//
|
// NOTE: The following source code is heavily derived from the
|
// iHarder.net public domain Base64 library. See the original at
|
// http://iharder.sourceforge.net/current/java/base64/
|
//
|
|
package com.gitblit.utils;
|
|
import java.io.UnsupportedEncodingException;
|
import java.text.MessageFormat;
|
import java.util.Arrays;
|
|
/**
|
* Encodes and decodes to and from Base64 notation.
|
* <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/base64">http://iharder.net/base64</a> periodically
|
* to check for updates or to contribute improvements.
|
* </p>
|
*
|
* @author Robert Harder
|
* @author rob@iharder.net
|
* @version 2.1, stripped to minimum feature set used by JGit.
|
*/
|
public class Base64 {
|
/** The equals sign (=) as a byte. */
|
private final static byte EQUALS_SIGN = (byte) '=';
|
|
/** Indicates equals sign in encoding. */
|
private final static byte EQUALS_SIGN_DEC = -1;
|
|
/** Indicates white space in encoding. */
|
private final static byte WHITE_SPACE_DEC = -2;
|
|
/** Indicates an invalid byte during decoding. */
|
private final static byte INVALID_DEC = -3;
|
|
/** Preferred encoding. */
|
private final static String UTF_8 = "UTF-8";
|
|
/** The 64 valid Base64 values. */
|
private final static byte[] ENC;
|
|
/**
|
* Translates a Base64 value to either its 6-bit reconstruction value or a
|
* negative number indicating some other meaning. The table is only 7 bits
|
* wide, as the 8th bit is discarded during decoding.
|
*/
|
private final static byte[] DEC;
|
|
static {
|
try {
|
ENC = ("ABCDEFGHIJKLMNOPQRSTUVWXYZ" //
|
+ "abcdefghijklmnopqrstuvwxyz" //
|
+ "0123456789" //
|
+ "+/" //
|
).getBytes(UTF_8);
|
} catch (UnsupportedEncodingException uee) {
|
throw new RuntimeException(uee.getMessage(), uee);
|
}
|
|
DEC = new byte[128];
|
Arrays.fill(DEC, INVALID_DEC);
|
|
for (int i = 0; i < 64; i++)
|
DEC[ENC[i]] = (byte) i;
|
DEC[EQUALS_SIGN] = EQUALS_SIGN_DEC;
|
|
DEC['\t'] = WHITE_SPACE_DEC;
|
DEC['\n'] = WHITE_SPACE_DEC;
|
DEC['\r'] = WHITE_SPACE_DEC;
|
DEC[' '] = WHITE_SPACE_DEC;
|
}
|
|
/** Defeats instantiation. */
|
private Base64() {
|
// Suppress empty block warning.
|
}
|
|
/**
|
* 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 accommodate
|
* <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
|
*/
|
private static void encode3to4(byte[] source, int srcOffset, int numSigBytes,
|
byte[] destination, int destOffset) {
|
// 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.
|
|
int inBuff = 0;
|
switch (numSigBytes) {
|
case 3:
|
inBuff |= (source[srcOffset + 2] << 24) >>> 24;
|
//$FALL-THROUGH$
|
|
case 2:
|
inBuff |= (source[srcOffset + 1] << 24) >>> 16;
|
//$FALL-THROUGH$
|
|
case 1:
|
inBuff |= (source[srcOffset] << 24) >>> 8;
|
}
|
|
switch (numSigBytes) {
|
case 3:
|
destination[destOffset] = ENC[(inBuff >>> 18)];
|
destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f];
|
destination[destOffset + 2] = ENC[(inBuff >>> 6) & 0x3f];
|
destination[destOffset + 3] = ENC[(inBuff) & 0x3f];
|
break;
|
|
case 2:
|
destination[destOffset] = ENC[(inBuff >>> 18)];
|
destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f];
|
destination[destOffset + 2] = ENC[(inBuff >>> 6) & 0x3f];
|
destination[destOffset + 3] = EQUALS_SIGN;
|
break;
|
|
case 1:
|
destination[destOffset] = ENC[(inBuff >>> 18)];
|
destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f];
|
destination[destOffset + 2] = EQUALS_SIGN;
|
destination[destOffset + 3] = EQUALS_SIGN;
|
break;
|
}
|
}
|
|
/**
|
* Encodes a byte array into Base64 notation.
|
*
|
* @param source
|
* The data to convert
|
* @return encoded base64 representation of source.
|
*/
|
public static String encodeBytes(byte[] source) {
|
return encodeBytes(source, 0, source.length);
|
}
|
|
/**
|
* 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
|
* @return encoded base64 representation of source.
|
*/
|
public static String encodeBytes(byte[] source, int off, int len) {
|
final int len43 = len * 4 / 3;
|
|
byte[] outBuff = new byte[len43 + ((len % 3) > 0 ? 4 : 0)];
|
int d = 0;
|
int e = 0;
|
int len2 = len - 2;
|
|
for (; d < len2; d += 3, e += 4)
|
encode3to4(source, d + off, 3, outBuff, e);
|
|
if (d < len) {
|
encode3to4(source, d + off, len - d, outBuff, e);
|
e += 4;
|
}
|
|
try {
|
return new String(outBuff, 0, e, UTF_8);
|
} catch (UnsupportedEncodingException uue) {
|
return new String(outBuff, 0, e);
|
}
|
}
|
|
/**
|
* 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 accommodate
|
* <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
|
*/
|
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset) {
|
// Example: Dk==
|
if (source[srcOffset + 2] == EQUALS_SIGN) {
|
int outBuff = ((DEC[source[srcOffset]] & 0xFF) << 18)
|
| ((DEC[source[srcOffset + 1]] & 0xFF) << 12);
|
destination[destOffset] = (byte) (outBuff >>> 16);
|
return 1;
|
}
|
|
// Example: DkL=
|
else if (source[srcOffset + 3] == EQUALS_SIGN) {
|
int outBuff = ((DEC[source[srcOffset]] & 0xFF) << 18)
|
| ((DEC[source[srcOffset + 1]] & 0xFF) << 12)
|
| ((DEC[source[srcOffset + 2]] & 0xFF) << 6);
|
destination[destOffset] = (byte) (outBuff >>> 16);
|
destination[destOffset + 1] = (byte) (outBuff >>> 8);
|
return 2;
|
}
|
|
// Example: DkLE
|
else {
|
int outBuff = ((DEC[source[srcOffset]] & 0xFF) << 18)
|
| ((DEC[source[srcOffset + 1]] & 0xFF) << 12)
|
| ((DEC[source[srcOffset + 2]] & 0xFF) << 6)
|
| ((DEC[source[srcOffset + 3]] & 0xFF));
|
|
destination[destOffset] = (byte) (outBuff >> 16);
|
destination[destOffset + 1] = (byte) (outBuff >> 8);
|
destination[destOffset + 2] = (byte) (outBuff);
|
|
return 3;
|
}
|
}
|
|
/**
|
* Low-level decoding ASCII characters from 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
|
* @throws IllegalArgumentException
|
* the input is not a valid Base64 sequence.
|
*/
|
public static byte[] decode(byte[] source, int off, int len) {
|
byte[] outBuff = new byte[len * 3 / 4]; // Upper limit on size of output
|
int outBuffPosn = 0;
|
|
byte[] b4 = new byte[4];
|
int b4Posn = 0;
|
|
for (int i = off; i < off + len; i++) {
|
byte sbiCrop = (byte) (source[i] & 0x7f);
|
byte sbiDecode = DEC[sbiCrop];
|
|
if (EQUALS_SIGN_DEC <= sbiDecode) {
|
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;
|
}
|
|
} else if (sbiDecode != WHITE_SPACE_DEC)
|
throw new IllegalArgumentException(MessageFormat.format(
|
"bad base64 input character {1} at {0}", i, source[i] & 0xff));
|
}
|
|
if (outBuff.length == outBuffPosn)
|
return outBuff;
|
|
byte[] out = new byte[outBuffPosn];
|
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
|
return out;
|
}
|
|
/**
|
* Decodes data from Base64 notation.
|
*
|
* @param s
|
* the string to decode
|
* @return the decoded data
|
*/
|
public static byte[] decode(String s) {
|
byte[] bytes;
|
try {
|
bytes = s.getBytes(UTF_8);
|
} catch (UnsupportedEncodingException uee) {
|
bytes = s.getBytes();
|
}
|
return decode(bytes, 0, bytes.length);
|
}
|
}
|
