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Google API Client Library for Java. Supports Java 5 (or higher) desktop (SE)
and web (EE), Android, and Google App Engine.
/*
* Copyright (c) 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.api.client.util;
// This code was copied from code at http://iharder.sourceforge.net/base64/
// Lots of extraneous features were removed: encodeObject, decodeToObject,
// encodeFromFile, encodeFileToFile, encodeToFile, InputStream, OutputStream,
// decode(String, ...), encode(ByteBuffer,...), encode3to4 not used, URL_SAFE
// and ORDERED *bets, options
// original class JavaDoc:
/*
* Encodes and decodes to and from Base64 notation.
Homepage: http://iharder.net/base64.
*
* Example:
*
* String encoded = Base64.encode( myByteArray );
byte[] myByteArray =
* Base64.decode( encoded );
*
* The options parameter, which appears in a few places, is used to pass several pieces
* of information to the encoder. In the "higher level" methods such as encodeBytes( bytes, options
* ) the options parameter can be used to indicate such things as first gzipping the bytes before
* encoding them, not inserting linefeeds, and encoding using the URL-safe and Ordered dialects.
*
* Note, according to RFC3548, Section 2.1,
* implementations should not add line feeds unless explicitly told to do so. I've got Base64 set to
* this behavior now, although earlier versions broke lines by default.
*
* The constants defined in Base64 can be OR-ed together to combine options, so you might make a
* call like this:
*
* String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DO_BREAK_LINES );
* to compress the data before encoding it and then making the output have newline
* characters.
Also...
String encoded = Base64.encodeBytes( crazyString.getBytes()
* );
*
*
*
* Change Log:
- v2.3.7 - Fixed subtle bug when base 64 input stream contained the
* value 01111111, which is an invalid base 64 character but should not throw an
* ArrayIndexOutOfBoundsException either. Led to discovery of mishandling (or potential for better
* handling) of other bad input characters. You should now get an IOException if you try decoding
* something that has bad characters in it.
- v2.3.6 - Fixed bug when breaking lines and the
* final byte of the encoded string ended in the last column; the buffer was not properly shrunk and
* contained an extra (null) byte that made it into the string.
- v2.3.5 - Fixed bug in
* {@code encodeFromFile} where estimated buffer size was wrong for files of size 31, 34, and 37
* bytes.
- v2.3.4 - Fixed bug when working with gzipped streams whereby flushing the
* Base64.OutputStream closed the Base64 encoding (by padding with equals signs) too soon. Also
* added an option to suppress the automatic decoding of gzipped streams. Also added experimental
* support for specifying a class loader when using the {@code decodeToObject(java.lang.String, int,
* java.lang.ClassLoader)} method.
- v2.3.3 - Changed default char encoding to US-ASCII which
* reduces the internal Java footprint with its CharEncoders and so forth. Fixed some javadocs that
* were inconsistent. Removed imports and specified things like java.io.IOException explicitly
* inline.
- v2.3.2 - Reduced memory footprint! Finally refined the "guessing" of how big the
* final encoded data will be so that the code doesn't have to create two output arrays: an
* oversized initial one and then a final, exact-sized one. Big win when using the {@code
* encodeBytesToBytes(byte[])} family of methods (and not using the gzip options which uses a
* different mechanism with streams and stuff).
- v2.3.1 - Added {@code
* encodeBytesToBytes(byte[], int, int, int)} and some similar helper methods to be more efficient
* with memory by not returning a String but just a byte array.
- v2.3 - This is not
* a drop-in replacement! This is two years of comments and bug fixes queued up and finally
* executed. Thanks to everyone who sent me stuff, and I'm sorry I wasn't able to distribute your
* fixes to everyone else. Much bad coding was cleaned up including throwing exceptions where
* necessary instead of returning null values or something similar. Here are some changes that may
* affect you:
- Does not break lines, by default. This is to keep in compliance
* with RFC3548.
- Throws exceptions
* instead of returning null values. Because some operations (especially those that may permit
* the GZIP option) use IO streams, there is a possiblity of an java.io.IOException being thrown.
* After some discussion and thought, I've changed the behavior of the methods to throw
* java.io.IOExceptions rather than return null if ever there's an error. I think this is more
* appropriate, though it will require some changes to your code. Sorry, it should have been done
* this way to begin with.
- Removed all references to System.out, System.err, and the
* like. Shame on me. All I can say is sorry they were ever there.
- Throws
* NullPointerExceptions and IllegalArgumentExceptions as needed such as when passed arrays are
* null or offsets are invalid.
- Cleaned up as much javadoc as I could to avoid any javadoc
* warnings. This was especially annoying before for people who were thorough in their own projects
* and then had gobs of javadoc warnings on this file.
- v2.2.1 - Fixed bug using
* URL_SAFE and ORDERED encodings. Fixed bug when using very small files (~< 40 bytes).
* - v2.2 - Added some helper methods for encoding/decoding directly from one file to the next.
* Also added a main() method to support command line encoding/decoding from one file to the next.
* Also added these Base64 dialects:
- The default is RFC3548 format.
- Calling
* Base64.setFormat(Base64.BASE64_FORMAT.URLSAFE_FORMAT) generates URL and file name friendly format
* as described in Section 4 of RFC3548. http://www.faqs.org/rfcs/rfc3548.html
- Calling
* Base64.setFormat(Base64.BASE64_FORMAT.ORDERED_FORMAT) generates URL and file name friendly format
* that preserves lexical ordering as described in http://www.faqs.org/qa/rfcc-1940.html
* Special thanks to Jim Kellerman at http://www.powerset.com/ for contributing the new Base64
* dialects.
*
* - 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 2.3.7
*/
public class Base64 {
/* ******** P R I V A T E F I E L D S ******** */
/** The equals sign (=) as a byte. */
private final static byte EQUALS_SIGN = (byte) '=';
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
/* ******** S T A N D A R D B A S E 6 4 A L P H A B E T ******** */
/** The 64 valid Base64 values. */
/* Host platform me be something funny like EBCDIC, so we hardcode these values. */
private final static byte[] 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) '/'};
/**
* 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,
-9 // Decimal 123 - 127
,
-9,
-9,
-9,
-9,
-9,
-9,
-9,
-9,
-9,
-9,
-9,
-9, // Decimal 128 - 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
};
/** 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.
*
*
* This is the lowest level of the encoding methods with all possible parameters.
*
*
* @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
/**
* Similar to {@link #encode(byte[])} but returns a byte array instead of instantiating a String.
* This is more efficient if you're working with I/O streams and have large data sets to encode.
*
*
* @param source The data to convert
* @return The Base64-encoded data as a byte[] (of ASCII characters)
* @throws NullPointerException if source array is null
* @since 2.3.1
*/
public static byte[] encode(byte[] source) {
return encode(source, 0, source.length);
}
/**
* Similar to {@link #encode(byte[], int, int)} but returns a byte array instead of instantiating
* a String. This is more efficient if you're working with I/O streams and have large data sets to
* encode.
*
*
* @param source The data to convert
* @param off Offset in array where conversion should begin
* @param len Length of data to convert
* @return The Base64-encoded data as a String
* @throws NullPointerException if source array is null
* @throws IllegalArgumentException if source array, offset, or length are invalid
* @since 2.3.1
*/
public static byte[] encode(byte[] source, int off, int len) {
if (source == null) {
throw new NullPointerException("Cannot serialize a null array.");
} // end if: null
if (off < 0) {
throw new IllegalArgumentException("Cannot have negative offset: " + off);
} // end if: off < 0
if (len < 0) {
throw new IllegalArgumentException("Cannot have length offset: " + len);
} // end if: len < 0
if (off + len > source.length) {
throw new IllegalArgumentException(
String.format("Cannot have offset of %d and length of %d with array of length %d", off,
len, source.length));
} // end if: off < 0
// Else, don't compress. Better not to use streams at all then.
// 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
// Try to determine more precisely how big the array needs to be.
// If we get it right, we don't have to do an array copy, and
// we save a bunch of memory.
int encLen = len / 3 * 4 + (len % 3 > 0 ? 4 : 0); // Bytes needed for actual encoding
byte[] outBuff = new byte[encLen];
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;
} // end for: each piece of array
if (d < len) {
encode3to4(source, d + off, len - d, outBuff, e);
e += 4;
} // end if: some padding needed
// Only resize array if we didn't guess it right.
if (e <= outBuff.length - 1) {
// If breaking lines and the last byte falls right at
// the line length (76 bytes per line), there will be
// one extra byte, and the array will need to be resized.
// Not too bad of an estimate on array size, I'd say.
byte[] finalOut = new byte[e];
System.arraycopy(outBuff, 0, finalOut, 0, e);
// System.err.println("Having to resize array from " + outBuff.length + " to " + e );
return finalOut;
}
// System.err.println("No need to resize array.");
return outBuff;
// end else: don't compress
} // end encodeBytesToBytes
/* ******** 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.
*
* This is the lowest level of the decoding methods with all possible parameters.
*
*
*
* @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
* @throws NullPointerException if source or destination arrays are null
* @throws IllegalArgumentException if srcOffset or destOffset are invalid or there is not enough
* room in the array.
* @since 1.3
*/
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset) {
// Lots of error checking and exception throwing
if (source == null) {
throw new NullPointerException("Source array was null.");
} // end if
if (destination == null) {
throw new NullPointerException("Destination array was null.");
} // end if
if (srcOffset < 0 || srcOffset + 3 >= source.length) {
throw new IllegalArgumentException(String.format(
"Source array with length %d cannot have offset of %d and still process four bytes.",
source.length, srcOffset));
} // end if
if (destOffset < 0 || destOffset + 2 >= destination.length) {
throw new IllegalArgumentException(
String
.format(
"Destination array with length %d cannot have offset of %d and still store three bytes.", destination.length, destOffset));
} // end if
// 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 {
// 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;
}
} // end decodeToBytes
/**
* Low-level access to decoding ASCII characters in the form of a byte array. Ignores
* GUNZIP option, if it's set. This is not generally a recommended method, although it is
* used internally as part of the decoding process. Special case: if len = 0, an empty array is
* returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping),
* consider this method.
*
* @param source The Base64 encoded data
* @return decoded data
* @since 2.3.1
*/
public static byte[] decode(byte[] source) throws java.io.IOException {
return decode(source, 0, source.length);
}
/**
* Low-level access to decoding ASCII characters in the form of a byte array. Ignores
* GUNZIP option, if it's set. This is not generally a recommended method, although it is
* used internally as part of the decoding process. Special case: if len = 0, an empty array is
* returned. Still, if you need more speed and reduced memory footprint (and aren't gzipping),
* consider this method.
*
* @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
* @throws java.io.IOException If bogus characters exist in source data
* @since 1.3
*/
@SuppressWarnings("cast")
public static byte[] decode(byte[] source, int off, int len) throws java.io.IOException {
// Lots of error checking and exception throwing
if (source == null) {
throw new NullPointerException("Cannot decode null source array.");
} // end if
if (off < 0 || off + len > source.length) {
throw new IllegalArgumentException(String.format(
"Source array with length %d cannot have offset of %d and process %d bytes.",
source.length, off, len));
} // end if
if (len == 0) {
return new byte[0];
} else if (len < 4) {
throw new IllegalArgumentException(
"Base64-encoded string must have at least four characters, but length specified was "
+ len);
} // end if
int len34 = len * 3 / 4; // Estimate on array size
byte[] outBuff = new byte[len34]; // Upper limit on size of output
int outBuffPosn = 0; // Keep track of where we're writing
byte[] b4 = new byte[4]; // Four byte buffer from source, eliminating white space
int b4Posn = 0; // Keep track of four byte input buffer
int i = 0; // Source array counter
byte sbiDecode = 0; // Special value from DECODABET
for (i = off; i < off + len; i++) { // Loop through source
sbiDecode = DECODABET[source[i] & 0xFF];
// White space, Equals sign, or legit Base64 character
// Note the values such as -5 and -9 in the
// DECODABETs at the top of the file.
if (sbiDecode >= WHITE_SPACE_ENC) {
if (sbiDecode >= EQUALS_SIGN_ENC) {
b4[b4Posn++] = source[i]; // Save non-whitespace
if (b4Posn > 3) { // Time to decode?
outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn);
b4Posn = 0;
// If that was the equals sign, break out of 'for' loop
if (source[i] == EQUALS_SIGN) {
break;
} // end if: equals sign
} // end if: quartet built
} // end if: equals sign or better
} // end if: white space, equals sign or better
else {
// There's a bad input character in the Base64 stream.
throw new java.io.IOException(
String.format("Bad Base64 input character decimal %d in array position %d",
(int) source[i] & 0xFF, i));
} // end else:
} // each input character
byte[] out = new byte[outBuffPosn];
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
return out;
} // end decode
} // end class Base64
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