nl.topicus.jdbc.util.Base64 Maven / Gradle / Ivy
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package nl.topicus.jdbc.util;
/**
* . This implementation is based on the implementation of PostgreSQL.
*
* PostgreSQL is released under the PostgreSQL License, a liberal Open Source license, similar to
* the BSD or MIT licenses.
*
* PostgreSQL Database Management System (formerly known as Postgres, then as Postgres95)
*
* Portions Copyright (c) 1996-2017, The PostgreSQL Global Development Group
*
* Portions Copyright (c) 1994, The Regents of the University of California
*
* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
* SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF
* THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
* PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* 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 static final int NO_OPTIONS = 0;
/**
* Specify encoding.
*/
public static final int ENCODE_FLAG = 1;
/**
* Specify decoding.
*/
public static final int DECODE_FLAG = 0;
/**
* Don't break lines when encoding (violates strict Base64 specification)
*/
public static final 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 static final int MAX_LINE_LENGTH = 76;
/**
* The equals sign (=) as a byte.
*/
private static final byte EQUALS_SIGN = (byte) '=';
/**
* The new line character (\n) as a byte.
*/
private static final byte NEW_LINE = (byte) '\n';
/**
* Preferred encoding.
*/
private static final String PREFERRED_ENCODING = "UTF-8";
/**
* The 64 valid Base64 values.
*/
private static final byte[] ALPHABET;
private static final 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);
} catch (java.io.UnsupportedEncodingException use) {
bytes = _NATIVE_ALPHABET; // Fall back to native encoding
}
ALPHABET = bytes;
}
/**
* Translates a Base64 value to either its 6-bit reconstruction value or a negative number
* indicating some other meaning.
**/
private static final 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 static final byte WHITE_SPACE_ENC = -5; // Indicates white space in
// encoding
private static final 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 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
* @return Base64 notation of input data
* @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
* @return Base64 notation
* @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
* @return Base64 notation
* @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
* @return Base64 notation
* @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);
return encodeBytes(source, off, len, dontBreakLines == 0);
}
private static String encodeBytes(byte[] source, int off, int len, boolean breakLines) {
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);
} catch (java.io.UnsupportedEncodingException uue) {
return new String(outBuff, 0, e);
}
}
/* ******** 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;
} else if (source[srcOffset + 3] == EQUALS_SIGN) {
/**
*
* Example: DkL=
* 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;
} else {
// Example: DkLE
try {
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) {
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
} else {
// end if: white space, equals sign or better
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);
} catch (java.io.UnsupportedEncodingException uee) {
bytes = s.getBytes();
}
//
// Decode
bytes = decode(bytes, 0, bytes.length);
return bytes;
} // end decode
} // end class Base64