/arch/src/org/arch/misc/crypto/base64/Base64.java

package org.arch.misc.crypto.base64;



import java.util.Arrays;



/**

 * A very fast and memory efficient class to encode and decode to and from

 * BASE64 in full accordance with RFC 2045.<br>

 * <br>

 * On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is

 * about 10 times faster on small arrays (10 - 1000 bytes) and 2-3 times as fast

 * on larger arrays (10000 - 1000000 bytes) compared to

 * <code>sun.misc.Encoder()/Decoder()</code>.<br>

 * <br>

 * 

 * On byte arrays the encoder is about 20% faster than Jakarta Commons Base64

 * Codec for encode and about 50% faster for decoding large arrays. This

 * implementation is about twice as fast on very small arrays (&lt 30 bytes). If

 * source/destination is a <code>String</code> this version is about three times

 * as fast due to the fact that the Commons Codec result has to be recoded to a

 * <code>String</code> from <code>byte[]</code>, which is very expensive.<br>

 * <br>

 * 

 * This encode/decode algorithm doesn't create any temporary arrays as many

 * other codecs do, it only allocates the resulting array. This produces less

 * garbage and it is possible to handle arrays twice as large as algorithms that

 * create a temporary array. (E.g. Jakarta Commons Codec). It is unknown whether

 * Sun's <code>sun.misc.Encoder()/Decoder()</code> produce temporary arrays but

 * since performance is quite low it probably does.<br>

 * <br>

 * 

 * The encoder produces the same output as the Sun one except that the Sun's

 * encoder appends a trailing line separator if the last character isn't a pad.

 * Unclear why but it only adds to the length and is probably a side effect.

 * Both are in conformance with RFC 2045 though.<br>

 * Commons codec seem to always att a trailing line separator.<br>

 * <br>

 * 

 * <b>Note!</b> The encode/decode method pairs (types) come in three versions

 * with the <b>exact</b> same algorithm and thus a lot of code redundancy. This

 * is to not create any temporary arrays for transcoding to/from different

 * format types. The methods not used can simply be commented out.<br>

 * <br>

 * 

 * There is also a "fast" version of all decode methods that works the same way

 * as the normal ones, but har a few demands on the decoded input. Normally

 * though, these fast verions should be used if the source if the input is known

 * and it hasn't bee tampered with.<br>

 * <br>

 * 

 * If you find the code useful or you find a bug, please send me a note at

 * base64 @ miginfocom . com.

 * 

 * Licence (BSD): ==============

 * 

 * Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com)

 * All rights reserved.

 * 

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice, this

 * list of conditions and the following disclaimer. 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. Neither the name of the MiG InfoCom AB nor the names

 * of its contributors may be used to endorse or promote products derived from

 * this software without specific prior written permission.

 * 

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS 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 COPYRIGHT OWNER OR 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.

 * 

 * @version 2.2

 * @author Mikael Grev Date: 2004-aug-02 Time: 11:31:11

 */



public class Base64

{

	private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

	        .toCharArray();

	private static final int[] IA = new int[256];

	static

	{

		Arrays.fill(IA, -1);

		for (int i = 0, iS = CA.length; i < iS; i++)

			IA[CA[i]] = i;

		IA['='] = 0;

	}



	// ****************************************************************************************

	// * char[] version

	// ****************************************************************************************



	/**

	 * Encodes a raw byte array into a BASE64 <code>char[]</code> representation

	 * i accordance with RFC 2045.

	 * 

	 * @param sArr

	 *            The bytes to convert. If <code>null</code> or length 0 an

	 *            empty array will be returned.

	 * @param lineSep

	 *            Optional "\r\n" after 76 characters, unless end of file.<br>

	 *            No line separator will be in breach of RFC 2045 which

	 *            specifies max 76 per line but will be a little faster.

	 * @return A BASE64 encoded array. Never <code>null</code>.

	 */

	public final static char[] encodeToChar(byte[] sArr, boolean lineSep)

	{

		// Check special case

		int sLen = sArr != null ? sArr.length : 0;

		if (sLen == 0)

			return new char[0];



		int eLen = (sLen / 3) * 3; // Length of even 24-bits.

		int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count

		int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of

																// returned

																// array

		char[] dArr = new char[dLen];



		// Encode even 24-bits

		for (int s = 0, d = 0, cc = 0; s < eLen;)

		{

			// Copy next three bytes into lower 24 bits of int, paying attension

			// to sign.

			int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8

			        | (sArr[s++] & 0xff);



			// Encode the int into four chars

			dArr[d++] = CA[(i >>> 18) & 0x3f];

			dArr[d++] = CA[(i >>> 12) & 0x3f];

			dArr[d++] = CA[(i >>> 6) & 0x3f];

			dArr[d++] = CA[i & 0x3f];



			// Add optional line separator

			if (lineSep && ++cc == 19 && d < dLen - 2)

			{

				dArr[d++] = '\r';

				dArr[d++] = '\n';

				cc = 0;

			}

		}



		// Pad and encode last bits if source isn't even 24 bits.

		int left = sLen - eLen; // 0 - 2.

		if (left > 0)

		{

			// Prepare the int

			int i = ((sArr[eLen] & 0xff) << 10)

			        | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);



			// Set last four chars

			dArr[dLen - 4] = CA[i >> 12];

			dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];

			dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';

			dArr[dLen - 1] = '=';

		}

		return dArr;

	}



	public final static char[] encodeToChar(byte[] sArr, int off, int len,

	        boolean lineSep)

	{

		// Check special case

		int sLen = (sArr != null && len > 0) ? len : 0;

		if (sLen == 0)

			return new char[0];



		int eLen = (sLen / 3) * 3; // Length of even 24-bits.

		int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count

		int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of

																// returned

																// array

		char[] dArr = new char[dLen];



		// Encode even 24-bits

		for (int s = 0, d = 0, cc = 0; s < eLen;)

		{

			// Copy next three bytes into lower 24 bits of int, paying attension

			// to sign.

			int i = (sArr[off + s++] & 0xff) << 16

			        | (sArr[off + s++] & 0xff) << 8 | (sArr[off + s++] & 0xff);



			// Encode the int into four chars

			dArr[d++] = CA[(i >>> 18) & 0x3f];

			dArr[d++] = CA[(i >>> 12) & 0x3f];

			dArr[d++] = CA[(i >>> 6) & 0x3f];

			dArr[d++] = CA[i & 0x3f];



			// Add optional line separator

			if (lineSep && ++cc == 19 && d < dLen - 2)

			{

				dArr[d++] = '\r';

				dArr[d++] = '\n';

				cc = 0;

			}

		}



		// Pad and encode last bits if source isn't even 24 bits.

		int left = sLen - eLen; // 0 - 2.

		if (left > 0)

		{

			// Prepare the int

			int i = ((sArr[off + eLen] & 0xff) << 10)

			        | (left == 2 ? ((sArr[off + sLen - 1] & 0xff) << 2) : 0);



			// Set last four chars

			dArr[dLen - 4] = CA[i >> 12];

			dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];

			dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';

			dArr[dLen - 1] = '=';

		}

		return dArr;

	}



	/**

	 * Decodes a BASE64 encoded char array. All illegal characters will be

	 * ignored and can handle both arrays with and without line separators.

	 * 

	 * @param sArr

	 *            The source array. <code>null</code> or length 0 will return an

	 *            empty array.

	 * @return The decoded array of bytes. May be of length 0. Will be

	 *         <code>null</code> if the legal characters (including '=') isn't

	 *         divideable by 4. (I.e. definitely corrupted).

	 */

	public final static byte[] decode(char[] sArr)

	{

		// Check special case

		int sLen = sArr != null ? sArr.length : 0;

		if (sLen == 0)

			return new byte[0];



		// Count illegal characters (including '\r', '\n') to know what size the

		// returned array will be,

		// so we don't have to reallocate & copy it later.

		int sepCnt = 0; // Number of separator characters. (Actually illegal

						// characters, but that's a bonus...)

		for (int i = 0; i < sLen; i++)

			// If input is "pure" (I.e. no line separators or illegal chars)

			// base64 this loop can be commented out.

			if (IA[sArr[i]] < 0)

				sepCnt++;



		// Check so that legal chars (including '=') are evenly divideable by 4

		// as specified in RFC 2045.

		if ((sLen - sepCnt) % 4 != 0)

			return null;



		int pad = 0;

		for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0;)

			if (sArr[i] == '=')

				pad++;



		int len = ((sLen - sepCnt) * 6 >> 3) - pad;



		byte[] dArr = new byte[len]; // Preallocate byte[] of exact length



		for (int s = 0, d = 0; d < len;)

		{

			// Assemble three bytes into an int from four "valid" characters.

			int i = 0;

			for (int j = 0; j < 4; j++)

			{ // j only increased if a valid char was found.

				int c = IA[sArr[s++]];

				if (c >= 0)

					i |= c << (18 - j * 6);

				else

					j--;

			}

			// Add the bytes

			dArr[d++] = (byte) (i >> 16);

			if (d < len)

			{

				dArr[d++] = (byte) (i >> 8);

				if (d < len)

					dArr[d++] = (byte) i;

			}

		}

		return dArr;

	}



	/**

	 * Decodes a BASE64 encoded char array that is known to be resonably well

	 * formatted. The method is about twice as fast as {@link #decode(char[])}.

	 * The preconditions are:<br>

	 * + The array must have a line length of 76 chars OR no line separators at

	 * all (one line).<br>

	 * + Line separator must be "\r\n", as specified in RFC 2045 + The array

	 * must not contain illegal characters within the encoded string<br>

	 * + The array CAN have illegal characters at the beginning and end, those

	 * will be dealt with appropriately.<br>

	 * 

	 * @param sArr

	 *            The source array. Length 0 will return an empty array.

	 *            <code>null</code> will throw an exception.

	 * @return The decoded array of bytes. May be of length 0.

	 */

	public final static byte[] decodeFast(char[] sArr)

	{

		// Check special case

		int sLen = sArr.length;

		if (sLen == 0)

			return new byte[0];



		int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.



		// Trim illegal chars from start

		while (sIx < eIx && IA[sArr[sIx]] < 0)

			sIx++;



		// Trim illegal chars from end

		while (eIx > 0 && IA[sArr[eIx]] < 0)

			eIx--;



		// get the padding count (=) (0, 1 or 2)

		int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count

																		 // '='

																		 // at

																		 // end.

		int cCnt = eIx - sIx + 1; // Content count including possible separators

		int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;



		int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded

													// bytes

		byte[] dArr = new byte[len]; // Preallocate byte[] of exact length



		// Decode all but the last 0 - 2 bytes.

		int d = 0;

		for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)

		{

			// Assemble three bytes into an int from four "valid" characters.

			int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12

			        | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];



			// Add the bytes

			dArr[d++] = (byte) (i >> 16);

			dArr[d++] = (byte) (i >> 8);

			dArr[d++] = (byte) i;



			// If line separator, jump over it.

			if (sepCnt > 0 && ++cc == 19)

			{

				sIx += 2;

				cc = 0;

			}

		}



		if (d < len)

		{

			// Decode last 1-3 bytes (incl '=') into 1-3 bytes

			int i = 0;

			for (int j = 0; sIx <= eIx - pad; j++)

				i |= IA[sArr[sIx++]] << (18 - j * 6);



			for (int r = 16; d < len; r -= 8)

				dArr[d++] = (byte) (i >> r);

		}



		return dArr;

	}



	// ****************************************************************************************

	// * byte[] version

	// ****************************************************************************************



	/**

	 * Encodes a raw byte array into a BASE64 <code>byte[]</code> representation

	 * i accordance with RFC 2045.

	 * 

	 * @param sArr

	 *            The bytes to convert. If <code>null</code> or length 0 an

	 *            empty array will be returned.

	 * @param lineSep

	 *            Optional "\r\n" after 76 characters, unless end of file.<br>

	 *            No line separator will be in breach of RFC 2045 which

	 *            specifies max 76 per line but will be a little faster.

	 * @return A BASE64 encoded array. Never <code>null</code>.

	 */

	public final static byte[] encodeToByte(byte[] sArr, boolean lineSep)

	{

		// Check special case

		int sLen = sArr != null ? sArr.length : 0;

		if (sLen == 0)

			return new byte[0];



		int eLen = (sLen / 3) * 3; // Length of even 24-bits.

		int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count

		int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of

																// returned

																// array

		byte[] dArr = new byte[dLen];



		// Encode even 24-bits

		for (int s = 0, d = 0, cc = 0; s < eLen;)

		{

			// Copy next three bytes into lower 24 bits of int, paying attension

			// to sign.

			int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8

			        | (sArr[s++] & 0xff);



			// Encode the int into four chars

			dArr[d++] = (byte) CA[(i >>> 18) & 0x3f];

			dArr[d++] = (byte) CA[(i >>> 12) & 0x3f];

			dArr[d++] = (byte) CA[(i >>> 6) & 0x3f];

			dArr[d++] = (byte) CA[i & 0x3f];



			// Add optional line separator

			if (lineSep && ++cc == 19 && d < dLen - 2)

			{

				dArr[d++] = '\r';

				dArr[d++] = '\n';

				cc = 0;

			}

		}



		// Pad and encode last bits if source isn't an even 24 bits.

		int left = sLen - eLen; // 0 - 2.

		if (left > 0)

		{

			// Prepare the int

			int i = ((sArr[eLen] & 0xff) << 10)

			        | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);



			// Set last four chars

			dArr[dLen - 4] = (byte) CA[i >> 12];

			dArr[dLen - 3] = (byte) CA[(i >>> 6) & 0x3f];

			dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f] : (byte) '=';

			dArr[dLen - 1] = '=';

		}

		return dArr;

	}



	/**

	 * Decodes a BASE64 encoded byte array. All illegal characters will be

	 * ignored and can handle both arrays with and without line separators.

	 * 

	 * @param sArr

	 *            The source array. Length 0 will return an empty array.

	 *            <code>null</code> will throw an exception.

	 * @return The decoded array of bytes. May be of length 0. Will be

	 *         <code>null</code> if the legal characters (including '=') isn't

	 *         divideable by 4. (I.e. definitely corrupted).

	 */

	public final static byte[] decode(byte[] sArr)

	{

		// Check special case

		int sLen = sArr.length;



		// Count illegal characters (including '\r', '\n') to know what size the

		// returned array will be,

		// so we don't have to reallocate & copy it later.

		int sepCnt = 0; // Number of separator characters. (Actually illegal

						// characters, but that's a bonus...)

		for (int i = 0; i < sLen; i++)

			// If input is "pure" (I.e. no line separators or illegal chars)

			// base64 this loop can be commented out.

			if (IA[sArr[i] & 0xff] < 0)

				sepCnt++;



		// Check so that legal chars (including '=') are evenly divideable by 4

		// as specified in RFC 2045.

		if ((sLen - sepCnt) % 4 != 0)

			return null;



		int pad = 0;

		for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0;)

			if (sArr[i] == '=')

				pad++;



		int len = ((sLen - sepCnt) * 6 >> 3) - pad;



		byte[] dArr = new byte[len]; // Preallocate byte[] of exact length



		for (int s = 0, d = 0; d < len;)

		{

			// Assemble three bytes into an int from four "valid" characters.

			int i = 0;

			for (int j = 0; j < 4; j++)

			{ // j only increased if a valid char was found.

				int c = IA[sArr[s++] & 0xff];

				if (c >= 0)

					i |= c << (18 - j * 6);

				else

					j--;

			}



			// Add the bytes

			dArr[d++] = (byte) (i >> 16);

			if (d < len)

			{

				dArr[d++] = (byte) (i >> 8);

				if (d < len)

					dArr[d++] = (byte) i;

			}

		}



		return dArr;

	}



	/**

	 * Decodes a BASE64 encoded byte array that is known to be resonably well

	 * formatted. The method is about twice as fast as {@link #decode(byte[])}.

	 * The preconditions are:<br>

	 * + The array must have a line length of 76 chars OR no line separators at

	 * all (one line).<br>

	 * + Line separator must be "\r\n", as specified in RFC 2045 + The array

	 * must not contain illegal characters within the encoded string<br>

	 * + The array CAN have illegal characters at the beginning and end, those

	 * will be dealt with appropriately.<br>

	 * 

	 * @param sArr

	 *            The source array. Length 0 will return an empty array.

	 *            <code>null</code> will throw an exception.

	 * @return The decoded array of bytes. May be of length 0.

	 */

	public final static byte[] decodeFast(byte[] sArr)

	{

		// Check special case

		int sLen = sArr.length;

		if (sLen == 0)

			return new byte[0];



		int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.



		// Trim illegal chars from start

		while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0)

			sIx++;



		// Trim illegal chars from end

		while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0)

			eIx--;



		// get the padding count (=) (0, 1 or 2)

		int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count

																		 // '='

																		 // at

																		 // end.

		int cCnt = eIx - sIx + 1; // Content count including possible separators

		int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;



		int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded

													// bytes

		byte[] dArr = new byte[len]; // Preallocate byte[] of exact length



		// Decode all but the last 0 - 2 bytes.

		int d = 0;

		for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)

		{

			// Assemble three bytes into an int from four "valid" characters.

			int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12

			        | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];



			// Add the bytes

			dArr[d++] = (byte) (i >> 16);

			dArr[d++] = (byte) (i >> 8);

			dArr[d++] = (byte) i;



			// If line separator, jump over it.

			if (sepCnt > 0 && ++cc == 19)

			{

				sIx += 2;

				cc = 0;

			}

		}



		if (d < len)

		{

			// Decode last 1-3 bytes (incl '=') into 1-3 bytes

			int i = 0;

			for (int j = 0; sIx <= eIx - pad; j++)

				i |= IA[sArr[sIx++]] << (18 - j * 6);



			for (int r = 16; d < len; r -= 8)

				dArr[d++] = (byte) (i >> r);

		}



		return dArr;

	}



	// ****************************************************************************************

	// * String version

	// ****************************************************************************************



	/**

	 * Encodes a raw byte array into a BASE64 <code>String</code> representation

	 * i accordance with RFC 2045.

	 * 

	 * @param sArr

	 *            The bytes to convert. If <code>null</code> or length 0 an

	 *            empty array will be returned.

	 * @param lineSep

	 *            Optional "\r\n" after 76 characters, unless end of file.<br>

	 *            No line separator will be in breach of RFC 2045 which

	 *            specifies max 76 per line but will be a little faster.

	 * @return A BASE64 encoded array. Never <code>null</code>.

	 */

	public final static String encodeToString(byte[] sArr, boolean lineSep)

	{

		// Reuse char[] since we can't create a String incrementally anyway and

		// StringBuffer/Builder would be slower.

		return new String(encodeToChar(sArr, lineSep));

	}

	

	public final static String encodeToString(byte[] sArr, int off, int len,boolean lineSep)

	{

		// Reuse char[] since we can't create a String incrementally anyway and

		// StringBuffer/Builder would be slower.

		return new String(encodeToChar(sArr,off, len, lineSep));

	}



	/**

	 * Decodes a BASE64 encoded <code>String</code>. All illegal characters will

	 * be ignored and can handle both strings with and without line separators.<br>

	 * <b>Note!</b> It can be up to about 2x the speed to call

	 * <code>decode(str.toCharArray())</code> instead. That will create a

	 * temporary array though. This version will use <code>str.charAt(i)</code>

	 * to iterate the string.

	 * 

	 * @param str

	 *            The source string. <code>null</code> or length 0 will return

	 *            an empty array.

	 * @return The decoded array of bytes. May be of length 0. Will be

	 *         <code>null</code> if the legal characters (including '=') isn't

	 *         divideable by 4. (I.e. definitely corrupted).

	 */

	public final static byte[] decode(String str)

	{

		// Check special case

		int sLen = str != null ? str.length() : 0;

		if (sLen == 0)

			return new byte[0];



		// Count illegal characters (including '\r', '\n') to know what size the

		// returned array will be,

		// so we don't have to reallocate & copy it later.

		int sepCnt = 0; // Number of separator characters. (Actually illegal

						// characters, but that's a bonus...)

		for (int i = 0; i < sLen; i++)

			// If input is "pure" (I.e. no line separators or illegal chars)

			// base64 this loop can be commented out.

			if (IA[str.charAt(i)] < 0)

				sepCnt++;



		// Check so that legal chars (including '=') are evenly divideable by 4

		// as specified in RFC 2045.

		if ((sLen - sepCnt) % 4 != 0)

			return null;



		// Count '=' at end

		int pad = 0;

		for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0;)

			if (str.charAt(i) == '=')

				pad++;



		int len = ((sLen - sepCnt) * 6 >> 3) - pad;



		byte[] dArr = new byte[len]; // Preallocate byte[] of exact length



		for (int s = 0, d = 0; d < len;)

		{

			// Assemble three bytes into an int from four "valid" characters.

			int i = 0;

			for (int j = 0; j < 4; j++)

			{ // j only increased if a valid char was found.

				int c = IA[str.charAt(s++)];

				if (c >= 0)

					i |= c << (18 - j * 6);

				else

					j--;

			}

			// Add the bytes

			dArr[d++] = (byte) (i >> 16);

			if (d < len)

			{

				dArr[d++] = (byte) (i >> 8);

				if (d < len)

					dArr[d++] = (byte) i;

			}

		}

		return dArr;

	}



	/**

	 * Decodes a BASE64 encoded string that is known to be resonably well

	 * formatted. The method is about twice as fast as {@link #decode(String)}.

	 * The preconditions are:<br>

	 * + The array must have a line length of 76 chars OR no line separators at

	 * all (one line).<br>

	 * + Line separator must be "\r\n", as specified in RFC 2045 + The array

	 * must not contain illegal characters within the encoded string<br>

	 * + The array CAN have illegal characters at the beginning and end, those

	 * will be dealt with appropriately.<br>

	 * 

	 * @param s

	 *            The source string. Length 0 will return an empty array.

	 *            <code>null</code> will throw an exception.

	 * @return The decoded array of bytes. May be of length 0.

	 */

	public final static byte[] decodeFast(String s)

	{

		// Check special case

		int sLen = s.length();

		if (sLen == 0)

			return new byte[0];



		int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.



		// Trim illegal chars from start

		while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)

			sIx++;



		// Trim illegal chars from end

		while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)

			eIx--;



		// get the padding count (=) (0, 1 or 2)

		int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count

																				 // '='

																				 // at

																				 // end.

		int cCnt = eIx - sIx + 1; // Content count including possible separators

		int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1

		        : 0;



		int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded

													// bytes

		byte[] dArr = new byte[len]; // Preallocate byte[] of exact length



		// Decode all but the last 0 - 2 bytes.

		int d = 0;

		for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)

		{

			// Assemble three bytes into an int from four "valid" characters.

			int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12

			        | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];



			// Add the bytes

			dArr[d++] = (byte) (i >> 16);

			dArr[d++] = (byte) (i >> 8);

			dArr[d++] = (byte) i;



			// If line separator, jump over it.

			if (sepCnt > 0 && ++cc == 19)

			{

				sIx += 2;

				cc = 0;

			}

		}



		if (d < len)

		{

			// Decode last 1-3 bytes (incl '=') into 1-3 bytes

			int i = 0;

			for (int j = 0; sIx <= eIx - pad; j++)

				i |= IA[s.charAt(sIx++)] << (18 - j * 6);



			for (int r = 16; d < len; r -= 8)

				dArr[d++] = (byte) (i >> r);

		}



		return dArr;

	}

}