package net.i2p.data;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Locale;
/**
* Encodes and decodes to and from Base64 notation.
*
* <p>
* Change Log:
* </p>
* <ul>
* <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
* <li>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.</li>
* <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
* <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
* </ul>
*
* <p>
* 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 <a href="http://iharder.net/xmlizable">http://iharder.net/xmlizable</a>
* periodically to check for updates or to contribute improvements.
* </p>
*
* Modified by jrandom for i2p, using safeEncode / safeDecode to create filesystem and URL safe
* base64 values (replacing / with ~, and + with -)
*
* @author Robert Harder
* @author rob@iharder.net
* @version 1.3.4
*/
public class Base64 {
//private final static Log _log = new Log(Base64.class);
/**
* Output will be a multiple of 4 chars, including 0-2 trailing '='
* As of 0.9.14, encodes the UTF-8 encoding of source. Prior to that, used the platform's encoding.
*
* @param source if null will return ""
*/
public static String encode(String source) {
return (source != null ? encode(DataHelper.getUTF8(source)) : "");
}
/**
* Output will be a multiple of 4 chars, including 0-2 trailing '='
* @param source if null will return ""
*/
public static String encode(byte[] source) {
return (source != null ? encode(source, 0, source.length) : "");
}
/**
* Output will be a multiple of 4 chars, including 0-2 trailing '='
* @param source if null will return ""
*/
public static String encode(byte[] source, int off, int len) {
return (source != null ? encode(source, off, len, false) : "");
}
/**
* Output will be a multiple of 4 chars, including 0-2 trailing '='
* @param source if null will return ""
* @param useStandardAlphabet Warning, must be false for I2P compatibility
*/
public static String encode(byte[] source, boolean useStandardAlphabet) {
return (source != null ? encode(source, 0, source.length, useStandardAlphabet) : "");
}
/**
* Output will be a multiple of 4 chars, including 0-2 trailing '='
* @param source if null will return ""
* @param useStandardAlphabet Warning, must be false for I2P compatibility
*/
public static String encode(byte[] source, int off, int len, boolean useStandardAlphabet) {
return (source != null ? safeEncode(source, off, len, useStandardAlphabet) : "");
}
/**
* Decodes data from Base64 notation using the I2P alphabet.
*
* As of 0.9.14, does not require trailing '=' if remaining bits are zero.
* Prior to that, trailing 1, 2, or 3 chars were ignored.
*
* As of 0.9.14, trailing garbage after an '=' will cause an error.
* Prior to that, it was ignored.
*
* As of 0.9.14, whitespace will cause an error.
* Prior to that, it was ignored.
*
* @param s Base 64 encoded string using the I2P alphabet A-Z, a-z, 0-9, -, ~
* @return the decoded data, null on error
*/
public static byte[] decode(String s) {
return safeDecode(s, false);
}
/**
* Decodes data from Base64 notation using the I2P alphabet.
*
* @param useStandardAlphabet Warning, must be false for I2P compatibility
* @return the decoded data, null on error
* @since 0.9.25
*/
public static byte[] decode(String s, boolean useStandardAlphabet) {
return safeDecode(s, useStandardAlphabet);
}
/** 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 64 valid Base64 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) '/'};
/**
* The I2P Alphabet.
* @since 0.9.29
*/
public static final String ALPHABET_I2P = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-~";
/** The 64 valid Base64 values for I2P. */
private final static byte[] ALPHABET_ALT = DataHelper.getASCII(ALPHABET_I2P);
/**
* Translates a Base64 value to either its 6-bit reconstruction value
* or a negative number indicating some other meaning.
* As of 0.9.14 this is the decoding for the I2P alphabet. See safeDecode().
**/
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, -9, -9, -9, 63, // + , - . / (43-47) NON-I2P
-9, -9, 62, -9, -9, // + , - . / (43-47) I2P
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 (126 is '~') NON-I2P
-9, -9, -9, 63 // Decimal 123 - 126 (126 is '~') I2P
,-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
};
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() { // nop
}
public static void main(String[] args) {
//test();
if (args.length == 0) {
help();
}
runApp(args);
}
private static void runApp(String args[]) {
String cmd = args[0].toLowerCase(Locale.US);
if ("encodestring".equals(cmd)) {
if (args.length != 2)
help();
System.out.println(encode(DataHelper.getUTF8(args[1])));
return;
}
if ("decodestring".equals(cmd)) {
if (args.length != 2)
help();
byte[] dec = decode(args[1]);
if (dec != null) {
try {
System.out.write(dec);
} catch (IOException ioe) {
System.err.println("output error " + ioe);
System.exit(1);
}
} else {
System.err.println("decode error");
System.exit(1);
}
return;
}
if ("test".equals(cmd)) {
System.err.println("test disabled");
System.exit(1);
}
if (!("encode".equals(cmd) || "decode".equals(cmd))) {
System.err.println("unknown command " + cmd);
System.exit(1);
}
InputStream in = System.in;
OutputStream out = System.out;
try {
if (args.length >= 3) {
out = new FileOutputStream(args[2]);
}
if (args.length >= 2) {
in = new FileInputStream(args[1]);
}
if ("encode".equals(cmd)) {
encode(in, out);
} else {
decode(in, out);
}
} catch (IOException ioe) {
ioe.printStackTrace(System.err);
} finally {
try { in.close(); } catch (IOException e) {}
try { out.close(); } catch (IOException e) {}
}
}
private static byte[] read(InputStream in) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);
DataHelper.copy(in, baos);
return baos.toByteArray();
}
private static void encode(InputStream in, OutputStream out) throws IOException {
String encoded = encode(read(in));
for (int i = 0; i < encoded.length(); i++)
out.write((byte)(encoded.charAt(i) & 0xFF));
}
private static void decode(InputStream in, OutputStream out) throws IOException {
byte decoded[] = decode(DataHelper.getUTF8(read(in)));
if (decoded == null)
throw new IOException("Invalid base 64 string");
out.write(decoded);
}
/** exits 1, never returns */
private static void help() {
System.err.println("Usage: Base64 encode <inFile> <outFile>");
System.err.println(" Base64 encode <inFile>");
System.err.println(" Base64 encode (stdin to stdout)");
System.err.println(" Base64 decode <inFile> <outFile>");
System.err.println(" Base64 decode <inFile>");
System.err.println(" Base64 decode (stdin to stdout)");
System.err.println(" Base64 encodestring 'string to encode'");
System.err.println(" Base64 decodestring 'string to decode'");
System.err.println(" Base64 test");
System.exit(1);
}
/*******
private static void test() {
String orig = "you smell";
String encoded = Base64.encode(orig.getBytes());
System.out.println("Encoded: [" + encoded + "]");
byte decoded[] = Base64.decode(encoded);
String transformed = new String(decoded);
if (orig.equals(transformed))
System.out.println("D(E('you smell')) == 'you smell'");
else
throw new RuntimeException("D(E('you smell')) != 'you smell'!!! transformed = [" + transformed + "]");
byte all[] = new byte[256];
for (int i = 0; i < all.length; i++)
all[i] = (byte) (0xFF & i);
encoded = Base64.encode(all);
System.out.println("Encoded: [" + encoded + "]");
decoded = Base64.decode(encoded);
if (DataHelper.eq(decoded, all))
System.out.println("D(E([all bytes])) == [all bytes]");
else
throw new RuntimeException("D(E([all bytes])) != [all bytes]!!!");
}
*******/
/* ******** E N C O D I N G M E T H O D S ******** */
/**
* Encodes the first three bytes of array <var>threeBytes</var>
* and returns a four-byte array in Base64 notation.
*
* @param threeBytes the array to convert
* @return four byte array in Base64 notation.
* @since 1.3
*/
/***** unused (standard alphabet)
private static byte[] encode3to4(byte[] threeBytes) {
return encode3to4(threeBytes, 3);
} // end encodeToBytes
******/
/**
* Encodes up to the first three bytes of array <var>threeBytes</var>
* and returns a four-byte array in Base64 notation.
* The actual number of significant bytes in your array is
* given by <var>numSigBytes</var>.
* The array <var>threeBytes</var> needs only be as big as
* <var>numSigBytes</var>.
*
* @param threeBytes the array to convert
* @param numSigBytes the number of significant bytes in your array
* @return four byte array in Base64 notation.
* @since 1.3
*/
/***** unused (standard alphabet)
private static byte[] encode3to4(byte[] threeBytes, int numSigBytes) {
byte[] dest = new byte[4];
encode3to4(threeBytes, 0, numSigBytes, dest, 0);
return dest;
}
******/
/**
* Encodes up to three bytes of the array <var>source</var>
* and writes the resulting four Base64 bytes to <var>destination</var>.
* The source and destination arrays can be manipulated
* anywhere along their length by specifying
* <var>srcOffset</var> and <var>destOffset</var>.
* This method does not check to make sure your arrays
* are large enough to accomodate <var>srcOffset</var> + 3 for
* the <var>source</var> array or <var>destOffset</var> + 4 for
* the <var>destination</var> array.
* The actual number of significant bytes in your array is
* given by <var>numSigBytes</var>.
*
* @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 <var>destination</var> array
* @since 1.3
*/
/***** unused (standard alphabet)
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
******/
/**
* @param alpha alphabet
*/
private static void encode3to4(byte[] source, int srcOffset, int numSigBytes, StringBuilder buf, byte alpha[]) {
// 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:
buf.append((char)alpha[(inBuff >>> 18)]);
buf.append((char)alpha[(inBuff >>> 12) & 0x3f]);
buf.append((char)alpha[(inBuff >>> 6) & 0x3f]);
buf.append((char)alpha[(inBuff) & 0x3f]);
return;
case 2:
buf.append((char)alpha[(inBuff >>> 18)]);
buf.append((char)alpha[(inBuff >>> 12) & 0x3f]);
buf.append((char)alpha[(inBuff >>> 6) & 0x3f]);
buf.append((char)EQUALS_SIGN);
return;
case 1:
buf.append((char)alpha[(inBuff >>> 18)]);
buf.append((char)alpha[(inBuff >>> 12) & 0x3f]);
buf.append((char)EQUALS_SIGN);
buf.append((char)EQUALS_SIGN);
return;
default:
return;
} // end switch
} // end encode3to4
/**
* Encodes a byte array into Base64 notation.
* Equivalen to calling
* <code>encodeBytes( source, 0, source.length )</code>
*
* @param source The data to convert
* @since 1.4
*/
/***** unused
private static String encodeBytes(byte[] source) {
return encodeBytes(source, false); // don't add newlines
} // end encodeBytes
******/
/**
* Same as encodeBytes, except uses a filesystem / URL friendly set of characters,
* replacing / with ~, and + with -
*/
private static String safeEncode(byte[] source, int off, int len, boolean useStandardAlphabet) {
if (len + off > source.length)
throw new ArrayIndexOutOfBoundsException("Trying to encode too much! source.len=" + source.length + " off=" + off + " len=" + len);
StringBuilder buf = new StringBuilder(len * 4 / 3);
if (useStandardAlphabet)
encodeBytes(source, off, len, false, buf, ALPHABET);
else
encodeBytes(source, off, len, false, buf, ALPHABET_ALT);
return buf.toString();
}
/**
* Same as decode, except from a filesystem / URL friendly set of characters,
* replacing / with ~, and + with -
*/
private static byte[] safeDecode(String source, boolean useStandardAlphabet) {
if (source == null) return null;
String toDecode;
if (useStandardAlphabet) {
//toDecode = source;
toDecode = source.replace('/', '~');
toDecode = toDecode.replace('+', '-');
} else {
//toDecode = source.replace('~', '/');
//toDecode = toDecode.replace('-', '+');
toDecode = source;
}
return standardDecode(toDecode);
}
/**
* Encodes a byte array into Base64 notation.
* Equivalen to calling
* <code>encodeBytes( source, 0, source.length )</code>
*
* @param source The data to convert
* @param breakLines Break lines at 80 characters or less.
* @since 1.4
*/
/***** unused
private static String encodeBytes(byte[] source, boolean breakLines) {
return encodeBytes(source, 0, source.length, breakLines);
} // 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
* @since 1.4
*/
/***** unused
private static String encodeBytes(byte[] source, int off, int len) {
return encodeBytes(source, off, len, true);
} // end encodeBytes
private static String encodeBytes(byte[] source, int off, int len, boolean breakLines) {
StringBuilder buf = new StringBuilder( (len*4)/3 );
encodeBytes(source, off, len, breakLines, buf, ALPHABET);
return buf.toString();
}
******/
/**
* 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 breakLines Break lines at 80 characters or less.
* @since 1.4
*/
private static void encodeBytes(byte[] source, int off, int len, boolean breakLines, StringBuilder out, byte alpha[]) {
//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 len2 = len - 2;
int lineLength = 0;
for (; d < len2; d += 3) {
//encode3to4(source, d + off, 3, outBuff, e);
encode3to4(source, d + off, 3, out, alpha);
lineLength += 4;
if (breakLines && lineLength == MAX_LINE_LENGTH) {
//outBuff[e + 4] = NEW_LINE;
out.append('\n');
lineLength = 0;
} // end if: end of line
} // en dfor: each piece of array
if (d < len) {
//encode3to4(source, d + off, len - d, outBuff, e);
encode3to4(source, d + off, len - d, out, alpha);
} // end if: some padding needed
//out.append(new String(outBuff, 0, e));
//return new String(outBuff, 0, e);
} // end encodeBytes
/**
* Encodes a string in Base64 notation with line breaks
* after every 75 Base64 characters.
*
* @param s the string to encode
* @return the encoded string
* @since 1.3
*/
/***** unused
private static String encodeString(String s) {
return encodeString(s, true);
} // end encodeString
******/
/* ******** D E C O D I N G M E T H O D S ******** */
/**
* Decodes the first four bytes of array <var>fourBytes</var>
* and returns an array up to three bytes long with the
* decoded values.
*
* @param fourBytes the array with Base64 content
* @return array with decoded values
* @since 1.3
*/
/***** unused
private static byte[] decode4to3(byte[] fourBytes) {
byte[] outBuff1 = new byte[3];
int count = decode4to3(fourBytes, 0, outBuff1, 0);
byte[] outBuff2 = new byte[count];
for (int i = 0; i < count; i++)
outBuff2[i] = outBuff1[i];
return outBuff2;
}
******/
/**
* Decodes four bytes from array <var>source</var>
* and writes the resulting bytes (up to three of them)
* to <var>destination</var>.
* The source and destination arrays can be manipulated
* anywhere along their length by specifying
* <var>srcOffset</var> and <var>destOffset</var>.
* This method does not check to make sure your arrays
* are large enough to accomodate <var>srcOffset</var> + 4 for
* the <var>source</var> array or <var>destOffset</var> + 3 for
* the <var>destination</var> 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 1-3, or -1 on error, never zero
* @since 1.3
*/
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset) {
byte decode0 = DECODABET[source[srcOffset++]];
byte decode1 = DECODABET[source[srcOffset++]];
if (decode0 < 0 || decode1 < 0)
return -1;
// Example: Dk==
if (source[srcOffset] == EQUALS_SIGN) {
if (source[srcOffset + 1] != EQUALS_SIGN)
return -1;
// verify no extra bits
if ((decode1 & 0x0f) != 0)
return -1;
int outBuff = (decode0 << 18)
| (decode1 << 12);
destination[destOffset] = (byte) (outBuff >> 16);
return 1;
}
// Example: DkL=
else if (source[srcOffset + 1] == EQUALS_SIGN) {
byte decode2 = DECODABET[source[srcOffset]];
if (decode2 < 0)
return -1;
// verify no extra bits
if ((decode2 & 0x03) != 0)
return -1;
int outBuff = (decode0 << 18)
| (decode1 << 12)
| (decode2 << 6);
destination[destOffset++] = (byte) (outBuff >> 16);
destination[destOffset] = (byte) (outBuff >> 8);
return 2;
}
// Example: DkLE
else {
byte decode2 = DECODABET[source[srcOffset++]];
byte decode3 = DECODABET[source[srcOffset]];
if (decode2 < 0 || decode3 < 0)
return -1;
int outBuff = (decode0 << 18)
| (decode1 << 12)
| (decode2 << 6)
| decode3;
destination[destOffset++] = (byte) (outBuff >> 16);
destination[destOffset++] = (byte) (outBuff >> 8);
destination[destOffset] = (byte) (outBuff);
return 3;
}
} // end decodeToBytes
/**
* Decodes data from Base64 notation.
* As of 0.9.14, this uses the I2P alphabet, so it is not "standard".
*
* @param s the string to decode
* @return the decoded data, null on error
* @since 1.4
*/
private static byte[] standardDecode(String s) {
// We use getUTF8() instead of getASCII() so we may verify
// there's no UTF-8 in there.
byte[] bytes = DataHelper.getUTF8(s);
if (bytes.length != s.length())
return null;
return decode(bytes, 0, bytes.length);
} // end decode
/**
* Decodes data from Base64 notation and
* returns it as a string.
* Equivlaent to calling
* <code>new String( decode( s ) )</code>
*
* As of 0.9.14, decodes as UTF-8. Prior to that, it used the platform's encoding.
* For best results, decoded data should be 7 bit.
*
* As of 0.9.14, does not require trailing '=' if remaining bits are zero.
* Prior to that, trailing 1, 2, or 3 chars were ignored.
*
* As of 0.9.14, trailing garbage after an '=' will cause an error.
* Prior to that, it was ignored.
*
* As of 0.9.14, whitespace will cause an error.
* Prior to that, it was ignored.
*
* @param s the string to decode
* @return The data as a string, or null on error
* @since 1.4
*/
public static String decodeToString(String s) {
byte[] b = decode(s);
if (b == null)
return null;
return DataHelper.getUTF8(b);
} // end decodeToString
/**
* Decodes Base64 content in byte array format and returns
* the decoded byte array.
*
* As of 0.9.14, does not require trailing '=' if remaining bits are zero.
* Prior to that, trailing 1, 2, or 3 chars were ignored.
*
* As of 0.9.14, trailing garbage after an '=' will cause an error.
* Prior to that, it was ignored.
*
* As of 0.9.14, whitespace will cause an error.
* Prior to that, it was ignored.
*
* @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, null on error
* @since 1.3
*/
private static byte[] decode(byte[] source, int off, int len) {
int len34 = len * 3 / 4;
byte[] outBuff = new byte[len34]; // size of output
int outBuffPosn = 0;
int i = off;
int end = off + len;
int converted = 0;
while (i + 3 < end) {
converted = decode4to3(source, i, outBuff, outBuffPosn);
if (converted < 0)
return null;
outBuffPosn += converted;
i += 4;
if (converted < 3)
break;
}
// process any remaining without '='
int remaining = end - i;
if (remaining > 0) {
if (converted > 0 && converted < 3)
return null;
if (remaining == 1 || remaining > 3)
return null;
byte[] b4 = new byte[4];
b4[0] = source[i++];
b4[1] = source[i++];
if (remaining == 3)
b4[2] = source[i];
else
b4[2] = EQUALS_SIGN;
b4[3] = EQUALS_SIGN;
converted = decode4to3(b4, 0, outBuff, outBuffPosn);
if (converted < 0)
return null;
outBuffPosn += converted;
}
// don't copy unless we have to
if (outBuffPosn == outBuff.length)
return outBuff;
// and we shouldn't ever... would have returned null before
byte[] out = new byte[outBuffPosn];
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
return out;
} // end decode
} // end class Base64