/client/android/src/org/xmlrpc/android/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, http://www.eclipse.org/legal

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

//  AL, Apache License, 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 org.xmlrpc.android;



/**

 * 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 / 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 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 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