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	/*
	* Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.util.prefs;

	/**
	* Static methods for translating Base64 encoded strings to byte arrays
	* and vice-versa.
	*
	* @author Josh Bloch
	* @see Preferences
	* @since 1.4
	*/
	class Base64 {
	/**
	* Translates the specified byte array into a Base64 string as per
	* Preferences.put(byte[]).
	*/
	static String byteArrayToBase64(byte[] a) {
	return byteArrayToBase64(a, false);
	}

	/**
	* Translates the specified byte array into an "alternate representation"
	* Base64 string. This non-standard variant uses an alphabet that does
	* not contain the uppercase alphabetic characters, which makes it
	* suitable for use in situations where case-folding occurs.
	*/
	static String byteArrayToAltBase64(byte[] a) {
	return byteArrayToBase64(a, true);
	}

	private static String byteArrayToBase64(byte[] a, boolean alternate) {
	int aLen = a.length;
	int numFullGroups = aLen/3;
	int numBytesInPartialGroup = aLen - 3*numFullGroups;
	int resultLen = 4*((aLen + 2)/3);
	StringBuffer result = new StringBuffer(resultLen);
	char[] intToAlpha = (alternate ? intToAltBase64 : intToBase64);

	// Translate all full groups from byte array elements to Base64
	int inCursor = 0;
	for (int i=0; i<numFullGroups; i++) {
	int byte0 = a[inCursor++] & 0xff;
	int byte1 = a[inCursor++] & 0xff;
	int byte2 = a[inCursor++] & 0xff;
	result.append(intToAlpha[byte0 >> 2]);
	result.append(intToAlpha[(byte0 << 4)&0x3f \| (byte1 >> 4)]);
	result.append(intToAlpha[(byte1 << 2)&0x3f \| (byte2 >> 6)]);
	result.append(intToAlpha[byte2 & 0x3f]);
	}

	// Translate partial group if present
	if (numBytesInPartialGroup != 0) {
	int byte0 = a[inCursor++] & 0xff;
	result.append(intToAlpha[byte0 >> 2]);
	if (numBytesInPartialGroup == 1) {
	result.append(intToAlpha[(byte0 << 4) & 0x3f]);
	result.append("==");
	} else {
	// assert numBytesInPartialGroup == 2;
	int byte1 = a[inCursor++] & 0xff;
	result.append(intToAlpha[(byte0 << 4)&0x3f \| (byte1 >> 4)]);
	result.append(intToAlpha[(byte1 << 2)&0x3f]);
	result.append('=');
	}
	}
	// assert inCursor == a.length;
	// assert result.length() == resultLen;
	return result.toString();
	}

	/**
	* This array is a lookup table that translates 6-bit positive integer
	* index values into their "Base64 Alphabet" equivalents as specified
	* in Table 1 of RFC 2045.
	*/
	private static final char intToBase64[] = {
	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
	'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
	'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
	};

	/**
	* This array is a lookup table that translates 6-bit positive integer
	* index values into their "Alternate Base64 Alphabet" equivalents.
	* This is NOT the real Base64 Alphabet as per in Table 1 of RFC 2045.
	* This alternate alphabet does not use the capital letters. It is
	* designed for use in environments where "case folding" occurs.
	*/
	private static final char intToAltBase64[] = {
	'!', '"', '#', '$', '%', '&', '\'', '(', ')', ',', '-', '.', ':',
	';', '<', '>', '@', '[', ']', '^', '`', '_', '{', '\|', '}', '~',
	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
	'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '?'
	};

	/**
	* Translates the specified Base64 string (as per Preferences.get(byte[]))
	* into a byte array.
	*
	* @throw IllegalArgumentException if <tt>s</tt> is not a valid Base64
	* string.
	*/
	static byte[] base64ToByteArray(String s) {
	return base64ToByteArray(s, false);
	}

	/**
	* Translates the specified "alternate representation" Base64 string
	* into a byte array.
	*
	* @throw IllegalArgumentException or ArrayOutOfBoundsException
	* if <tt>s</tt> is not a valid alternate representation
	* Base64 string.
	*/
	static byte[] altBase64ToByteArray(String s) {
	return base64ToByteArray(s, true);
	}

	private static byte[] base64ToByteArray(String s, boolean alternate) {
	byte[] alphaToInt = (alternate ? altBase64ToInt : base64ToInt);
	int sLen = s.length();
	int numGroups = sLen/4;
	if (4*numGroups != sLen)
	throw new IllegalArgumentException(
	"String length must be a multiple of four.");
	int missingBytesInLastGroup = 0;
	int numFullGroups = numGroups;
	if (sLen != 0) {
	if (s.charAt(sLen-1) == '=') {
	missingBytesInLastGroup++;
	numFullGroups--;
	}
	if (s.charAt(sLen-2) == '=')
	missingBytesInLastGroup++;
	}
	byte[] result = new byte[3*numGroups - missingBytesInLastGroup];

	// Translate all full groups from base64 to byte array elements
	int inCursor = 0, outCursor = 0;
	for (int i=0; i<numFullGroups; i++) {
	int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt);
	int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt);
	int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt);
	int ch3 = base64toInt(s.charAt(inCursor++), alphaToInt);
	result[outCursor++] = (byte) ((ch0 << 2) \| (ch1 >> 4));
	result[outCursor++] = (byte) ((ch1 << 4) \| (ch2 >> 2));
	result[outCursor++] = (byte) ((ch2 << 6) \| ch3);
	}

	// Translate partial group, if present
	if (missingBytesInLastGroup != 0) {
	int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt);
	int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt);
	result[outCursor++] = (byte) ((ch0 << 2) \| (ch1 >> 4));

	if (missingBytesInLastGroup == 1) {
	int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt);
	result[outCursor++] = (byte) ((ch1 << 4) \| (ch2 >> 2));
	}
	}
	// assert inCursor == s.length()-missingBytesInLastGroup;
	// assert outCursor == result.length;
	return result;
	}

	/**
	* Translates the specified character, which is assumed to be in the
	* "Base 64 Alphabet" into its equivalent 6-bit positive integer.
	*
	* @throw IllegalArgumentException or ArrayOutOfBoundsException if
	* c is not in the Base64 Alphabet.
	*/
	private static int base64toInt(char c, byte[] alphaToInt) {
	int result = alphaToInt[c];
	if (result < 0)
	throw new IllegalArgumentException("Illegal character " + c);
	return result;
	}

	/**
	* This array is a lookup table that translates unicode characters
	* drawn from the "Base64 Alphabet" (as specified in Table 1 of RFC 2045)
	* into their 6-bit positive integer equivalents. Characters that
	* are not in the Base64 alphabet but fall within the bounds of the
	* array are translated to -1.
	*/
	private static final byte base64ToInt[] = {
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54,
	55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4,
	5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
	24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34,
	35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
	};

	/**
	* This array is the analogue of base64ToInt, but for the nonstandard
	* variant that avoids the use of uppercase alphabetic characters.
	*/
	private static final byte altBase64ToInt[] = {
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1,
	2, 3, 4, 5, 6, 7, 8, -1, 62, 9, 10, 11, -1 , 52, 53, 54, 55, 56, 57,
	58, 59, 60, 61, 12, 13, 14, -1, 15, 63, 16, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, 17, -1, 18, 19, 21, 20, 26, 27, 28, 29, 30, 31, 32, 33,
	34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
	51, 22, 23, 24, 25
	};

	public static void main(String args[]) {
	int numRuns = Integer.parseInt(args[0]);
	int numBytes = Integer.parseInt(args[1]);
	java.util.Random rnd = new java.util.Random();
	for (int i=0; i<numRuns; i++) {
	for (int j=0; j<numBytes; j++) {
	byte[] arr = new byte[j];
	for (int k=0; k<j; k++)
	arr[k] = (byte)rnd.nextInt();

	String s = byteArrayToBase64(arr);
	byte [] b = base64ToByteArray(s);
	if (!java.util.Arrays.equals(arr, b))
	System.out.println("Dismal failure!");

	s = byteArrayToAltBase64(arr);
	b = altBase64ToByteArray(s);
	if (!java.util.Arrays.equals(arr, b))
	System.out.println("Alternate dismal failure!");
	}
	}
	}
	}

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