org.gatein.common.util.Base64 Maven / Gradle / Ivy
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* Copyright 2009, Red Hat Middleware, LLC, and individual *
* contributors as indicated by the @authors tag. See the *
* copyright.txt in the distribution for a full listing of *
* individual contributors. *
* *
* This is free software; you can redistribute it and/or modify it *
* under the terms of the GNU Lesser General Public License as *
* published by the Free Software Foundation; either version 2.1 of *
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* *
* This software is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
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* 02110-1301 USA, or see the FSF site: http://www.fsf.org. *
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package org.gatein.common.util;
/**
* Encodes and decodes to and from Base64 and URL-safe Base64 encodings. URL-safe Base64 encoding being defined here
* as standard Base64 encoding with the following modifications:
*
* - use '-' and '_' instead of '+' and '/'
* - no line feeds
* - padding character is '*' instead of '='
*
*
* Based on version 2.1 of the Base64 class developed by Robert Harder (public domain).
* Please visit http://iharder.net/base64
* periodically to check for updates or to contribute improvements.
*
* @author Robert Harder
* @author Chris Laprun
* @since 2.4 (Apr 30, 2009)
*/
public class Base64
{
/* ******** P R I V A T E F I E L D S ******** */
/** Maximum line length (76) of Base64 output. */
private final static int MAX_LINE_LENGTH = 76;
/** The equals sign (=) as a byte. */
private final static byte EQUALS_SIGN = (byte)'=';
/** '*' as a byte */
private final static byte STAR = (byte)'*';
/** The character to be used as a padding character in the encoded Strings. */
private byte PADDING_CHAR;
/** The new line character (\n) as a byte. */
private final static byte NEW_LINE = (byte)'\n';
/** Preferred encoding. */
private final static String PREFERRED_ENCODING = "UTF-8";
public static enum EncodingOption { USEURLSAFEENCODING, NOCARRIAGERETURN, STANDARD};
/** The 64 valid Base64 values. */
private byte[] ALPHABET;
private final static byte[] NATIVE_ALPHABET = /* May be something funny like EBCDIC */
{
(byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
(byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
(byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
(byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
(byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
(byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
(byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
(byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5',
(byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/'
};
private final static byte[] NATIVE_URL_SAFE_ALPHABET =
{
(byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
(byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
(byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
(byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
(byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
(byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
(byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
(byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5',
(byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'-', (byte)'_'
};
private static final int IGNORE = -9; // Indicates ignored characters
private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
private final static byte PADDING_CHAR_ENC = -1; // Indicates equals sign in encoding
/**
* Translates a value to either its 6-bit reconstruction value
* or a negative number indicating some other meaning.
*/
private byte[] DECODABET;
/**
* Translates a Base64 value to either its 6-bit reconstruction value
* or a negative number indicating some other meaning.
*/
private final static byte[] BASE64_DECODABET =
{
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 0 - 8
WHITE_SPACE_ENC, WHITE_SPACE_ENC, // Whitespace: Tab and Linefeed
IGNORE, IGNORE, // Decimal 11 - 12
WHITE_SPACE_ENC, // Whitespace: Carriage Return
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 14 - 26
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 27 - 31
WHITE_SPACE_ENC, // Whitespace: Space
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 33 - 42
62, // Plus sign at decimal 43
IGNORE, IGNORE, IGNORE, // Decimal 44 - 46
63, // Slash at decimal 47
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
IGNORE, IGNORE, IGNORE, // Decimal 58 - 60
PADDING_CHAR_ENC, // Equals sign at decimal 61 (padding character)
IGNORE, IGNORE, IGNORE, // Decimal 62 - 64
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 91 - 96
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
IGNORE, IGNORE, IGNORE, IGNORE // Decimal 123 - 126
};
/**
* Translates a URL-modified Base64 value to either its 6-bit reconstruction value
* or a negative number indicating some other meaning.
*/
private final static byte[] URL_SAFE_DECODABET =
{
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 0 - 8
WHITE_SPACE_ENC, WHITE_SPACE_ENC, // Whitespace: Tab and Linefeed
IGNORE, IGNORE, // Decimal 11 - 12
WHITE_SPACE_ENC, // Whitespace: Carriage Return
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 14 - 26
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 27 - 31
WHITE_SPACE_ENC, // Whitespace: Space
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 33 - 41
PADDING_CHAR_ENC, // Star sign at decimal 42 (padding character)
IGNORE, IGNORE, // Decimal 43 - 44
62, // Minus sign at decimal 45
IGNORE, IGNORE, // Decimal 46 - 47
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 58 - 64
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
IGNORE, IGNORE, IGNORE, IGNORE, // Decimal 91 - 94
63, // Underscore at decimal 95
IGNORE, // Decimal 96
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
IGNORE, IGNORE, IGNORE, IGNORE // Decimal 123 - 126
};
/** Determine which ALPHABET to use. */
public void initAlphabets(boolean useURLSafeEncoding)
{
byte[] __bytes;
String alphabetString;
byte[] nativeAlphabet;
if (useURLSafeEncoding)
{
alphabetString = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
nativeAlphabet = NATIVE_URL_SAFE_ALPHABET;
PADDING_CHAR = STAR;
DECODABET = URL_SAFE_DECODABET;
}
else
{
alphabetString = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
nativeAlphabet = NATIVE_ALPHABET;
PADDING_CHAR = EQUALS_SIGN;
DECODABET = BASE64_DECODABET;
}
try
{
__bytes = alphabetString.getBytes(PREFERRED_ENCODING);
} // end try
catch (java.io.UnsupportedEncodingException use)
{
__bytes = nativeAlphabet; // Fall back to native encoding
} // end catch
ALPHABET = __bytes;
} // end initAlphabets
private static final Base64 STANDARD_BASE64 = new Base64();
private static final Base64 URL_SAFE_BASE64 = new Base64(true);
private Base64()
{
this(false);
}
private Base64(boolean useURLSafeEncoding)
{
initAlphabets(useURLSafeEncoding);
}
private static Base64 getBase64(EncodingOption option)
{
return EncodingOption.USEURLSAFEENCODING.equals(option) ? URL_SAFE_BASE64 : STANDARD_BASE64;
}
/* ******** E N C O D I N G M E T H O D S ******** */
/**
* Encodes up to three bytes of the array source
* and writes the resulting four Base64 bytes to destination.
* The source and destination arrays can be manipulated
* anywhere along their length by specifying
* srcOffset and destOffset.
* This method does not check to make sure your arrays
* are large enough to accomodate srcOffset + 3 for
* the source array or destOffset + 4 for
* the destination array.
* The actual number of significant bytes in your array is
* given by numSigBytes.
*
* @param source the array to convert
* @param srcOffset the index where conversion begins
* @param numSigBytes the number of significant bytes in your array
* @param destination the array to hold the conversion
* @param destOffset the index where output will be put
* @return the destination array
*/
private byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes,
byte[] destination, int destOffset)
{
// 1 2 3
// 01234567890123456789012345678901 Bit position
// --------000000001111111122222222 Array position from threeBytes
// --------| || || || | Six bit groups to index ALPHABET
// >>18 >>12 >> 6 >> 0 Right shift necessary
// 0x3f 0x3f 0x3f Additional AND
// Create buffer with zero-padding if there are only one or two
// significant bytes passed in the array.
// We have to shift left 24 in order to flush out the 1's that appear
// when Java treats a value as negative that is cast from a byte to an int.
int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
| (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
| (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);
switch (numSigBytes)
{
case 3:
destination[destOffset] = ALPHABET[(inBuff >>> 18)];
destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
return destination;
case 2:
destination[destOffset] = ALPHABET[(inBuff >>> 18)];
destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
destination[destOffset + 3] = PADDING_CHAR;
return destination;
case 1:
destination[destOffset] = ALPHABET[(inBuff >>> 18)];
destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = PADDING_CHAR;
destination[destOffset + 3] = PADDING_CHAR;
return destination;
default:
return destination;
} // end switch
} // end encode3to4
/**
* Encodes a byte array into Base64 notation using the standard Base64 encoding.
*
* @param source The data to convert
*/
public static String encodeBytes(byte[] source)
{
return encodeBytes(source, EncodingOption.STANDARD);
} // end encodeBytes
/**
* Encodes a byte array into Base64 notation.
*
* @param source The data to convert
* @param option Encoding option
*/
public static String encodeBytes(byte[] source, EncodingOption option)
{
return encodeBytes(source, 0, source.length, option);
} // end encodeBytes
/**
* Encodes a byte array into Base64 notation.
*
* @param source The data to convert
* @param off Offset in array where conversion should begin
* @param len Length of data to convert
* @param option Encoding option
*/
public static String encodeBytes(byte[] source, int off, int len, EncodingOption option)
{
Base64 b64 = getBase64(option);
int len43 = len * 4 / 3;
byte[] outBuff = new byte[(len43) // Main 4:3
+ ((len % 3) > 0 ? 4 : 0) // Account for padding
+ ((EncodingOption.STANDARD.equals(option)) ? (len43 / MAX_LINE_LENGTH) : 0)]; // New lines
int d = 0;
int e = 0;
int len2 = len - 2;
int lineLength = 0;
for (; d < len2; d += 3, e += 4)
{
b64.encode3to4(source, d + off, 3, outBuff, e);
lineLength += 4;
if (EncodingOption.STANDARD.equals(option) && lineLength == MAX_LINE_LENGTH)
{
outBuff[e + 4] = NEW_LINE;
e++;
lineLength = 0;
} // end if: end of line
} // en dfor: each piece of array
if (d < len)
{
b64.encode3to4(source, d + off, len - d, outBuff, e);
e += 4;
} // end if: some padding needed
// Return value according to relevant encoding.
try
{
return new String(outBuff, 0, e, PREFERRED_ENCODING);
} // end try
catch (java.io.UnsupportedEncodingException uue)
{
return new String(outBuff, 0, e);
} // end catch
} // end encodeBytes
/* ******** D E C O D I N G M E T H O D S ******** */
/**
* Decodes four bytes from array source
* and writes the resulting bytes (up to three of them)
* to destination.
* The source and destination arrays can be manipulated
* anywhere along their length by specifying
* srcOffset and destOffset.
* This method does not check to make sure your arrays
* are large enough to accomodate srcOffset + 4 for
* the source array or destOffset + 3 for
* the destination array.
* This method returns the actual number of bytes that
* were converted from the Base64 encoding.
*
* @param source the array to convert
* @param srcOffset the index where conversion begins
* @param destination the array to hold the conversion
* @param destOffset the index where output will be put
* @return the number of decoded bytes converted
*/
private int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset)
{
// Example: Dk==
if (source[srcOffset + 2] == PADDING_CHAR)
{
// Two ways to do the same thing. Don't know which way I like best.
//int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
// | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
| ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12);
destination[destOffset] = (byte)(outBuff >>> 16);
return 1;
}
// Example: DkL=
else if (source[srcOffset + 3] == PADDING_CHAR)
{
// Two ways to do the same thing. Don't know which way I like best.
//int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
// | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
// | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
| ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
| ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6);
destination[destOffset] = (byte)(outBuff >>> 16);
destination[destOffset + 1] = (byte)(outBuff >>> 8);
return 2;
}
// Example: DkLE
else
{
try
{
// Two ways to do the same thing. Don't know which way I like best.
//int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
// | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
// | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
// | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
| ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
| ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6)
| ((DECODABET[source[srcOffset + 3]] & 0xFF));
destination[destOffset] = (byte)(outBuff >> 16);
destination[destOffset + 1] = (byte)(outBuff >> 8);
destination[destOffset + 2] = (byte)(outBuff);
return 3;
}
catch (Exception e)
{
System.out.println("" + source[srcOffset] + ": " + (DECODABET[source[srcOffset]]));
System.out.println("" + source[srcOffset + 1] + ": " + (DECODABET[source[srcOffset + 1]]));
System.out.println("" + source[srcOffset + 2] + ": " + (DECODABET[source[srcOffset + 2]]));
System.out.println("" + source[srcOffset + 3] + ": " + (DECODABET[source[srcOffset + 3]]));
return -1;
} //e nd catch
}
} // end decodeToBytes
/**
* Very low-level access to decoding ASCII characters in
* the form of a byte array.
*
* @param source The Base64 encoded data
* @param off The offset of where to begin decoding
* @param len The length of characters to decode
* @return decoded data
*/
private byte[] decode(int len, int off, byte[] source)
{
int len34 = len * 3 / 4;
byte[] outBuff = new byte[len34]; // Upper limit on size of output
int outBuffPosn = 0;
byte[] b4 = new byte[4];
int b4Posn = 0;
int i = 0;
byte sbiCrop = 0;
byte sbiDecode = 0;
for (i = off; i < off + len; i++)
{
sbiCrop = (byte)(source[i] & 0x7f); // Only the low seven bits
sbiDecode = DECODABET[sbiCrop];
if (sbiDecode >= WHITE_SPACE_ENC) // White space, padding character or better
{
if (sbiDecode >= PADDING_CHAR_ENC)
{
b4[b4Posn++] = sbiCrop;
if (b4Posn > 3)
{
outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn);
b4Posn = 0;
// If that was the padding char, break out of 'for' loop
if (sbiCrop == PADDING_CHAR)
{
break;
}
} // end if: quartet built
} // end if: padding character or better
} // end if: white space, padding character or better
else
{
System.err.println("Bad Base64 input character at " + i + ": " + source[i] + "(decimal)");
return null;
} // end else:
} // each input character
byte[] out = new byte[outBuffPosn];
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
return out;
}
/**
* Very low-level access to decoding ASCII characters in
* the form of a byte array.
*
* @param source The Base64 encoded data
* @param off The offset of where to begin decoding
* @param len The length of characters to decode
* @param optionThatWasUsed EncodingOption used during the encoding
* @return decoded data
*/
public static byte[] decode(byte[] source, int off, int len, EncodingOption optionThatWasUsed)
{
return getBase64(optionThatWasUsed).decode(len, off, source);
} // end decode
/**
* Decodes data from Base64 notation
*
* @param s the string to decode
* @param urlSafeEncodingWasUsed true if the URL-safe was used to encode the data to be decoded
* @param optionThatWasUsed EncodingOption used during the encoding
* @return the decoded data
*/
public static byte[] decode(String s, EncodingOption optionThatWasUsed)
{
byte[] bytes;
try
{
bytes = s.getBytes(PREFERRED_ENCODING);
} // end try
catch (java.io.UnsupportedEncodingException uee)
{
bytes = s.getBytes();
} // end catch
// Decode
bytes = decode(bytes, 0, bytes.length, optionThatWasUsed);
return bytes;
} // end decode
/**
* Decodes data from Base64 notation
*
* @param s the string to decode
* @return the decoded data
*/
public static byte[] decode(String s)
{
return decode(s, EncodingOption.STANDARD);
} // end decode
} // end class Base64