iLen = in.length;
if (iLen % 4 != 0)
throw new IllegalArgumentException("Length of Base64 encoded input string is not a multiple of 4.");
while (iLen > 0 && in[iLen - 1] == '=')
iLen--;
int oLen = (iLen * 3) / 4;
byte[] out = new byte[oLen];
int ip = 0;
int op = 0;
while (ip < iLen) {
int i0 = in[ip++];
int i1 = in[ip++];
int i2 = ip < iLen ? in[ip++] : 'A';
int i3 = ip < iLen ? 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;
}
}