com.foundationdb.sql.jdbc.util.Base64 Maven / Gradle / Ivy
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package com.foundationdb.sql.jdbc.util;
/**
* This code is a stripped down version of Robert Harder's Public Domain
* Base64 implementation. GZIP support, InputStream and OutputStream stuff
* and some unneeded encode/decode methods have been removed.
*
* -- Original comments follow --
*
* Encodes and decodes to and from Base64 notation.
*
*
* Change Log:
*
*
* - v2.1 - Cleaned up javadoc comments and unused variables and methods. Added
* some convenience methods for reading and writing to and from files.
* - v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems
* with other encodings (like EBCDIC).
* - v2.0.1 - Fixed an error when decoding a single byte, that is, when the
* encoded data was a single byte.
* - v2.0 - I got rid of methods that used booleans to set options.
* Now everything is more consolidated and cleaner. The code now detects
* when data that's being decoded is gzip-compressed and will decompress it
* automatically. Generally things are cleaner. You'll probably have to
* change some method calls that you were making to support the new
* options format (ints that you "OR" together).
* - v1.5.1 - Fixed bug when decompressing and decoding to a
* byte[] using decode( String s, boolean gzipCompressed ).
* Added the ability to "suspend" encoding in the Output Stream so
* you can turn on and off the encoding if you need to embed base64
* data in an otherwise "normal" stream (like an XML file).
* - v1.5 - Output stream pases on flush() command but doesn't do anything itself.
* This helps when using GZIP streams.
* Added the ability to GZip-compress objects before encoding them.
* - v1.4 - Added helper methods to read/write files.
* - v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.
* - v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream
* where last buffer being read, if not completely full, was not returned.
* - v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.
* - v1.3.3 - Fixed I/O streams which were totally messed up.
*
*
*
* I am placing this code in the Public Domain. Do with it as you will.
* This software comes with no guarantees or warranties but with
* plenty of well-wishing instead!
* Please visit http://iharder.net/base64
* periodically to check for updates or to contribute improvements.
*
*
* @author Robert Harder
* @author [email protected]
* @version 2.1
*/
public class Base64
{
/* ******** P U B L I C F I E L D S ******** */
/** No options specified. Value is zero. */
public final static int NO_OPTIONS = 0;
/** Specify encoding. */
public final static int ENCODE = 1;
/** Specify decoding. */
public final static int DECODE = 0;
/** Don't break lines when encoding (violates strict Base64 specification) */
public final static int DONT_BREAK_LINES = 8;
/* ******** 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)'=';
/** 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";
/** The 64 valid Base64 values. */
private final static 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)'/'
};
/** Determine which ALPHABET to use. */
static
{
byte[] __bytes;
try
{
__bytes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".getBytes( PREFERRED_ENCODING );
} // end try
catch (java.io.UnsupportedEncodingException use)
{
__bytes = _NATIVE_ALPHABET; // Fall back to native encoding
} // end catch
ALPHABET = __bytes;
} // end static
/**
* Translates a Base64 value to either its 6-bit reconstruction value
* or a negative number indicating some other meaning.
**/
private final static byte[] DECODABET =
{
-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 0 - 8
-5,-5, // Whitespace: Tab and Linefeed
-9,-9, // Decimal 11 - 12
-5, // Whitespace: Carriage Return
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 14 - 26
-9,-9,-9,-9,-9, // Decimal 27 - 31
-5, // Whitespace: Space
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 33 - 42
62, // Plus sign at decimal 43
-9,-9,-9, // Decimal 44 - 46
63, // Slash at decimal 47
52,53,54,55,56,57,58,59,60,61, // Numbers zero through nine
-9,-9,-9, // Decimal 58 - 60
-1, // Equals sign at decimal 61
-9,-9,-9, // 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'
-9,-9,-9,-9,-9,-9, // 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'
-9,-9,-9,-9 // Decimal 123 - 126
/*,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 127 - 139
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255 */
};
// I think I end up not using the BAD_ENCODING indicator.
//private final static byte BAD_ENCODING = -9; // Indicates error in encoding
private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding
/** Defeats instantiation. */
private Base64(){}
/* ******** E N C O D I N G M E T H O D S ******** */
/**
* Encodes up to the first three bytes of array threeBytes
* and returns a four-byte array in Base64 notation.
* The actual number of significant bytes in your array is
* given by numSigBytes.
* The array threeBytes needs only be as big as
* numSigBytes.
* Code can reuse a byte array by passing a four-byte array as b4.
*
* @param b4 A reusable byte array to reduce array instantiation
* @param threeBytes the array to convert
* @param numSigBytes the number of significant bytes in your array
* @return four byte array in Base64 notation.
* @since 1.5.1
*/
private static byte[] encode3to4( byte[] b4, byte[] threeBytes, int numSigBytes )
{
encode3to4( threeBytes, 0, numSigBytes, b4, 0 );
return b4;
} // end encode3to4
/**
* 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
* @since 1.3
*/
private static 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 ] = EQUALS_SIGN;
return destination;
case 1:
destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ];
destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
destination[ destOffset + 2 ] = EQUALS_SIGN;
destination[ destOffset + 3 ] = EQUALS_SIGN;
return destination;
default:
return destination;
} // end switch
} // end encode3to4
/**
* Encodes a byte array into Base64 notation.
* Does not GZip-compress data.
*
* @param source The data to convert
* @since 1.4
*/
public static String encodeBytes( byte[] source )
{
return encodeBytes( source, 0, source.length, NO_OPTIONS );
} // end encodeBytes
/**
* Encodes a byte array into Base64 notation.
*
* Valid options:
* GZIP: gzip-compresses object before encoding it.
* DONT_BREAK_LINES: don't break lines at 76 characters
* Note: Technically, this makes your encoding non-compliant.
*
*
* Example: encodeBytes( myData, Base64.GZIP ) or
*
* Example: encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )
*
*
* @param source The data to convert
* @param options Specified options
* @see Base64#DONT_BREAK_LINES
* @since 2.0
*/
public static String encodeBytes( byte[] source, int options )
{
return encodeBytes( source, 0, source.length, options );
} // end encodeBytes
/**
* Encodes a byte array into Base64 notation.
* Does not GZip-compress data.
*
* @param source The data to convert
* @param off Offset in array where conversion should begin
* @param len Length of data to convert
* @since 1.4
*/
public static String encodeBytes( byte[] source, int off, int len )
{
return encodeBytes( source, off, len, NO_OPTIONS );
} // end encodeBytes
/**
* Encodes a byte array into Base64 notation.
*
* Valid options:
* GZIP: gzip-compresses object before encoding it.
* DONT_BREAK_LINES: don't break lines at 76 characters
* Note: Technically, this makes your encoding non-compliant.
*
*
* Example: encodeBytes( myData, Base64.GZIP ) or
*
* Example: encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )
*
*
* @param source The data to convert
* @param off Offset in array where conversion should begin
* @param len Length of data to convert
* @param options Specified options
* @see Base64#DONT_BREAK_LINES
* @since 2.0
*/
public static String encodeBytes( byte[] source, int off, int len, int options )
{
// Isolate options
int dontBreakLines = ( options & DONT_BREAK_LINES );
// Else, don't compress. Better not to use streams at all then.
{
// Convert option to boolean in way that code likes it.
boolean breakLines = dontBreakLines == 0;
int len43 = len * 4 / 3;
byte[] outBuff = new byte[ ( len43 ) // Main 4:3
+ ( (len % 3) > 0 ? 4 : 0 ) // Account for padding
+ (breakLines ? ( 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 )
{
encode3to4( source, d+off, 3, outBuff, e );
lineLength += 4;
if( breakLines && 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 )
{
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 else: don't compress
} // 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
* @since 1.3
*/
private static int decode4to3( byte[] source, int srcOffset, byte[] destination, int destOffset )
{
// Example: Dk==
if( source[ srcOffset + 2] == EQUALS_SIGN )
{
// 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 ] == EQUALS_SIGN )
{
// 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. Does not support automatically
* gunzipping or any other "fancy" features.
*
* @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
* @since 1.3
*/
public static byte[] decode( byte[] source, int off, int len )
{
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, Equals sign or better
{
if( sbiDecode >= EQUALS_SIGN_ENC )
{
b4[ b4Posn++ ] = sbiCrop;
if( b4Posn > 3 )
{
outBuffPosn += decode4to3( b4, 0, outBuff, outBuffPosn );
b4Posn = 0;
// If that was the equals sign, break out of 'for' loop
if( sbiCrop == EQUALS_SIGN )
break;
} // end if: quartet built
} // end if: equals sign or better
} // end if: white space, equals sign 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;
} // end decode
/**
* Decodes data from Base64 notation, automatically
* detecting gzip-compressed data and decompressing it.
*
* @param s the string to decode
* @return the decoded data
* @since 1.4
*/
public static byte[] decode( String s )
{
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 );
return bytes;
} // end decode
} // end class Base64