android-ibc-forum

Base64Coder.java (5441B)

---

 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>
  * This is "Open Source" software and released under the <a
  * href="http://www.gnu.org/licenses/lgpl.html">GNU/LGPL</a> license.<br>
  * It is provided "as is" without warranty of any kind.<br>
  * Copyright 2003: Christian d'Heureuse, Inventec Informatik AG, Switzerland.<br>
  * Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br>
  * 
  * <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>
  * &nbsp; Method encode(String) renamed to encodeString(String).<br>
  * &nbsp; Method decode(String) renamed to decodeString(String).<br>
  * &nbsp; New method encode(byte[],int) added.<br>
  * &nbsp; New method decode(String) added.<br>
  */
 
 class Base64Coder {
 
 	// 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 with the Base64 encoded data.
 	 */
 	static String encodeString(String s) {
 		return new String(encode(s.getBytes()));
 	}
 
 	/**
 	 * 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.
 	 */
 	static char[] encode(byte[] in) {
 		return encode(in, 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.
 	 */
 	static char[] 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
 		char[] out = new char[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] = op < oDataLen ? map1[o2] : '=';
 			op++;
 			out[op] = 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.
 	 */
 	static String decodeString(String s) {
 		return new String(decode(s));
 	}
 
 	/**
 	 * Decodes a byte array from Base64 format.
 	 * 
 	 * @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.
 	 */
 	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 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.
 	 */
 	static byte[] decode(char[] 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;
 	}
 
 	// Dummy constructor.
 	private Base64Coder() {
 	}
 }