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Base64: Reformat to match JGit style 

Rewrite the initialization of the encoding tables to be more clear,
but slightly slower to setup.  We generally perfer a clear definition
of the data over a slightly slower class load time.

Change-Id: I0c7f89b6ab82dcf71525ffb69a388c312c195913
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
stable-0.10
Shawn O. Pearce 14 years ago
parent
d2ce91199e
commit
ef70a12fd1
1 changed files with 270 additions and 369 deletions
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  1. 455
      org.eclipse.jgit/src/org/eclipse/jgit/util/Base64.java

455
org.eclipse.jgit/src/org/eclipse/jgit/util/Base64.java
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@ -1,13 +1,14 @@
//
// NOTE: The following source code is the iHarder.net public domain
// Base64 library and is provided here as a convenience. For updates,
// problems, questions, etc. regarding this code, please visit:
// 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 org.eclipse.jgit.util;
import java.io.UnsupportedEncodingException;
import java.text.MessageFormat;
import java.util.Arrays;
import org.eclipse.jgit.JGitText;
@ -25,314 +26,229 @@ import org.eclipse.jgit.JGitText;
* @author rob@iharder.net
* @version 2.1, stripped to minimum feature set used by JGit.
*/
public class Base64
{
/* ******** P R I V A T E F I E L D S ******** */
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;
/** Preferred encoding. */
private final static String PREFERRED_ENCODING = "UTF-8";
/** 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;
/** 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
/** 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.
**/
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
* 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
// 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>.
* 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
* @return the <var>destination</var> array
* @since 1.3
* @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 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.
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 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 );
// 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;
//$FALL-THROUGH$
switch( numSigBytes )
{
case 2:
inBuff |= (source[srcOffset + 1] << 24) >>> 16;
//$FALL-THROUGH$
case 1:
inBuff |= (source[srcOffset] << 24) >>> 8;
}
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;
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 ] = ALPHABET[ (inBuff >>> 18) ];
destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>> 6) & 0x3f ];
destination[destOffset] = ENC[(inBuff >>> 18)];
destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = ENC[(inBuff >>> 6) & 0x3f];
destination[destOffset + 3] = EQUALS_SIGN;
return destination;
break;
case 1:
destination[ destOffset ] = ALPHABET[ (inBuff >>> 18) ];
destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
destination[destOffset] = ENC[(inBuff >>> 18)];
destination[destOffset + 1] = ENC[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = EQUALS_SIGN;
destination[destOffset + 3] = EQUALS_SIGN;
return destination;
default:
return destination;
} // end switch
} // end encode3to4
break;
}
}
/**
* Encodes a byte array into Base64 notation.
*
* @param source The data to convert
* @param source
* The data to convert
* @return encoded base64 representation of source.
* @since 1.4
*/
public static String encodeBytes( byte[] source )
{
public static String encodeBytes(byte[] source) {
return encodeBytes(source, 0, source.length);
} // 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
* @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.
* @since 1.4
*/
public static String encodeBytes( byte[] source, int off, int len )
{
int len43 = len * 4 / 3;
byte[] outBuff = new byte[ ( len43 ) // Main 4:3
+ ( (len % 3) > 0 ? 4 : 0 ) // Account for padding
];
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);
} // end for: each piece of array
if( d < len )
{
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)
{
try {
return new String(outBuff, 0, e, UTF_8);
} catch (UnsupportedEncodingException uue) {
return new String(outBuff, 0, e);
} // end catch
} // end encodeBytes
/* ******** D E C O D I N G M E T H O D S ******** */
}
}
/**
* 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.
* 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
* @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 )
{
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 );
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 )
{
// 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 );
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
{
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 ) );
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;
}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.
* Low-level decoding ASCII characters from a byte array.
*
* @param source
* The Base64 encoded data
@ -341,53 +257,44 @@ public class Base64
* @param len
* The length of characters to decode
* @return decoded data
* @since 1.3
* @throws IllegalArgumentException
* the input is not a valid Base64 sequence.
*/
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
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;
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 )
{
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 )
{
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 if (sbiDecode != WHITE_SPACE_DEC)
throw new IllegalArgumentException(MessageFormat.format(
JGitText.get().badBase64InputCharacterAt, i,
source[i] & 0xff));
}
} // end if: white space, equals sign or better
else
{
System.err.println(MessageFormat.format(JGitText.get().badBase64InputCharacterAt, i+ source[i]));
return null;
} // end else:
} // each input character
if (outBuff.length == outBuffPosn)
return outBuff;
byte[] out = new byte[outBuffPosn];
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
return out;
} // end decode
}
/**
* Decodes data from Base64 notation.
@ -395,20 +302,14 @@ public class Base64
* @param s
* the string to decode
* @return the decoded data
* @since 1.4
*/
public static byte[] decode( String s )
{
public static byte[] decode(String s) {
byte[] bytes;
try
{
bytes = s.getBytes( PREFERRED_ENCODING );
} // end try
catch( java.io.UnsupportedEncodingException uee )
{
try {
bytes = s.getBytes(UTF_8);
} catch (UnsupportedEncodingException uee) {
bytes = s.getBytes();
} // end catch
}
return decode(bytes, 0, bytes.length);
} // end decode
} // end class Base64
}
}

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